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Energy performance of the office building ENERGYbase (heating, cooling, air conditioning, lighting) 09/09 to 09/10

by Thomas Goschenhofer A-1120 Vienna, Schönbrunnerstr. 223

Supervisor:

DI (FH) Florian Dubisch

Vienna, 14th of January 2011

BACHELOR THESIS at the University of Applied Sciences Technikum Wien Urban Renewable Energy Technologies

Declaration „I confirm that this paper is entirely my own work. All sources and quotations have been fully acknowledged in the appropriate places with adequate footnotes and citations. Quotations have been properly acknowledged and marked with appropriate punctuation. The works consulted are listed in the bibliography. This paper has not been submitted to another examination panel in the same or a similar form, and has not been published.“

Vienna, 14th of Jan 2011

Th. Goschenhofer 1

Kurzfassung Die folgende Bachelorarbeit behandelt die energetische Gesamtbewertung des Bürogebäudes ENERGYbase, ein Passivbürogebäude im 21. Wiener Gemeindebezirk. Das Gebäude, welches 2008 fertiggestellt wurde, zeichnet sich vor allem durch seine innovative Architektur sowie sein nachhaltiges Energiekonzept aus, was durch die Zertifizierung mit dem Passivhaus-Standard und im Rahmen einer Nachhaltigkeitsbewertung bestätigt wurde. In Kooperation mit renommierten Unternehmen wurde eine Reihe von innovativen und erneuerbaren Energietechnologien, wie Wärmepumpen, fassadenintegrierte Photovoltaik, solarthermische Kollektoren, Solar-Cooling oder Betonkernaktivierung, eingesetzt. Um die verschiedenen Systeme gemeinsam effizient betreiben zu können, müssen sie kontinuierlich überwacht werden. Deshalb wurde ein Monitoring-System im ENERGYbase installiert, welches aktuelle Werte und Betriebsstände aufzeichnet und zusätzlich in einer Datenbank abspeichert. Mit der Software „ADPExplorer“ können anschließend Datenserien erzeugt werden, um eine Erhebung des Monitorings durchführen zu können.

Diese Arbeit beschäftigt sich in der Datenauswertung mit der Berechnung des End- und Primärenergieverbrauchs des ENERGYbase sowie die Analyse von gebäude- und nutzerspezifischen Verbräuchen im Zeitraum von September 2009 bis September 2010. Der daraus einhergehende Endenergieverbrauch wird auf die Bereiche Heizung, Kühlung, Lüftung, Beleuchtung, Warmwasserbereitung und sonstige nutzerspezifische Verbräuche aufgeteilt und auf die Bruttogrundfläche (BGF) bezogen. Anschließend wird der Primärenergieverbrauch berechnet, indem der Endenergiebedarf mit dem Primärenergiefaktor des versorgenden Energieunternehmens multipliziert wird. Mit dem ermittelten Primärenergieverbrauch wird anschließend ein Vergleich mit anderen Bürogebäuden gezogen und gegenübergestellt, um die verbesserte Energieeffizienz neuer Gebäudetypen aufzuzeigen.

Die Untersuchung der Daten ergibt, dass das ENERGYbase für den untersuchten Zeitraum eines Jahres einen Primärenergieverbrauch von 50,2 kWh/m2

BGF aufweist. Dabei resultieren 29,6 kWh/m2

BGF bzw. 59 % der gesamten Primärenergie aus nutzerspezifischen Verbräuchen, 20,6 kWh/m²BGF bzw. 41 % resultieren aus dem gebäudespezifischem Verbrauch.

Verglichen mit anderen Bürogebäuden besitzt das ENERGYbase eine gute energetische Gesamtbewertung. Besonders konnte eine Reduzierung von Primärenergie in den Bereichen Heizung, Kühlung, Warmwassererzeugung und Beleuchtung festgestellt werden. Gegenüber einem Standardbürogebäude bedeutet dies eine Reduktion des Primärenergieverbrauchs von über 80 %.

Dieses Ergebnis zeigt, dass die Verwendung von energieeffizienten und erneuerbaren Energiesystemen eine erhebliche Einsparung von Primärenergie mit sich bringt. Dadurch können nachhaltig Ressourcen geschont und klimaschädliche Emissionen minimiert werden.

Schlagwörter: Passivbürogebäude, ENERGYbase, Monitoring, energetische Gesamtbewertung, Primärenergieverbrauch

Th. Goschenhofer 2

Abstract This bachelor thesis analyses the energy performance of the passive house ENERGYbase in Vienna´s 21st district. The building, completed in 2008, distinguishes with the use of modern building technologies and innovative architecture and received certificates for its passive house standard and environmental sustainability. To achieve this, a lot of modern, innovative and sustainable energy technologies such as heat pumps, photovoltaic façade, solar cooling and concrete core activation, had been installed. In order to adjust the different systems, they have to be controlled continuously. For this purpose a monitoring system was implemented recording figures and status of more than 400 sensors. Assisted by the software program „ADPExplorer“, data series were generated.

In this study evaluation concepts occupy with the calculation of the final and primary energy consumption of the ENERGYbase and the separation of building- and user-specific consumption between September 2009 and September 2010. As a first step, the final energy for heating, cooling, air ventilation, lighting, hot water and the remaining building- and user-specific consumption are calculated and related to the building’s gross building area (GBA). After that, the primary energy consumption is calculated by multiplying the final energy consumption with the primary energy factor of the providing power company. Subsequently the primary energy consumption is compared and contrasted with other office building types in order to display the improved energy efficiency in newer buildings.

The final results indicate that the building has an annual primary energy consumption of 50.2 kWh/m2

GBA related to the net building area. 29.6 kWh/m2GBA or 59 % of the total primary

consumption constitute from the user-specific part, 20.6 kWh/m²GBA or 41 % come up from the building specific consumption.

Compared to other office types the ENERGYbase features a good energy performance, especially in terms of heating, cooling, hot water and lighting consumption. That result reflects the use of energy efficient building services and sustainable energy systems. According to a standard office building this means a reduction of primary energy of over 80 %.

Conclusively these results show the enormous reduction of primary energy by using energy efficient and renewable energy systems. Thereby climate-damaging emissions can be minimized and energy sources protected sustainably.

Keywords: passive office building, ENERGYbase, monitoring, energy performance, primary energy consumption, comparison of office buildings

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Table of Contents 1 Introduction ........................................................................................................................ 5 2 Monitoring description ....................................................................................................... 6

2.1 ENERGYbase .............................................................................................................. 6 2.2 Building services .......................................................................................................... 7 2.3 Measurement procedure ............................................................................................... 9

2.3.1 Sensors .................................................................................................................. 9 2.3.2 Building Automation System ............................................................................. 10 2.3.3 Monitoring software ........................................................................................... 11

3 System performance evaluation ........................................................................................ 13 3.1 Final energy consumption .......................................................................................... 13

3.1.1 Thermal energy ................................................................................................... 14 3.1.2 Electric heating energy qel.Heating ......................................................................... 14 3.1.3 Electric cooling energy qel.Cooling ......................................................................... 15 3.1.4 Air ventilation consumption qel.AV ...................................................................... 15 3.1.5 Lighting consumption qel.Light .............................................................................. 16 3.1.6 Hot water consumption qel.HW ............................................................................. 16 3.1.7 Other specific consumption qel.Other .................................................................... 17 3.1.8 Photovoltaic yields qPV ....................................................................................... 17 3.1.9 Building-specific energy consumption qel.Building ................................................ 17

3.2 Primary energy consumption ..................................................................................... 18 3.3 Comparison of different office buildings ................................................................... 18

3.3.1 Old building ........................................................................................................ 19 3.3.2 Standard buildings .............................................................................................. 20 3.3.3 Low energy building ........................................................................................... 20 3.3.4 Passive house ‘98 ................................................................................................ 21 3.3.5 ENERGYbase ‘08 ............................................................................................... 22

3.4 Results check of reliability monitoring data collection ............................................. 23 3.4.1 Completeness ...................................................................................................... 25 3.4.2 Continuous recording ......................................................................................... 26 3.4.3 Plausibility .......................................................................................................... 27

4 Results of the monitoring evaluation ................................................................................ 28 4.1 Final energy consumption .......................................................................................... 28

4.1.1 Thermal energy ................................................................................................... 28 4.1.2 Electric heating energy qel.Heating ......................................................................... 31

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4.1.3 Electric cooling energy qel.Cooling ......................................................................... 32 4.1.4 Air ventilation consumption qel.AV ...................................................................... 33 4.1.5 Lighting energy consumption qel.Light .................................................................. 33 4.1.6 Hot water consumption qel.HW ............................................................................. 35 4.1.7 Other specific consumption qel.Other .................................................................... 36 4.1.8 Photovoltaic yields qPV ....................................................................................... 37 4.1.9 Building-specific energy consumption qel.Building ................................................ 38 4.1.10 Total final energy consumption qel.final ............................................................... 40

4.2 Primary energy consumption ..................................................................................... 42 4.3 Comparison of different office buildings ................................................................... 43

5 Conclusion ........................................................................................................................ 45 5.1 Monitoring system ..................................................................................................... 45 5.2 Evaluation concepts ................................................................................................... 45

5.2.1 Heating ................................................................................................................ 45 5.2.2 Cooling ............................................................................................................... 45 5.2.3 Air ventilation ..................................................................................................... 46 5.2.4 Lighting .............................................................................................................. 46 5.2.5 Hot water ............................................................................................................ 46 5.2.6 Other specific consumption ................................................................................ 46 5.2.7 Total primary energy consumption ..................................................................... 46

5.3 Forecasts .................................................................................................................... 47 Bibliography ............................................................................................................................. 48 List of Figures ........................................................................................................................... 50 List of Tables ............................................................................................................................ 51 List of Abbreviations ................................................................................................................ 52 A: Calculation process comparison office types ...................................................................... 53 B: Detailed schedule of the final energy consumption ............................................................. 54 C: Detailed schedule of the primary energy consumption ....................................................... 55

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1 Introduction In June 2009 the European Commission passed a law binding the Member States of the European Union to tackle the climate change threat with a series of demanding targets by 2020, also known as the “20-20-20” targets, which also have to be implemented into national directives and laws. In that resolution, Europe commits itself to reduce its greenhouse gas emissions by 20% from 1990 levels, to reduce the primary energy use compared to projected levels by 20% and to raise the energy production coming from renewable resources by 20%, cf. [CEP10].

Against this background an Austrian directive, named “Energie Strategie Österreich”, was established in March 2010 presenting the national aims to reach the stipulated targets. This national directive is seeking the development of a sustainable energy system, the gain of energy efficiency, an expansion of usage of renewable energy resources up to 34% and a reduction of carbon emissions by 18%. According to this strategy-paper, the end energy consumption has reduplicated between 1970 and 2008 up to 1088 PJ and will rise continuously in decades to come. About one Third of Austria’s final energy consumption attributes to the building sector whose biggest consumption come from the heating and cooling energy, cf. [ESA10], p. 19.

Moreover, the European Commission's “Directive on energy end-use efficiency and energy services” (ESD) defines and sets saving targets stimulating activities of the Member States and sectors in order to save energy in final use, cf. [WIN09], p. 5. That means that new concepts have to be developed on a national level. Whereas energy consumption of residential houses have been examined very carefully in the last years, energy-intensive users, such as the service industry or building complexes, were neglected. However, especially in office buildings, claiming a big amount of resources, energy can be saved.

This was the basis for the decision of the German Federal Ministry of Economics and Technology to start evaluating building’s performances with an annual balance based on monitoring data of already finished projects. With these results, new concepts can be tested and further improvements can be developed. Furthermore, this enables comparison of different building types on the basis of their energy parameters, cf. [EOB10]. The Austrian Institute of Technology (AIT), which is taking up a leadership position in research topics, has also concentrated on research reducing energy in the building sector. In 2008, the AIT engineered a monitoring system with more than 400 sensors at the office building ENERGYbase to supervise the energy consumption of this new and innovative building. The University of Applied Sciences Technikum Wien supported the monitoring of data and reported the energy performance of the ENERGYbase within several studies and bachelor thesis since 2009.

The AIT analyses the monitoring data in cooperation with the UAS Technikum Wien, in order to demonstrate the potential for improvement. In his bachelor thesis [STA10] Starl has already examined the energy performance of the ENERGYbase with data series from 2008/2009. In this study, the energy performance is analysed on the basis of the existing monitoring data series from September 2009 until September 2010 and results of past experiences of ENERGYbase’s facility manager Werner Wiedermann from “Siemens Gebäudemanagement & -Services”. With these data the final and primary energy consumption is calculated by the consumption of heating, cooling, hot water, lighting and other consumption. Preisler has already calculated the final and primary energy demand of the

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ENERGYbase in [EGB08]. Now, it should be investigated if the monitored energy consumption is equivalent to the outcome of previous calculation.

2 Monitoring description This chapter deals with an introduction of the examined office building ENERGYbase and its innovative building services, such as the concrete core activation and the solar cooling system. Furthermore, the measurement procedure is introduced. This subchapter contains also the electric and ultrasonic flow meters, the connected interfaces and networks, the Building Automation and Control network (BACnet) and the Local Operating Network (LON) that are transferring the data to a central unit and the “DESIGO Insight” software. With this software the supervisor can interfere in several operations and control the building’s services.

In general, monitoring can be defined as a long-term supervision and evaluation of several conditions. With reference to buildings, a monitoring system is used to record consumption of physical statuses such as temperature, air humidity, energy consumption and positions of technical devices. The main aim of this bachelor thesis is to monitor and calculate the consumption of specific building services and beyond that, the building’s performance. With these results, it is possible to identify incorrect sensors, increase the energy efficiency and optimise the services’ interactions in order to create the best balance between the highest comfort for the user and the lowest energy consumption.

2.1 ENERGYbase The reviewed object of this paper is a passive house office building called ENERGYbase, located in Vienna’s 21st district featuring a gross building area (GBA) of 11,700 m2 and a net building area (NBA) of 7,500 m2. The project was developed by the “Wirtschafts Agentur Wien” former “Wiener Wirtschaftsförderungsfond-WWFF” and was finished in 2008. Besides typical office units, two universities of applied sciences (UAS) and an institute for research and development are situated in the building.

Figure 1: Passive house office building ENERGYbase [HUR10].

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The ENERGYbase distinguishes with the usage of modern building technologies and innovative architecture and was certificated according to the German “Passivhaus Institut” in 2009, cf. [IBO09]. The building concept is based on energy efficiency as well as the usage of renewable resources, with the additional target of a maximum user comfort. Due to this, the energy consumption is covered exclusively from renewable and ecologically sustainable energy resources, cf. [ENB11].

2.2 Building services In [STA10] Starl elaborates on detailed explanations about the building and its building services, which is why this chapter is only giving an overview of the installed technologies, also see figure 2 the process diagram of the energy system.

The passive house ENERGYbase obtains its needed energy in part from the ground water below the building. Pumps transport water from the soil in order to extract its energy and later restore the water to the ground. The cold water is either used for the building’s cooling pipe system or as heat source for the heat pumps which supply the heat energy to the heating pipe system.

The cold water provided by the cooling pipe system is mostly used to cool the house with concrete core activation (CCA). Water is streaming through pipes in the concrete and is so tempering the rooms. Due to a cross valve it is suitable to cool the building in summer as well as to heat it on cold days.

A solar thermal system with a collector surface of ca. 285 m2 on top of the building produces warm water which is stored in a 15 m3 tank. Via a heating pipe system, installed in the whole building, the heating water is allocated to several buildings end devices, such as heating coils, air heating apparatuses and CCA.

Two air handling units (AHU) have been built in on the building’s roof to supply the offices on the upper floors and an AHU in the engineering room to supply the UAS on the first floors. Each of them is arranged with heat recoveries that are using the heat from the discharged air to warm up cooler supply air. In addition, two units are featured with a so-called desiccant and evaporative cooling (DEC) system, which generates cooling energy, by using the solar heating energy.

With a surface area of about 400 m2, about 20 % of the auxiliary energy for pumps and fans of the ENERGYbase can be guaranteed by photovoltaic cells on its façade with a work angle of 30°. In case of an acquired surplus, the energy is fed into the grid.

To assess the performance of the described systems, the amount of energy which is consumed or generated needs to be monitored. Therefore several electric and heat meters are installed. The position and naming of these meters can be seen in the process diagram of the energy system (cf. figure 2). The monitored data of these metering points will be used in the following chapters to elaborate the energy performance of the ENERGYbase.

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Figure 2: Process diagram of utilized building services, adapted by [KWI07].

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2.3 Measurement procedure In this chapter, the measurement procedure is presented in order to describe the monitoring process of the building systems. In general the process can be divided into the building’s end devices recording the physical parameter and the Building Automation System (BAS). BAS is applied for the data transport of the devices controlled by a Direct Digital Control (DDC) component. This device is sending all data to the responsible facility manager's central monitoring unit. BACnet and LON are used as automation system in the ENERGYbase building.

2.3.1 Sensors

Ultrasonic flow meter

Ultrasonic flow meters are utilised to measure heat flow volumes for example in district heating or cooling systems. This metering technique uses the basic principle of the difference of the transmit time of an ultrasonic signal, which is either propagated in and against flow direction or reflected by suspended particles or alternatively by gas bubbles in motion. A transmitter creates the signal in form of a sound wave. This wave changes its frequency when being reflected by moving discontinuities in a flowing liquid which are reflecting the ultrasonic wave with a slightly different frequency directly proportional to the liquid's rate of flow (figure 3). The volume flow can be calculated by comparing the emitted and received frequencies.

Figure 3: Schematic of an ultrasonic flow meter, adapted by [ALF10].

Two platinum resistors in the flow and return flow pipes meter the difference of the temperatures. With the help of these two parameters, one is able to record the heat flow volume, cf. [OER10]. Ultrasonic flow meters type “Ultraheat50” by Siemens are used to measure the flow rates in the reviewed object. More information about the flow meter can be found in [UHM07]. In connection with a network interface the measured data can be transmitted to a central building control system.

Electric meter

An electric meter records the amount of electric energy drawn by devices like pumps, fans or lighting. Modern and intelligent meters, so-called smart meters, are able to pass their data to an interface in order to monitor its consumption.

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Figure 4: Implemented digital electric meter in the ENERGYbase.

The electric meter in figure 4, used in an office unit, is a three-phase electric power measuring device. It has an accuracy class 2 pursuant EN 62053, meters the current up to 63 Ampere and electric energy in two tariffs. With that feature it is possible to count the amount of the energy depending on defined points in time of day and varying prices.

2.3.2 Building Automation System

BACnet

The Building Automation and Control Network is a standard data communication system, which provides a neutral basis for building services engineering with a trade-spanning integration of several services such as lighting control, heating, ventilation, air conditioning (HVAC) and energy supply. Furthermore, it is possible to connect the automation and management levels with a compatibility and conformity to other automation systems, as you can see in figure 5.

Figure 5: Positioning of BACnet in a level process diagram [BAC10].

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LON

The Local Operating Network, called LonWorks, is a network protocol that has been standardised by ISO and IEC in 2008. Due to this technology it is possible to integrate building service devices from different systems and providers in one single system in order to record performance data or to control equipment.

In the reviewed ENERGYbase, BACnet is used as way of communication between the AHUs, the controlling and supervision unit and LON for the remaining building services. In the figure below the monitoring topology with the installed interfaces is displayed.

Figure 6: Topology of network interfaces, adapted by [SBT08].

Network interface

The connection between BAS and the building’s end devices, such as sensors, actuators or controllers, is established through network interfaces. These devices convert commands and operating conditions or send the measured data to the central monitoring unit. With the “PXC-U” built by Siemens, more than 200 data points per device can be transferred, cf. [PXC10].

2.3.3 Monitoring software

With the monitoring software “DESIGO Insight” by Siemens, the ENERGYbase can control its services by using a graphical user interface (GUI). The software gives a detailed summary of the whole building and every single system part, for instance of an AHU (figure 7) where current figures and statuses are being displayed.

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Figure 7: Process diagram of an AHU in DESIGO Insight [DES10].

Position plans of devices, pipes and sensors and also single rooms can be shown including their particular figures, such as humidity, temperature or air quality, see figure 8. Due to an overview of all relevant meters, all consumption and important figures can be checked on one single screen.

Figure 8: Drawing of an upper floor in DESIGO Insight [DES10].

In case of unscheduled operations, an integrated alarm system informs the supervisor and shows the incorrect sensor or device and can then be disabled or even readjusted via buttons on the GUI.

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3 System performance evaluation This chapter is about the data transfer of the measured figures to a structured data series storage program, which will be used for further investigations and the creation of evaluation concepts. These concepts, which will be elaborated in chapters 3.1 and 3.2, deal with the determination of the final and primary energy consumption of the ENERGYbase focussing on the heating, cooling, air ventilation, hot water, lighting and remaining consumption and will be compared to other office building types in chapter 3.3. With the “Matlab” software, advanced computations, such as the completeness and plausibility can be checked, this issue will be broached in chapter 3.4. Via the monitoring system devices, the monitored figures are transmitted to a “PDM” database on a server located in the office building. The research company AIT has installed the software “ADPExplorer” in order to generate individual data series and to use it for researching purposes.

3.1 Final energy consumption During the planning period, the ENERGYbase energy performance has already been calculated and simulated; results, equations and details can be found in [EGB08]. Two years after the dedication of the ENERGYbase, it should be investigated if the monitored energy consumption is identical to the outcome of the calculation. For this reason, all relevant energy consumption are classified and finally summarised.

In general, the energy consumption has to be divided into parts coming from heating, cooling, air ventilation, lighting and domestic hot water and the respective energy resource. The total of all consumption generates the energy performance and the final energy consumption. In this study the consumption of the whole building are regarded and related to its gross building area.

The two components of the basic equation (1) are the final thermal and electric energy consumption, herein the amount of individual consumption is also included.

qfinal = qfinal.therm + qfinal.el (1)

qfinal final energy consumption in kWh/m2a qfinal.therm thermal final energy consumption in kWh/m2a qfinal.el electric final energy consumption in kWh/m2a

In this calculation, the thermal final energy consumption is set to zero because the produced energy comes from renewable energy sources or is generated by electrical systems.

qfinal.therm = 0 (2)

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Thus, the final energy consumption is only expressed by the electric energy consumption with following equation (3):

qfinal.el = qel.Heating + qel.Cooling + qel.AV + qel.Light.Building + qel.Other.Building + qel.User – qPV (3)

qel.Heating electric heating energy in kWh/m²a qel.Cooling electric cooling energy in kWh/m²a qel.AV electric energy for air ventilation in kWh/m²a qel.Light.Building electric energy for building-specific lighting in kWh/m²a qel.Other.Building electric energy for other building-specific consumption in kWh/m²a qel.User electric energy for user-specific consumption in kWh/m²a qPV electric yield by photovoltaic cells in kWh/m²a

3.1.1 Thermal energy

Because the installed heat meters were not able to make a difference between the heating and cooling energy, an approach had to be found in order to assign the auxiliary energy consumption in heating and cooling mode. This approach bases on the data of consumed thermal energy of different building’s end devices for heating and cooling purposes, displayed in chapter 4.1. With the numbers of these consumption, a ratio between consumed and accordingly provided thermal heating and cooling energy can be calculated for different systems, such as the concrete core activation, ground water or solar-thermal system. Consequently, the auxiliary energy consumption of each system can be prorated to the heating and cooling purposes by using this ratio.

3.1.2 Electric heating energy qel.Heating

The electric heating energy consumption qel.Heating is the summation of the consumption from the heat pumps and the auxiliaries used for heating purposes.

qel.Heating = qel.HP + qel.CCA.H + qel.GW.H + qel.ST.H (4)

qel.HP electric energy for heat pump consumption in kWh/m²a qel.CCA.H electric energy for concrete core activation pumps in heating mode in kWh/m²a qel.GW.H electric energy for ground water pumps in heating mode in kWh/m²a qel.ST.H electric energy for solar-thermal pumps in heating mode in kWh/m²a

Electric energy for heat pump qel.HP

In the ENERGYbase, the heating energy is produced by the solar-thermal system on the roof as well as by two heat pumps. The electric consumption for the heat pumps is calculated on the basis of data series of the meters “WP-31” and “WP-33” (cf. figure 2).

Electric energy for CCA pumps qel.CCA.H

In principle, the concrete core activation in the ENERGYbase is divided into four zones: two in the north and two in the south. Moreover, CCA is used for heating and cooling purposes. The final energy is calculated by multiplying the consumption of the meter points “BTA-21”, “BTA-22”, “BTA-23” and “BTA-24” with the above-mentioned ratio in heating mode.

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Electric energy for ground water pumps qel.GW.H

Like the concrete core activation, the ground water below the ENERGYbase is used for heating and cooling purposes. In heating mode, the ground water is required for the heat pump system. This electric energy consumption of the ground water pumps is calculated on the basis of data series of the meter points “WP-32” and “WP-34”. In addition, the electric consumption had to be assumed with 1 % of the heat meter “WP-42”, due to a lack of monitoring electric meter.

Electric energy for solar-thermal pumps qel.ST.H

Also the solar-thermal system is applied for heating and cooling purposes which is why the ratio is also used in order to separate the auxiliary energy for both purposes. The consumption of the electric meter “Solar-29” is used to analyse the final energy consumption for heating purpose by multiplying it with the ratio for heating mode.

3.1.3 Electric cooling energy qel.Cooling

The electric cooling energy qel.Cooling is the summation of the consumption from the auxiliaries used for cooling purposes.

qel.Cooling = qel.CCA.C + qel.GW.C + qel.ST.C (5)

qel.CCA.C electric energy for concrete core activation pumps in cooling mode in kWh/m²a qel.GW.C electric energy for ground water pumps in cooling mode in kWh/m²a qel.ST.C electric energy for solar-thermal/desiccant and evaporative pumps in cooling mode in kWh/m²a

Electric energy for CCA pumps qel.CCA.C

As mentioned in chapter 3.1.1, the consumption of the meter points “BTA-21”, “BTA-22”, “BTA-23” and “BTA-24” are calculated to get the final energy.

Electric energy for ground water pumps qel.GW.C

The energy consumption qel.GW.C is calculated on the basis of data series of meter points “WP-32” and “WP-34”. In addition, the electric consumption had to be assumed with 1 % of the heat meter “WP-42” (realistic assumption), due to a lack of a monitoring electric meter.

Electric energy for solar-thermal/DEC water pumps qel.ST.C

The auxiliary energy consumption of the solar-thermal/DEC water pumps qel.ST.C is only reckoned up for cooling mode. This time, the ratio mentioned in 3.2.3, is used for cooling purposes multiplied with the “Solar-29” meter and the consumption of circulation pumps transporting the water to the DEC system. Due to a lack of monitoring electric meters, the electric consumption had to be assumed with 1 % of the AHU heat meters “LA0X-40”.

3.1.4 Air ventilation consumption qel.AV

The final energy consumption for air ventilation in the ENERGYbase is measured with the summation of all electric meters in the AHUs. The consumption of the utilized heat meters “LA0x-39”, “LA0x-41”, “LA0x-42” and “LA03-22” are used for heating mode and heat meters “LA0x-40” and “LA03-23” for cooling mode.

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3.1.5 Lighting consumption qel.Light

The lighting consumption contains all lamps in the office building. In general, the consumption is divided into building- and user-specific parts.

qel.Light = qel.Light.Building + qel.Light.User (6)

qel.Light.Building electric energy for building-specific lighting in kWh/m²a qel.Light.User electric energy for user-specific lighting in kWh/m²a

Building-specific lighting consumption qel.Light.Building

Lighting in stairs, entry and parking areas are parts of the building-specific lighting consumption. The emergency light system is not considered as a building-specific part, because it is rather a component of the building-specific security system and is listed as one of the other building-specific consumption in chapter 3.1.6.

User-specific lighting consumption qel.Light.User

The user-specific lighting consumption is the summation of the lighting consumption of each tenant, including unused office units, including the lighting in each room or corridor of each office unit.

3.1.6 Hot water consumption qel.HW

Unlike other office buildings, in the ENERGYbase the domestic hot water is heated by gasholders electrical instantaneous water heater underneath the sinks. Due to a lack of sensors in the electric circuit the energy consumption for the hot water preparation can only be estimated by following acceptances and equation:

- daily water consumption: 2-3 l/person

- 251 days per year in regarded period

- average 270 attending persons

- heating water temperature from 8 to 40 °C

V .

volume flow rate in m3/h ρW density water in kg/m3 cp specific heat capacity in Wh/kgK ΔT difference in temperature in K qel.HW electric energy for hot water consumption in kWh/m²a

Because the hot water preparation is part of the user-specific consumption, this amount of energy is imputed to user-specific consumption later on.

qel.HW =V .

⋅ ρW ⋅ cp ⋅ ΔT (7)

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3.1.7 Other specific consumption qel.Other

Other consumption are the summation of other remaining energy consumption and basically divided into building- and user-specific consumption, expressed by equation (8).

qel.Other = qel.Other.Building + qel.Other.User (8)

qel.Other electric energy for other specific consumption in kWh/m²a qel.Other.User electric energy for other user-specific consumption in kWh/m²a

Other building-specific consumption qel.Other.Building

The building-specific consumption qel.Other.Building contain all devices and systems which belong to the building services engineering but had not been monitored yet. These consumption are based on past experiences made by the facility manager of the ENERGYbase Werner Wiedermann.

Other user-specific consumption qel.Other.User

Other user-specific consumption qel.Other.User are the summation of consumption of all office units, measured at the tenant’s electric meters. In order to calculate remaining user-specific consumption representing all connected devices in the office units, such as PCs, notebooks, printers and white goods, the user-specific lighting and hot water consumption have to be subtracted from the total electric energy consumption by the following equation:

qel.Other.User = qel.User.Total - qel.Light.User - qel.HW (9)

qel.User.Total total electric energy consumption for users in kWh/m2a

This amount of energy can also be regarded as the user-spcecific energy consumption qel.User.

qel.User = qel.Other.User (10)

3.1.8 Photovoltaic yields qPV

The photovoltaic yields are the summation of all PV cell strings in the façade at meter points “PV3”, “PV4” and “PV5”.

3.1.9 Building-specific energy consumption qel.Building

The total final energy consumption can be separated into building- and user-specific amounts, displaying the consumption of building services engineering and building’s tenants. Moreover, the energy consumption of the building services are divided into parts for heating and cooling purposes. This energy consumption for auxiliaries, considering the parts of heating qel.Heating - without the heat pump energy qel.HP -, cooling qel.Cooling and air ventilation qel.AV, can also be regarded as the auxiliary energy consumption qel.Aux, see equation (11).

qel.Building = qel.HP + qel.Aux + qel.Light.Building + qel.Other.Building - qPV (11)

qel.Building building-specific final energy consumption in kWh/m2a

Th. Goschenhofer 18

3.2 Primary energy consumption The primary energy consumption is the amount of primary energy needed to generate final energy. The necessary primary energy depends on the used energy source, like gas, oil, coal or wood, the utilisation efficiency and the necessary transport energy. The thermal final energy consumption will not be considered in this paper which is why the primary thermal energy is negligible. The primary energy factor used in this study is taken from the local power company “WienStrom”. The primary energy consumption can be calculated by multiplying the electric final energy consumption with the corresponding primary energy factors, cf. equation (12).

qprimary = qfinal.el ⋅ fp.el (12)

qprimary primary energy consumption in kWh/m2a fp.therm primary thermal energy factor fp.el primary electric energy factor

Related to its building area, the primary energy consumption of a building is a useful ecological parameter for a comparison with other buildings. Furthermore, the amount of primary energy is a significant parameter providing information about building’s energy efficiency. The second evaluation concept uses the primary energy consumption for a comparison of the ENERGYbase with other office building types. Subsequently a detailed ranking of compared buildings is given also taking into account individual consumption in the buildings.

3.3 Comparison of different office buildings With its innovative and sustainable building concept, the passive house ENERGYbase constitutes a role model in the modern office-building field. This is caused by using renewable energy and energy efficient building technologies, cf. [ENB11]. With the energy performance of buildings, different kinds of office blocks can be compared by their performances. In this process, building standards represent a typical technological progress of recent decades. In the next subchapters, different office types are presented with a detailed description of their structural shell and installation engineering.

Knissel surveyed for the German Institute “Living and Environment” in [KNI99] a progressive reduction of primary energy of an office building observing newer and more effective building- and equipment standards. In this case, energy consumption of old, standard, low energy buildings and a passive house are calculated and compared to each other. Now, the passive house ENERGYbase constituting a role model in modern office buildings with its innovative and sustainable concept is compared under the same prerequisites.

Th. Goschenhofer 19

The computation process and the detailed equations are listed in appendix A. The primary factors for the calculation were generated with the software “Gemis 3.01” and are listed in table 1.

Energy source Primary energy factor

in kWhPrim/kWhEnd Natural gas PfGas 1,07 Electricity mix PfElectricity 2,97

Table 1: Primary energy factors according Gemis 3.01, adopted by [KNI99].

3.3.1 Old building

This office type represents a typical office building, which was constructed between 1952 and 1977. The lighting system was replaced over the last years without considering energy efficiency.

In addition, there is no air conditioning and handling unit in the office building which is why the ventilation is made through the windows. Moreover, the heating energy demand was determined with a virtual simulation. A detailed description for this office type can be gathered from the following table 2.

Structural shell

Exterior

wall Roof Cellar ceiling Window Insulation thickness (cm) - - - g=0,74* k-Value (W/(m2K)) 1,56 1 1 k=2,8 Solar protection external blades, closed at 300 W/m2 irradiation, external temperature over 15 °C Air tightness: permeable, average air change via leaks nu=0,3 1/h Thermal storage mass: exterior wall, floor * further factors: fouling = 0,9, Frame = 0,7, clouding = 0,84 Installation engineering Heating Gas boiling system Air Conditioning Windows Air change rate in 1/h Office Corridor Side room During useful life Wind.** +0,3 Wind.** +0,3 Wind.** +0,3 Outside useful life (leaks) 0,3 0,3 0,3 **October - March average air change rate n= 1,2 1/h via windows during useful life Climate: Cold Non-existing

Air dehumidification Non-existing Air humidification Non-existing

Table 2: Detailed descriptions for office type old building, adopted by [KNI99].

Th. Goschenhofer 20

3.3.2 Standard buildings

Standard buildings comply with a regulation of 1995's heat insulation. The building had been refurbished several years before. An air conditioning system to cool the floors was also installed; an efficient power management was renounced. A detailed description for this office type can be gathered from the following table 3.

Structural shell Exterior wall Roof Cellar ceiling Window Insulation thickness (cm) 6 12 4 g=0,63* k-Value (W/(m2K)) 0,54 0,3 0,64 k=1,8 Solar protection external blades, closed at 300 W/m2 irradiation, external temperature over 15 °C Air tightness: normal, average air change via leaks nu=0,2 1/h Thermal storage mass: exterior wall, floor *) further factors: fouling = 0,9, Frame = 0,7, clouding = 0,84 Installation engineering Heating Gas calorific value boiler Air Conditioning Air handling unit Air change rate in 1/h Office Corridor Side room During useful life 1,3 + 0,2 0,4 + 0,2 0,4 + 0,2 Outside useful life (leaks) 0,2 0,2 0,3 Climate: Cold cooling ceiling Air dehumidification dehumidification chiller Air humidification steam humidifier

Table 3: Detailed descriptions for office type standard building, adopted by [KNI99].

3.3.3 Low energy building

Increasing costs for energy and resources and the aggravation of the climate change in the last years have led to bigger awareness for energy efficiency in society and led to a minimising of energy consumption. In low energy buildings, bigger insulation layers, airtight constructions and efficient equipment, such as lighting or computing are used. Detailed information about this office type can be seen from the following table.

Th. Goschenhofer 21

Structural shell Exterior wall Roof Cellar ceiling Window Insulation thickness (cm) 18 22 14 g=0,53* k-Value (W/(m2K)) 0,21 0,17 0,25 k=1,4 Solar protection external blades, closed at 300 W/m2 irradiation, external temperature over 15 °C Air tightness: high, average air change via leaks nu=0,1 1/h Thermal storage mass: exterior wall, floor, ceiling *) further factors: fouling = 0,9, Frame = 0,7, clouding = 0,84 Installation engineering Heating Gas calorific value boiler Air Conditioning Air handling unit, heat recovery of 60% Air change rate in 1/h Office Corridor Side room During useful life 1,3 + 0,1 0,4 + 0,1 0,4 + 0,1 Outside useful life (leaks) 0,1 0,1 0,1 Climate: Cold cooling ceiling Air dehumidification dehumidification chiller Air humidification steam humidifier

Table 4: Detailed descriptions for office type low energy building, adopted by [KNI99].

3.3.4 Passive house ‘98

Buildings constructed with the passive house technology, are even better than the above described buildings because a passive house has to boast defined energy parameters in order to be certified by the German “Passivhaus Institut”.

Today, this quality characteristic represents the highest efficiency building standard with small energy consumption. Energy leaks have been minimized due to big insulation thickness, a high air tightness and high efficient equipment. Moreover, this type labels a solely usage of the highest energy efficiency equipment coupled with the use of renewable energy sources.

This office type constitutes the highest level of office buildings in 1998, due to a lot of research in the last decades, passive houses have improved and are even more efficient nowadays. For this paper, the following acceptances are used for the passive house office building:

Th. Goschenhofer 22

Structural shell Exterior wall Roof Cellar ceiling Window Insulation thickness (cm) 30 40 30 g=0,49* k-Value (W/(m2K)) 0,13 0,1 0,12 k=0,78 Solar protection external blades, closed at 300 W/m2 irradiation, external temperature over 15 °C Air tightness: very high, average air change via leaks nu=0,05 1/h Thermal storage mass: exterior wall, floor, ceiling *) further factors: fouling = 0,9, Frame = 0,7, clouding = 0,84 Installation engineering Heating Gas calorific value boiler

Air Conditioning Air handling unit, heat recovery of 75 %, terrestrial heat exchanger

Air change rate in 1/h Office Corridor Side room During useful life 1,3 + 0,05 0,4 + 0,05 0,4 + 0,05 Outside useful life (leaks) 0,05 0,05 0,05 Climate: Cold supply air cooling, max. 8 K below Tint Air dehumidification dehumidification chiller Air humidification steam humidifier

Table 5: Detailed descriptions for office type passive house, adopted by [KNI99].

3.3.5 ENERGYbase ‘08

Ten years later, the ENERGYbase was built with the aim of providing a minimum of energy consumption and a high comfort for its users. Certificates for its environmental sustainability and passive house standard confirm that it distinguishes with the use of modern building technologies, such as concrete core activation or solar-cooling and innovative architecture. The following information originates from [EGB08]:

Structural shell Exterior wall Roof Cellar ceiling Window Insulation thickness (cm) 25 29 23 g=0,53* k-Value (W/(m2K)) 0,16 0,12 0,18 k=0,7 Solar protection external blades, solar façade external temperature over 15 °C Air tightness: very high, average air change via leaks nu=0,05 1/h Thermal storage mass: exterior wall, floor, ceiling *)further factors: fouling = 0,7, Frame = 0,1, clouding = 0,2 Installation engineering Heating Heat pumps, solar thermal system

Air Conditioning Air handling unit, heat recovery of 75 %, terrestrial heat exchanger, solar thermal/DEC system

Air change rate in 1/h Office Corridor Side room During useful life 3 1 1 Outside useful life (leaks) 0,1 0,1 0,1 Climate: Cold free cooling via ground source wells Air dehumidification dehumidification chiller Air humidification steam humidifier

Table 6: Detailed descriptions for office type ENERGYbase, adapted by [EGB08].

Th. Goschenhofer 23

In principle, the method of calculating the primary energy consumption in [KNI99], p. 8, deflects from the method in chapter 3.1; in appendix A the calculation process of each category can be found. For this purpose, several adjustments had to be done in order to compare the primary energy of the ENERGYbase to other office types.

First, the primary factor of the existing office types which was quoted by the “GEMIS 3.01” software, differs from the ENERGYbase primary energy factor fp.el by the power company “WienStrom”. Comparing all types in one chart, the primary energy of the ENERGYbase was converted with a primary factor of 2.97. Then, the parts of energy consumption in chapter 3.1 were adapted because different categories were used in [KNI99]. However, the consumption are based on the building-specific consumption qel.Building by equation (10). Other building-specific consumption qel.Other.Building, itemised in chapter 3.1, are split in corresponding categories. The photovoltaic yields qPV are divided on a percentage basis of all consumption.

The category “office equipment” displays the user-specific part of the primary energy. Indeed, the method of calculation of the user-specific consumption qel.Other.User cannot be equated with the calculation of category “office equipment”. Therefore, an additional calculation considering the same requirements was accomplished.

3.4 Results check of reliability monitoring data collection This chapter deals with the results of previous chapters generating the data series and calculating several energy consumption. The program “Excel” was used for most of the calculations, for advanced calculations such as completeness or data’s plausibility the software “Matlab” was applied. Further on, data’s completeness and continuous recording are checked.

The required data series for the evaluation concepts were downloaded for the analysed period from the ADP database. The following tables show a detailed list of all used heat and electric meters of each system.

Name of series acc. ADP Title of series Consumed

energy Unit Interval

KW 5 Electric meter cold water consumer 714 kWhel 3 h WP 31 Power consumption heat pump 1 12,686 kWhel 3 h WP 32 Power consumption sink pump 12,944 kWhel 3 h WP 33 Electric meter heat pump 2 20,407 kWhel 3 h WP 34 Power consumption heat pump 1+2 3,848 kWhel 3 h WP 35 Heating consumer 754 kWhtherm 3 h WP 36 Heat pump 1 51,240 kWhtherm 3 h WP 39 Heat pump 2 84,970 kWhtherm 3 h WP 42 HP heat quantity consumer 157,070 kWhtherm 3 h WP 47 Cold quantity meter sink pump 2 101,650 kWhtherm 3 h WP 48 Cold quantity meter consumer 109,990 kWhtherm 3 h WP 49 Cold quantity meter sink pump 1 12,420 kWhtherm 3 h

Table 7: Used data series for the heat pump and ground water system.

Th. Goschenhofer 24



BTA 21 NW electric power pump 171 kWhel 3 h BTA 22 SW electric power pump 588 kWhel 3 h BTA 23 NO electric power pump 234 kWhel 3 h BTA 24 SO electric power pump 747 kWhel 3 h

Table 8: Used data series for the CCA system.



Solar 29 Total power consumption 579 kWhel 3 h Solar 30 Secondary circuit heat quantity 75,720 kWhtherm 3 h Solar 35 Primary circuit heat quantity 80,219 kWhtherm 3 h

Table 9: Used data series for the solar thermal system.

Due to implausible data of the PV sensors, measuring the power, a separated calculation had to be performed. The titles of the series display the appendix “calculated”.



PV3 17 AC converter 1 2,555 kWhel 1 h PV3 18 AC converter 2 2,804 kWhel 1 h PV3 19 AC converter 3 2,809 kWhel 1 h PV3 20 AC converter 4 5,485 kWhel 1 h PV4 17 AC converter 5 2,548 kWhel 1 h PV4 18 AC converter 6 4,671 kWhel 1 h PV4 19 AC converter 7 2,822 kWhel 1 h PV4 20 AC converter 8 1,983 kWhel 1 h PV5 19 AC converter 9 3,257 kWhel 1 h PV5 20 AC converter 10 10 kWhel 1 h PV5 21 AC converter 11 1,894 kWhel 1 h PV5 29 AC converter 12 346 kWhel 1 h PV3 17 AC converter 1 calculated 4,066 kWhel 1 h PV3 18 AC converter 2 calculated 5,167 kWhel 1 h PV3 19 AC converter 3 calculated 3,998 kWhel 1 h PV3 20 AC converter 4 calculated 4,163 kWhel 1 h PV4 17 AC converter 5 calculated 4,167 kWhel 1 h PV4 18 AC converter 6 calculated 4,292 kWhel 1 h PV4 19 AC converter 7 calculated 4,056 kWhel 1 h PV4 20 AC converter 8 calculated 2,131 kWhel 1 h PV5 19 AC converter 9 calculated 3,257 kWhel 1 h PV5 20 AC converter 10 calculated 10 kWhel 1 h PV5 21 AC converter 11 calculated 1,894 kWhel 1 h PV5 29 AC converter 12 calculated 346 kWhel 1 h

Table 10: Used data series for the photovoltaic system.

Th. Goschenhofer 25



LA01 36 Total power consumption 14,598 kWhel 3 h LA01 37 Fan, humidifier, heat recovery 1,258 kWhel 3 h LA01 38 Electric heater regeneration 28 kWhel 3 h LA01 39 Heater battery supply air 6,967 kWhtherm 3 h LA01 40 Heater battery regeneration 19,177 kWhtherm 3 h LA01 41 Heater batter plant buffer 4,291 kWhtherm 3 h LA01 42 Heater battery supply air office cube 514 kWhtherm 3 h LA01 51 Heater battery supply air office 45 kWhel 3 h LA02 37 Total power consumption 16,052 kWhel 3 h LA02 39 Heater battery supply air 5,990 kWhtherm 3 h LA02 40 Heater battery regeneration 16,188 kWhtherm 3 h LA02 41 Heater batter plant buffer 5,214 kWhtherm 3 h LA02 42 Heater battery supply air office cube 363 kWhtherm 3 h LA03 19 Electric meter 12,670 kWhel 3 h LA03 22 Heater heat quantity 20,494 kWhtherm 3 h LA03 23 Chiller heat quantity 2,168 kWhtherm 3 h

Table 11: Used data series for the AHU system.

The data series for the lighting consumption were downloaded from a single database. It is incomplete which is visible through a number of breaks. However, they contain more than 1600 single lamps which is why it is possible to assign them to office units. Table 12 shows the lighting consumption from September 2009 to September 2010 and the name of the lamp with the minimal and maximal consumption per year.

Office units

Total in kWh/a

Min. in kWh/a Name of Minimum Max.

in kWh/a Name of Maximum

Tenant A 976 1,44 WC-M room 10_G3 21,56 Kitchen ServerroomR9 Tenant B 811 4,58 Office 2 room R36\G1 19,69 WC room R50G3 Tenant C 187 0,80 Anteroom WC R70\G1 11,41 Corridor room R80\G3 Tenant D 634 2,28 Corridor room R60\G3 42,73 Kitchen Installation room R49G2 Tenant E 522 3,34 Meeting room R8\G1 59,61 Corridor room R20\G3 Tenant F 339 4,55 Corridor room R60\G2 74,73 Kitchen Installation room R49G2 Tenant G 292 3,97 Anteroom WC R10\G1 17,97 Kitchen Installation room R29G2 Tenant H 634 5,81 Room R23G1 85,99 Kitchen Installation room R29G2 Unused 2.591 2,18 WC room R10\G3 235,87 Labor1 room R21\G1 anteroom Other 1.317 4,44 Room low-voltage R1\G2 99,21 Underground garage R66\G4

Table 12: List of the lighting consumption of several areas.

3.4.1 Completeness

The data series from the “ADP” database used for the evaluation concepts were approximately complete. For a comprehensible tracing of all steps, some sensors or pieces of information are missing. For example, the amount of heating energy coming from the solar system is not monitored which means that the amount has to be determined with an energy balance, where further parameters, such as losses of tanks, are also missing. Energy losses should be minimised, wherefore additional sensors recording losses or the solar system heating quantity should be installed. In addition, the voltage and current at AC converters 9 to 12 are not monitored. The completeness of the lighting data was unobjectionable.

Th. Goschenhofer 26

3.4.2 Continuous recording

In general, all heat meters recorded correctly, but in the course of the screening minor failures came up. On October 4th, the hour meter, which counts the operating hours of the sink wells, broke down for three days.

Figure 9: Breakdown of a sensor for several days.

Another failure was recorded at the sorption heating coil “LA40” of AHU2. From the beginning of monitoring until October 14th, the heating coil did not log any dates. After that date, the sensor charted correctly. A reason for this discontinuity could have been a disconnection between the sensor and the central monitoring unit. The following stagnation came from the coil’s disuse and it was not until the summer that the device was in operation again.

Figure 10: Failure of sensor “heating coil sorption LA 40” of AHU2.

sensor's failure hour meter "pump 1/2 sink well"

4000

4050

4100

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4250

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4350

01.10.09 04.10.09 07.10.09 10.10.09 13.10.09 16.10.09 19.10.09 22.10.09 25.10.09 28.10.09 31.10.09

coun

ted

hour

s

Continuous recording

0

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40000

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2009-09-01 2009-12-01 2010-03-01 2010-06-01 2010-09-01

ener

gy d

eman

d in

kW

h

damper registersorption AHU1damper registersorption AHU2

Th. Goschenhofer 27

In contradistinction to the “ADP” series, the lighting energy data series stored on an external server shows a lot of breaks in the analysed period. Therefore, only series between July and September in the years 2009 and 2010 were available, for following studies the lighting consumption was assumed with data series from September to December 2010.

Due to a lack of an efficient storage system the lighting data was overwritten automatically and had to be downloaded manually. Consequently, the data series show a lot of missing recordings in the analysed period, which has to be considered for future studies.

3.4.3 Plausibility

In order to create the evaluation concepts, several data series had to be checked for plausibility. In the process, the results of the generated series have been probed for anomalous and unrealistic figures.

The power of the photovoltaic strings, measured at each electric meter, revealed an annual production of about 31,183 kWh. Compared to previous recordings, this result implies an incorrect metering of the electric meters. An analytical assumption of the voltage and current revealed an annual yield of 36,237 kWh, which is more plausible to the previous recordings and is used in the further progress. Besides, “AC converter 10” metered 10 kWh/a which is just a fractional part compared to other strings. After consulting the facility manager, the strings were checked and it was revealed that some photovoltaic modules had not been connected. However, it has not been able to define the real production of the photovoltaic system due to unknown string relays.

For the evaluation concepts, the storage and distribution losses have to be determined due to their importance for the efficiency of building services. Because of missing sensors, especially the storage losses of the tanks had to be assumed in the calculation process. While the losses in the solar tank on the roof are able to cast up via an energy balance, the losses in the heating tank are estimated to be 4 % of the outgoing heating energy, which is reaching real figures according to other external calculations. The distribution losses are also assumed at 1 % of the considered heat or cold quantity.

According to the concept, specifying the end energy consumption, electric energy has to be separated for heating and cooling purposes. This distribution was realised with several ratios concerning the amount of heating and cooling energy. The resulting energy consumption are close to the actual ones, but more time had been spent to get a detailed analysis.

The measured lighting consumption in unused office units (cf. table 8) had the highest consumption which seems very implausible. Considering the maximum consumer in each unit of the building, the lamps in kitchen or in installation rooms are spending by far the most energy. According to the data series, all devices are not connected to single lamps but to switching contacts. It is a debatable point whether the consumption are only resulting from the lighting devices or also from white goods.

Th. Goschenhofer 28

4 Results of the monitoring evaluation This chapter contains the results of the evaluated concepts determining the final and primary energy consumption of the ENERGYbase. These parameters are split up into heating, cooling, air ventilation, lighting and other specific consumption. The final energy consumption in the regarded period accounts to 343,450 kWh/a or 29.35 kWh/m2

GBAa, the primary energy consumption adds up to 587,300 kWh/a or 50.20 kWh/m2

GBAa. Compared to other office buildings, the ENERGYbase has a good energy performance, especially in parts of heating, cooling, hot water and lighting.

4.1 Final energy consumption The final energy consumption is calculated with equations of chapter 3.1 and consists of the summation of the energy for heating, cooling, air ventilation, lighting, hot water and other specific consumption.

In order to separate the electric auxiliary energy consumption into heating and cooling purposes, different ratios between consumed thermal heating energy and consumed thermal cooling energy had to be found. These ratios bases on numbers of consumption of different building services systems (cf. table 9 and 10).

4.1.1 Thermal energy

The energy consumption are the amount of thermal energy of building services needed to keep the room temperature on a comfortable level and are monitored at the building’s end devices. Due to a lack of monitoring meters the distribution losses qtherm.Dist are assumed to be 1 % and the storage losses of the heating tank at 4 % of the outgoing energy, because all pipes and components in the building are isolated. The storage losses qtherm.Stor are the summation of the heating and the solar tank. The losses of the solar tank on the roof, which is located outside the buildings shell, are calculated by taking the difference between the net solar thermal yields from the collectors and the gross consumption of the DEC heating. Useable solar-thermal yields qtherm.STu.H consist of the heating energy consumption from the solar tank for heating purposes.

Thermal heating energy in kWh Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Heat pumps qtherm.HP 0 3,900 12,260 27,850 43,810 35,280 11,560 1,550 0 0 0 0 Ground water system qtherm.GW.H 0 2,514 2,136 512 160 1,182 2,957 1,285 0 0 0 0 Concrete Core Activation qtherm.CCA.H 0 4,143 11,073 22,600 31,554 25,142 11,861 5,735 1,002 130 0 0 Air handling units qtherm.AHU.H 3 2,077 3,687 6,280 12,006 12,298 6,399 1,075 8 0 0 0 Solar-thermal system qtherm.ST.H 0 3,248 3,459 2,271 1,349 4,075 9,220 6,936 1,993 151 0 0 Useable solar-th. yields qthermal.STu.H 0 2,530 2,968 1,907 1,054 3,305 7,315 5,517 1,050 135 0 0 Distribution losses qtherm.Dist.H 0 127 301 588 886 762 372 139 21 3 0 0 Storage losses qtherm.Stor.H 0 749 858 1,368 1,934 2,021 2,050 1,192 821 13 0 0

Table 13: Thermal energy consumption for heating purposes.

Table 13 shows the individual amounts of energy consumption per month. The expected high consumption in winter can also be seen. In spring, the storage losses are conspicuously high, the reason is that the solar thermal yields are not used and so remain in the solar tank on the roof. In general, a lot of auxiliary energy is used to power the heat pumps. In February and March, the solar tank features maximum losses of approx. 2,000 kWh thermal heating energy. If the provided heating energy in the solar tank were used primarily, the heat pumps would not have to produce the energy.

Th. Goschenhofer 29

Separating the amounts of energy into supply and consumption the proportion of the different systems can be displayed in figure 11. The CCA and AHUs constitute the consuming systems. The ground source, heat pumps and solar system are the supplying systems. The gap between the two bars expresses the losses.

Figure 11: Supply and consumption of energy in heating mode.

In general, the heating period starts in October and ends in April, the consumption ascends steeply from October to January and declines again until May. Thereby the CCA needs more than 60 % of the consumed energy. Between November and March the supplied energy is exclusively generated by the heat pumps. Out of this period, most of the energy is delivered by the solar system, but even in the cold months heating energy from the solar tank is used. In October, November and March most of the energy for heating purposes is supplied from the ground source.

Thermal cooling energy in kWh Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Ground water system qtherm.GW.C 14,170 4,176 434 8 0 38 923 4,435 7,950 18,180 27,980 25,030 Concrete Core Activation qtherm.CCA.C 13,093 6,315 2,490 420 0 1,120 3,601 5,247 7,375 16,603 26,972 24,586 Air handling units qtherm.AHU.C 4,311 1,249 0 1 4 1 46 419 1,395 8,957 13,152 7,998 Solar-thermal system qtherm.ST.C 10,380 1,392 0 1 5 1 47 397 2,315 8,934 15,061 8,984 Distribution losses qtherm.Dist.C 452 207 76 14 2 35 111 167 243 613 952 823 Storage losses qtherm.Stor.C 5,881 981 0 1 5 1 44 355 1,477 574 1224 513

Table 14: Thermal energy consumption for cooling purposes.

Due to missing data, the storage losses in September and October are unusually high, in fact the losses should be distinctly smaller. In May, the losses also show a high figure, which comes from a high solar-thermal yield and no heating requirement in the solar tank. So the energy will get lost unused.

Separating the amounts of energy into supply and consumption, the proportion between the different systems can be displayed in figure 12. Whereas CCA and AHU contribute to the

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Th. Goschenhofer 30

consuming systems, the ground source and the solar system outline the supplying. The gap between the two bars expresses the losses.

Figure 12: Supply and consumption of energy in cooling mode.

Not only in the heating mode in figure 11 but also in the cooling mode, the expected seasonal energy is displayed with a peak in July. Whereas the energy for air transport climaxes in May and June, the cooling consumption comes to its peak in July and August. Consequently, the air in the building had to be cooled via the AHUs up until June and it was only in midsummer additional head loads had to be dissipated by the CCA system. Nevertheless, the DEC system had been running during the whole cooling period indicating a high operating time and ratio of use.

In September, there are conspicuous high losses in the solar tank. Even though almost 10,000 kWh solar thermal yields are available, only 4,000 kWh are being used. For this reason, the losses display an unsuspectedly high figure, which should have been prevented. In general, losses from the ground source to the CCA amount to less than 10 % of the supplied energy, but in months of transition, in October or May for instance, the losses in the solar tank reach a significant level of about 50 %, while they descend to circa 8 % in midsummer.

The following figure 13 shows the heating and cooling energy to compare the thermal energy consumption. Generally, more energy is needed for heating than for cooling, though cooling energy is consumed almost throughout the whole year.

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Th. Goschenhofer 31

Figure 13: Thermal heating and cooling energy per month.

With less than 10 %, the losses are small, which argues an energy efficient system. But it has to be taken into account that if the consumption is high, the losses are small. The high losses in September, already mentioned, are being caused due to missing data in the sorption heating coil.

4.1.2 Electric heating energy qel.Heating

Electric energy for heat pump qel.HP

The electric consumption for the heat pumps is calculated on the basis of data series of the meters “WP-31” and “WP-33” and amounts to 33,093 kWh.

Heating energy consumption kWh/a kWh/m2GBA*a

Heat pumps qel.HP 33,093 2.83

Table 15: Annual final energy for heat pumps.

Electric energy for CCA pumps qel.CCA.H

The final energy for CCA pumps is calculated by multiplying the consumption of the meter points “BTA-21”, “BTA-22”, “BTA-23” and “BTA-24” with the above-mentioned ratio. The annual average consumption in heating mode adds up to 46 % of the thermal energy, which is why the ratio is used for calculation of the electric energy consumption of CCA pumps qel.CCA.H.

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Th. Goschenhofer 32

Electric energy for ground water pumps qel.GW.H

The electric energy consumption of the ground water pumps is calculated on the basis of data series of the meter points “WP-32” and “WP-34”. In addition, the electric consumption had to be assumed with 1 % of the heat meter “WP-42”, due to a lack of monitoring electric meter. The annual average consumption in heating mode adds up to 43 %.

Electric energy for solar-thermal pumps qel.ST.H

The ratio for heating mode bases on the used thermal energy consumption of the solar-thermal consumption and adds up to 59 % of the total thermal energy in heating mode. The consumption of the electric meter “Solar-29” is used to analyse the final energy consumption for heating purpose by multiplying it with the ratio for heating mode.

Table 16 displays the auxiliary energy consumption of the pumps in kWh per year related to GBA. Whereas the CCA and solar-thermal pumps feature just little electric energy, the ground water pumps constitute the large part of the consumed auxiliary energy.

Auxiliary energy consumption in heating mode kWh/a kWh/m2GBA*a

CCA pumps qel.CCA.H 501 0.04 Ground water pumps qel.GW.H 24,853 2.12 Solar-thermal pumps qel.ST.H 350 0.00

Table 16: Annual auxiliary energy consumption in heating mode.

4.1.3 Electric cooling energy qel.Cooling

Electric energy for CCA pumps qel.CCA.C

The consumption of the meter points “BTA-21”, “BTA-22”, “BTA-23” and “BTA-24” are calculated to get the final energy. In average, 54 % of the thermal energy of CCA is used for cooling purposes, thus the electric energy consumption qel.CCA.C is regarded with this ratio.

Electric energy for ground water pumps qel.GW.C

The energy consumption qel.GW.C is calculated on the basis of data series of meter points “WP-32” and “WP-34”. In addition, the electric consumption had to be assumed with 1 % of the heat meter “WP-42”, due to a lack of a monitoring electric meter. The ratio for cooling purposes for the ground water pumps adds up to approx. 57 % in the regarded period.

Electric energy for solar-thermal/DEC water pumps qel.ST.C

The auxiliary energy consumption of the solar-thermal/DEC water pumps qel.ST.C is only reckoned up for cooling mode. This time, the ratio is used for cooling purposes multiplied with the “Solar-29” meter and the consumption of circulation pumps transporting the water to the DEC system. Due to a lack of monitoring electric meters, the electric consumption had to be assumed with 1 % of the AHU heat meters “LA0X-40”. The auxiliary energy for solar-thermal/DEC pumps adds up to 41 % of the electric energy.

According to table 17, the auxiliary energy consumption of each system is computed. The total consumption of all systems in cooling mode is almost twice as high as the auxiliary energy in heating mode. The ground water pumps in heating mode also need most of the electric energy.

Th. Goschenhofer 33

Auxiliary energy consumption in cooling mode kWh/a kWh/m2GBA*a

CCA pumps qel.CCA.C 808 0.07 Ground water pumps qel.GW.C 8,360 0.71 Solar-thermal/DEC water pumps qel.ST.C 3,800 0.32

Table 17: Annual auxiliary energy consumption in cooling mode.

4.1.4 Air ventilation consumption qel.AV

The consumption of the utilized heat meters “LA0x-39”, “LA0x-41”, “LA0x-42” and “LA03-22” are used for heating mode and heat meters “LA0x-40” and “LA03-23” for cooling mode. Considering the whole regarded period, an arithmetic average amounts to 57 % for heating and to 43 % for cooling purposes.

Figure 14: Final energy consumption for air ventilation.

Figure 14 shows the final energy consumption with the heating and cooling separation. The annual energy consumption amounts to 44,651 kWh.

Auxiliary energy air ventilation kWh/a kWh/m2GBA*a

Consumption in heating mode qel.AV.H 27,068 2.31 Consumption in cooling mode qel.AV.C 17,583 1.50

Table 18: Annual auxiliary energy for air ventilation.

4.1.5 Lighting energy consumption qel.Light

The data series for the lighting energy consumption was stored in a single database, which is not connected to the ENERGYbase monitoring system. As a result of mostly constant lighting consumption throughout the year the data series are used for the energy consumption from October to December 2010. The database shows a detailed list of all installed lamps in the building which is why a rigorous reallocation per office unit is possible. In order to use the

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Th. Goschenhofer 34

lighting energy consumption for further purposes it is distributed into building- and user-specific consumption.

Lighting in kWh Sep Oct1 Nov1 Dec1 Jan Feb Mar Apr May Jun Jul Aug Tenant A 105 252 395 416 - - - - - - 97 138 Tenant B 334 152 226 214 - - - - - - 102 138 Tenant C 214 172 294 268 - - - - - - 70 104 Tenant D 3 51 103 74 - - - - - - 29 59 Tenant E 52 271 407 442 - - - - - - 198 437 Tenant F 36 60 110 98 - - - - - - 18 37 Tenant G 22 31 77 53 - - - - - - 21 59 Tenant H 170 97 214 207 - - - - - - 23 137 Unused office units 178 101 134 229 - - - - - - 57 91 Other areas 203 413 685 706 - - - - - - 384 433 Sum 1317 1599 2646 2706 24002 15002 12002 11002 9002 8002 999 1633

Table 19: Lighting energy consumption of separated areas in the ENERGYbase.

1 data series from October to December 2010

2 realistic acceptances due to missing data

From January until June 2010, data is missing which means that realistic acceptances had to be used to determine an annual lighting consumption. In winter, the lighting consumption climaxes due to low daylight conditions; in June and July the building had the expectably lowest consumption, showed in figure 15's graphical progression.

Figure 15: Monthly lighting consumption of each office unit.

Building-specific lighting consumption qel.Light.Building

Lighting in stairs, entry and parking areas are parts of the building-specific lighting consumption. The emergency light system is not considered as a building-specific part, because it is rather a component of the building-specific security system and is listed as one of the other building-specific consumption in chapter 2.7.1.

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User-specific lighting consumption qel.Light.User

The user-specific lighting consumption is the summation of the lighting consumption of each tenant, including unused office units, including the lighting in each room or corridor of each office unit.

Lighting consumption kWh/a kWh/m2GBA*a

Building-specific qel.Light.Building 5,674 0.48 User-specific qel.Light.User 13,130 1.12

Table 20: Annual energy consumption for lighting.

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Figure 16: Final energy consumption for lighting.

4.1.6 Hot water consumption qel.HW

The electric generated hot water consumption is calculated with equation (7). The water density and the specific heat capacity are assumed with an arithmetic average.

The hot water consumption depends on particular days per month and accounts to 6,287 kWh per year. Because the hot water is part of the user-specific consumption, this amount of energy is imputed to user-specific consumption later on in chapter 4.1.6.

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Month Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Weekdays per month 22 21 21 20 19 20 23 21 19 21 22 22 Req. water volume in m3/month 14,9 14,2 14,2 13,5 12,8 13,5 15,5 14,2 12,8 14,2 14,9 14,9 Heating demand in kWh/month 551 526 526 501 476 501 576 526 476 526 551 551

Table 21: Monthly hot water demand.

In table 22, the user-specific hot water consumption is displayed and adds up to 6,287 kWh per year.

Hot water consumption qel.HW kWh/a kWh/m2GBA*a

User-specific 6,287 0.5

Table 22: Annual hot water energy consumption.

4.1.7 Other specific consumption qel.Other

Other consumption are the summation of other remaining energy consumption and basically divided into building- and user-specific consumption.

Other building-specific consumption qel.Other.Building

These consumption had not been monitored yet and are based on past experiences made by the facility manager of the ENERGYbase.

Building-specific consumption

Other building services in kWh/a

Suctions 1,500 Auxiliary heating 3,000 Control technology/Computer 23,000 Elevators 4,000 Emergency lighting 22,000 Security Systems 500 Water treatment etc. 1,000 Total 55,000

Table 23: Annual consumption of other building services, adopted by [WIE09].

The energy for suctions results from fans in installations rooms sucking off e.g. gas emitted by batteries. The auxiliary heating is put to use in the underground garage whereas the energy for water treatment is displaying the amount of energy pumping the purified water from the installation room to the AHUs on the roof. The large part of the energy for other building services constitutes the control technology, which is used for the management of all utilized building services and computer units.

Other user-specific consumption qel.Other.User

Due to applicable data privacies, the results of the building’s tenants are based on assumptions only. For that reason, the amount of electric energy is split into tenant A to H. Due to a lack of measuring data the electric energy consumption of each tenant is calculated by taking a daily average value between the start of the electric meter’s measuring and November 2010, cf. table 24.

Th. Goschenhofer 37

Start End Consumption of Measuring in kWh/a

Tenant A 2008-08-01 2010-11-10 18,998 Tenant B 2008-08-01 2010-11-10 24,098 Tenant C 2008-10-30 2010-11-10 7,636 Tenant D 2008-11-17 2010-11-10 76,474 Tenant E 2008-11-10 2010-11-10 38,090 Tenant F 2009-12-10 2010-11-10 4,838 Tenant G 2010-03-10 2010-11-10 24,506 Tenant H 2010-06-07 2010-11-10 3,721

Total 198,361

Table 24: Annual electric consumption of each office unit.

The measurement in the office units of tenant G and H did not start until 2010. As a result, the amount of electric energy is calculated at tenant G with 50 % and at tenant H with 25 % of the annual consumption.

In order to calculate remaining user-specific consumption representing all connected devices in the office units, such as PCs, notebooks, printers and white goods, the user-specific lighting and hot water consumption have to be subtracted from the total electric energy consumption.

User-specific consumption

qel.User.Total qel.Light qel.HW qel.Other.User in kWh/a in kWh/a in kWh/a in kWh/a

Tenants 198,361 12,062 6,287 180,012 Unused areas 9,750 6,583 - 3,167 Total 208,111 18,645 6,287 183,179

Table 25: Annual electric energy for other user-specific consumption.

Table 25 shows the total electric energy consumption with the summation of lighting and hot water consumption and comes up to a final user-specific consumption for devices of 183,179 kWh per year.

In table 26, the building- and user-specific consumption are displayed and account to 55,000 kWh or 183,179 kWh per year.

Other consumption kWh/a kWh/m2GBA*a

Building-specific qel.Other.Building 55,000 4.70 User-specific qel.Other.User 183,179 15.66

Table 26: Annual final energy for other specific consumption.

4.1.8 Photovoltaic yields qPV

The photovoltaic yields are the summation of all PV cell strings in the façade at meter points “PV3”, “PV4” and “PV5”. The annual yield of the cells comes up 36,237 kWh.

Photovoltaic yields kWh/a kWh/m2GBA*a

Building-specific qPV 36,237 3.10

Table 27: Annual final energy for other specific consumption.

Th. Goschenhofer 38

4.1.9 Building-specific energy consumption qel.Building

In order to display the final energy consumption for the building service engineering in seasonal progress, the consumption is separated into two bar charts for heating or cooling purposes.

Final energy consumption for building services in heating mode

In heating mode, the consumption of heat pumps, pumps of the CCA, ground water, air ventilation and solar-thermal system are outlined in figure 17. The heat pumps and ground water pumps cause the peak of consumption in winter.

Figure 17: Final energy consumption for building services in heating mode.

Final energy consumption for building services in cooling mode

Figure 18 displays the consumption in cooling mode. It is clear to see that the energy consumption for cooling is smaller than the one for heating. The largest part of consumed energy results from the air ventilation in summer.

Final energy consumption for buildings services -‐ heating mode

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Auxiliary energy groundwater pumps -‐ Heat

Auxiliary energy solar-‐thermal pumps -‐ Heat

Auxiliary energy airventilation -‐ Heat

Th. Goschenhofer 39

Figure 18: Final energy consumption for building services in cooling mode.

Final energy consumption for building services

The building-specific final energy consumption is calculated by matching all parts of equation (11). Figure 19 shows the seasonal progress of each part in one bar chart with a maximum in January. Due to missing monitoring data, the hot water and specific consumption were arithmetically averaged, the photovoltaic yields are not yet regarded.

Figure 19: Final energy consumption for building services.

The electric energy consumption of building services are outlined in a flow chart (cf. figure 20). It can be seen that the energy for heating purpose is responsible for consuming the largest share of final energy. The energy produced by photovoltaic can provide approx. 20,5 % of building-specific energy consumption, whereby the cooling and lighting consumption can be covered.

Final energy consumption for building services -‐ cooling mode

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Th. Goschenhofer 40

Figure 20: Energy flow chart of the electric final energy consumption for building services.

4.1.10 Total final energy consumption qel.final

The summation of all electric energy consumption in the building accounts the total final energy consumption qel.final. A detailed schedule of the final energy consumption of each system per month and the separation into heating and cooling purposes can be found in appendix B. As a last step the total results are displayed in total consumption as well as building- and user-specific amounts. In this schedule, the PV yields are not yet regarded nor subtracted. In figure 20 the final energy consumption is outlined with building- and user-specific consumption in seasonal progress.

Th. Goschenhofer 41

Figure 21: Total final energy consumption.

Table 28 shows the ENERGYbase’s final energy consumption in an absolute value and related to GBA and NBA.

Final energy kWh/a kWh/m²GBA*a kWh/m²NBA*a Building-specific 140,854 12.04 18.78 User-specific 202,596 17.32 27.01 Total 343,450 29.35 45.79

Table 28: Final energy consumption related to GBA and NBA.

With these results, the actual final energy consumption can be compared to the expected energy demand, calculated by Preisler in [EGB08], in table 29.

Expected consumption Actual consumption in kWh/a in kWh/a Heating energy consumption 75,896 85,865 Cooling energy consumption 45,365 30,552 Lighting consumption 55,629 18,804 Hot water consumption 17,267 6,287 Other consumption 285,994 238,179 Photovoltaic yields -36,800 -36,237

Final energy consumption 443,351 343,450

Table 29: Comparison of the expected and actual final energy consumption.

The comparison shows that the actual consumption is much lower than the expected energy. The biggest variations figure the lighting and the hot water consumption. The actual cooling energy is smaller by 33 %, the other consumption and photovoltaic yields have almost the same figure. Only the actual heating consumption is higher than the expected amount this is caused by higher storage losses and auxiliary energies. The difference between the expected

Final energy consumption -‐ total

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Lighting

Other building-‐specific

Other user-‐specific

Photovoltaic yields

Th. Goschenhofer 42

and the actual consumption is caused by the fact that the office units in the ENERGYbase are often underused. Still, the number of the actual heating energy consumption exceeds the expected consumption which has to be examine more closely in following monitoring analyses preventing high energy consumption in this part.

4.2 Primary energy consumption The primary energy consumption is the amount of energy, which is needed to generate energy in power plants and calculates the final thermal and electric energy consumption with their respective primary energy factors.

Because the ENERGYbase building only consumes electricity and no further primary energy, the calculation of the primary energy consumption confines itself to the electric part and can be expressed by equation 12. Determining the real primary energy consumption, the primary electric energy factor fp.el from the local power company “WienStrom” is used and adds up to 1.71, cf. [WEN10].

The primary energy consumption are listed in appendix C and summarized as building- and user-specific consumption; the subtraction of the PV yields is not yet regarded. They are displayed in figures 22 and 23 as negative bars showing the savings of primary energy.

Figure 22: Primary energy consumption for building services.

Primary energy consumption -‐ building services

-‐1,0

-‐0,5

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

5,5

6,0

6,5


prim

ary en

ergy co

nsum

ption in kWh/m

2 GFA

Heat pumps

Auxiliary energy

Air ventilation


Other -‐ building-‐specific

Photovoltaic Yields

Th. Goschenhofer 43

Figure 23: Total primary energy consumption.

Table 30 shows the ENERGYbase primary energy consumption in an absolute value and related to GBA and NBA.

Primary energy kWh/a kWh/m²GBA*a kWh/m²NBA*a Building-specific 240.860 20,59 32,11 User-specific 346.440 29,61 46,19 Total 587.300 50,20 78,31

Table 30: Final energy consumption related to GBA and NBA.

4.3 Comparison of different office buildings The primary energy consumption of a building is a useful parameter providing information about its energy efficiency and about its caused CO2 emissions. This chapter deals with the comparison of the primary energy of different office types, regarding the categories “heating”, “cooling”, “supply air”, “lighting”, “hot water”, “several devices” and “office equipment”.

The category “office equipment” displays the user-specific part of the primary energy. Because of different calculations in chapter 3.1 and [KNI99] the consumption for the “office equipment” of the ENERGYbase building was estimated, considering the same requirements. For this calculation, the electric demand of the office equipment, composed of PC or notebooks, flat-screen monitor, and printers (MFD), by the latest generation was calculated on the basis of data from the German Energy Agency “DENA” in [DEN11]. According to that, the final energy for office equipment in the ENERGYbase building accounts to 10,200 kWh/a final energy.

Primary energy consumption -‐ total

-‐1,0

-‐0,5

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

5,5

6,0

6,5


prim

ary en

ergy co

nsum

ption in kWh/m

2 GFA Heat pumps

Auxiliary energy

Air ventilation

Hot water -‐ user-‐specific


Lighting -‐ user-‐specific

Other -‐ building-‐specific

Other -‐ user-‐specific

Photovoltaic Yields

Th. Goschenhofer 44

Old

building Standard building

Low energy building

Passive house '98 ENERGYbase '08

in kWh/m2a in kWh/m2a in kWh/m2a in kWh/m2a in kWh/m2a Heating 140 68 34 18 7 Cooling 0 22 17 11 3 Supply air 0 9 11 9 12 Lighting 56 82 32 10 5 Hot water 6 6 6 6 2 Several devices 20 21 19 18 14 Office equipment 27 27 17 4 4 Total 249 235 136 76 46

Table 31: Primary energy consumption of different office types, adapted by [KNI99].

Unlike the energy computations in chapters 4.2, the primary energy of the ENERGYbase up to 46 kWh/m2a. That results from a different calculation method and a higher primary factor. Nevertheless, primary energy consumption in total is still smaller. Compared to the “passive house ‘98”, the energy consumption can be lowered by 30 kWh/m2a. Big savings of primary energy are recorded especially in the categories “Heating”, “Cooling”, “Lighting” and “Hot water”.

Figure 24 shows a bar chart of the progressive reduction of primary energy. More than 50 % of the total primary energy consumption are used for heating in the old building. By preventing the losses with an improvement of the structure shell, such as insulation, the heating consumption can be minimised into the standard type. However, the lighting consumption has increased. That means, that there has not only to be a focus on the building envelope, but also on interior devices, such as lighting or computing. A big conservation of primary energy is still possible by using the passive house technology. Due to an additional improvement of the building services and the use of renewable energy, more primary energy can be saved.

Figure 24: Primary energy consumption of different office types, adapted by [KNI99].

Primary energy consumption of different office types

0

25

50

75

100

125

150

175

200

225

250

275

Old building Standard building Low energy building Passive house '98 ENERGYbase '08

prim

ary

ener

gy in

kW

h/m² G

BAa

Office equipment

Several devices

Hot water

Lighting

Supply air

Cooling

Heating

Th. Goschenhofer 45

5 Conclusion In this chapter, the main results of the evaluation concepts and potential improvements are outlined subsequently the results are discussed.

5.1 Monitoring system First of all, the monitoring data series from the ADP database were put to a good use for further computations. The failure rates were very low despite a small exception at a specific heat coil in the AHU2. However, the series of the lighting monitoring boasted a constant failure in continuous recordings caused by a missing storage system. For further studies, an automatic storage system should be installed, additionally with access to the ADP database in order to use only one monitoring system although the existing lighting monitoring system draws on a very detailed and useful database showing each installed lamp.

In general, an additional sensor measuring the heat flow from the solar system to the heating tank can improve the ENERGYbase monitoring system. This way, not only the solar fraction for heating purposes but also the losses in the solar and heating tank can be determined more easily.

5.2 Evaluation concepts The computation of the final energy and primary energy consumption was only possible by making several assumptions, especially for the allocation of auxiliary energy for heating and cooling purposes. For a detailed determination of the auxiliary energy consumption, more sensors and time would have been necessary. Furthermore, with past experiences carried out by the facility manager a lot of consumption, which were needed for the calculation, were made available.

5.2.1 Heating

The ENERGYbase needs its greatest amount of primary energy in winter. The heat pump and the ground water pumps have an annual primary energy consumption of 4.84 kWh/m2

GBAa. The CCA and solar-thermal pumps only feature a small consumption indicating that efficient devices were installed. The most of the losses stem from the solar tank and account 6 %. In spring, however, the solar yields are directly used for heating. But in months of transition the AHUs have the highest electric consumption especially in November, February and March and also the losses in the solar tank increase significantly by approximately 50 % due to solar inputs and no usage of the energy. The primary energy consumption for heat and auxiliary pumps in heating mode adds up to 8.59 kWh/m2

GBAa.

5.2.2 Cooling

In the cooling mode the AHUs and ground source reveal a high consumption with a peak in July. The DEC system in the AHUs is constantly used from April until October showing a good utilization ratio, which is why the losses in the solar tank decrease to about 8 % in midsummer. Consequently, the heat in this tank could be used in a better way to temper the building. Although a big amount of thermal energy was transported, the consumption of other auxiliary pumps in cooling mode are still very small due to efficient devices. For that reason, the primary consumption for CCA, ground-water and for solar-thermal or DEC pumps adds up to a total primary energy consumption of 1.90 kWh/m2

GBAa in cooling mode and accounts

Th. Goschenhofer 46

just to a fifth of the heating energy. At this point, the use of renewable energy resources for the production of cooling energy plays a noticeable role.

5.2.3 Air ventilation

Most of the total consumption of the building services engineering comes from the air ventilation with 6.53 kWh/m2

GBAa of the primary energy. Especially in the months of transition, the air ventilation constitutes the main part of the building-specific consumption. A detailed allocation of particular devices, responsible for the high consumption, was not possible due to a lack of measuring meters.

5.2.4 Lighting

The small lighting consumption of 18,804 kWh/a resulted from efficient lamps and an efficient lighting concept. The calculation for this amount of energy was based on assumptions, because, the needed data series were unfortunately only available for six months. When separating the lighting in the ENERGYbase, the building-specific amount becomes nearly constant, whereas the user-specific consumption has a seasonal progress with a peak in winter. The annual primary energy consumption for building-specific lighting adds up to 0.83 kWh/m2

GBAa.

5.2.5 Hot water

With realistic acceptances the electric generated hot water consumption was calculated and displays a very small figure of 6,287 kWh/a or 0.5 kWh/m2

GBAa. Compared to other office types the preparation of hot water made by energy efficient electrical instantaneous water heaters causes less primary energy than hot water heated up by gas-fired boilers. Although this consumption had no big impact on the final energy consumption, the hot water could also be heated up with energy from the solar system.

5.2.6 Other specific consumption

Most parts of the other building-specific final energy consumption, 45,000 kWh/a, came from the control technology and the emergency light system and constitute a not inconsiderable amount of the primary energy with 8.04 kWh/m2

GBAa. A possible solution for reducing the used energy could be the usage of more efficient emergency lights. Currently, fluorescent lamps with a power of 13 W are used, with new LED devices the consumption could be lowered by 70 %.

Still, with 346,440 kWh/a about 59 % of the building’s energy consumption are responsible for user-specific primary energy consumption and result from parts of the users’ lighting, hot water preparation and connected devices such as IT equipment or white goods.

5.2.7 Total primary energy consumption

The office building ENERGYbase features a total primary energy consumption of 587,300 kWh/a, related to its gross and net building area this would be converted to 50.20 kWh/m2

GBAa and 78.31 kWh/m2NBAa.

The expected primary energy consumption calculation made in the planning phase, revealed diverging results. On the one hand, the actual consumption list a higher figure in the heating sector caused by higher storage losses and auxiliary energies but on the other hand showed

Th. Goschenhofer 47

lower figures in the remaining sectors. Special variations show the hot water and lighting consumption illustrating just one third of the calculated energy.

Compared to existing office buildings, the ENERGYbase has an excellent energy performance. Additional, the heating, cooling, hot water and lighting lead to a notable conservation of energy. Using renewable energy technologies can provide especially the whole cooling energy, which is used more often in office buildings.

5.3 Forecasts The study comes to the results, that the usage of efficient and sustainable energy systems is reducing the primary energy consumption and is saving energy sources. The main electric consumers in office buildings, however, are user-specific consumption, which should be prevented or minimised.

On top of this, the findings brought to question whether the generating of energy for heating or cooling purposes should come exclusively from electricity as is the case in ENERGYbase which is producing its heat mostly via heat pumps. By taking increasing electricity rates into account, the question arises if there is no better way for energy efficient buildings. Only if the usage of renewable energy resources and sustainable energy systems and also the gain of efficient devices will be more encouraged, primary energy can be reduced. That leads to a reduction of carbon emissions and could be a solution to reach the “20-20-20”-targets and tackle the climate change.

Th. Goschenhofer 48

Bibliography [ALF10] Alfaomega, Sensor Anordnung Ultraschall Durchflussmesser,

http://upload.wikimedia.org/wikipedia/de/7/75/Dibujo_Ultraschall2.PNG (available at 17th of October 2010).

[BAC10] BACnet Interest Group Europe e.V., http://www.big-eu.org (available at 17th of October 2010).

[CEP10] European Commission Climate Action, The EU climate and energy package, http://ec.europa.eu/clima/policies/brief/eu/package_en.htm (available at 02nd of January 2011).

[DES10] SIEMENS DESIGO Insight, Monitoring Software in ENERGYbase.

[DEN11] German Energy Agency, Office-TopTen, http://www.energieeffizienz-im-service.de/it-geraete/office-topten/kategorie-auswaehlen.html (available at 10th

of January 2011).

[EGB08] A. Preisler, ENERGYbase, Austrian Institute of Technology, Vienna 2008.

[ENB11] ENERGYbase, http://www.energybase.at (available 02nd of January 2011).

[EOB10] German Federal Ministry of Economics and Technology – Forschung für Energieoptimiertes Bauen, Performance von Gebäuden in der Jahresbilanz, http://www.enob.info/de/analysen/analyse/details/performance-von-gebaeuden-in-der-jahresbilanz/ (available at 17th of October 2010).

[ESA10] Federal Ministry of Economy, Family and Youth, EnergieStrategie Österreich, http://www.energiestrategie.at/images/stories/pdf/longversion/energiestrategie_oesterreich.pdf(available at 02nd of January 2011).

[HUR10] H. Hurnaus, ENERGYbase, http://www.hurnaus.com (available at 17th of October 2010).

[KNI99] J. Knissel, Energieeffiziente Büro- und Verwaltungsgebäude, Hinweise zur primärenergetischen und wirtschaftlichen Optimierung, 1st edition, Institute Living and Environment, Darmstadt 1999.

[KWI07] KWI Consulting Engineers GmbH, Einreichplan, Vienna 2007.

[IBO09] Institut für Baubiologie und -ökologie, Passivhauszertifikat, http://www.pos-architecture.com/fileadmin/pos/media/Projekte/ENB/Zertifikat-Urkunde_Energybase_Maerz2009.pdf (available at 02nd of January 2011)

[OER10] OMEGA Engineering Technical Reference, http://www.omega.com/prodinfo/ultrasonicflowmeters.html (available at 17th of October 2010).

[PXC10] SIEMENS, Datasheet Automation stations modular model,http://www.big-eu.org/catalog/siemens/023_PXC..U_CA1N9221en_02.pdf (available at 04th of January 2011).

Th. Goschenhofer 49

[SBT08] SIEMENS Building Technologies GmbH, Topologieschemata, Vienna 2008.

[STA10] C. Starl, Energetische Gesamtbewertung des Passivhaus-Bürogebäudes ENERGYbase anhand der Monitoring Ergebnisse 2008/2009, Bachelor thesis, UAS Technikum Vienna, Vienna 2009.

[UHM07] SIEMENS, Datasheet Heat meter Ultrasonic UH50, https://www.siemens.be/cmc/upload/cms/docs/sbt/hvac/Brochures_Datasheets_manuals/FR/10_Comptage_énergie/Manuels/UH50_InstallServiceInstruct.pdf (available at 04th of January 2011)

[WEN10] HOFMANN, P. ([email protected]), 09 Dec 2010. Primärenergiefaktor für Strom von Wien Energie. e-Mail to T. GOSCHENHOFER ([email protected]).

[WIE09] W. Wiedermann, Verbrauchsstruktur ENERGYbase, Vienna 2009.

[WIN09] Wuppertal Institute, T. Stefan et al., Measuring and reporting energy savings for the Energy Services Directive – how it can be done, http://www.evaluate-energy-savings.eu/emeees/en/publications/reports/EMEEES_Final_Report.pdf (available at 04th of January 2011).

Th. Goschenhofer 50

List of Figures Figure 1: Passive house office building ENERGYbase [HUR10]. ............................................ 6 Figure 2: Process diagram of utilized building services, adapted by [KWI07]. ......................... 8 Figure 3: Schematic of an ultrasonic flow meter, adapted by [ALF10]. .................................... 9 Figure 4: Implemented digital electric meter in the ENERGYbase. ........................................ 10 Figure 5: Positioning of BACnet in a level process diagram [BAC10]. .................................. 10 Figure 6: Topology of network interfaces, adapted by [SBT08]. ............................................. 11 Figure 7: Process diagram of an AHU in DESIGO Insight [DES10]. ..................................... 12 Figure 8: Drawing of an upper floor in DESIGO Insight [DES10]. ......................................... 12 Figure 9: Breakdown of a sensor for several days. ................................................................... 26 Figure 10: Failure of sensor “heating coil sorption LA 40” of AHU2. .................................... 26 Figure 11: Supply and consumption of energy in heating mode. ............................................. 29 Figure 12: Supply and consumption of energy in cooling mode. ............................................. 30 Figure 13: Thermal heating and cooling energy per month. .................................................... 31 Figure 14: Final energy consumption for air ventilation. ......................................................... 33 Figure 15: Monthly lighting consumption of each office unit. ................................................. 34 Figure 16: Final energy consumption for lighting. ................................................................... 35 Figure 17: Final energy consumption for building services in heating mode. ......................... 38 Figure 18: Final energy consumption for building services in cooling mode. ......................... 39 Figure 19: Final energy consumption for building services. .................................................... 39 Figure 20: Energy flow chart of the electric final energy consumption for building services. 40 Figure 21: Total final energy consumption. ............................................................................. 41 Figure 22: Primary energy consumption for building services. ............................................... 42 Figure 23: Total primary energy consumption. ........................................................................ 43 Figure 24: Primary energy consumption of different office types, adapted by [KNI99]. ........ 44

Th. Goschenhofer 51

List of Tables Table 1: Primary energy factors according Gemis 3.01, adopted by [KNI99]. ........................ 19 Table 2: Detailed descriptions for office type old building, adopted by [KNI99]. .................. 19 Table 3: Detailed descriptions for office type standard building, adopted by [KNI99]. .......... 20 Table 4: Detailed descriptions for office type low energy building, adopted by [KNI99]. ...... 21 Table 5: Detailed descriptions for office type passive house, adopted by [KNI99]. ................ 22 Table 6: Detailed descriptions for office type ENERGYbase, adapted by [EGB08]. .............. 22 Table 7: Used data series for the heat pump and ground water system. ................................... 23 Table 8: Used data series for the CCA system. ........................................................................ 24 Table 9: Used data series for the solar thermal system. ........................................................... 24 Table 10: Used data series for the photovoltaic system. .......................................................... 24 Table 11: Used data series for the AHU system. ...................................................................... 25 Table 12: List of the lighting consumption of several areas. .................................................... 25 Table 13: Thermal energy consumption for heating purposes. ................................................ 28 Table 14: Thermal energy consumption for cooling purposes. ................................................ 29 Table 15: Annual final energy for heat pumps. ........................................................................ 31 Table 16: Annual auxiliary energy consumption in heating mode. .......................................... 32 Table 17: Annual auxiliary energy consumption in cooling mode. ......................................... 33 Table 18: Annual auxiliary energy for air ventilation. ............................................................. 33 Table 19: Lighting energy consumption of separated areas in the ENERGYbase. .................. 34 Table 20: Annual energy consumption for lighting. ................................................................. 35 Table 21: Monthly hot water demand. ...................................................................................... 36 Table 22: Annual hot water energy consumption. .................................................................... 36 Table 23: Annual consumption of other building services, adopted by [WIE09]. ................... 36 Table 24: Annual electric consumption of each office unit. ..................................................... 37 Table 25: Annual electric energy for other user-specific consumption. ................................... 37 Table 26: Annual final energy for other specific consumption. ............................................... 37 Table 27: Annual final energy for other specific consumption. ............................................... 37 Table 28: Final energy consumption related to GBA and NBA. .............................................. 41 Table 29: Comparison of the expected and actual final energy consumption. ......................... 41 Table 30: Final energy consumption related to GBA and NBA. .............................................. 43 Table 31: Primary energy consumption of different office types, adapted by [KNI99]. ......... 44

Th. Goschenhofer 52

List of Abbreviations ADP Advanced Data Processing

AHU Air Handling Unit

BACnet Building Automation and Control network

BAS Building Automation System

CCA Concrete Core Activation

DDC Direct Digital Control

DEC Desiccant and Evaporative Cooling

ESD Directive on energy end-use efficiency and energy services

GBA Gross building area

HVAC Heating, Ventilation, Air Conditioning

IEC International Electrotechnical Commission

ISO International Organization for Standardization

LON Local Operating Network

MFD Multifunction device

NBA Net building area

UAS University of Applied Sciences

Th. Goschenhofer 53

pro

vis

ion o

f energ

yConsum

er

Meth

od o

f calc

ula

tion

com

ment/

notice

Heating

pH

Result o

f sim

ula

tion

Hot

wate

rp

HW

5,7

kW

h/(

m2a)*

Pf G

as

[SIA

380/1

, D

1-1

]

Severa

l devic

es

pSD

Auxilia

ry e

nerg

y h

eating/h

ot

wate

rp

SD

,Aux

pSD

,Aux=

(pH+

pH

W)*

0,0

1re

alistic a

ssum

ption a

cc.

[SIA

380/4

1992]

Tra

nsport

(one e

levato

r per

1500m

2p

SD

,Tp

SD

,T=

2 k

Wh/(

m2a)*

Pf E

lectr

icity

accord

ing [

SIA

380/4

1992]

with 3

000 k

Wh/a

)

Losses (

Tra

nsfo

rmers

,...

)p

SD

,Lp

SD

,L=

(pSD+

pEQ+

pCO+

pLI)

*0,0

25

accord

ing [

SIA

380/4

1992]

Com

munic

ation (

sw

itchboard

)p

SD

,Cp

SD

,C=

3,5

kW

h/(

m2a)*

Pf E

lectr

icity

consta

nt

acc.

[SIA

380/4

1992,

Exam

ple

]

Supply

air

pSA

min

. supply

air t

ransport

pSA,T

Result o

f sim

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Auxilia

ry a

nd s

tand-b

y e

nerg

yp

SA,A

ux

pSA,A

ux=

Pm

ax,F

,SA*0,0

3*Pf E

lectr

icity

accord

ing [

SIA

380/4

1992]

Pm

ax,F

,SA:

max.

fan p

ow

er

for

hygie

nic

min

imum

tra

nsport

of

supply

air

Conditio

nin

gp

CO

Air t

ransport

fre

e c

ooling

pCO

,TResult o

f sim

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tion

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ry a

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tand-b

y e

nerg

yp

CO

,Aux

pCO

,Aux=

Pm

ax,F

,CO*0,0

3*Pf E

lectr

icity

accord

ing [

SIA

380/4

1992]

Pm

ax,V

,KO:

max.

fan p

ow

er

for

cool

air t

ransport

Wate

r tr

ansport

pCO

,Wp

CO

,W=

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,C*0,0

1*Pf E

lectr

icity

depart

ing f

rom

[SIA

380/4

1992]

Cold

genera

tion

pCO

,CResult o

f sim

ula

tion

Hum

idific

ation

pCO

,Hu

Result o

f sim

ula

tion

Dehum

idific

ation

pCO

,Deh

Result o

f sim

ula

tion

Lig

hting

pLI

boundary

conditio

n o

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ula

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Equip

ment

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n o

f sim

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tion

Energ

y s

ourc

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ary

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y f

acto

r

kW

hPrim/k

Wh

End

Natu

ral gas

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rs a

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em

is 3

.01

A: Calculation process comparison office types

Th. Goschenhofer 54

B: Detailed schedule of the final energy consumption

Th. Goschenhofer 55

C: Detailed schedule of the primary energy consumption

energy performance of the office building energybase (heating, … › forschung › pdf ›...

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