master level thesis - du.diva-portal.org1451781/fulltext01.pdf · unit heat reduction in stockholm...

Master Level Thesis Energy Efficient Built Environment

No.18, Jun 2020

Energy savings in multi-family building after using an innovative

retrofitting package

Master thesis 15 credits, 2020 Energy Efficient Built Environment Author: Kosmas Kasolas

Supervisors: Jonn Are Myhren, Jingchun Shen

Examiner: Xingxing Zhang

Course Code: EG3020

Examination date: 2020-06-17

K

Dalarna University

Energy Engineering

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Abstract The building sector is one of the sectors that consume the most energy in Sweden. In order to deal with this problem Swedish government aims to reduce the energy consumption in the building sector 50% by 2050. Another ambitious goal set by the Swedish government is zero greenhouse gas emissions by 2040. Most of the buildings in Sweden were built during 1950-1990 before the first energy regulations were voted in Europe. A high percentage of these buildings date to 1950 and the majority of them are multi family buildings. Apartments built during this period are now requiring major renovation and retrofitting measures in order to comply with the energy and indoor environment regulations.Despite the urgent need for retrofitting expressed above, the retrofitting ratio in Sweden was 0.88% in 2013, so the number of buildings that haven’t gone through any energy retrofitting is still high making it clear that the biggest opportunity for energy savings lies within the existing building stock and that the retrofitting ratio has to enhance in order to achieve the governments energy and emission goals for 2050. In this study a new patented innovative energy retrofitting method is studied within IDA-ICE simulation program in order to find the heat load and the energy savings after applying this method. The simulated building is a three story multi family building with building characteristics from 1950 and the simulation takes place in two different climate zones (Stockholm and Umeå). Three different insulation thicknesses were tested creating three different variant cases in order to investigate the difference in energy savings an increase of the insulation thickness will bring. This retrofitting method except installation of extra facade insulation includes roof insulation, replacement of the air handling unit with heat recovery ventilation whose pipe system runs through the insulation behind the radiators of each zone and replacement of the old windows with triple glazed low U-value windows. The results show a high reduction in heat supplied after the retrofit, 66.4% room unit heat reduction in Stockholm and 59.6% in Umeå and even higher energy reduction 68.3% in Stockholm and 68.9% in Umeå. The CO2 emission reduction was 58.4% in Stockholm and 60.9% in Umeå. The difference in room unit heat, energy consumption and CO2 emissions among the Variant cases varies between 1-2%. The explanation for such a small difference lies in the fact that the only difference among these cases is the insulation thickness of the facade. The thermal comfort was also investigated and has shown an increase in hours of dissatisfaction after the retrofitting and as the insulation increased due to overheating. However it must be stated here that the reason behind the increase in dissatisfaction is that no window shading or window opening schedules were taken into account in the simulation maximizing the solar heat gains of the building. The study concludes that the studied retrofitting method is very efficient and the studied building achieves higher energy reduction than the goal that the Swedish government has set for 2050. The results of this study bring this retrofitting method ahead of the 2050 energy reduction goals set by the Swedish government with significant reductions in CO2 emissions and heat load.

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Acknowledgements First, I would like to express my gratitude to my supervisor Jonn Are Myhren for helping me connect with the company and also for guiding me throughout this study. I would also like to thank Jingchun Shen for advising and guiding me to complete all the simulations in IDA-ICE, her office door was always open to me, without her help this thesis would not have been possible. I would also like to thank Stefan Forsberg the CEO of Smart Front for giving me the opportunity and honor to study this interesting, innovative retrofitting method and write this thesis. I would like to thank EQUA Simulation AB for providing me with license for IDA-ICE. Without this tool, I would have not been able to conduct this thesis. Last but not least, I am thankful to have the support of my girlfriend, my family and my friends throughout my educational journey, during good and more difficult times. Thank you! Thank you all very much! Kosmas Kasolas

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Abbreviations

GHG Green House Gases MFB Multi Family Building EEM Energy Efficient Measures AHU Air Handling Unit HRV Heat Recovery Ventilation BBR Boverkets Byggregler COP Coefficient of Performance HVAC Heating Ventilation Air Conditioning Kr Swedish krona, Swedish crown LCC Life Cycle Cost LCA Life Cycle Analysis DOE Department Of Energy ACH Air Change per Hour MET Metabolic rate FT Till-och frånluftsventilation (Supply and exhaust air

ventilation) FTX Till-och frånluftsventilation med värmeåtervining

(Supply and exhaust air ventilation with heat recovery) CAV Constant Air Volume ESBO Early Stage Building Optimization DH District Heating DHW Domestic Hot Water BBR Boverkets Byggregler SMHI Swedish Meteorological and Hydrological Institute

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Table of contents Abstract ................................................................................................................. iii Acknowledgements ............................................................................................... iv Table of contents .................................................................................................. vi List of Figures ...................................................................................................... viii List of tables ........................................................................................................... x 1 Introduction ......................................................................................................... 1 2 Literature Review ................................................................................................ 2 2.1 Retrofitting status in Sweden ........................................................................... 2 2.2 Mechanical ventilation system in Sweden ....................................................... 3 3 Research materials ............................................................................................. 4 3.1 Climate ............................................................................................................. 5 3.1.1. Stockholm climate ........................................................................................ 5 3.1.2. Umeå climate ............................................................................................... 7 3.2 Building model description ............................................................................... 9 3.2.1. Building Materials ...................................................................................... 11 3.2.2. Baseline case material information ............................................................ 11 3.2.3. Variant cases material information ............................................................ 12 3.3 Internal heat loads ......................................................................................... 15 3.4 Emissions and energy pricing ........................................................................ 16 3.5 HVAC System ................................................................................................ 16 3.5.1. Baseline AHU ............................................................................................ 16 3.5.2. Variant AHU Configurations ....................................................................... 17 4 Methodology ..................................................................................................... 17 4.1.1. Retrofitting method description .................................................................. 18 4.1.2. Simulation strategy .................................................................................... 19 5 Results and analyzing ....................................................................................... 21 5.1 Baseline case in Stockholm and Umeå ......................................................... 21 5.1.1. Heating load variations .............................................................................. 21 5.1.2. Energy consumption .................................................................................. 23 5.2 Variant A case in Stockholm and Umeå ........................................................ 28 5.2.1. Heating load variations .............................................................................. 28 5.2.2. Energy consumption .................................................................................. 30 5.3 Variant B case in Stockholm and Umeå ........................................................ 34 5.3.1. Heating load variations .............................................................................. 34 5.3.2. Energy consumption .................................................................................. 36 5.4 Variant C case in Stockholm and Umeå ........................................................ 40 5.4.1. Heating load variations .............................................................................. 40 5.4.2. Energy consumption .................................................................................. 42 5.5 Summary of all cases .................................................................................... 46 5.5.1. Total heat supplied .................................................................................... 47

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5.5.2. Total final energy consumption .................................................................. 48 5.5.3. Annual CO2 emissions ............................................................................... 49 6 Limitations ......................................................................................................... 50 7 Conclusion and Future work ............................................................................. 51 7.1 Feasibility results ........................................................................................... 51 7.1.1. Thermal comfort study ............................................................................... 51 7.1.2. Operational suggestion .............................................................................. 54 7.1.3. Environmental impacts .............................................................................. 54 7.2 Future works .................................................................................................. 54 8 References ....................................................................................................... 55 Appendixes .......................................................................................................... 58 8.1 Different cases information ............................................................................ 60 8.1.1. Baseline ..................................................................................................... 60 8.1.2. Variant A .................................................................................................... 61 8.1.3. Variant B .................................................................................................... 63 8.1.4. Variant C .................................................................................................... 64

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List of Figures Figure 1-Reference Building with dimensions[22] ................................................. 5 Figure 2-Daily maximum and minimum temperature profile [25] ........................... 6 Figure 3-Monthly mean temperature[25] ............................................................... 6 Figure 4-Monthly total solar radiation profile[25] .................................................... 7 Figure 5-Monthly wind speed ................................................................................. 7 Figure 6-Monthly wind speed direction [25] ........................................................... 7 Figure 7-Daily maximum and minimum temperature profile [25] ........................... 8 Figure 8-Monthly mean temperature[25] ............................................................... 8 Figure 9-Monthly total solar radiation profile[25] .................................................... 8 Figure 10-Monthly wind speed [25] ........................................................................ 9 Figure 11-Monthly wind speed direction [25] ......................................................... 9 Figure 12-Multi Family Building model built up in IDA-ICE 4.8 ............................ 10 Figure 13-Floor blueprint of the Multi Family Building ......................................... 10 Figure 14- Baseline graph of AHU ....................................................................... 16 Figure 15-Variant graph of AHU .......................................................................... 17 Figure 16-Smart Front insulation overview[31] .................................................... 19 Figure 17-Working flow of this study .................................................................... 20 Figure 18- Room unit heat in W for Baseline Stockholm ..................................... 22 Figure 19-Room unit heat in W for Baseline Umeå ............................................. 23 Figure 20-Monthly consumption in KWh for DH and DHW in Baseline Stockholm ............................................................................................................................. 25 Figure 21-Monthly consumption in KWh for DH and DHW in Baseline Umeå ..... 27 Figure 22-Room unit heat in W for Variant A Stockholm ..................................... 29 Figure 23-Room unit heat in W for Variant A Umeå ............................................ 30 Figure 24-Monthly consumption in KWh for DH and DHW in Variant A Stockholm ............................................................................................................................. 31 Figure 25-Monthly consumption in KWh for DH and DHW in Variant A Umeå .... 33 Figure 26-Room unit heat in W for Variant B Stockholm ..................................... 35 Figure 27-Room unit heat in W for Variant B Umeå ............................................ 36 Figure 28- Monthly consumption in KWh for DH and DHW in Variant B Stockholm ............................................................................................................................. 38 Figure 29-Monthly consumption in KWh for DH and DHW in Variant B Umeå .... 40 Figure 30-Room unit heat in W for Variant C Stockholm ..................................... 41 Figure 31-Room unit heat in W for Variant C Umeå ............................................ 42 Figure 32-Monthly consumption in KWh for DH and DHW in Variant C Stockholm ............................................................................................................................. 44 Figure 33-Monthly consumption in KWh for DH and DHW in Variant C Umeå ... 46 Figure 34-Graph presenting the total heat supplied in all cases Stockholm and Umeå ................................................................................................................... 47 Figure 35-Graph presenting the total final energy consumption in all cases Stockholm and Umeå .......................................................................................... 48 Figure 36-Graph presenting the total final energy consumption in KWh/m2 for all cases Stockholm and Umeå ................................................................................ 49

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Figure 37-Graph presenting the annual CO2 emissions for all cases in Stockholm and Umeå ............................................................................................................ 50 Figure 38-Graph showing the percentage of total occupant hours with thermal dissatisfaction for Stockholm and Umeå .............................................................. 53 Figure 39- Electricity pricing from Borlänge Energi ............................................. 58 Figure 40-District heating price from esbo ........................................................... 58 Figure 41- CO2 emissions from district heating esbo ........................................... 59 Figure 42- CO2 emissions from district heating Borlänge Energi ......................... 59

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List of tables Table 1-Overview of Baseline building envelope ................................................. 11 Table 2-Overview of Variant A building envelope ................................................ 12 Table 3-Overview of Variant B building envelope ................................................ 13 Table 4-Overview of Variant C building envelope ................................................ 14 Table 5-Internal heat loads of the building and schedules .................................. 15 Table 6-Break down of total 8 simulated cases ................................................... 18 Table 7- Baseline Stockholm Heating Load information ...................................... 21 Table 8-Baseline Umea Heating load information ............................................... 22 Table 9- Zone MIN-MAX temp baseline Stockholm ............................................. 23 Table 10- District heating and Domestic hot water for Baseline Stockholm ........ 24 Table 11-Delivered energy overview for Baseline Stockholm ............................. 25 Table 12-Zone MIN-MAX temp. Baseline Umeå ................................................. 25 Table 13-District heating and Domestic hot water for Baseline Umeå ................ 26 Table 14- Delivered energy overview for Baseline Umeå .................................... 27 Table 15- Variant A Stockholm Heating load information .................................... 28 Table 16-Variant A Umeå Heating load information ............................................ 29 Table 17-Zone MIN-MAX temp. Variant A Stockholm ......................................... 30 Table 18- District heating and Domestic hot water for Variant A Stockholm ....... 31 Table 19-Delivered energy overview for Variant A Stockholm ............................ 32 Table 20-Zone MIN-MAX temp Variant A Umeå ................................................. 32 Table 21-District heating and Domestic hot water for Variant A Umeå ............... 33 Table 22-Delivered energy overview for Variant A Umeå .................................... 34 Table 23-Variant B Stockholm Heating load information ..................................... 34 Table 24-Variant B UmeåHeating load information ............................................. 35 Table 25-Zone MIN-MAX temp Variant B Stockholm .......................................... 36 Table 26- District heating and Domestic hot water for Variant B Stockholm ....... 37 Table 27-Delivered energy overview for Variant B Stockholm ............................ 38 Table 28- Zone MIN-MAX temp Variant B Umeå ................................................ 38 Table 29-District heating and Domestic hot water for Variant B Umeå ............... 39 Table 30-Delivered energy overview for Variant B Umeå .................................... 40 Table 31-Variant C Stockholm Heating load information ..................................... 41 Table 32-Variant C Umeå Heating load information ............................................ 41 Table 33-Zone MIN-MAX temp Variant C Stockholm .......................................... 42 Table 34-District heating and Domestic hot water for Variant C Stockholm ........ 43 Table 35-Delivered energy overview for Variant C Stockholm ............................ 44 Table 36- Zone MIN-MAX temp Variant C Umeå ................................................ 44 Table 37-District heating and Domestic hot water for Variant C Umeå ............... 45 Table 38-Delivered energy overview for Variant C Umeå ................................... 46 Table 39- Total room unit heat for all cases in Stockholm and Umeå ................. 47 Table 40-Total final energy consumption for all cases in Stockholm and Umeå . 48 Table 41-Total final energy consumption in KWh/m2 for all cases in Stockholm and Umeå ............................................................................................................ 49 Table 42- Annual CO2 emissions for all cases in Stockholm and Umeå .............. 50 Table 43-Percentage of hours with thermal dissatisfaction Baseline Stockholm . 52

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Table 44-Percentage of hours with thermal dissatisfaction Variant A Stockholm 52 Table 45-Percentage of hours with thermal dissatisfaction Variant B Stockholm 52 Table 46-Percentage of hours with thermal dissatisfaction Variant C Stockholm52 Table 47-Percentage of hours with thermal dissatisfaction Baseline Umeå ........ 52 Table 48-Percentage of hours with thermal dissatisfaction Variant A Umeå ....... 52 Table 49-Percentage of hours with thermal dissatisfaction Variant B Umeå ....... 53 Table 50-Percentage of hours with thermal dissatisfaction Variant C Umeå ....... 53 Table 51- Summary of total occupant hours with thermal dissatisfaction ............ 53 Table 52-Material information Baseline ............................................................... 60 Table 53-thermal bridges Baseline ...................................................................... 60 Table 54-Windows characteristics Baseline ........................................................ 60 Table 55- AHU information Baseline ................................................................... 61 Table 56- Domestic hot water use Baseline ........................................................ 61 Table 57- Occupant schedules Baseline ............................................................. 61 Table 58-Lighting schedules Baseline ................................................................. 61 Table 59-Equipment schedules Baseline ............................................................ 61 Table 60-Temperature setpoints Baseline ........................................................... 61 Table 61- Material information Variant A ............................................................. 61 Table 62- thermal bridges Variant A .................................................................... 62 Table 63- Windows characteristics Variant A ...................................................... 62 Table 64- AHU information Variant A .................................................................. 62 Table 65-Domestic hot water use Variant A ........................................................ 62 Table 66-Occupant schedules Variant A ............................................................. 62 Table 67-Lighting schedules Variant A ................................................................ 62 Table 68-Equipment schedules Variant A ........................................................... 63 Table 69-Temperature setpoints Variant A .......................................................... 63 Table 70- Material information Variant B ............................................................. 63 Table 71- thermal bridges Variant B .................................................................... 63 Table 72- Windows characteristics Variant B ...................................................... 64 Table 73- AHU information Variant B .................................................................. 64 Table 74-Domestic hot water use Variant B ........................................................ 64 Table 75-Occupant schedules Variant B ............................................................. 64 Table 76-Lighting schedules Variant B ................................................................ 64 Table 77-Equipment schedules Variant B ........................................................... 64 Table 78-Temperature setpoints Variant B .......................................................... 64 Table 79- Material information Variant C ............................................................. 64 Table 80- thermal bridges Variant C .................................................................... 65 Table 81- Windows characteristics Variant C ...................................................... 65 Table 82- AHU information Variant C .................................................................. 65 Table 83-Domestic hot water use Variant C ........................................................ 65 Table 84-Occupant schedules Variant C ............................................................. 66 Table 85-Lighting schedules Variant C ................................................................ 66 Table 86-Equipment schedules Variant C ........................................................... 66 Table 87-Temperature setpoints Variant C .......................................................... 66

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1 Introduction A substantial amount of our time is spent indoors and with the recent global pandemic phenomena governments of many countries applied quarantine in order to protect their civilians from spreading the virus and risking the health of their community, forcing people to stay in their living spaces for a long period. This incident helps us realize that a good indoor environment is essential for maintaining a good health. Nevertheless, a majority of residents that live in Sweden, whose apartment buildings were built between 1961-1975 experienced problems related to thermal comfort such as cold air draughts, low indoor temperatures and undesirable indoor temperature variants [1]. Building sector has a share of 30% of the total energy use in EU, 64% out of this 30% is used for space heating. Low energy use and improvement of energy efficiency in the building sector is a central goal for the European Union as well as the rate of improved energy efficiency should be doubled by 2030[2]. Sweden has set a national goal of contributing no net GHG emissions by 2050 and a specified objective for improving energy performance by 50% by 2050 in Swedish building stock[3]. The majority of buildings in Sweden are older than 30 years old, making it clear that the greatest potential for lowering the energy use lies within the existing housing stock[4]. According to findings of several recent studies related to energy retrofitting of residential apartment buildings, most of them were built between 1950-1990 with significant energy saving potential in many European countries including Sweden. Multi-family buildings is Sweden have an average heat demand for space heating and DHW of 135kWh/m2year. At present the building regulation demands a maximum of 70 kWh/m2year for MFB in southern climate zones and 100 kWh/m2year for northern climate zones in Sweden [34]. Apartment buildings built during this era are now requiring major renovation and retrofitting measures in order to comply with the standards for a good indoor environment while at the same time minimizing the energy consumption [5]–[7]. Despite the urgent need for retrofitting expressed above, the retrofitting ratio in Sweden was 0.88% in 2013 so it was made clear that it must be enhanced in order to achieve the ambitious goal of zero GHG emissions by 2050[8]. Numerous studies regarding the already existing stock, energy efficient measures (EEM) and retrofit options have been conducted[4], [5], [9]–[12]. The amount of scientific knowledge and experience in the field of EEM and retrofitting on buildings located in the sub –Arctic regions of Sweden is still low, even though the most challenges occur in these regions. In this study a new patented retrofitting method is studied in order to find out the energy saving potentials in two different climate zones of Sweden, Stockholm and Umeå. Three insulation thicknesses were studied: 50mm, 80mm and 180mm in order to find the energy consumption and savings among these three insulation thicknesses. The retrofitting process includes window replacement with

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triple glazed low U-value and AHU replacement from Supply and exhaust to Heat Recovery Ventilation with 80% efficiency. 2 Literature Review Research on scientific articles that dealt with similar themes were compiled, studied and analyzed in this chapter helping the reader to understand the objectives that are studied in this thesis. For that reason this chapter is divided in two sections: 2.1 Retrofitting status in Sweden and 2.2 Mechanical ventilation system in Sweden. 2.1 Retrofitting status in Sweden This section contains some of the most important projects, surveys and studies, developed to investigate the effects of retrofitting in terms of energy performance and indoor environment before and after the studied retrofitting methods in a home environment within Sweden. La fleur et al.[10] investigates the energy use and thermal climate of a MFB in southern Sweden, before and after renovation. They found that under winter conditions the minimum operative temperature was increased by nearly 2°C after the renovation. After an extensive study in the thermal comfort, this study concluded that a higher degree of insulation and heated supply air results in a more stable internal environment during winter. The renovation of the studied buildings reveals a significant reduction in the annual energy use by 44%. Gustafsson et al.[13] presented economic and environmental analyses of energy renovation packages in MFB buildings. It was shown that the energy renovations result in lower Life Cycle Cost (LCC) and lower environmental impact. They found that the final energy cost was reduced by 70% in the Nordic climate and the total annualized costs over 30 years could be reduced by 11%. The studied renovations resulted in 79% lower climate change impact, 66% lower particulate matter and 76% lower water eutrophication. Ardente et al.[14] performed Life Cycle Analysis (LCA) on six MFB and found that insulation is the most environmentally beneficial renovation measure followed by new windows. Also looking at the assessment outcomes, the most significant benefits were related to improvement of the envelope thermal insulation. Finally, in all six buildings the renovation of Air Handling Unit AHU plants provided significant energy benefits. Liu et al.[15] studied eleven MFB that went through different energy retrofitting methods which had varying building characteristic and were spread through Gävleborg which is a sparsely populated forest region. This project has shown that the MFB in that region have the potential to reduce 50% their energy use by 2050 after installing extra wall insulation adjusting their heating systems and install Heat Recovery Ventilation HRV. Bonakdar et al.[5] studied the renovation measures of the building envelope in four different climate zones in Sweden, noting that the interaction between the efficiency measures of different

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components may alter the results of a study when the considered measures are combined. However, the energy efficiency measures that were taken into account in this study were limited to building envelope thermal improvement. Finally, they suggested that the renovations may need different approaches depending on the climate. Ferrara et al.[16] performed a profound literature review in renovation methods and found that the different techniques and heat-saving measures can be implied to most buildings regardless of their location. However, buildings located in cold climate are deeply influenced by the energy performance and indoor climate, so manual selection and optimization of the retrofitting solutions in different climate zones might give a more precise overview of the most beneficial solution. Wang and Holmberg [9] showed that retrofitting by adding insulation and changing the windows is profitable and almost in all cases cost-effective. Also that in the sub-arctic region of Sweden, retrofitting by adding insulation and windows is the most common and straight forward measurement. Gustafsson et al.[4] revealed that in a district heated MFB after applying energy saving retrofitting, it is possible to reduce the cost and the environmental impact. These measures can lead to 24% LCC reduction, 58% reduction in energy consumption compared with pre retrofitting conditions, 65% reduced CO2 emissions and finally 56%reduction in non renewable energy consumption. Noris et al.[17] developed a protocol for selecting packages of retrofits that save energy and improve the indoor environment quality. Examples of retrofits selected via this protocol include improvement of air tightness of the building envelope coupled with HRV system, thermal insulation of the building envelope and also the replacement of old windows with low U-value ones. Nik et al.[18] quantifies the energy saving potential and effectiveness of nine energy retrofitting measures and four combinations of these for MFB in Sweden and for five future climate scenarios. Among the retrofitting measure study, the improvement of thermal insulation of the building envelope and the replacement of the windows with new low U-value windows proved to be the most effective energy efficient retrofitting measure. Also, the indoor set-point temperature if set to 20°C contributes significantly in energy savings. It was made clear from the above researches that energy retrofitting can significantly improve the energy performance of an existing building decreasing the building’s carbon footprint while at the same time ensuring a good indoor environment for its occupants. 2.2 Mechanical ventilation system in Sweden Mechanical ventilation systems use electric fans to direct the airflow in the building. Mechanical ventilation can provide a constant air change rate independently of external weather conditions. There are several variations of mechanical ventilations. The two types of ventilation that are going to be studied are supply and exhaust air ventilation (before the retrofit) and Heat Recovery Ventilation (HRV) which is installed after the retrofitting process. HRV reuses the heat of the extract air that would otherwise be lost to heat the supply air that has the outdoor temperature, saving a lot of energy. In the following paragraph some

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scientific articles that provide the results of studies in energy retrofitting that focus on ventilation efficiency are going to be examined. Nimela et al.[6] found that significant cost saving improvements in energy performance and reduction of CO2 emissions can be achieved by investing in renewable energy production and HVAC systems, and not only on improving the thermal insulation building envelope. Finally, they concluded that during a renovation, if the ventilation system is altered, the indoor air quality of the building has to be considered also. Dodoo et al.[19] explored the primary energy implications of HRV in residential buildings and concluded that HRV can lead in significant energy savings in the Swedish climate. Also, the size of the savings in district heated houses depends on the energy mix of the local district heat production. The European TIP-Vent in Blomsterberg et al.[20] explored the impacts of the HRV systems on the energy performance of different types of buildings in several EU countries including Sweden. They found that HRV systems reduced the total energy for space heating by 20-50% depending on the building type and air tightness of the building envelope. There are several studies that also prove the importance of including the installation of an HRV system in an energy retrofit in order to achieve significant energy savings[10], [12], [14], [15], [17]. From the literature review we can see the importance of applying energy retrofitting methods in the current building stock. This indicates that there is a need to increase the understanding of the effects that an energy renovation will bring. What makes this research interesting is that this patented retrofitting method hasn’t been studied in the past and can bring significant results that can be useful for future studies and help create the sustainable buildings of the future. 3 Research materials This chapter represents the MFB that is going to be studied, which includes information about the building envelope, internal heat loads, HVAC system and the climate information of the zones that the building exists in. EQUA has developed IDA Indoor Climate and Energy (IDA ICE), which is a simulation software that through time became a useful program in the building industry for the simulation of indoor climate and energy consumption of buildings[21]. This simulation program gives us the ability to develop a model of a building that is similar with an already existing one that we want to study depending of course on how well the model is designed. The advantage that this feature of the program provides is that by creating a model of the studied building, all the building characteristics can be changed relatively easily making it possible to do several investigations on the energy performance of different elements within the building (e.g. different ventilation systems, insulation materials or envelope replacements). In this study, the reference building model

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was taken from residential building prototype from the USA Department of Energy (DOE) website, which is widely selected as a reference case in analyzing energy efficient relevant research questions [22].

Figure 1-Reference Building with dimensions[22] 3.1 Climate In this chapter information for the two climate zones are going to be presented.

3.1.1. Stockholm climate Stockholm has a humid continental climate. Although winters are cold, average temperatures generally remain above 0 °C for much of the year. Summers are mild, and precipitation occurs throughout the year. The average low temperature is -4°C and the average high is 24°C [23], [24], [25]. Figure 2 below shows the Min/Max temperature fluctuation in Stockholm, Figure 3 the mean temperature, Figure 4 the solar radiation, Figure 5 the wind speed and finally Figure 6 the wind direction.

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Figure 2-Daily maximum and minimum temperature profile [25]

Figure 3-Monthly mean temperature[25]

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Figure 4-Monthly total solar radiation profile[25]

Figure 5-Monthly wind speed

Figure 6-Monthly wind speed direction [25]

3.1.2. Umeå climate The climate of Umeå is bordering on a humid continental and a subarctic climate, with low winter temperatures and short and fairly warm summers. The average low temperature is -12°C and the average high temperature is 20°C [23], [24], [25]. Figure 7 below shows the Min/Max temperature fluctuation in Umeå, Figure 8 the mean temperature, Figure 9 the solar radiation, Figure 10 the wind speed and finally Figure 11 the wind direction.

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Figure 7-Daily maximum and minimum temperature profile [25]

Figure 8-Monthly mean temperature[25]

Figure 9-Monthly total solar radiation profile[25]

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Figure 10-Monthly wind speed [25]

Figure 11-Monthly wind speed direction [25] 3.2 Building model description Figure 12, Figure 13 illustrate the constructed Multi Family Building. It is a three-story building with a total floor area of 2897,4 m2 including the roof attic zone and the corridors. The building has two long facade surfaces directed to North and South directions and two shorter facade surfaces directed towards East and West direction. The windows of the building are equally sized and distributed (window/envelope= 17%). The zones that have surfaces in two different oriented facades have two windows while the zones that are situated between them have only one window. The attic zone has no windows. Finally the zones in every floor share the same dimensions with each other making every floor of the building construction identical.

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Figure 12-Multi Family Building model built up in IDA-ICE 4.8 Every floor in the building consists of six apartments with a corridor between them. Three apartments are facing North and three apartments are facing South. The entrance of the building is located in the East facade of the building.

Figure 13-Floor blueprint of the Multi Family Building Both Baseline and Variant cases of the building share the same construction but the Variant cases have extra materials added following the retrofitting process.

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3.2.1. Building Materials In this section information regarding the materials used in the constructed building is going to be presented. Since there are different studied cases with different materials, information for both the Baseline and the three different Variant cases are going to be provided.

3.2.2. Baseline case material information The materials that were used for the construction of the Baseline model were gathered from Velux energy and indoor climate visualizer program construction material panel [26], in an attempt to construct a building with materials used among the periods of 1950-1960. The building envelope has a significant impact in the overall building energy consumption and thermal comfort as it determines the building’s ability to resist the stress generated from the surrounding environment. The building envelope consists of cement with light insulation and double glazed windows. Parts of the building envelope that have poorer insulation and higher conduction losses called thermal bridges occur when elements of the construction are in contact with warm and cold parts (e.g. connection and junction). Thermal bridges in IDA ICE can be defined for each joint by a five-graded scale according to None, Good, Typical, Poor, and Very poor[27]. The Baseline case was set to ‘Poor value’ since the building envelope was built in the 60s. Due to the poor tightness of the building envelope the infiltration losses of the building were set to 6 ACH at 50Pa and a pressure coefficient defined as ‘sheltered’ since the building is assumed to be surrounded by other buildings within a city context. Table 1 gives an overview of the building elements for Baseline case. Table 1-Overview of Baseline building envelope Building component Description Value External wall Gypsum 26mm

l/w Concrete 200mm Mineral wool 50mm l/w Concrete 200mm

Uext.wall=0.23 W/m2k

Internal wall

Gypsum 26mm Air in 70mm vert. Air gap 7mm Gypsum 26mm

Uint.wall=1.707 W/m2k

Internal slab

Coating, l/w Concrete 20mm, Concrete 150mm

Uint.slab=2.38 W/m2k

External slab

Floor coating 5mm Concrete 145mm

Uext.slab=0.17 W/m2k

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Light insulation 200

Roof

Roof material 20mm Mineral wool 50mm Concrete medium Density150mm Plaster coating 10mm

URoof=0.59 W/m2k

Glazing

Double glazed

Uglazing=2.9 W/m2k

Thermal Bridges

‘Poor value’ for all joints

Infiltration Wind driven flow pressure is set to ‘Sheltered’

6 ACH at 50Pa [26]

The leakiness of the building is defined as the leakiness of a building pressurized at 50 Pa with the leakage equally distributed on the facades.

3.2.3. Variant cases material information The Variant cases are three, Variant A, Variant B and Variant C. Variant A has extra insulation on the outer surface of the building envelope which is mineral wool 50mm and plaster coating 10mm in order to provide air tightness and protect the extra insulation added from moisture and wind. 400mm of additional mineral wool insulation was added to the roof attic in the interior of the roof. The additional change in Variant B and Variant C in terms of envelope characteristics is extra insulation on the outer surface of the building envelope which is mineral wool 80mm and 180mm respectively. Table 2, Table 3, Table 4 give an overview of the building elements for Variant A-B-C cases. Table 2-Overview of Variant A building envelope Building component Description Value External wall Gypsum 26mm

l/w Concrete 200mm Mineral wool 50mm l/w Concrete 200mm Mineral wool 50mm Plaster coating 10mm


Internal wall



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Internal slab



Floor towards ground

Floor coating 5mm Concrete 145mm Light insulation 200

Ufloor towards ground =0.17 W/m2k

Roof

Mineral wool 400mm Roof material 20mm Mineral wool 50mm Concrete medium Density150mm Plaster coating 10mm

URoof=0.08 W/m2k

Glazing

Triple glazed

Uglazing=0.9 W/m2k

Thermal Bridges

‘Good value’ for all joints


0.5 ACH at 50Pa[26]

The leakiness of the building is defined as the leakiness of a building pressurized at 50 Pa with the leakage equally distributed on the facades. Table 3-Overview of Variant B building envelope Building component Description Value External wall Gypsum 26mm



Internal wall



Internal slab




Floor Coating 5mm Concrete 145mm Light insulation 200

Ufloor towards ground =0.17 W/m2k

Roof

Mineral wool 400mm

URoof=0.08 W/m2k

14

Roof material 20mm Mineral wool 50mm Concrete medium Density150mm Plaster coating 10mm

Glazing

Triple glazed

Uglazing=0.9 W/m2k

Thermal Bridges



0.5 ACH at 50Pa[26]

The leakiness of the building is defined as the leakiness of a building pressurized at 50 Pa with the leakage equally distributed on the facades. Table 4-Overview of Variant C building envelope Building component Description Value External wall Gypsum 26mm



Internal wall



Internal slab




Floor Coating 5mm Concrete 145mm Light insulation 200

U floor towards ground =0.17 W/m2k

Roof

Mineral wool 400mm Roof material 20mm Mineral wool 50mm Concrete medium Density150mm Plaster coating 10mm

URoof=0.08 W/m2k

Glazing

Triple glazed

Uglazing=0.9 W/m2k

15

Thermal Bridges



0.5 ACH at 50Pa[26]

The leakiness of the building is defined as the leakiness of a building pressurized at 50 Pa with the leakage equally distributed on the facades. 3.3 Internal heat loads Internal heat loads influence significantly the final results of heat load in a building; for this reason the internal gains of the studied building had to be taken into account. IDA ICE determines internal heat load in the building by analyzing three main sources which are lighting, equipment and occupancy. In order to determine the amount of internal gains from occupancy, the activity level and clothing had to be set within the program but also the number of occupants per zone so that the software can automatically distribute the occupants in the building. In this study the occupancy for every zone was set to 2.2 persons for all zones with activity level of 1 MET. The occupants were set to be present in the house from 17:00pm to 7:00am for the whole weekend including holidays. No occupants are present in the corridors and in the roof attic zone [28], [29]. Lighting system and electronic devices are also producing internal heat. The lighting system was set to 0.53 W/m2 and the equipment to 3.42 W/m2 and their schedules were set to follow the occupancy schedule 14 hours of presence. The corridors and the attic zones have no equipment but the corridors have lighting system of 0.36 W/m2. Table 5 shows a summary of the internal loads in the building and the schedules used. Table 5-Internal heat loads of the building and schedules Building component Description Value Occupant Number of persons per

zone 2.2 0.0197 person per m2 Activity level: 1 MET

Occupant schedule According to SVEBY 14 hours of presence

17:00pm - 7:00am in weekdays, weekends and holidays

Interior lighting Assumed 0.53 W/m2 60 W per unit

Interior lighting schedule According to SVEBY 14 hours of presence


Equipment

Assumed 3.42 W/m2

16

Equipment schedule According to SVEBY 14 hours of presence


3.4 Emissions and energy pricing The heating system of the building is district heating with an efficiency of 1 COP and a water storage tank for domestic hot water supply heated through district system with a volume of 36 m3. The prices for purchased energy, the primary energy factor and the CO2 emissions were set according to information gathered from Borlänge Energi website [30] for electricity and from esbo (default from program) for district heating. Figure 39, Figure 40 show the cost of the energy purchased while Figure 41, Figure 42 show the CO2 emissions for district heating and electricity production. These numbers were taken into account for the simulations considering that Sweden has on average the same energy production methods and charges for all the country. However changes in price and CO2 emissions might occur between different regions. No cooling system was installed in the building. 3.5 HVAC System In this study, the AHU system is different in Baseline and Variant cases since during the retrofitting procedure it is being replaced from a supply-exhaust (FT) to Heat Recovery Ventilation (FTX).

3.5.1. Baseline AHU

Figure 14- Baseline graph of AHU In Baseline case the AHU method of supply was set to Graph which means that the supply air is extracted directly from the outside having the temperature of the environment, the heat exchanger operation was set off and the efficiency of the

17

exchanger turned to 0 in order to deactivate the function in this case. Also the heating and cooling coils were set off to deactivate the auxiliary heating and cooling of the ventilation system. Finally, the supply and return air for CAV was set to 0.35 L/(s m2).

3.5.2. Variant AHU Configurations

Figure 15-Variant graph of AHU In Variant cases the AHU supply method was set to ‘constant’ supplying constant air temperature of 20°C. The reason behind this selection lies in two facts: 1) the ventilation system used is HRV which means that the air coming from the outside is mixed with inside air that has a higher temperature inside the heat exchanger rising the temperature of the supply air, 2) during the retrofitting, the supply air ducts are installed behind the radiators of the building which means that the air is warmed up for a second time by the radiators that have supply water temperature between 60-70 °C. The supply and return air for CAV was set to 0.35 L/(s m2), the exchanger efficiency was set to 0.8 (80%) and the heating and cooling coils were again set off. 4 Methodology In this study the heating load and the total energy consumption of the MFB described previously are going to be examined in IDA-ICE before and after a retrofitting including the AHU replacement with HRV in two different climate zones, Umeå and Stockholm. Also three different thicknesses of insulation are going to be studied in each climate zone to find their influence in the final results. After the simulations 8 different cases are going to be compared in terms of heating load and total energy consumption, shown in Table 6.

18

Table 6-Break down of total 8 simulated cases Case Location Description Construction

Material Baseline

Stockholm

no retrofitmeasures+FT

Table 1

Variant A

Renovation with Smart Front Op. 1+FTX

Table 2

Variant B


Table 3

Variant C


Table 4

Baseline

Umeå

no retrofitmeasures FT

Table 1

Variant A


Table 2

Variant B


Table 3

Variant C


Table 4

4.1.1. Retrofitting method description Smart Front method is a new patented retrofitting method that takes place in the outside of the house installing first a heat recovery ventilation system HRV (FTX) in the attic of the house with pipeline system that runs through the 180mm mineral wool insulation in the facade and ends behind the radiators. In addition, 400mm of insulation is applied in the attic and the facade is finished with a plaster layer that provides extra wind and moisture protection. The windows are also replaced in this retrofitting project with new low U-value windows that increase further the energy performance of the building envelope [31], shown in Figure 16.

19

Figure 16-Smart Front insulation overview[31]

4.1.2. Simulation strategy The simulation strategy in this study starts by gathering the information about the building characteristics for the simulated period, then continues by designing the building prototype within IDA-ICE 4.8. The MFB dimensions were taken from DOE USA, which is widely selected as a reference case in analyzing energy efficient relevant research questions [22]. The materials of the building were after inserted creating the different cases and the different climate files for two different climate zones. Also the lighting, equipment occupancy, thermal bridges, infiltration rates, emissions and costs were inserted in the program. Four different cases for every climate zone occurred that were simulated for heat load and energy consumption. For heating load simulation the DVUT was used which is the coldest day during a whole year in the simulated climate zone. Each case and climate zone had a different DVUT value which was gathered from Boverkets website and was created by SMHI [32]. 5,6,7and 8 number of days with mean air temperature DVUT value were chosen accordingly for Baseline, Variant A, Variant B and Variant C cases taking into account the building's inertia. Large heat inertia reduces the building's power requirements. Low inertia Baseline case has 5 days DVUT value and high inertia Variant C has 8 days DVUT value. Then the heat load and the energy consumption for each case were gathered, analyzed and compared leading to the final results of the study. The following chart in Figure 17 shows the simulation procedure followed in order to get the results of the study.

20

Figure 17-Working flow of this study

21

5 Results and analyzing In this chapter all the information gathered after running the simulations are going to be presented and analyzed. More specifically the heating load and the final energy consumption for every climate zone separately are going to be presented bellow. 5.1 Baseline case in Stockholm and Umeå

5.1.1. Heating load variations In Stockholm the coldest day through the whole year was 14 February, the total room unit heat was 65341.4 W [Maximal value of the heating power delivered to the zone by room units (both convective and radiative)]. The highest value of supplied room unit heat (excluding the corridors and the roof attic because these zones are unoccupied) was in zone N-W (4248 W). This zone is located in the bottom corner and has two windows, one faced North and one faced West and the lowest supply was observed in S-M1 (2689 W) which is the middle apartment on the second floor with South faced window as seen from the graph Figure 18. The reason why N-W zone has the highest room unit heat supply is because it has two exposed facade sides with windows that increase the U-value of the envelope further and the North faced side has decreased solar gains that contribute positively in the heating load of the building. On the other hand S-M1 has the lowest room unit heat supply because it is located in the second floor surrounded by other zones and the corridor, having only one exposed side that face South taking advantage of the positive solar gains.

Table 7- Baseline Stockholm Heating Load information Zone Zone

multiplier, M Time Room unit

heat, W Room unit

heat for multiplied zones, W

Temp., °C

S-W 1 14 Feb 18:05 4163 4163 21 S-M 1 14 Feb 18:05 3090 3090 21 S-E 1 14 Feb 18:05 4226 4226 21 N-W 1 14 Feb 18:05 4248 4248 21 N-M 1 14 Feb 18:05 3097 3097 21 N-E 1 14 Feb 18:05 4230 4230 21 Corridor 1 14 Feb 18:05 1160 1160 21 N-W1 2 14 Feb 18:05 3581 7162 21 N-M1 2 14 Feb 18:05 2693 5386 21 N-E1 2 14 Feb 18:05 3577 7154 21 Corridor1 2 14 Feb 18:05 885,7 1771,4 21 S-E1 2 14 Feb 18:05 3573 7146 21 S-M1 2 14 Feb 18:05 2689 5378 21 S-W1 2 14 Feb 18:05 3565 7130 21 Roof Attic 1 15 Feb 00:00 0 0 -13,86

22

Sum 65341,4

Figure 18- Room unit heat in W for Baseline Stockholm

In Umeå the coldest day through the whole year was February 14 and the total room unit heat was 82323 W .The highest and the lowest values of supplied unit heat were again observed in the same zones as in Stockholm N-W (5324 W) and S-M1 (3414 W) respectively. The explanation for these observations depends on the location and direction of the studied zones and is the same as in Stockholm case. In Figure 19 the room unit heat for each zone for Baseline Umeå is shown. Table 8-Baseline Umea Heating load information Zone Zone


heat, W Room unit

heat for multiplied zones, W

Temp., °C

S-W 1 14 Feb 17:00 5152 5152 21 S-M 1 14 Feb 17:00 3918 3918 21 S-E 1 14 Feb 17:00 5311 5311 21 N-W 1 14 Feb 17:00 5324 5324 21 N-M 1 14 Feb 17:00 3928 3928 21 N-E 1 14 Feb 17:00 5318 5318 21 Corridor 1 14 Feb 17:00 1428 1428 21 N-W1 2 14 Feb 17:00 4509 9018 21 N-M1 2 14 Feb 17:00 3419 6838 21 N-E1 2 14 Feb 17:00 4503 9006 21 Corridor1 2 14 Feb 17:00 1137 2274 21 S-E1 2 14 Feb 17:00 4497 8994 21 S-M1 2 14 Feb 17:00 3414 6828 21 S-W1 2 14 Feb 17:00 4493 8986 21 Roof Attic 1 15 Feb 00:00 0 0 -21,43

23

SUM 82323

Figure 19-Room unit heat in W for Baseline Umeå

5.1.2. Energy consumption In Stockholm Baseline case the most vulnerable Zones in terms of temperature are S-E with the lowest temperature observed and S-E1 with the highest temperature observed. These zones were more vulnerable compared to others due to the solar gains that they receive and their location in the MFB. In general, all the zones that had two sides facing outside had similar results making them more vulnerable to temperature fluctuations, shown in Table 9.

.

Table 9- Zone MIN-MAX temp baseline Stockholm Zone Min temp °C Max temp

°C S-W 18.88 31.98 S-M 20.21 30.11 S-E 18.85 32.04 N-W 18.89 29.6 N-M 20.48 28.09 N-E 19.07 29.4 Corridor 18.94 28.44 N-W1 19.77 30.62 N-M1 20.63 28.96 N-E1 20.38 30.35 Corridor1 20.15 29.42 S-E1 19.99 32.94 S-M1 20.39 30.98 S-W1 20.02 33.13

24

Roof Attic

-8.11 26.32

The total energy used for District Heating and Domestic Hot Water was 152687.9 KWh and 18229KWh respectively from Table 10. Also, Figure 20 shows the graph for monthly consumption in KWh for DH and DHW and the only month with no heating supplied is July. The total CO2 emissions are 4880kg and the annual cost for the purchased energy is 153358Kr. Prices for electric were gathered from Borlänge Energi website [30] but district heating was set to default which was ESBO district heating price 0,07 €/KWh that was converted afterwards to Swedish krona according to the exchanging rate during data analyses that was €/Kr=1/10, shown in Table 11. Table 10- District heating and Domestic hot water for Baseline Stockholm Month Zone heating

KWh Dom. hot water KWh

████ ████

1 29906.0 1544.0

2 25996.0 1445.0

3 20253.0 1544.0

4 10702.0 1494.0

5 3179.0 1544.0

6 850.0 1494.0

7 0.0 1544.0

8 57.9 1544.0

9 4379.0 1494.0

10 11997.0 1544.0

11 20131.0 1494.0

12 25237.0 1544.0

Total 152687.9 18229.0

25

Figure 20-Monthly consumption in KWh for DH and DHW in Baseline Stockholm Table 11-Delivered energy overview for Baseline Stockholm

Used energy Purchased energy Peak

demand Cost CO2 Primary energy

kWh kWh/m2 kWh kWh/m2 kW Kr Kr/m2 kg kg/m2 kWh kWh/m2

██ Lighting, facility 316 0.1 316 0.1 0.04 1663 0.6 13 0.0 506 0.2

██ HVAC aux 11610 4.0 11610 4.0 1.51 10744 3.7 464 0.2 18577 6.4

Total, Facility electric 11926 4.1 11926 4.1 12407 4,3 477 0.2 19083 6.6

██ District heating 171277 59.1 171277 59.1 69.94 119900 40,1 3426 1.2 171277 59.1

Total, Facility district 171277 59.1 171277 59.1 119900 40,1 3426 1.2 171277 59.1

██ Equipment, tenant 24432 8.4 24432 8.4 4.77 21051 7,3 977 0.3 39091 13.5

Total, Tenant electric 24432 8.4 24432 8.4 21051 7,3 977 0.3 39091 13.5

Grand total 207635 71.7 207635 71.7 153358 51,7 4880 1.7 229451 79.2

In Umeå case the most vulnerable rooms were N-E with the minimum temperature and S-W1with the maximum temperature. The reason behind these results is that N-E had the least solar heat gains because of its position and S-W1 had the highest solar gains. Both rooms had the same window area but N-E had also a side facing North, a fact that made the zone more susceptible to cold, as shown in Table 12. Table 12-Zone MIN-MAX temp. Baseline Umeå Zone Min temp °C Max temp °C

S-W 19.5 29.5 S-M 20.86 28.19

26

S-E 19.97 29.3 N-W 19.7 26.56 N-M 20.89 25.7 N-E 19.35 26.76 Corridor 18.77 26.06 N-W1 20.55 27.34 N-M1 21.01 26.3 N-E1 20.67 27.53 Corridor1 20.55 26.68 S-E1 20.82 29.93 S-M1 20.97 28.71 S-W1 20.62 30.56 Roof Attic -12.79 22.8 The total energy used for District Heating and Domestic Hot Water was 212150.6 KWh and 18229KWh respectively from Table 13. Also Figure 21 shows the graph for monthly consumption in KWh for DH and DHW and there isn’t a month with any heating supplied. The total CO2 emissions are 6075kg and the annual cost for the purchased energy is 195071 Kr as shown in Table 14.

Table 13-District heating and Domestic hot water for Baseline Umeå Month Zone

heating KWh

Dom. hot water KWh

████ ████

1 36235.0 1544.0

2 32126.0 1445.0

3 27450.0 1544.0

4 17330.0 1494.0

5 8623.0 1544.0

6 909.2 1494.0

7 7.4 1544.0

8 1292.0 1544.0

9 8459.0 1494.0

10 17123.0 1544.0

11 28234.0 1494.0

12 34362.0 1544.0

Total 212150.6 18229.0

27

Figure 21-Monthly consumption in KWh for DH and DHW in Baseline Umeå

Table 14- Delivered energy overview for Baseline Umeå





██ HVAC aux 11775 4.1 11775 4.1 1.66 10876 3.8 471 0.2 18840 6.5


██ District heating 230677 79.6 230677 79.6 99.72 161480 50,6 4614 1.6 230677 79.6

28

5.2 Variant A case in Stockholm and Umeå

5.2.1. Heating load variations In Variant A Stockholm after the retrofit the total room unit heat was 24284.9 W, the zone with the highest room unit heat was S-W with 1540 W and the zones with the lowest were N-M1and S-M1 with 1024 W according to Table 15. Figure 22 shows the room unit heat in W for each zone accordingly represented with colours from blue-low to red-high.

Table 15- Variant A Stockholm Heating load information Zone Zone


heat, W Room unit heat for M zones, W

Temp., °C

S-W 1 14 Feb 18:05 1540 1540 21 S-M 1 14 Feb 18:05 1154 1154 21 S-E 1 14 Feb 18:05 1500 1500 21 N-W 1 14 Feb 18:05 1499 1499 21 N-M 1 14 Feb 18:05 1156 1156 21 N-E 1 14 Feb 18:05 1499 1499 21 Corridor 1 14 Feb 18:05 479,3 479,3 21 N-W1 2 14 Feb 18:05 1329 2658 21 N-M1 2 14 Feb 18:05 1024 2048 21 N-E1 2 14 Feb 18:05 1329 2658 21 Corridor1 2 14 Feb 18:05 374,8 749,6 21 S-E1 2 14 Feb 18:05 1329 2658 21 S-M1 2 14 Feb 18:05 1024 2048 21 S-W1 2 14 Feb 18:05 1319 2638 21 Roof Attic 1 0 0 14,95 Sum 24284,9

Total, Facility district 230677 79.6 230677 79.6 161480 50,6 4614 1.6 230677 79.6

██ Equipment, tenant 24431 8.4 24431 8.4 4.77 21052 7.3 977 0.3 39090 13.5


Grand total 267199 92.2 267199 92.2 195071 62,2 6075 2.1 289113 99.8

29

Figure 22-Room unit heat in W for Variant A Stockholm In Variant A Umeå after the retrofit the total room unit heat was 36165.2 W, the zones with the highest room unit heat were N-W with 2185 W and the zones with the lowest were N-M1and S-M1 with 1578 W according to Table 16-Variant A Umeå Heating load informationTable 16. Figure 23 shows the room unit heat in W for each zone accordingly represented with colours from blue-low to red-high. Table 16-Variant A Umeå Heating load information Zone Zone



Temp., °C

S-W 1 14 Feb 17:00 2143 2143 21 S-M 1 14 Feb 17:00 1752 1752 21 S-E 1 14 Feb 17:00 2184 2184 21 N-W 1 14 Feb 17:00 2185 2185 21 N-M 1 14 Feb 17:00 1755 1755 21 N-E 1 14 Feb 17:00 2184 2184 21 Corridor 1 14 Feb 17:00 720,4 720,4 21 N-W1 2 14 Feb 17:00 1970 3940 21 N-M1 2 14 Feb 17:00 1578 3156 21 N-E1 2 14 Feb 17:00 1970 3940 21 Corridor1 2 14 Feb 17:00 592,9 1185,8 21 S-E1 2 14 Feb 17:00 1969 3938 21 S-M1 2 14 Feb 17:00 1578 3156 21 S-W1 2 14 Feb 17:00 1963 3926 21 Roof Attic 1 0 0 13,03 SUM 36165,2

30

Figure 23-Room unit heat in W for Variant A Umeå

5.2.2. Energy consumption In Stockholm case the most vulnerable rooms were N-M with the minimum temperature and S-W1with the maximum temperature. From Table 17 it can be clearly seen that the minimum temperatures of all heated zones are relatively similar, which shows that after the retrofitting, by increasing the insulation and replacing the windows a more stable indoor temperature was achieved between the different zones. In maximum temperatures though, a higher fluctuation is observed and this happens because no shading method was applied in the windows of the building, resulting in maximum acceptable values due to different solar heat gains among the zones. Table 17-Zone MIN-MAX temp. Variant A Stockholm Zone Min temp., °C Max temp., °C S-W 21,13 33,76 S-M 21,16 32,17 S-E 21,14 33,86 N-W 21,05 32,17 N-M 21,05 30,74 N-E 21,06 31,9 Corridor 20,88 31,03 N-W1 21,07 32,86 N-M1 21,06 31,33 N-E1 21,07 32,55 Corridor1 20,84 31,69 S-E1 21,14 34,48 S-M1 21,14 32,8 S-W1 21,13 34,63 Roof Attic 3,254 21,82 The total energy used for District Heating and Domestic Hot Water was 15798.8 KWh and 18229 KWh accordingly from Table 18. Also Figure 24 shows the

31

graph for monthly consumption in KWh for DH and DHW and it is clearly shown that after the retrofit from May till October no heating is required. The total CO2 emissions are 2106kg and the annual cost for the purchased energy is 56728 Kr from Table 19. Table 18- District heating and Domestic hot water for Variant A Stockholm Month Zone

heating KWh

Dom. hot water KWh

████ ████

1 5411.0 1544.0

2 3956.0 1445.0

3 1249.0 1544.0

4 11.8 1494.0

5 0.0 1544.0

6 0.0 1494.0

7 -0.0 1544.0

8 -0.0 1544.0

9 0.0 1494.0

10 0.0 1544.0

11 1547.0 1494.0

12 3624.0 1544.0

Total 15798.8 18229.0

Figure 24-Monthly consumption in KWh for DH and DHW in Variant A Stockholm

32

Table 19-Delivered energy overview for Variant A Stockholm





██ HVAC aux

10886 3.8 10886 3.8 1.27 10161 3.5 435 0.2 17417 6.0

Total, Facility electric

11202 3.9 11202 3.9 11824 4,1 448 0.2 17923 6.2

██ District heating 34065 11.8 34065 11.8 27.53 23850 8 681 0.2 34065 11.8

Total, Facility district

34065 11.8 34065 11.8 23850 8 681 0.2 34065 11.8


Total, Tenant electric

24433 8.4 24433 8.4 21054 7,3 977 0.3 39093 13.5

Grand total 69700 24.1 69700 24.1 56728 19,4 2106 0.7 91081 31.4

In Umeå case the most vulnerable rooms were N-M with the minimum temperature and S-W1with the maximum temperature. It is clearly seen again from Table 20 that after the retrofitting the minimum temperature among the different zones is relatively the same. On the other hand due to the lack of shading the maximum temperature fluctuates more.

Table 20-Zone MIN-MAX temp Variant A Umeå Zone Min temp., °C Max temp., °C S-W 21,58 32,2 S-M 21,56 30,86 S-E 21,58 32,18 N-W 21,58 30,45 N-M 21,55 29,42 N-E 21,58 30,55 Corridor 21,47 29,73 N-W1 21,56 30,92 N-M1 21,53 29,83 N-E1 21,56 31,03 Corridor1 21,44 30,25 S-E1 21,57 32,74 S-M1 21,54 31,34 S-W1 21,57 33,04

33

Roof Attic 0,1539 19,63

The total energy used for District Heating and Domestic Hot Water was 34571.6 KWh and 18229KWh accordingly from Table 21. Also Figure 25-Monthly consumption in KWh for DH and DHW in Variant A Figure 25 shows the graph for monthly consumption in KWh for DH and DHW and from May till September no heating is required after the retrofit. The total CO2 emissions are 2481kg and the annual cost for the purchased energy is 69855 Kr from Table 22.

Table 21-District heating and Domestic hot water for Variant A Umeå Month Zone heating Dom. hot

water

████ ████

1 9127.0 1544.0

2 7578.0 1445.0

3 3752.0 1544.0

4 363.7 1494.0

5 0.0 1544.0

6 0.0 1494.0

7 -0.0 1544.0

8 0.0 1544.0

9 0.0 1494.0

10 435.9 1544.0

11 5347.0 1494.0

12 7968.0 1544.0

Total 34571.6 18229.0

Figure 25-Monthly consumption in KWh for DH and DHW in Variant A Umeå

34

Table 22-Delivered energy overview for Variant A Umeå

5.3 Variant B case in Stockholm and Umeå

5.3.1. Heating load variations In Variant B Stockholm after the retrofit the total room unit heat was 23550.8 W, the zone with the highest room unit heat was S-W with 1497 W and the zones with the lowest were N-M1and S-M1 with 995 W according to Table 23-Variant B Stockholm Heating load informationTable 23. Figure 22 shows the room unit heat in W for each zone respectively represented with colours from blue-low to red-high.

Table 23-Variant B Stockholm Heating load information Zone Zone



Temp., °C

S-W 1 14 Feb 18:05 1497 1497 21 S-M 1 14 Feb 18:05 1125 1125 21 S-E 1 14 Feb 18:05 1456 1456 21 N-W 1 14 Feb 18:05 1455 1455 21 N-M 1 14 Feb 18:05 1128 1128 21 N-E 1 14 Feb 18:05 1456 1456 21 Corridor 1 14 Feb 18:05 468,4 468,4 21 N-W1 2 14 Feb 18:05 1285 2570 21 N-M1 2 14 Feb 18:05 995,1 1990,2 21

Used energy Purchased energy Peak demand Cost CO2 Primary energy



██ HVAC aux 10860 3.7 10860 3.7 1.31 10140 3.5 434 0.1 17376 6.0



Total, Facility district 52863 18.2 52863 18.2 37000 13 1057 0.4 52863 18.2



Grand total 88469 30.5 88469 30.5 69855 24,4 2481 0.9 109833 37.9

35

N-E1 2 14 Feb 18:05 1285 2570 21 Corridor1 2 14 Feb 18:05 362,8 725,6 21 S-E1 2 14 Feb 18:05 1285 2570 21 S-M1 2 14 Feb 18:05 994,8 1989,6 21 S-W1 2 14 Feb 18:05 1275 2550 21 Roof Attic 1 0 0 14,96 SUM 23550,8

Figure 26-Room unit heat in W for Variant B Stockholm In Variant B Umeå after the retrofit the total room unit heat was 34706.7 W, the zone with the highest room unit heat was N-E with 2100 W and the zones with the lowest were N-M1and S-M1 with 1516 W according to Table 24. Figure 27 shows the room unit heat in W for each zone accordingly represented with colours from blue-low to red-high.

Table 24-Variant B UmeåHeating load information Zone Zone



Temp., °C

S-W 1 14 Feb 17:00 2064 2064 21 S-M 1 14 Feb 17:00 1690 1690 21 S-E 1 14 Feb 17:00 2099 2099 21 N-W 1 14 Feb 17:00 2100 2100 21 N-M 1 14 Feb 17:00 1693 1693 21 N-E 1 14 Feb 17:00 2100 2100 21 Corridor 1 14 Feb 17:00 696,3 696,3 21 N-W1 2 14 Feb 17:00 1885 3770 21 N-M1 2 14 Feb 17:00 1516 3032 21 N-E1 2 14 Feb 17:00 1885 3770 21 Corridor1 2 14 Feb 17:00 568,2 1136,4 21

36

S-E1 2 14 Feb 17:00 1884 3768 21 S-M1 2 14 Feb 17:00 1516 3032 21 S-W1 2 14 Feb 17:00 1878 3756 21 Roof Attic 1 0 0 13,14 SUM 34706,7

Figure 27-Room unit heat in W for Variant B Umeå

5.3.2. Energy consumption In Stockholm case as seen from Table 25 the minimum temperatures of the zones are equal. This means that the extra insulation added reduced further the thermal losses resulting in a more homogenous temperature within the building envelope. Maximum temperature though again fluctuates more due to the absence of window shading. Table 25-Zone MIN-MAX temp Variant B Stockholm Zone Min temp.,

°C Max temp., °C

S-W 21,16 33,85 S-M 21,18 32,26 S-E 21,17 33,96 N-W 21,08 32,22 N-M 21,08 30,83 N-E 21,09 32,02 Corridor 20,91 31,13 N-W1 21,1 32,9 N-M1 21,08 31,41 N-E1 21,11 32,66 Corridor1 20,88 31,78

37

S-E1 21,17 34,58 S-M1 21,16 32,88 S-W1 21,16 34,72 Roof Attic 3,234 21,82 The total energy used for District Heating and Domestic Hot Water was 14575.6 KWh and 18229KWh accordingly from Table 26. Also Figure 28 shows the graph for monthly consumption in KWh for DH and DHW and from April that has only 2.6 KWh of DH consumption till October the building does not require heating power. The total CO2 emissions are 2081kg and the annual cost for the purchased energy is 55834 Kr from Table 27. Table 26- District heating and Domestic hot water for Variant B Stockholm Month Zone

heating KWh

Dom. hot water KWh

████ ████

1 5112.0 1544.0

2 3694.0 1445.0

3 1104.0 1544.0

4 2.6 1494.0

5 0.0 1544.0

6 0.0 1494.0

7 -0.0 1544.0

8 -0.0 1544.0

9 0.0 1494.0

10 0.0 1544.0

11 1308.0 1494.0

12 3355.0 1544.0

Total 14575.6 18229.0

38

Figure 28- Monthly consumption in KWh for DH and DHW in Variant B Stockholm Table 27-Delivered energy overview for Variant B Stockholm





██ HVAC aux 10883 3.8 10883 3.8 1.27 10159 3.5 435 0.2 17413 6.0






Grand total 68438 23.6 68438 23.6 55834 19,4 2081 0.7 89818 31.0

In Umeå case as seen from Table 28 the minimum temperatures of the zones are equal. This means that the extra insulation added reduced further the thermal losses resulting in a more homogenous temperature within the building envelope. Maximum temperature though again fluctuates more due to the absence of window shading.

Table 28- Zone MIN-MAX temp Variant B Umeå

39

Zone Min temp., °C Max temp., °C S-W 21,59 32,31 S-M 21,56 30,96 S-E 21,59 32,29 N-W 21,58 30,54 N-M 21,55 29,5 N-E 21,58 30,62 Corridor 21,48 29,83 N-W1 21,57 31,01 N-M1 21,54 29,91 N-E1 21,57 31,1 Corridor1 21,45 30,34 S-E1 21,57 32,87 S-M1 21,55 31,43 S-W1 21,58 33,15 Roof Attic 0,1307 19,62 The total energy used for District Heating and Domestic Hot Water was 32750.8 KWh and 18229KWh accordingly from Table 29. Also Figure 29 shows the graph for monthly consumption in KWh for DH and DHW showing that from May till September no heating power is required to maintain the required indoor temperature. The total CO2 emissions are 2445kg and the annual cost for the purchased energy is 68587 Kr from Table 30. Table 29-District heating and Domestic hot water for Variant B Umeå Month Zone

heating KWh

Dom. hot water KWh

████ ████

1 8779.0 1544.0

2 7264.0 1445.0

3 3466.0 1544.0

4 281.7 1494.0

5 0.0 1544.0

6 0.0 1494.0

7 -0.0 1544.0

8 -0.0 1544.0

9 0.0 1494.0

10 300.1 1544.0

11 5026.0 1494.0

12 7634.0 1544.0

Total 32750.8 18229.0

40

Figure 29-Monthly consumption in KWh for DH and DHW in Variant B Umeå Table 30-Delivered energy overview for Variant B Umeå





██ HVAC aux 10856 3.7 10856 3.7 1.3 10138 3.5 434 0.1 17370 6.0






Grand total 86649 29.9 86649 29.9 68587 23,4 2445 0.8 108013 37.3

5.4 Variant C case in Stockholm and Umeå

5.4.1. Heating load variations In Variant C Stockholm after the retrofit the total room unit heat was 21916.3 W, the zone with the highest room unit heat was S-W with 1400 W and the zones with the lowest were N-M1and S-M1 with 929 W according to Table 31. Figure 30

41

shows the room unit heat in W for each zone respectively represented with colours from blue-low to red-high.

Table 31-Variant C Stockholm Heating load information Zone Zone



Temp., °C

S-W 1 14 Feb 18:05 1400 1400 21 S-M 1 14 Feb 18:05 1061 1061 21 S-E 1 14 Feb 18:05 1359 1359 21 N-W 1 14 Feb 18:05 1359 1359 21 N-M 1 14 Feb 18:05 1063 1063 21 N-E 1 14 Feb 18:05 1359 1359 21 Corridor 1 14 Feb 18:05 443,5 443,5 21 N-W1 2 14 Feb 18:05 1188 2376 21 N-M1 2 14 Feb 18:05 929,3 1858,6 21 N-E1 2 14 Feb 18:05 1188 2376 21 Corridor1 2 14 Feb 18:05 335,7 671,4 21 S-E1 2 14 Feb 18:05 1188 2376 21 S-M1 2 14 Feb 18:05 928,9 1857,8 21 S-W1 2 14 Feb 18:05 1178 2356 21 Roof Attic 1 0 0 15,01 SUM 21916,3

Figure 30-Room unit heat in W for Variant C Stockholm In Variant C Umeå after the retrofit the total room unit heat was 33206.3 W, the zone with the highest room unit heat was S-W with 1973 W and the zones with the lowest were N-M1and S-M1 with 1459 W according to Table 32. Figure 31-Room unit heat in W for Variant C Figure 31 shows the room unit heat in W for each zone accordingly represented with colours from blue-low to red-high.

Table 32-Variant C Umeå Heating load information

42

Zone Zone multiplier, M

Time Room unit heat, W

Room unit heat for M zones, W

Temp., °C

S-W 1 14 Feb 17:00 1973 1973 21 S-M 1 14 Feb 17:00 1637 1637 21 S-E 1 14 Feb 17:00 2010 2010 21 N-W 1 14 Feb 17:00 2011 2011 21 N-M 1 14 Feb 17:00 1639 1639 21 N-E 1 14 Feb 17:00 2011 2011 21 Corridor 1 14 Feb 17:00 676,3 676,3 21 N-W1 2 14 Feb 17:00 1792 3584 21 N-M1 2 14 Feb 17:00 1460 2920 21 N-E1 2 14 Feb 17:00 1792 3584 21 Corridor1 2 14 Feb 17:00 545,5 1091 21 S-E1 2 14 Feb 17:00 1791 3582 21 S-M1 2 14 Feb 17:00 1459 2918 21 S-W1 2 14 Feb 17:00 1785 3570 21 Roof Attic 1 0 0 13,1 33206,3

Figure 31-Room unit heat in W for Variant C Umeå

5.4.2. Energy consumption In Stockholm case as seen from Table 33 the minimum temperatures of the zones are equal. This means that the extra insulation added reduced further the thermal losses resulting in a more homogenous temperature within the building envelope. Maximum temperature though again fluctuates more due to the absence of window shading.

Table 33-Zone MIN-MAX temp Variant C Stockholm Zone Min temp, °C Max temp, °C

43

S-W 21,21 34,05 S-M 21,22 32,45 S-E 21,22 34,16 N-W 21,14 32,46 N-M 21,13 31,03 N-E 21,15 32,21 Corridor 20,96 31,33 N-W1 21,16 33,14 N-M1 21,13 31,61 N-E1 21,16 32,84 Corridor1 20,95 31,99 S-E1 21,22 34,78 S-M1 21,2 33,07 S-W1 21,21 34,92 Roof Attic 3,193 21,82

The total energy used for District Heating and Domestic Hot Water was 12108 KWh and 18229KWh accordingly from Table 34. Also Figure 32 shows the graph for monthly consumption in KWh for DH and DHW and again in Variant C no heating power is required from April till October. The total CO2 emissions are 2029kg and the annual cost for the purchased energy is 53999Kr from Table 35.

Table 34-District heating and Domestic hot water for Variant C Stockholm Month Zone

heating Dom. hot water

████ ████

1 4487.0 1544.0

2 3158.0 1445.0

3 849.0 1544.0

4 0.0 1494.0

5 0.0 1544.0

6 0.0 1494.0

7 -0.0 1544.0

8 -0.0 1544.0

9 0.0 1494.0

10 0.0 1544.0

11 821.0 1494.0

12 2793.0 1544.0

Total 12108.0 18229.0

44

Figure 32-Monthly consumption in KWh for DH and DHW in Variant C Stockholm Table 35-Delivered energy overview for Variant C Stockholm





██ HVAC aux 10878 3.8 10878 3.8 1.27 10155 3.5 435 0.2 17405 6.0






Grand total 65809 22.7 65809 22.7 53999 18,4 2029 0.7 87184 30.1

In Umeå case as seen from Table 36 the minimum temperatures of the zones are equal. This means that the extra insulation added reduced further the thermal losses resulting in a more homogenous temperature within the building envelope. Maximum temperature though again fluctuates more due to the absence of window shading.

Table 36- Zone MIN-MAX temp Variant C Umeå

45

Zone Min temp., °C Max temp., °C

S-W 21,6 32,57 S-M 21,57 31,18 S-E 21,6 32,58 N-W 21,59 30,82 N-M 21,56 29,76 N-E 21,59 30,9 Corridor 21,49 30,09 N-W1 21,58 31,28 N-M1 21,54 30,17 N-E1 21,58 31,39 Corridor1 21,46 30,6 S-E1 21,58 33,16 S-M1 21,55 31,66 S-W1 21,59 33,41 Roof Attic 0,07864 19,63 The total energy used for District Heating and Domestic Hot Water was 29076.5 KWh and 18229KWh accordingly from Table 37. Also Figure 33 shows the graph for monthly consumption in KWh for DH and DHW showing that April has only 137 KWh of heating power while from May till September the consumption is zero and October has 85KWh. The total CO2 emissions are 2371kg and the annual cost for the purchased energy is 66009 Kr from Table 38.

Table 37-District heating and Domestic hot water for Variant C Umeå Month Zone

heating Dom. hot water

████ ████

1 8060.0 1544.0

2 6624.0 1445.0

3 2893.0 1544.0

4 137.8 1494.0

5 0.0 1544.0

6 0.0 1494.0

7 -0.0 1544.0

8 -0.0 1544.0

9 0.0 1494.0

10 85.7 1544.0

11 4333.0 1494.0

12 6943.0 1544.0

Total 29076.5 18229.0

46

Figure 33-Monthly consumption in KWh for DH and DHW in Variant C Umeå Table 38-Delivered energy overview for Variant C Umeå





██ HVAC aux 10850 3.7 10850 3.7 1.3 10132 3.5 434 0.1 17360 6.0






Grand total 82968 28.6 82968 28.6 66009 22,4 2371 0.8 104328 36.0

5.5 Summary of all cases In this chapter an overview of the final results is presented in order to compare the cases and find the differences in heating demand, energy consumption and CO2 emissions before and after retrofitting but also among the different insulation thicknesses.

47

5.5.1. Total heat supplied From Table 39 after the retrofitting from Baseline to Variant A a 62.8% reduction in heat supplied is observed for Stockholm and 56.1% for Umeå, from Baseline to Variant B 63.9% and 57.8% reduction and from Baseline to Variant C 66.4% and 59.6% heat supply reduction for each climate zone respectively. Also from graph in Figure 34 it is clearly shown that the overall heat supply reduction is almost 2/3 compared with the Baseline case for all Variants and for both climate zones. Finally it is worth to be mentioned that no adjustment was made to the heating system after the renovation. There are energy savings from reduced use of water pumps due to significant reduction in water supply to the radiators after the retrofitting but a heating system study and adjustment after the retrofitting can significantly improve its overall performance according to Lundqvist et al.[33] Table 39- Total room unit heat for all cases in Stockholm and Umeå

Room unit heat (kW) Stockholm Umeå Stockholm Umeå

Room unit heat kW Room unit heat kW

% reduction % reduction

Baseline 65,3 82,3 - - Variant A

24,2 36,1 62,8 56,1

Variant B

23,5 34,7 63,9 57,8

Variant C

21,9 33,2 66,4 59,6

Figure 34-Graph presenting the total heat supplied in all cases Stockholm and Umeå

0

10

20

30

40

50

60

70

80

90

Baseline Variant A Variant B Variant C

Room unit heat (kW)

Stockholm

Umeå

48

5.5.2. Total final energy consumption In Table 40 a higher reduction in total final energy consumption is presented showing that from Baseline to Variant A a 66.4% and 66.8% reduction in energy consumption for Stockholm and for Umeå, from Baseline to Variant B 67% and 67.5% and from Baseline to Variant C 68.3% and 68.9%. In addition, from graph in Figure 35 it is clearly shown that the overall energy reduction is almost 2/3 compared with the Baseline case for all Variants and for both climate zones and in some cases it exceeds 2/3 proving that the efficiency of this retrofitting method has better outcomes than expected. Table 41 and Figure 36 show the energy consumption per m2. Table 40-Total final energy consumption for all cases in Stockholm and Umeå

Total final energy consumption

Stockholm Umeå Stockholm Umeå KWh KWh % reduction % reduction

Baseline 207635 267199 - - Variant A 69700 88469 66,4 66,8 Variant B 68438 86649 67,0 67,5 Variant C 65809 82968 68,3 68,9

Figure 35-Graph presenting the total final energy consumption in all cases Stockholm and Umeå

0

50000

100000

150000

200000

250000

300000


Energy consumption (kWh)

Stockholm

Umeå

49

Table 41-Total final energy consumption in KWh/m2 for all cases in Stockholm and Umeå

Total final energy consumption

Stockholm Umeå

KWh/m2 KWh/m2

Baseline 71,7 92,2

Variant A 24,1 30,5

Variant B 23,6 29,9

Variant C 22,7 28,6

Figure 36-Graph presenting the total final energy consumption in KWh/m2 for all cases Stockholm and Umeå

5.5.3. Annual CO2 emissions In Table 42 the reduction annual CO2 emissions is presented showing that from Baseline to Variant A a 56.8% and 59.1% reduction for Stockholm and for Umeå, from Baseline to Variant B 57.4% and 59.7% and from Baseline to Variant C 58.4% and 60.9%. In Figure 37 Graph this 60% on average reduction in CO2 is presented.

0

10

20

30

40

50

60

70

80

90

100


Energy consumption (kWh/m2 )

Stockholm

Umeå

50

Table 42- Annual CO2 emissions for all cases in Stockholm and Umeå Annual CO2 emissions

Stockholm Umeå Stockholm Umeå Kg Kg % reduction % reduction

Baseline 4880 6075 - - Variant A 2106 2481 56,8 59,1 Variant B 2081 2445 57,4 59,7 Variant C 2029 2371 58,4 60,9

Figure 37-Graph presenting the annual CO2 emissions for all cases in Stockholm and Umeå 6 Limitations The average energy consumption of a MFB built in the 50s is 157 kWh/m2year. At present the building regulation demands a maximum of 70 kWh/m2year for MFB in southern climate zones and 100 kWh/m2year for northern climate zones in Sweden [34]. The baseline cases chosen for this study has 71.7 and 92.2 kWh/m2 for Stockholm and Umeå accordingly. Stockholm is slightly above the recommendations and Umeå is 8 kWh/m2 bellow the maximum energy consumption for MFB making the studied cases energy-efficient buildings before the energy retrofit. Domestic hot water consumption for a MFB according to SVEBY is 25 kWh/m2 and electricity consumption 30 kWh/m2 and from this amount 70% stands for equipment and 30% for lighting, 21 kWh/m2 and 9 kWh/m2 accordingly. The occupancy for a MFB apartment with four rooms and a kitchen according to

0

1000

2000

3000

4000

5000

6000

7000


CO2 emissions

Stockholm

Umeå

51

SVEBY is 3.06 persons/apartment. The default program settings that were chosen for this study were 6.2 kWh/m2 for DHW, 0.1 kWh/m2 for lighting, 8.4 kWh/m2 for equipment and 2.2 persons/apartment. The chosen values are bellow the recommended values set by SVEBY influencing the final results. Even though a cost calculation for energy supply was conducted by the program after inserting the price of DH and DHW, it needs to be mentioned that in Sweden the price for energy is covered by the rent fee. Finally the solar heat loads of the building are maximized due to the absence of window shading during the simulation process. 7 Conclusion and Future work Concluding, after running the simulations, gathering the data and analyzing them as shown in the previous chapter the total room unit heat supply reduction is 66.4% for Stockholm and 59.6% for Umeå from Baseline to Variant C, 68% and 69% total energy consumption reduction for Stockholm and Umeå and finally 58% and 61% reduction in CO2 emissions for Stockholm and Umeå respectively. The difference in room unit heat, energy and CO2 emissions among the Variant cases varies between 1-2%. The explanation for such a small difference lies in the fact that the only difference among these cases is the insulation thickness, from Variant A to Variant B 3cm thickness increase and from Variant B to Variant C 10cm of additional insulation. These results show that a further increase of insulation, even though it might further increase the thermal insulation of the building envelope and provide extra air tightness, the reduction in energy consumption, room unit heat and CO2 emissions will be only 1-2%. Finally, the retrofitting method study proved to be very efficient since it had higher energy reduction than the one set by the Swedish government for 2050. Even though the baseline case chosen for this study is already an energy-efficient case the results of the study show more than 50% reduction in energy consumption after the retrofitting process proving that the method is highly efficient and that it would cause even higher reductions in a poorly insulated 1950s MFB with U-value=0.79 kWh/m2 °C. 7.1 Feasibility results

7.1.1. Thermal comfort study In this chapter the thermal comfort of the building is going to be studied after analyzing the tables of temperature dissatisfaction for every different case and climate zone. Table 43, Table 44, Table 45, Table 46 show the percentage of hours with thermal dissatisfaction in Stockholm. Table 47, Table 48, Table 49, Table 50 show the percentage of hours with thermal dissatisfaction in Umeå.

52

Finally Table 51 shows the summarised total occupant hours with thermal dissatisfaction. Table 43-Percentage of hours with thermal dissatisfaction Baseline Stockholm Percentage of hours when operative temperature is above 27°C in worst zone

12%

Percentage of hours when operative temperature is above 27°C in average zone

6%

Percentage of total occupant hours with thermal dissatisfaction 13% Table 44-Percentage of hours with thermal dissatisfaction Variant A Stockholm Percentage of hours when operative temperature is above 27°C in worst zone

44%


37%

Percentage of total occupant hours with thermal dissatisfaction 19% Table 45-Percentage of hours with thermal dissatisfaction Variant B Stockholm Percentage of hours when operative temperature is above 27°C in worst zone

45%


38%

Percentage of total occupant hours with thermal dissatisfaction 20% Table 46-Percentage of hours with thermal dissatisfaction Variant C Stockholm Percentage of hours when operative temperature is above 27°C in worst zone

47%


40%

Percentage of total occupant hours with thermal dissatisfaction 21% Table 47-Percentage of hours with thermal dissatisfaction Baseline Umeå Percentage of hours when operative temperature is above 27°C in worst zone

6%


2%

Percentage of total occupant hours with thermal dissatisfaction 13% Table 48-Percentage of hours with thermal dissatisfaction Variant A Umeå Percentage of hours when operative temperature is above 27°C in worst zone

33%


28%

Percentage of total occupant hours with thermal dissatisfaction 17%

53

Table 49-Percentage of hours with thermal dissatisfaction Variant B Umeå Percentage of hours when operative temperature is above 27°C in worst zone

34%


29%

Percentage of total occupant hours with thermal dissatisfaction 17% Table 50-Percentage of hours with thermal dissatisfaction Variant C Umeå Percentage of hours when operative temperature is above 27°C in worst zone

36%


31%

Percentage of total occupant hours with thermal dissatisfaction 18% Table 51- Summary of total occupant hours with thermal dissatisfaction

Percentage of total occupant hours with thermal dissatisfaction

Stockholm Umeå

Baseline 13% 13%

Variant A 19% 17%

Variant B 20% 17%

Variant C 21% 18%

Figure 38-Graph showing the percentage of total occupant hours with thermal dissatisfaction for Stockholm and Umeå From the above tables it is clearly seen that the overall dissatisfaction increased in both climate zones and for all variants. This happened because by increasing

0%

5%

10%

15%

20%

25%


Percentage of totaloccupant hours withthermal dissatisfactionStockholm

Percentage of totaloccupant hours withthermal dissatisfactionUmeå

54

the insulation the overheating of the building during the summer months increased due to the increased solar heat gains. It should be mentioned although here that the windows of the building during the simulation had no shading devices and the windows were set to “always closed” which means that the building could not be cross ventilated to drop the indoor temperature.

7.1.2. Operational suggestion After the retrofit the heating load of the building was reduced drastically in both climate zones that the building was simulated. The reduction of heat load reduced also the operation of the water pumps that supply radiators saving some energy. However, with a readjustment of the heating system after the retrofitting even higher heat load savings can be achieved. Despite the high heat load reduction and the energy savings the drawbacks of this retrofit were higher levels of dissatisfaction of the occupants. That happened because windows were simulated with no shading devices and the windows were always closed which led to maximum solar heat gains and no natural ventilation. Installing external shading devices and putting schedules for opening the windows for cross ventilation during summer months are two suggested passive measures that can prevent the overheating of the building and ensure good thermal comfort for the occupants.

7.1.3. Environmental impacts As mentioned before, the reduction in CO2 emissions was 60% on average in both cases after applying the retrofitting method. This study has shown a huge reduction in emissions which complies with the Swedish government goals for GHG emissions by 2050. Concluding, this retrofitting method is strongly suggested in order to reduce the emissions of the building sector to the environment. 7.2 Future works As mentioned before, in this study no shading for widows was taken into account maximizing the solar heat gains and creating overheating of the interior of the building during summer months. Also as the windows were set always closed with no opening schedule the building could not be naturally ventilated to decrease the indoor temperature. It would be very interesting in the future to conduct a solar heat gain study of the building and apply external shadings and natural ventilation schedules to drop the indoor temperature. By doing this we can investigate the energy savings and the thermal comfort after the application of these two passive measures.

Another study that can be conducted in the future is the optimization and adjustment of the heating system after the retrofit in order to further reduce the heating load during winter months and make the heating system more efficient saving even more energy.

55

LCC & LCA studies can also be done in the future to assess the environmental impact of the product and the overall cost, including the maintenance costs through its lifetime. Finally a payback period calculation of the whole retrofit project can be calculated in order to make this retrofitting method more attractive to the customers. 8 References [1] A. Zalejska-Jonsson and M. Wilhelmsson, “Impact of perceived indoor

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[17] F. Noris, W. W. Delp, K. Vermeer, G. Adamkiewicz, B. C. Singer, and W. J. Fisk, “Protocol for maximizing energy savings and indoor environmental quality improvements when retrofitting apartments,” Energy Build., vol. 61, pp. 378–386, Jun. 2013, doi: 10.1016/j.enbuild.2013.02.046.

[18] V. M. Nik, E. Mata, A. Sasic Kalagasidis, and J.-L. Scartezzini, “Effective and robust energy retrofitting measures for future climatic conditions—Reduced heating demand of Swedish households,” Energy Build., vol. 121, pp. 176–187, Jun. 2016, doi: 10.1016/j.enbuild.2016.03.044.

[19] A. Dodoo, L. Gustavsson, and R. Sathre, “Primary energy implications of ventilation heat recovery in residential buildings,” Energy Build., vol. 43, no. 7, pp. 1566–1572, Jul. 2011, doi: 10.1016/j.enbuild.2011.02.019.

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[28] “Boverket´s mandatory provisions and general recommendations, BBR, BFS 2011:6 with amendments up to BFS 2018:4,” p. 154.

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[32] “Öppna data - Dimensionerande vinterutetemperatur (DVUT 1981-2010) för 310 orter i Sverige,” Boverket. https://www.boverket.se/sv/om-boverket/publicerat-av-boverket/oppna-data/dimensionerande-vinterutetemperatur-dvut-1981-2010/ (accessed Jun. 02, 2020).

[33] P. Lundqvist, M. Risberg, and L. Westerlund, “The importance of adjusting the heating system after an energy-retrofit of buildings in a sub-Arctic climate,” Energy Build., vol. 217, p. 109969, Jun. 2020, doi: 10.1016/j.enbuild.2020.109969. [34] K. Haugbølle and D. Boyd, Clients and Users in Construction: Agency,

Governance and Innovation. Taylor & Francis, 2017.

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Appendixes

Figure 39- Electricity pricing from Borlänge Energi

Figure 40-District heating price from esbo

59

Figure 41- CO2 emissions from district heating esbo

Figure 42- CO2 emissions from district heating Borlänge Energi

60

8.1 Different cases information

8.1.1. Baseline Wind driven infiltration airflow rate 11909.869 l/s at 50.000 Pa

Table 52-Material information Baseline

Building envelope Area [m2] U [W/(m2 K)] U*A [W/K] % of total Walls above ground 853.32 0.27 228.71 14.62

Broof 83.05 0.60 49.81 3.19 BWext1 770.27 0.23 178.90 11.44

Walls below ground 0.00 0.00 0.00 0.00 Roof 788.99 0.60 473.20 30.25 Broof 788.99 0.60 473.20 30.25

Floor towards ground 737.64 0.09 62.90 4.02 My slab 737.64 0.09 62.90 4.02

Floor towards amb. air 0.00 0.00 0.00 0.00 Windows 164.70 2.94 485.04 31.01

2 pane, clear, 4-12-4 (example) 164.70 2.94 485.04 31.01 Doors 1.60 1.01 1.61 0.10

External door U<1.3 1.60 1.00 1.61 0.10 Thermal bridges 312.61 19.99

Total 2546.24 0.61 1564.07 100.00

Table 53-thermal bridges Baseline Thermal bridges Area or Length Avg. Heat conductivity Total [W/K]

External wall / internal slab 603.24 m 0.066 W/(m K) 39.633 External wall / internal wall 124.80 m 0.066 W/(m K) 8.199 External wall / external wall 31.20 m 0.200 W/(m K) 6.240 External windows perimeter 343.20 m 0.400 W/(m K) 137.280

External doors perimeter 5.60 m 0.400 W/(m K) 2.240 Roof / external walls 88.67 m 0.400 W/(m K) 35.468

External slab / external walls 112.72 m 0.700 W/(m K) 78.904 Balcony floor / external walls 0.00 m 0.000 W/(K m) 0.000 External slab / Internal walls 0.00 m 0.000 W/(K m) 0.000

Roof / Internal walls 73.08 m 0.064 W/(m K) 4.641 External walls, inner corner 0.00 m 0.000 W/(K m) 0.000

Roof / external walls, inner corner 0.00 m 0.000 W/(K m) 0.000 External slab / external walls, inner corner 0.00 m 0.000 W/(K m) 0.000

Total envelope (incl. roof and ground) 2469.90 m2 0.000 W/(m2 K) 0.000 Extra losses - - 0.004

Sum - - 312.609

Table 54-Windows characteristics Baseline Windows Area [m2] U Glass [W/(m2

K)] U Frame [W/(m2 K)] U Total [W/(m2 K)] U*A [W/K] Shading factor g

N 49.41 3.05 2.00 2.94 145.51 0.77 E 32.94 3.05 2.00 2.94 97.01 0.77 S 49.41 3.05 2.00 2.94 145.51 0.77 W 32.94 3.05 2.00 2.94 97.01 0.77

Total 164.70 3.05 2.00 2.94 485.04 0.77

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Table 55- AHU information Baseline Air

handling unit

Pressure head supply/exhaust [Pa/Pa]

Fan efficiency supply/exhaust [-/-]

System SFP [kW/(m3/s)]

Heat exchanger temp. ratio/min exhaust temp. [-

/C] AHU 600.00/400.00 0.60/0.60 1.00/0.67 0.00/1.00

Table 56- Domestic hot water use Baseline

DHW use kWh/m2 floor area and year Total, [l/s] 2.000 0.003

Table 57- Occupant schedules Baseline Occupant schedules in zones

Schedule name Percentage of zones with this schedule (% of total zone area). Personer bostad 100.00

Table 58-Lighting schedules Baseline Lighting schedules in zones

Schedule name Percentage of zones with this schedule (% of total zone area). ALWAYS_ON 7.57

Personer bostad 92.43

Table 59-Equipment schedules Baseline Equipment schedules in zones


Table 60-Temperature setpoints Baseline Controller setpoints in zones

Setpoints Max/Min Percentage of zones with these setpoints (% of total zone area). 25.00/21.00 69.33 24.00/21.00 30.67

8.1.2. Variant A

Wind driven infiltration airflow rate 992.642 l/s at 50.000 Pa

Table 61- Material information Variant A


Dalarnas Villa Roof-vertical 83.05 0.12 9.64 2.19 SFW +50mm 770.27 0.18 136.00 30.88

Walls below ground 0.00 0.00 0.00 0.00 Roof 788.99 0.08 63.23 14.36

SFroof +400mm 788.99 0.08 63.23 14.36 Floor towards ground 737.64 0.09 62.90 14.28

My slab 737.64 0.09 62.90 14.28 Floor towards amb. air 0.00 0.00 0.00 0.00

Windows 164.70 1.02 167.68 38.08 SGG Planitherm Ultra-N 2+1-panes 164.70 1.02 167.68 38.08

Doors 1.60 1.01 1.61 0.37 External door U<1.3 1.60 1.00 1.61 0.37 Thermal bridges -0.69 -0.16

62

Total 2546.24 0.17 440.37 100.00

Table 62- thermal bridges Variant A Thermal bridges Area or Length Avg. Heat conductivity Total [W/K]

External wall / internal slab 603.24 m -0.029 W/(m K) -17.675 External wall / internal wall 124.80 m -0.029 W/(m K) -3.657 External wall / external wall 31.20 m 0.060 W/(m K) 1.872 External windows perimeter 343.20 m 0.020 W/(m K) 6.864



Roof / Internal walls 73.08 m -0.032 W/(m K) -2.302 External walls, inner corner 0.00 m 0.000 W/(K m) 0.000



Sum - - -0.688

Table 63- Windows characteristics Variant A Windows Area [m2] U Glass [W/(m2 K)] U Frame [W/(m2 K)] U Total [W/(m2

K)] U*A [W/K] Shading factor g

N 49.41 0.91 2.00 1.02 50.30 0.52 E 32.94 0.91 2.00 1.02 33.54 0.52 S 49.41 0.91 2.00 1.02 50.30 0.52 W 32.94 0.91 2.00 1.02 33.54 0.52

Total 164.70 0.91 2.00 1.02 167.68 0.52

Table 64- AHU information Variant A

Air handling

unit





/C] AHU 600.00/400.00 0.60/0.60 1.00/0.67 0.80/1.00

Table 65-Domestic hot water use Variant A


Table 66-Occupant schedules Variant A Occupant schedules in zones


Table 67-Lighting schedules Variant A Lighting schedules in zones


63


Table 68-Equipment schedules Variant A Equipment schedules in zones


Table 69-Temperature setpoints Variant A Controller setpoints in zones


8.1.3. Variant B Wind driven infiltration airflow rate 992.642 l/s at 50.000 Pa

Table 70- Material information Variant B


Dalarnas Villa Roof-vertical 83.05 0.12 9.64 2.28 SFW +80mm1 770.27 0.15 119.00 28.11






Total 2546.24 0.17 423.37 100.00

Table 71- thermal bridges Variant B

Thermal bridges Area or Length Avg. Heat conductivity Total [W/K] External wall / internal slab 603.24 m -0.029 W/(m K) -17.675 External wall / internal wall 124.80 m -0.029 W/(m K) -3.657 External wall / external wall 31.20 m 0.060 W/(m K) 1.872 External windows perimeter 343.20 m 0.020 W/(m K) 6.864






Sum - - -0.688

64

Table 72- Windows characteristics Variant B Windows Area [m2] U Glass [W/(m2


N 49.41 0.91 2.00 1.02 50.30 0.52 E 32.94 0.91 2.00 1.02 33.54 0.52 S 49.41 0.91 2.00 1.02 50.30 0.52 W 32.94 0.91 2.00 1.02 33.54 0.52

Total 164.70 0.91 2.00 1.02 167.68 0.52

Table 73- AHU information Variant B

Air handling

unit





/C] AHU 600.00/400.00 0.60/0.60 1.00/0.67 0.80/1.00

Table 74-Domestic hot water use Variant B


Table 75-Occupant schedules Variant B Occupant schedules in zones


Table 76-Lighting schedules Variant B Lighting schedules in zones



Table 77-Equipment schedules Variant B Equipment schedules in zones


Table 78-Temperature setpoints Variant B Controller setpoints in zones


8.1.4. Variant C Wind driven infiltration airflow rate 992.642 l/s at 50.000 Pa

Table 79- Material information Variant C


Dalarnas Villa Roof-vertical 83.05 0.12 9.64 2.48 SFW +180mm2 770.27 0.11 83.96 21.62

65






Total 2546.24 0.15 388.33 100.00

Table 80- thermal bridges Variant C

Thermal bridges Area or Length Avg. Heat conductivity Total [W/K] External wall / internal slab 603.24 m -0.029 W/(m K) -17.675 External wall / internal wall 124.80 m -0.029 W/(m K) -3.657 External wall / external wall 31.20 m 0.060 W/(m K) 1.872 External windows perimeter 343.20 m 0.020 W/(m K) 6.864






Sum - - -0.688

Table 81- Windows characteristics Variant C Windows Area [m2] U Glass [W/(m2


N 49.41 0.91 2.00 1.02 50.30 0.52 E 32.94 0.91 2.00 1.02 33.54 0.52 S 49.41 0.91 2.00 1.02 50.30 0.52 W 32.94 0.91 2.00 1.02 33.54 0.52

Total 164.70 0.91 2.00 1.02 167.68 0.52

Table 82- AHU information Variant C

Air handling

unit





/C] AHU 600.00/400.00 0.60/0.60 1.00/0.67 0.80/1.00

Table 83-Domestic hot water use Variant C


66

Table 84-Occupant schedules Variant C Occupant schedules in zones


Table 85-Lighting schedules Variant C Lighting schedules in zones



Table 86-Equipment schedules Variant C Equipment schedules in zones


Table 87-Temperature setpoints Variant C Controller setpoints in zones


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