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International Journal of Contemporary Architecture ”The New ARCH“ Vol. 2, No. 1 (2015) ISSN 2198-7688 ___________________________________________________________________________________________________________

___________________________________________________________________________________________________________ D. Juračić, H. Bradić: “Design Energy Efficient Architecture. The 1st Prize of the Competition for Design of …”, pp. 22–29 22

DOI: 10.14621/tna.20150203

Design of Energy Efficient Architecture The 1st Prize at the Competition for Design of the Faculty of Pharmacy and Biochemistry

of the Zagreb University, 2014

Drazen Juračić1, Haris Bradić2

1Faculty of Architecture, University of Zagreb Fra Andrije Kačića Miošića 26, 10000 Zagreb, Croatia, [email protected]

2Faculty of Architecture, University of Sarajevo Department of Architectural Construction and Building Technology

Patriotske Lige 30, 71000 Sarajevo, Bosnia and Herzegovina, [email protected] Abstract This Paper is a presentation of the First Prize entry on the International competition for the new Faculty of Pharmacy and Biochemistry building, by architect Dražen Juračić. The main idea was to incorporate the new building within the context characterized by distinct topography, oak forests and, above all, by Mirogoj cemetery and its sepulchral Arcades, master pieces of Herman Bolle and of Zagreb historicist architecture and urbanism. The new structure follows the slopes of the terrain, enabling entrances on different levels. Besides the functional and aesthetic properties of the building recognized and awarded by the Competition judges, the design is also particular for its low energy needs and CO2 emission, creating strong sustainable relation between men, building and environment. Shape factor of the heated part of the building is 0.2, and the percentage of transparent vs. non-transparent areas is 37%. Great attention was given to installation of highly insulated windows with maximum U-value of 1.1 W/m2K, and assembling of the double skin facade. The mean U-value of the enclosure between the heated and non-heated areas (garages) and the outdoor environment is U=0.51 W/m2K. The final result is 85.6 kWh/m2/year for all energy needs: heating, cooling, dhw, etc.

1. Introduction The main purpose of the FPB (Faculty of Biochemistry and Pharmacy) building is to provide an array of efficient, highly technological, flexible, scientific and educational facilities: laboratory, practicum, classrooms and supporting facilities for teaching, student standards, etc. Net area of the building is 9,895 m², with corridors and area under walls of 3,616 m2, overall area is totalling 13,511 m².

Important aspect of the building is its sustainability, i.e. its energy efficiency. The main goal was to design a building with minimum energy needs, excellent internal comfort, i.e. temperature, humidity, natural insolation, ventilation, air quality, etc. This was achieved by assembling a thermally well-insulated envelope, using solar energy (passive and active) and recovering heat from the outgoing air.

All of the above design requirements are additionally emphasized by the delicate position of the new faculty building: along the Mirogoj arcades, next to the masterpiece of Herman Bolle and of the Zagreb’s historicism.

2. Location To place the FPB building within the Mirogoj plateau, in the axis of the Alagovićeva Street, is a complex task that must provide answers to important questions about urban and conservatory issues: the first question is how to design a large building within the Mirogoj ensemble? How to preserve the visual contact of the city with the most prominent historical achievement built on the Zagreb necropolis?

To allow visual of the Arcades from the city hills, Mlinarska str, Jurjevska str. and Cmrok park, the new building must not exceed the height of their pediments.

Keywords: Design, Architecture, Historic environment, Location potential and constraints, Renewable energy sources

Article history: Received: 09 March 2015 Revised: Accepted: 31 March 2015



Figure 1. Location The FPB building must enable clear views of the Arcades, and leave space for pedestrian paths from the Alagovićeva Street towards the Cemetery complex on the north (Figure 1).

3. Organisation of the building The main layout indicates compact and logical organization of the functional facilities (Figure 2). The ground floor and the floor below contain classrooms, students’ practicums, library and the Faculty administration.

Research laboratories and staff offices are located in a separate wing on the same levels, and they expand also to the first floor (+1) entirely intended for the teaching staff. The lowest floor (-2), directly accessible from pedestrian path/scalinade, contains a students’ lounge, café, shop and technical facilities.

Chillers and heat pumps are on the roof, as well as photovoltaic cells, all of them surrounded by greenery. They are connected to the mechanical room located on lowest level (-2) via installation ducts.

Entrances are dispersed to complement the clearness and readability of the building as well as efficient

integration of its facilities. The main entrance (Figure 3) is articulated as a propylaea that opens up towards the Mirogoj sepulchral arcades on the north.

The entrance axis divides the classrooms on the east from the practicums and laboratories on the west.

Another entrance (Figure 4), from the Gubčeva zvijezda square via Zmajevac scalinade , is to be accessed by tram users, mostly students, who enter the lowest level of the building by passing by the lounge, café and shop.

The driveway from the Zmajevac Street reach the -1 level and semi-open garage with 187 lots. The fire fighter access is also from the Zmajevac Street, as there are no other option, because the building will be built before the northern bypass.

4. Articulation The building must be unnoticeable not only from the direction of the Mirogoj plateau but also from the Jurjeva, Mlinarska, Ksaver Streets and Cmrok park. The building by its form and size, abstract envelope, green roof, gardens and green walls mimics the environment.



Figure 2. Layout of the building Figure 4. A rendering of the lower entrance

Figure 5. Section

Figure 3. A rendering of the upper entrance



It is hidden among the oak tree crowns on the north and north-west, and overtopped by trees from the botanic garden on the south (Figure 5). The façade is cladded with large greenish and greyish HDL panels. Horizontal movable glass lamellas in front of the windows reflect vibrant images of tree crowns and the sky.

The interior space design is compliant with the main idea clarity and fluency. Longitudinal corridors are accentuated by broadenings and visual penetrations to the exterior (Figure 6).

5. Flexibility The FPB building has been design to allow technical and spatial alterations i.e. to enable new activities and functions. The structure with shallow beams facilitates free layout of floor plans and efficient conduction of installation systems in suspended ceilings. On the ceilings there are connections for all installations

(except for sewage, which are, for obvious reasons, in the floor). This enables laboratories to be equipped with traditional 75 – 90 cm deep fixed cabinets, but also with more modern, easily movable cabinets and counters.

Should partitioning be required to increase the number and size of practicums and laboratories, the modular facade window line enables construction of partition walls on each connection of windows at the width of 165 cm (sufficient for installation of 75 cm wide cabinets with 90 cm of usable space and 90 cm cabinets with 75 cm of usable area). Other rooms are also designed to be easily transformable. The café can be transformed to cafeteria, which will probably be needed, because there are not many restaurants in the neighbourhood due to the relative isolation of the new Faculty building. It goes without saying that spacious and well-illuminated corridors and foyers of the FPB building may host different gatherings, exhibitions, ad hoc discussion circles, workshops, etc.

Figure 6. 3d models



6. Architectural physics, feasibility study and calculation of all energy needs of the building

6.1. Envelope of the building

Under the design, the FPB building has a highly insulated envelope (Figure 7), whose maximum U-values do not exceed 0.22 W/m2K, and stationary flow of water vapour and high values of external envelope mass, satisfying the thermal stability of the structure during summer use. The temperature differences between vertical and horizontal structural elements were reduced to minimum. The shape factor of the heated part of the building is 0.2, and the percentage of transparent against non-transparent surfaces is 37%. Great attention was given to installation of highly insulated windows, whose maximum U-value is 1.1 W/m2K, and assembling of the double skin facade. The mean U-value of the

entire border between the heated and non-heated areas (garages) and the outdoors is U=0.51 W/m2K.

The double skin facade under the solar radiation generates hot air that is used for heating and cooling. Besides, it also prevents excessive insolation through transparent surfaces by means of automatic venetian blinds in the double skin facade. The data presented in Table 1 are part of the competition design.

6.2. Proposed energy efficiency solution

The Faculty of Biochemistry and Pharmacy (FBP) is part of the Northern Campus of the Zagreb University. The energy efficiency concept of the Northern Campus is based on the principles of as rational as possible functioning at maximum use of renewable energy sources (RES). This means that the highest possible level and 24/7 use of RES must be enabled, i.e. it is important to ensure as many energy users as possible even when it is not required solely for classes.

Figure 7. Envelope structure



Table 1. Geometric properties of the building

REQUESTED DATA AREA OR RATIO

Gross volume above the ground 74.540 m3

Gross area above the ground 13.511 m2

Net area above the ground 12.160 m2

Facade area 9.818 m2

North facade 1.589 m2

North glazed area 402 m2

South facade 1884 m2

South glazed area 709 m2

East facade 2.947 m2

East glazed area 1.115 m2

West facade 3.398 m2

West glazed area 1.416 m2

Gross volume above the ground / Gross area above the ground 5.5 .

Gross volume above the ground / Net area above the ground 6.1 .

Volume above the ground / Facade area 7.5 .

Figure 8. Energy flow The main source of energy will be an energy plant with three-generation gas installations for production of electricity and energy for heating and cooling, and air heat pumps with high COP1. After the energy plant is constructed in the Borongaj campus, three-generation in the FBP building will use synthetic natural gas (SNG) produced from wood, which will enable the building to use only renewable energy sources. Given that this is an educational institution, the project proposes the use of

1 Coefficient of Performance

recuperators to recover waste heat generated by the occupants during different activities.

The project proposes use of the BLUE&GREEN energy concept – a synergy between BLUE, natural gas (future SNG) and GREEN, i.e. renewable sources of energy (Figure 8).

ELECTRICITY:

GREEN – Green electricity from photovoltaic roof cells



BLUE – Blue electricity from gas engine – three-generation cogeneration system

HEATING:

GREEN – Green thermal energy, heat pump and solar water heating collectors

BLUE – Blue thermal energy, exchanger of gases and waste heat of gas engine from the three-generation system

COOLING:

GREEN – Green cooling energy, heat pump

BLUE – Blue cooling energy, absorption cooling system of three-generation

Electricity produced by gas engines – generators of the three-generation system and photovoltaic cells on the roof of the building would be sold to distributers of electricity, while the building itself would use the grid electricity. The gas engine cogeneration system of high performance of 84-87% is installed on the -2 level, in the boiler room, while the photovoltaic solar cells are located on the flat roofs of the building. Electricity production is fully automated, with a switching device and transformer for energy transmission to the grid and energy supply from the electric utility. Gas engines – cogenerators of the three-generation system, enable the building to have independent electricity generation, whereas the production of electricity by means of photovoltaic convectors will be commercial.

Thermal energy for domestic hot water and water for heating is generated from several energy sources. The main source of thermal energy is the three-generation system, i.e. the waste heat from gas engine cooling and heat of gases from the gas engine, used to via heat exchanged produce water for heating and domestic hot water used in toilets, laboratories and cafeteria. Additional sources (RES) that cover one portion of the energy needs are heat pump (air-to-water) and solar collectors for water heating (Diagram 1). All installations for production of thermal energy are located on the -2 level, in the boiler room and on the roof of the building.

Water cooling is done via the tree-generation system, i.e. the waste heat from cooling of the gas engine – cogenerator, which ignites the absorption cooling power generator as the main source of cooling energy. Additional energy generator (RES) is a heat pump (air-to-water). All installations for production of thermal energy are located on the -2 level, in the boiler room and on the roof of the building. For other needs of the Faculty, systems would be installed in the boiler rooms to supply technical-technological power generators in the form of joint station of technical gases, vacuum and compressed air, water and sewage processing, and technical rooms for maintenance. The systems are automatic, both in the management and monitoring and measurement part of

all types of energy to ensure optimum spending and system maintenance (Figure 9).

Climate chambers with high level of heat recovery (above 90%) will provide air conditioning and ventilation, allowing for less spending of thermal and cooling energy for air heating and cooling. This device that two thermal packages with highly sensitive accumulation mass, used to exchange the fresh and exhaust air. All air conditioning systems and local exhaust systems intended for laboratories are highly automatized to enable minimum use of energy during the period of work and preparation. In addition, all air conditioning and ventilation systems are equipped with high-efficiency engines (HEE). The climate chambers are on the roof of the building connected with the air distribution elements through vertical and horizontal ceiling vents.

Diagram 1. Total energy needs

Figure 9. Total energy and CO2 emission



Table 2. Materials used in construction of the FBP building

TYPE OF MATERIAL CO2 t / t TOTAL USED t TOTAL CO2 t

Wood -0.54 6.7 3.6 t

Granite 0.09 67.8 6.1 t

Asphalt 0.14 39.2 5.5 t

Reinforced concrete 0.22 16,520.0 3,634.4 t

Ceramic tiles 0.30 6.3 1.9 t

Glass 0.85 1,268.9 1,078.6 t

Stone wool 1.12 201.6 225.8 t

Mineral wool 1.28 11.8 15.1 t

Steel 2.78 7.9 22.1 t

Aluminum 11.5 85.8 986.7 t

GK 1.28 725.76 928.9 t

TOTAL CO2 6,908.7 t

Interior heating and cooling is provided through combination of static surface heating and cooling, and, if so required, ceiling mounted fan convectors. The main heating and cooling piping run through vertical and horizontal vents in the suspended ceiling. The interior heating and cooling system is highly automatized to save energy. All fan convectors will be equipped with HEE.

The lighting systems installed in the building are highly efficient LED fixtures, regulated, supervised and managed using the control for space illumination and natural light penetration, with shading and cooling properties.

All energy systems have the measurement and regulation equipment installed, management and energy to use as minimum energy of all types as possible, with rational selection of energy ratios and optimal maintenance expenses during the building’s lifetime.

Note: The calculations have been done using the Ki Expert 2013 Software (in line with EN ISO 13790:2008) and the input data on the envelope, climate and energy needs of the building.

Table 2 shows the data on the total amount of carbon emissions from the construction.

7. Conclusion Use of renewable energy sources and the above mentioned systems will reduce the total energy needs of the building by 30-40%. The surplus electricity generated by photovoltaic cells (ca 5,5 kWh/m2/year) will be sent to the electric grid.

The actual result will depend on the quality of windows, facade systems, the level of use of energy plants and the way the interior space is used. Mean U-value of the entire envelope, i.e. the space between heated and non-heated (garages) space and the external environment is U=0,51 W/m2K. This result indicates that the envelope has excellent thermal insulation, which reduced the total energy needs for heating and cooling to minimum. The final results of all energy calculations range between 85,6-88,0 kWh/m2/year, which makes this building a low-energy building with small amount of CO2 emission and high share of renewable sources.

Nowadays, the ideas of sustainable energy use form integral parts of contemporary design from its earliest stage (e.g. design project). Good-quality architecture now has a new dimension, i.e. energy efficiency that is easily measurable and detectable. Energy efficiency objectives set in this case has been fully met.

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