Roof: The roof was a so-called minimal construction – meaning that its load bearing capacity was very limited. It turned out that it could hardly carry the weight of the insulation according to the requirements in the building regulations, so an additional 10 cm as required by the BRITa-in-PuBs project would require costly construction strengthening, which would be out of the question. So, this part was almost given up, when the project architect suddenly came to think of the fact that most part of the roof was already strengthened because of a large crane that was hanging from the roof to move the isolators to be tested. This meant that only a small part of the roof had to be strengthened and thus the BRITA-in-PuBs requirements could be carried through. The resulting U-value of the roof is 0,13 W/m²K compared to 0,2 W/m²K which is required in the Danish Building Regulations.
Walls: Originally it was the intention to insulate the external walls on the inside to keep the architectural expression of the buildings old brick walls. However, it turned out that for fire protection reasons (law and regulations) this would require quite substantial and extremely costly treatments of the metal beam load supporting parts of the wall. Therefore it was decided to insulate the wall externally. This has not economical consequences to the project and from a technical point of view it is a clear advantage, as it is well known that external insulation is better at preventing thermal bridges than internal insulation.The following U-value was specified: 0,18 W/m²K – the corresponding requirement in the Danish Building Regulations was 0,4 W/m²K.
Windows: The new windows had to be designed in the same way (with the same look) as the existing windows. This meant that the subdivision of the larger windows had to have the same shape and size as before. The size of these are approximately 30 x 42 cm². The main part of the design process was therefore to search for a window product that both aesthetically and thermally could live up to the requirements. The system selected is from a renowned Danish company called HS Hansen – generally they are very expensive, but they gave a special offer and won the order. With a center U-value of the glazing of 1,1 W/m²K the overall U-value of the windows became 1,56 W/m²K. What is required in the Danish Building Regulations is 1,8 W/m²K.
Ventilation: The building is ventilated by a combination of natural ventilation – of the upper floor – and mechanical ventilation of the lower floors which includes bathroom and toilets. The upper parts of the high windows are used for natural ventilation of the upper floor. As the openings are placed high above the ceiling the incoming air will be mixed with the indoor air – thus reducing the risks for cold draughts. This ventilation will be required only when the gym on the upper floor is used by people generating heat which has to vented out, so preheating and heat recovery is not needed for this air exchange. The opening of the windows will be demand-controlled according to CO2 and temperature.
An efficient air-to-air heat exchanger is used for the mechanically ventilated part of the building. This balanced ventilation system keeps a minimum low ventilation for the toilets and supply additional ventilation when the CO2, humidity (in the bathrooms) and temperature sensors calls show that there is a demand for additional air exchange.
Based on the use of the naturally ventilated upper floor and the efficient heat exchanger in the mechanical ventilation system the solar preheating of air could not be economically justified. The benefit and costs of solar preheating of ventilation air had not been explicitly calculated and shown in the original proposal, so this modification does not mean any changes for these calculations.
Solar PV: The solar cells was shifted to the south gable wall. The additional bearing for the solar cells was mounted while the external insulation was added and is already in place. This was necessary to allow the mounting on the existing wall – these bearings are used for the normal mounting system of the cells. Furthermore the gable solution makes the solar cells more visible – as explained: the gable can be seen from the local subway-train which passes close by and everyday transports 400.000 of people to and from work.
PVT - system and heat-pump installed. Test of PV-cells on south gable wall installed.
Solar PV/Thermal (PV/T): 6 kWp of PVT are placed on the roof of an adjacent building towards south with an optimal slope of 40-45 degrees from horizontal.
The solar collectors will be cooled by a heat pump and the heat delivered to the heating plant of Proevehallen. The idea of the solar energy system for DHW for Proevehallen is to utilise an innovative Photo¬vol¬taic/¬Ther¬mal (PV/T ) solar collector which both produces electricity and heat.
Heating: The basic heating system selected for Proevehallen is a standard hydronic radiator system. This is not a special energy saving measure of the project, so standard procedures for sizing the radiators, piping, pumps, etc. have been used. The piping has been isolated according to Danish standard specifications. The air supply in the mechanical ventilation system is preheated - if needed - by a heating coil. This is supplied also from the hydronic system. The monitoring of the heating energy consumption also include this consumption.
A Building Energy Management System (BEMS) has been designed and installed to control the heating and ventilation systems. This will assure optimal control of the building and thus save energy compared to simpler or manual control systems. The BEMS system will also be used to capture energy consumptions and data for temperature, CO2, humidity plus external weather conditions that can be used for analysis with respect to indoor comfort, air quality and energy consumptions. It will be a LON-based system, connected to the Internet, allowing in principle any PC (with username / password) access to the data.