To get an impression of the comfort level inside the room behind window collectors outdoor measurements under realistic weather and building conditions has to be carried out. To improve the simulation model realistic values of the important parameters like k and g-values should be measured.

For this purpose a test facility developed in the frame of the European project " Passive Solar System and Component Testing” (PASSYS) is used.

Fig. 5: Construction of a PASSYS Cell with Test and Service Room

The PASSYS cell consists of a test room of a volume of 38 m3 and floor area of 13.8 m2. The south oriented wall is removable a solar activated glass facade up to an area of 7.6 m2 can be integrated. The facade is connected to an acclimatised room. Computer controlled heating and cooling systems allows a wide range of control strategies. Using heat flux plates we are able to measure in and outgoing heat fluxes. The principle of the PASSYS procedure consists of an energy balance over the whole test room. All heat fluxes over the cell walls are known except the one over the test fagade, which can be described using a RC-model containing the unknown k — and g-Values. The unknown k — and g-values are determined using parameter identification. The comfort level can also be monitored by the measurement of room temperature, surface temperatures and humidity.

2. Conclusion

A collector test in accordance with EN 12975-2 is carried out for a new window collector. The collector parameters were used in simulations to calculate the yearly energy savings for a typical one-family house in Germany.

Considerable energy savings are calculated for the configuration of conventional flat plate collectors mounted on a vertical wall. Further investigations are necessary to improve the numerical model and to adapt it to the real working conditions. Outdoor measurements under realistic conditions are necessary to investigate and to ensure the comfort level in the room behind.