Hello together, for my simulation of a solar cooled building I want to determine the solar fraction. The system works without backup (so, if solar power is to low, room temperature rises above set temperature). This I calculate the cooling load in a separate simulation, then I divide the produced cooling power (which I suppose is entirely transmitted to the building) by the cooling load. So far so well.
Problem No. 1 is that I use a hysteresis controller which has my building cooled from 26°C to 24°C. If I calculate the cooling load for 26°C I may get values greater 1 for the solar fraction since the building is cooled down to 24°C. If I take 24°C for calculating the cooling load I make it bigger than it acutally is. Does anyone have an idea how to solve this problem? Problem No. 2: I have a 3-zone building. One zone is cooled by a chilled ceiling, the remaining two by providing the active layer in the floor (floor heating) with cold water. Even in july/august, when all 3 rooms are above set-temperature a great part of the time, I get solar fractions of min. 43% (for 24°C-cooling load) and min. 62% (for 26°C cooling load). To me this seems too much. Is it possible that I mustn't compare cold from active layers directly to the cold load (Qcool-demand output of the building)?? I use the operative temperature for controlling my system. To obtain the cooling load I calculate the required set temperature input for every zone from the mean surface temperature in a seperate equation. I hope i explained myself. Thanks for any help! Björn -- Björn Nienborg Thermal Systems and Buildings Fraunhofer Institut für Solare Energiesysteme ISE Heidenhofstr. 2, 79110 Freiburg, Germany Tel.: +49 (0)761 4588-5303 FAX: +49 (0)761 4588-9333 http://www.ise.fraunhofer.de _______________________________________________ TRNSYS-users mailing list [email protected] https://www.cae.wisc.edu/mailman/listinfo/trnsys-users
