Experimental determination of parameters in models of indoor air temperature response to reduction in supplied energy

Abstract

To diminish peaks of energy power demand in buildings, we need to determine parameters in transmittance models that describe indoor temperature response to changes in heating. This article discusses first- and second-order models as well as an integration model. Calculations deal with indoor temperature drop in the range to −2 K following the heating power reduction for a period of 4–6 h. The second-order model was found to be the most accurate in showing the decrease in temperature. The calculated values of parameters vary within wide ranges, with significant differences occurring even with values obtained in consecutive measurement series. It was shown that the use of averaged values produce large result errors in the predictions of indoor temperature changes. This renders an offline method useless and promotes an online method. The average value of the time constant in the first-order model correlates well with the value of the time constant calculated as a ratio of the heat storage mass to the room heat loss coefficient. This is true if we take into account exclusively this part of the building partition layer that contributes to the heat storage.