The analysis of the temperature performance can be combined with the energy balance of the building. Table 2 shows the essential values required to evaluate the thermal building performance in summer.

The heat gains can be taken directly from measurements (i. e. internal heat gains) or have been calculated (i. e. solar heat gains) from the building geometry, material properties and meteorological data.

The heat losses are mainly caused by ventilation. Consequently, the air change rate determines the heat loss in each building. (Notice: The Lamparter building gets additionally cool supply air from an earth-to-air heat exchanger during the working hours.)

The heat storage capacity is (almost) identical in each building for the daily period. Since the building constructions are very similar, the heat storage capacity for longer cycle periods are (almost) identical, too.

Table 1: Energy balance (working days) room temperature (only working hours) for the

summer period 2002 and 2003.

On the one hand, it was found in the previous Section that all buildings responded to changes of the ambient air temperature faster in 2003 than in 2002. Obviously, the buildings’ thermal inertia could not compensate for the high ambient air temperatures because the available heat storage capacity had been already utilised completely. On the other hand, the excess temperature is smaller in 2003 than in 2002.