For kindergarten operation there are available monitored data that we can expect to approximate by calculations the changing of the studied variables, for example solar storage temperature, within a few percentages accuracy. Comparison of the calculation by the physically-based model and the measurements is shown to this case thereinafter.

Both for the swimming pool and for the kindergarten models there are parameters of which the exact values are not known, they must be determined somehow. Such parameters are the optical efficiency (no) and the overall heat loss coefficient (UL) of the collector in the collector sub-model, the ke coefficient of the heat exchanger in the heat exchanger sub-model, the heat loss coefficient (ks) and the surface area (As) of the wall of the solar storage tank in the solar storage sub-model.

Given values for the calculations are as follows:

П0 = 0,74, catalog data for the SlU-system,

UL = 7 W/(m2K), recommendation from [9],

ke = 2461,5 W(m2K), determined from data given by manufacturer, ks = 0, assuming storage with no heat loss.

Since the storage has no heat loss the value of As is of no interest.

In accordance with Fig. 3 the temperature of the solar storage has been determined for two independent day (8 March, 2005, 8 April, 2005), by running the model with available measured data. Fig. 4 and Fig. 5 contain the comparison of the calculated and the measured values, as well.

As a result of the modelling the absolute difference of the calculated solar storage — and the measured solar storage outlet temperature has a mean value of 1,11°C, standard deviation of 0,6°C, maximum value of 2,32°C and residual value of 0,51°C for the day 8th of March, 2005.

As a result of the modelling the absolute difference of the calculated solar storage — and the measured solar storage outlet temperature has a mean value of 0,73°C, standard deviation of 0,49°C, maximum value of 1,78°C and residual value of 0,69°C for the day 8th of April, 2005.