EXPERIENCE WITH A SOLAR HEATING ATES SYSTEM FOR A UNIVERSITY BUILDING

At Stuttgart University, a solar heating system for an office building with laboratories and lecture rooms was installed in 1985. It consist s of 211 m2 of unglazed solar collectors, a 1050 m3 water-flooded pebb le bed heat store, and a heat pump. Heat can be supplied to the store from the solar collectors or from a power station (as waste heat). The whole system has worked successfully for five years under varied stra tegies. In the first two heating periods, the heating strategy was aim ed to collect as much solar energy as possible. Thus, about 60 percent of the heat demand could be covered by solar energy; but the yearly h eat pump coefficient of performance (COP) was only around 2.76. With a n improved heat pump, a monthly COP of 3.6 was obtained. Heat losses f rom the storage amounted to about 20 percent.