ABSTRACT
To increase cost effectiveness of solar domestic hot water systems new designs of one family systems are developed together with the manufacturers and a new design of a solar heating system for an apartment building is developed together with a consultant engineering firm. The designs are making use of drain back in the collector loop in most cases combined with the low flow principle.
The systems have been installed and monitored. They are operating without problems but it seems from the experiences that special precautions have to be considered concerning freezing in the collector loop. Experiments are performed at the Laboratory to investigate these problems.
