STRATIFIED THERMAL STORAGE IN RESIDENTIAL SOLAR-ENERGY APPLICATIONS

The benefits of thermal stratification in sensible heat storage were investigated for several residential solar applications. The operation of space heating, air conditioning, and water heating systems with water storage was simulated on a computer. The performance of comparable systems with mixed and stratified storage was determined in terms of the fraction of the total load supplied by solar energy. The effects of design parameters such as collector efficiency, storage volume, flow rates, etc. , on the relative advantage of stratified over well-mixed storage were assessed. The results show that significant improvements in system performance (5-15%) may be realized if stratification can be maintained in the storage tank. The magnitude of the improvement is greatest and the sensitivity to design variables smallest in the service hot water application.