HEAT DELIVERY PERFORMANCE IN COMBINATION SOLAR THERMAL SYSTEMS: STRATEGIES FOR INCREASING DELIVERY TEMPERATURE

摘要

Residential combination solar thermal systems, a.k.a combisystems, serve a combination of domestic hot water heating and space heating loads. In residential retrofit applications, the method of delivering heat to the space heating load often poses a particular challenge, as the original heating system can have a physical configuration and design delivery temperature that is not well matched to the solar thermal source. Typical options for space heating delivery are reviewed in light of solar thermal heat delivery temperature considerations. Two strategies that allow for better transfer of heat from the collectors to the space heating load, reducing the collector storage volume to collector area ratio, and delivery of solar thermal energy directly from the collectors to the space heating load, are discussed. Data from actual retrofit combisystems is presented to demonstrate these strategies.