Passive space heating with a self-pumping vapor system

In this system, which should be useful for space or water heating, a refrigerant is evaporated in a solar collector and condensed within thermal storage located in the building below the collector. The vapor pressure generated in the collector periodically forces the condensed liquid upward to the location of the collector. This paper reports results of an operational test, in which this system provided passive space heating for an outdoor test cell during a winter season. The daily average energy yield and the elevation of collector temperature caused by self-pumping are reported, as well as observations on failure modes, system reliability, and suggestions for a practical configuration.