Testing flat-plate collectors charged with phase-changing fluids

The performances of flat-plate collectors charged with R-11 as the working fluid have been studied experimentally. A test loop consisting of collectors, a shell and tube condenser and a recirculation pump was used. Collector efficiencies were obtained for a range of flow rates, saturation temperatures and liquid levels. The liquid level was found to be an important parameter affecting the collector efficiency. Collector efficiency plots similar to those of Hottel, Whillier and Bliss were obtained incorporating the liquid level fraction Y as a parameter. The values of collector efficiency were found to agree well with those predicted earlier.