Experimental study of boiling collectors in thermal siphon operation

Experiments with both conventional sheet-with-tube and waffled-plate collectors operating with R-113 in a boiling, thermal siphon loop provide insight into the role of collector geometry on boiling performance. Comparison of thermal performance of two collectors shows that a larger ratio of wetted area to total collector area improves performance. Efficiency may be expressed as a linear function of saturation temperature. Comparison of boiling collector system performance to performance of a conventional indirect hot water system indicates that the primary advantage of a boiling collector is the reduction in parasitic power. This comparison is however, biased by the fact that collector design is not optimized in terms of thermal efficiency for boiling operation.