Testing of Liquid Collectors

Abstract

Unlike a centrifugal pump (see appendix — I) or a D.C.shunt generator, the performance of a solar collector is a strong function of the climatic conditions, and it is not quite proper to quote its numerical value. However, it is possible to specify the collector parameters — the optical efficiency factor and the heat loss factor — that are relatively independent of the climatic variables. The study—state performance of a solar collector can be described by a simple parametric equation, as a function of the climatic variables. The efficiency of conversion of solar energy into thermal energy is given by

$$\eta = {\text{F}}^{\prime}[\eta _{\text{o}} - \frac{{{\text{U}}_{\text{L}} (\bar{\text{T}}_{\text{f}} - {\text{T}}_{\text{a}} )}} {{{\text{I}}_{\dagger} }}]$$

(1)