STEADY-STATE SALT GRADIENT SOLAR POND

The three-zone salt gradient solar pond is analyzed as a steady-state flat-plate solar energy collector. The resultant efficiency equation is of the Hottel-Whillier-Bliss type commonly used for flat-plate collectors. The quantities that occur in this equation-the effective absorptivity-transmissivity product ατ, the loss factor UL, the heat removal factor FR, and the incident angle modifier θ(i)-are related to the physical properties and dimensions of the pond. For a given ΔT H [(fluid inlet temperature-surface temperature)/insolation], the thickness of the nonconvective zone can be adjusted for maximum efficiency. UL and ατ are smaller than the equivalent quantities for flat-plate collectors, while θ(i) and FR are close to unity. As a consequence, steady-state salt-gradient solar ponds are less efficient than common flat-plate collectors at low ΔT H, but they are more efficient at high ΔT H. © 1979.