TECHNICAL AND ECONOMIC ANALYSIS OF THE THERMAL PERFORMANCE OF A SOLAR BOILING CONCENTRATOR FOR POWER GENERATION

A system for power generation using solar energy collected by compound parabolic concentrators (CPC) incorporated into a Rankine cycle system is studied by developing a model to simulate the CPC performance. The power cycle is also modeled under quasi-steady and transient conditions. An economic analysis is performed through an model developed to study the economic viability of the power system.; The CPC performance is sensitive to the ratio of diffuse to beam components of the solar incident irradiation. This ratio, along with the concentration ratio, govern the CPC optical efficiency which in turn determine the thermal efficiency.; The performance of the CPC working under boiling and superheating conditions is governed by the axial fractional lengths of the non-boiling and the superheating regions. The overall thermal loss coefficient is formulated as a function of the local thermal loss coefficient in the different regions and the length of each region. An expression for a new "Generalized Heat Removal Factor" for solar collectors under any operation mode, F(,s), is developed. The thermal efficiency of CPC's and flat plates, whether under non-boiling, boiling or superheating conditions, is evaluated using this Generalized Heat Removal Factor which enables the selection of a suitable collector design and concentration ratio at some specified operational temperature. The agreement between the model results and the experimental results is excellent.; The CPC working under superheating conditions has a good potential for solar powered Rankine cycles. System efficiencies as high as 11.3% could be obtained at R-11 evaporation temperature of 120(DEGREES)C and a condensation temperature of 20(DEGREES)C. Under clear skies, this corresponds to a peak power output of about 120 watts per m('2) of aperture area. The system performance is more sensitive to the irradiation intensity than it is to the ambient temperature. The seasonal variation in the system efficiency could be minimized by seasonal adjustment of the collector slope angle to maximize the incident normal irradiation on the aperture area.; Power generation from solar energy is economically feasible at current fuel costs of about 7.0 {dollar}/GJ and collector installed costs of 215 {dollar}/m('2). The system in the present study is typical for applications, such as irrigation, in arid locations. (Abstract shortened with permission of author.)...