Determination of the optical efficiency of a parabolic disc collector by calorimetry

Abstract

The development of human life depends on the energy supply that is obtained mainly by burning fossil fuels. These energy sources are limited, and their availability is not guaranteed forever. The continuity of human civilization demands a sufficient and continuous energy supply. Solar energy is an alternative, the sun can supply in one hour the energy required by the entire population of the earth in a year. It is possible to take advantage of solar energy by applying a technology capable of concentrating the sun's rays on a receiver to transform them into thermal energy with high exergy. A parabolic disk collector consists of a concentrator formed by a reflective surface that approaches a paraboloid of revolution and the receiver located at the focal point of the concentrator mirror. It is presented a simple method to evaluate the optical efficiency with which to obtain reliable results to size the equipment built according to the required power. The receiver is a calorimeter that contains a fluid that absorbs the radiative energy from the parabolic solar concentrator, and transforms it into thermal energy. The thermal power can be obtained by measuring the temperature of the calorimeter fluid as a function of time