Description and characterization of an adjustable flux solar simulator for solar thermal, thermochemical and photovoltaic applications

A high flux solar simulator for indoor performance assessment of systems in solar thermal, thermochemical and high concentration photovoltaic research offers repeatability under controlled climate conditions. This paper presents a new high flux solar simulator where a 7kW xenon short arc lamp coupled with a truncated ellipsoid reflector is used as the light source. The flux mapping method is used to evaluate performance of this high flux solar simulator on the basis of flux distribution, temporal instability, spatial non-uniformity, peak flux, conversion efficiency and power intercepted on a circular target placed at the focal plane. The input current of the simulator is adjusted in the range of 113-153A to quantify the maximum and minimum peak flux output per power settings of the solar simulator, which yield different flux distribution at different power level. A theoretical comparative analysis of manufacturer's sensor scaling factor of the circular foil heat flux gage with literature is performed and an optimum scaling factor of 491.46kWm^-2/mV is selected to relate measured incident flux with CCD (charge-coupled device) camera's greyscale value of acquired image. It was observed that at an input current of 153A, the simulator delivers a peak flux of 3583kWm^-2, temporal instability of radiative output less than 3%, and cumulative beam power of 1.642kW at a circular target radius of 110mm placed at the focal plane. A conversion efficiency at 153A and 110mm radius was determined to be 47%. For a photovoltaic cell size of 1.5mm radius, the solar simulator provides an average incident flux in the range of 1200-3000 suns with class 'A' temporal instability and class 'B' spatial non-uniformity. The simulator is capable of adjusting peak flux in the range of 2074-3583kWm^-2 and can produce a theoretical black body stagnation temperature of 1857K.