An extensive indoor experimental characterisation program to investigate the heat loss from a point focus Fresnel lens PV Concentrator (FPVC) with a concentration ratio of 100x was performed for a range of simulated solar radiation intensities between 200 and 1000 W/m(2), different ambient air temperatures, and natural and forced convection. From the experimental program it was found that the solar cell temperature increased proportionally with the increase in simulated solar radiation for all experimental tests, indicating that conductive and convective heat transfer were significantly larger than the long wave radiative heat transfer within and from the FPVC system. For the simulated worst case scenario, in which the FPVC system was tested under a simulated solar radiation intensity of 1000 W/m(2) and ambient air temperature of 50 degrees C with no forced convection, the predicted silicon solar cell efficiency in the FPVC system was reduced to approximately half that at standard test conditions. (C) 2011 Elsevier Ltd. All rights reserved.