| Abstract: | A solar test collector has been designed for the testing of thermally absorbing coatings under controlled conditions. The design consists of a collector fed by a controlled temperature fluid within the range of 25–90°C (77–194°F). This temperature is maintained by a custom electronic controller. A small variable flow pump circulates water through three collector pipes at selected flow rates. Strip heaters coupled with a differential temperature controller compensate for edge losses associated with small collectors. Detailed design and operation data are presented and three black chrome and one non-selective absorber are analysed in detail by test collector measurements. Results show that efficiencies as high as 77 and 75 per cent (ΔT = 0) are obtained for 1.0 μm black chrome on copper and nickel plated steel, respectively. The lowest loss coefficients are about 3.8 W/m2°C for all black chrome/metal surfaces, with the highest being 8.4 W/m2°C for the black paint/metal sample. Also, a collector model is presented for comparison. |
