Study On The Effect Of The Performance Of Flat Plate Solar Collector By Dust

In the study on the performance of flat plate solar collector(FPSC), the analysis for the matter of dust accumulation is not comprehensive and intensive by reviewing the domestic and foreign literatures, and the problem of dust is ignored usually by investigating the operating maintenance of the flat plate solar water heater. So the problem of dust accumulation is studied as an important factor which effects the performance of the FPSC, and the theory of the dust accumulated on the FPSC is suggested.Theory research on the performance of FPSC is carried out, and the major factors effecting its performance are analysised qualitatively. In fact, the operating performance of FPSC is not only decided by its quality, but also by external factors, such as weather conditions, parameters of the working fluid and orientation and angle of the FPSC etc.The theory research of dust on FPSC is carried out. The property, source and establishment of dust are researched, and the effect factors on the mass of dirt sedimentation and washed on the FPSC are studied, model of dir sedimentation and washed on the the collector is builded, at last the model of the mass of dirt accumulated on the collector is builded too.We theoretically research the effect of dirt accumulation on the performance of FPSC. We study the effect of dirt on the performance of FPSC from the optic, dynamic and chemic angles, and parameters which are used to evaluate the effect of dirt on the performance of optics, calorifics of the FPSC——coefficient of dirt shading(CODS) and degree of dirt efficiency declining(DOED) are suggested, and we study their influencing factors too. We research experimentally the CODS and DOED, and several conclusion are obtained:(1) In the experiment of CODS, when the mass of dust is 3.40 g/m2, 5.11 g/m2, 7.47 g/m2, 14.68 g/m2 and 21.95 g/m2, the CODS is 0.90, 0.87, 0.70, 0.58 and 0.56, the mass of dust is in inverse proportion to CODS, and its fitted relation isζ= 1. 287M?0.28.(2) In the experiment of natural DOED, when the mass of dust on two collector groups is 4.05g/m2, the DOED is 2% and 3%; In the simulative experiment of DOED, when the mass of dirt is 4.70 g/m2, 6.59 g/m2, 17.63 g/m2 and 25.38 g/m2, the DOED is 2%, 5%, 14% and 17%, the mass of dust is in proportion to DOED, and its fitted relation isΔη=0. 089ln(M)?0.118.(3) The effect of dust accumulation on the light-shading is prominent, but the heat effect is non-prominert; The dust reduce the hightest efficientcy and temperature which the collector can reach; In the initial stages of dust accumulation, the CODS and DOED are changing faster as the mass of dust, so it should be notice that the dust on the collectors must be clean in time.At last, we research the applications of dirt accumulation in the stage of designing and operating maintenance of flat plate solar heater.