EVALUATION OF EVACUATED TUBULAR SOLAR COLLECTORS FOR LARGE SOLAR HEATING SYSTEMS

摘要

In the present study, detailed investigations on evacuated tubular solar collectors for large solarrnheating systems have been carried out. Four types of evacuated tubular solar collectors were used in therninvestigation. Based on laboratory tests, simulation models for the collectors were determined. Based on thesernmodels, the thermal performance of large solar domestic hot water (DHW) systems and combined domesticrnhot water and space heating systems with the four evacuated tubuIa r collectors was determined. To make arncomparison with traditional flat-plate collectors, similar simulations were also carried out for systems with arntypical flat-plate collector. The results show that the thermal advantage of evacuated tubular collectors variesrngreatly from system to system, and increases with the solar fraction. Furthermore, the higher the operationrntemperature of the collector in the system is, the greater the thermal advantage of evacuated tubular solarrncollectors will be.