Simulation of solar hot-water supply and air-conditioning/ventilation system

As the solar thermal system with the floor heating and the hot-water supply system need low temperature of 40-50 degC, the effectiveness of solar collector is high. However, in the summer season, floor heating is unnecessary, and so there emerges a lot of surplus solar heat. By utilizing such surplus heat in summer as heat source for desiccant dehumidification activated with hot water at a temperature of about 70 degC 1) , it would be possible to use a solar heat collecting system efficiently all year round. Therefore, a new solar thermal system was developed with the purpose of utilizing solar heat with high efficiency all year round. In this paper, we reported that the field measurement in winter and the numerical simulation using TRNSYS for the annual performance evaluation of the developed solar thermal system ware carried out. As a result, it was found that annual system COP was as high as over 4, and it is possible to reduce running cost by about 9% by installing the cheaper midnight heating operation control based on the weather forecast of the following day.