Performance Of A Solar-Air Composite Heat Source Heat Pump System

With the consideration of to the advantages and disadvantages of single air source heat pump, single solar energy heat pump and switch solar-air dual heat source heat pumps, a new type of solar-air composite heat source heat pump system(SACHP) has been proposed to realize the utilization and complementary advantages of two renewable energy:air and solar. This system was especially suitable to meet the heating and air conditioning demands for the urban villas residential areas and rural independent residential areas in cold ares. Additionally, it also provided a feasible method to improve the city's ecological environment, and plays a leading role in the villages and small towns' construction. This paper we mainly carried out a theoretical analysis to the working principle of SACHP, and put forword a new basic concept and mathematical model of SACHP, designed and set up a comprehensive test rigs of SACHP, made a thorough simulation and experimental research on its heating characteristics, and revealed the basic influential rules of the main characteristic parameters of the SACHP. This work laid a foundation for the development of practical effect of SACHP. The main research contents and the results were as follows:(1) Proposed and designed SACHP. The system can achieve a batter work mode of three heating sources:the single air, the air and the single solar energy, and offered a better solution to the prominent question of a single heat source heat pump and heat exchanger switching so as to cover the requirements of different users in different regions for maximum. It also realized the heat pump's composite effective utilization to many low-temperature heat sources as well as offerd the system provided reliable guarantee. The new technology of SACHP has got the state invention patent license.(2) Proposed and designed the composite heat exchanger of the homomorphisms double heat sources. The heat exchanger had dual function of tube-fin and tube heat exchangers, break through the traditional model that heat exchanger in working can realize heat exchange only between the same gases or liquid heat sources, and realized the heat exchange between two heat sources. It laid the technological and equipmental foundation for realizing the synchronization and composite using of solar energy and air. The heat exchanger had got the national utility model patents. The invention patent had been through trial and entered the public stage.(3) Based on the characteristics of composite heat coupling heat transfer, put forward the important conceptions:"composite heat source effective temperature differences" and "the maximum composite heat source effective temperature differences". According to the results of the experiments, we fitted the correlation of the maximum composite heat source effective temperature differences, which can be used as the forecast to the effective temperature differences range. The research had the vital significance to SACHP heat working mode, control strategy, system design and application scope limits.(4) Established the mathematical model of composite heat pump system with concentrated parameter method and made computation on the heating character in solar-air double heat source work mode. Analysed the working characteristics of the SACHP with different temperature of air heat source and solar heat source as well as different solar heat source flow. The influence of composite heat source temperature differences on the SACHP's working characteristics were analysed too.(5) Designed and set up a SACHP performance experimental platform and test the heating performance in three different heat source working modes. And experimental results show that:above 0℃of ambient temperature conditions, SACHP run by single air-source model; in 0-10℃of ambient temperature conditions, SACHP by solar-air dual heat mode and below-10℃of ambient temperature condition, SACHP by single solar heat mode can meet the heating needs of the user.(6) Initially established the climate region suitable for SACHP use and the suitable heating mode for the climate region. According to national building thermal design district standards, solar energy resource distribution and the experimental results, presented that the SACHP technology is more suitable for cold regions and bitter cold regions in the popularization and application.