摘要
根据单一空气源热泵、单一太阳能热泵及多换热器切换式太阳能-空气双热源热泵的优缺点,提出了一种新型的太阳能-空气复合热源热泵系统(Solar-Air Composite Heat Source Heat Pump System, SACHP),实现了对空气、太阳能两种可再生能源的综合利用和优势互补,尤其适合我国寒冷地区城镇别墅住宅和乡村独立住宅空调采暖及卫生热水需求,对改善城市生态环境,引领新农村住宅环境建设,提供了一种可行的技术方法。本文对该SACHP工作原理进行了理论分析,建立了SACHP数学模型,设计并搭建了SACHP性能综合测试平台,对其制热特性进行了全面、深入地模拟与实验研究,揭示了SACHP主要特性参数的基本影响规律,为下一步开发实用型SACHP奠定了基础。本文研究成果包括以下几个方面：
(1)提出并设计了SACHP,该系统可实现单一空气、太阳能-空气、单一太阳能三种热源工作模式,较好地解决单一热泵源热泵及多换热器切换式热泵的突出问题,为最大限度地满足不同地区和不同用户的需求,实现热泵对多种低温热源的复合有效利用提供了可靠的系统保证。SACHP已获得国家发明专利授权。
(2)提出并设计了太阳能-空气双热源复合换热器,该换热器具有管翅式和套管式换热器的双重功能,突破了传统换热器中热泵工质只能与单一气态或液态热源进行换热的模式,可实现热泵工质在同一换热器中与空气和太阳能热媒两种热源进行同步耦合换热,为实现对太阳能、空气两种热源的同步复合利用奠定了技术设备基础。该换热器已获国家实用新型专利授权,发明专利已通过初审,进入公开阶段。
(3)依据复合换热器中复合热源的耦合换热特性,提出了“复合热源有效温差”和“复合热源最大有效温差”的概念。根据实验结果,拟合出了最大有效复合换热温差关联式,可用作复合热源有效温差范围的预测计算。“复合热源有效温差”的研究对SACHP热源工作模式和控制策略的确定、系统优化设计以及适用范围界定具有重要的意义。
(4)建立了复合热源热泵系统数学模型。采用集中参数法建立了SACHP模型,对太阳能-空气双热源工作模式下系统的制热特性进行了模拟计算,分析了空气热源温度,太阳能热媒流量及温度,以及双热源有效温差对太阳能-空气复合热源热泵系统运行特性的影响。并将模拟结果与实验结果进行对比分析,二者变化趋势相同,能够较好吻合。
(5)设计并搭建了SACHP性能实验平台,分别完成了复合热源热泵在三种热源工作模式下系统的性能实验。实验研究结果表明：在0℃以上环境温度工况范围,SACHP按单一空气热源模式运行,在0℃-10℃低温环境温度工况范围内,SACHP按太阳能-空气双热源模式运行,在-10℃以下的超低温环境温度工况下,SACHP按单一太阳能热源模式运行能较好地满足用户供热需求。
(6)初步确立了SACHP的气候适用区域和各区域的热源工作模式。依据国家建筑热工设计分区标准、太阳能资源分布及实验研究结果,提出SACHP更适合于在寒冷地区和严寒地区推广应用。
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.
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