太阳能热泵供热系统性能的试验研究

对太阳能热泵系统的不同运行工况进行了试验研究。分析了蒸发器入口水温、冷凝器入口水温对热泵系统性能的影响。通过研究分析得出:太阳能集热器面积与热泵机组的匹配为影响系统性能的重要参数,应根据用户对热量的需求来选择;蒸发器入口水温可在5℃—20℃之间变化,在20℃时,系统COP最高达到3.6。通过对试验结果的分析,为太阳能热泵系统的设计和运行控制提供了依据。     

无散热损失的热泵型供热系统研究

提出了一种可在环境温度下实现能量输运的供热系统。该系统利用吸收式热泵原理,以氨水为工作流体,发生器和冷凝器布置在热源端,而吸收器和蒸发器布置在热用户端,利用吸收器中溶液吸收蒸气所放出的吸收热来提供热能。由于采用质量分数不同的氨水作为能量载体,因此,可以在环境温度下实现能量输运,没有散热损失;同时,由于该系统利用潜热供热,大大减少了泵功耗。分析结果表明,当供热距离较远时,该系统具有明显优势。     

污水源热泵机组冬季运行工况实测与分析

以采用城市原生污水为热泵冷热源的北京悦都大酒店的热泵机组为研究对象,测试了机组的污水进出口温度,蒸发器侧、冷凝器侧的进出口温度争压缩机的耗电量,根据测试数据考察了热泵机组在以城市污水为热源时的工作性能.测试期间机组运行稳定,冬季的平均制热性能系数COP为3.71,测试分析结果可供污水源热泵系统的设计和工程应用参考和借鉴.     

热泵热回收新风机在寒冷地区的实验研究

为解决寒冷地区冬季空气源热泵运行效率、新风机冻损等运行问题,保证冬季室内良好的空气品质,设计了在冬季将排风引入热泵蒸发器,通过热交换回收排风的能量,并利用热泵冷凝器加热引入室内新风的热泵热回收新风机。采用空气焓差法对该机组在利用排风及排风混室外空气2种运行工况下的制热量、输入功率、热泵能效比(COP)、热回收效率的对比实验。用热泵热回收新风机引进新风后基本没有改变机组输入功率,相同环境条件下的制热量增加,COP值增大,焓差热回收效率最高可达到51.4%。新风机和热泵相结合,利用排风余热提高热泵蒸发器工作温度,改善了热泵和新风机在北方寒冷地区冬季的运行性能。     

多种生活热水供热系统技术及经济对比分析

以小区中央热水系统改造为背景,对太阳能集热器+电加热器热水系统、空气源热泵+电加热器热水系统、空气源热泵+板式换热器+电加热器热水系统、水源热泵、地源热泵热水系统等几种热源供热系统进行了对比分析,结果表明利用空气源热泵+板式换热器+电加热器热水系统最节能,与小区原电加热系统相比可以使热水工作费用降低76.8％.     

基于(火用)分析的水源热泵系统运行优化

为了减少热泵系统运行的有效能损失,提高能量利用的完善度,在满足系统供冷、供热的可靠运行条件下,建立了水源热泵空调系统的压缩机、冷凝器、电子膨胀阀、蒸发器、冷凝器侧的水泵及蒸发器侧的水泵的(火用)损失数学模型,以总(火用)损失(热泵机组和水泵(火用)损失)最小为目标函数,对水.水热泵系统进行运行优化,得出相应的运行参数范围.     

间歇运行下土壤源热泵性能及土壤温度模拟

采用动态仿真软件TRANSYS建立土壤源热泵空调系统模型。针对供热工况,模拟地埋管换热器连续运行模式、不同间歇运行模式(日运行时间不同)下,土壤源热泵蒸发器出水温度、土壤温度随时间的变化以及供暖期能效比。地埋管换热器日运行时间越短,越有利于土壤源热泵的高效运行。     

地埋管地源热泵制热性能测试与分析

理论分析地埋管地源热泵相比空气源热泵的节能率。结合工程实例,对地埋管地源热泵地埋管换热器进出水温度、冷凝器进出水温度、热泵机组日能效比、供暖期能效比进行了实测计算。在测试期,地埋管换热器进出水温度、冷凝器进出水温度均在正常范围内波动。日能效比基本不随室外温度的变化而波动,说明热泵机组的制热性能比较稳定。供暖期能效比为3.05,说明该项目地源热泵的制热性能比较理想。     

Modelling and simulation of a heat pump for simultaneous heating and cooling

The heat pump for simultaneous heating and cooling (HPS) carries out space heating, space cooling and hot water production for small office and residential buildings. It works under heating, cooling and simultaneous modes to produce hot and chilled water according to the thermal demand of the building. A subcooler connected to a water tank is placed after the condenser to recover some energy by subcooling of the refrigerant during a heating mode. The water loop at a higher temperature than ambient air is used subsequently as a source for a water evaporator. Average winter performance is improved compared to a standard reversible heat pump (HP). The air evaporator is defrosted by a two-phase thermosiphon without stopping the heat production. The operation of the HPS is modelled using TRNSYS software. The model is validated using results of an experimental study carried out on a HPS prototype working with R407C. Annual simulations of the HPS coupled to a hotel are run in order to evaluate annual performance and energy consumption of the system. The results are compared to the ones of a standard reversible HP. Depending on the scenario, savings in electric energy consumption and annual performance improvement can reach respectively 55% and 19%.     

太阳能辅助地源热泵供热运行特性研究

介绍了太阳能辅助地源热泵,对其各装置性能进行了研究。分析了地下埋管换热器进出口水温及有、无蓄热水箱对太阳能辅助地源热泵性能的影响。太阳能辅助地源热泵制热性能系数随地下埋管换热器进口水温的升高呈下降趋势,随其出口水温的升高呈上升趋势。随地下埋管换热器出口水温升高,蒸发器传热量增大。当太阳能辅助地源热泵中无蓄热水箱时太阳能集热器的瞬时集热效率高于有蓄热水箱时的瞬时集热效率。就总体效果而言,有蓄热水箱要优于无蓄热水箱,这样可使地源热泵运行更加稳定。     

Development and experimental validation of a novel indirect-expansion solar-assisted multifunctional heat pump

This paper proposes a novel indirect-expansion solar-assisted multifunctional heat pump (IX-SAMHP) which integrates a domestic heat pump with a solar water heater. The IX-SAMHP can not only work in operation modes included in the two household appliances, but also operate in four new energy-saving operation modes for the space cooling, space heating and water heating. All operation modes have functioned successfully and can be switched to each other smoothly on a purpose-built experimental setup. Experiments of the heat pump water heating mode at outdoor air temperatures of 8 °C and 15 °C and the solar-assisted space heating mode at indoor air temperatures of 20 °C have been investigated in detail. Electric heaters were used to simulate solar radiation intensity in different weather conditions. The experimental results show that the IX-SAMHP can produce hot water with much less electric consumption in cloudy days compared with a solar water heater and can operate in much higher coefficient of performance than a domestic heat pump in cold winter. The IX-SAMHP is especially suitable for the regions abundant in solar radiation where the space heating, space cooling and water heating are required all the year round.     

燃气热泵仿真研究

以天然气发动机驱动的压缩式水-水热泵系统为例,建立其各部件数学模型,包括天然气发动机、压缩机、板式蒸发器、板式冷凝器、热力膨胀阀、发动机水套换热器和排烟换热器等的数学模型。利用该模型,研究了不同转速下的热泵系统特性和整体性能特性,与试验结果进行对比,二者吻合良好,证明了燃气热泵系统具有较好的部分负荷特性及较好的节能环保效果。     

热泵＋太阳能热水系统的工程设计与经济分析

以空气源热泵为辅助热源的太阳能集中热水系统,不仅节能效率高,而且能保证全天候连续热水供应,是近年来太阳能利用的发展方向之一。淮海工学院学生浴室采用了空气源热泵辅助太阳能热水系统,设计用水人数17000人,日需热水量184t。介绍了该热水系统的3-作原理及设计计算,并对5种热水工程方案从初期投资和运行费用方面进行了详细的经济性分析,结果表明：以空气源热泵为辅助热源的热水方案较其他方案具有更好的经济、环保效益。     

基于全寿命周期成本的建筑生活热水供应方案的经济性对比研究

以南京某高校新建学生宿舍区为研究对象,选取了 4 种建筑生活热水供应系统:电热水系统、太阳能热水系统、空气源热泵热水系统、加光热的热源塔热泵热水系统。分别计算 4 种系统的全寿命周期成本,即初投资和年运行成本,并利用设计热水单价、净现值 NPV、净现值率 NPVR 及动态投资回收期等指标对 4 种生活热水供应方案进行全寿命周期的经济性评估,结果表明,分散式的电热水系统全寿命周期内经济性最差,加光热的热源塔热泵热水供应系统投资净收益最高,收益率高,投资回收期短,具备很好的投资与建设价值。通过对 4 种方案的经济性评估,可以为中大型建筑的生活热水方案选择提供参考,在我国夏热冬冷地区有很大的推广和应用前景。     

Experimental performance analysis of a solar assisted ground-source heat pump greenhouse heating system

Ground-source heat pumps (GSHPs), also known as geothermal heat pumps (GHPs), are recognized to be outstanding heating, cooling and water heating systems, and have been used since 1998 in the Turkish market. Greenhouses also have important economical potential in Turkey’s agricultural sector. In addition to solar energy gain, greenhouses should be heated during nights and cold days. In order to establish optimum growth conditions in greenhouses, renewable energy sources should be utilized as much as possible. It is expected that effective use of heat pumps with a suitable technology in the modern greenhouses will play a leading role in Turkey in the foreseeable future.The main objective of the present study is to investigate to the performance characteristics of a solar assisted ground-source heat pump greenhouse heating system (SAGSHPGHS) with a 50 m vertical 1 × 1/4 in. nominal diameter U-bend ground heat exchanger using exergy analysis method. This system was designed and constructed in Solar Energy Institute of Ege University, Izmir, Turkey. The exergy transports between the components and the destructions in each of the components of the SAGSHPGHS are determined for the average measured parameters obtained from the experimental results. Exergetic efficiencies of the system components are determined in an attempt to assess their individual performances and the potential for improvements is also presented. The heating coefficient of performances of the ground-source heat pump unit and the overall system are obtained to be 2.64 and 2.38, respectively, while the exergetic efficiency of the overall system is found to be 67.7%.     

热电厂凝汽器循环冷却水余热利用供热技术

介绍热电厂凝汽器循环冷却水常规余热利用供热技术。对吸收式热泵机组与吸收式换热机组(吸收式换热机组将热水型吸收式热泵与板式换热器相结合,替代热力站的传统换热机组)联合供热方式的技术经济性进行了分析。     

A review on performance improvement of an absorption refrigeration system by modification of basic cycle

The vapour absorption refrigeration system is not so much used commercially because of its low performance. The performance of an absorption refrigeration system is required to make it an efficient alternative of vapour compression refrigeration systems. This paper reviews different research on modification of absorption systems contributing to enhance the performance of absorption refrigeration systems. This study suggests that the performance of absorption refrigeration is improved by using double-effect and semi-generator absorber solution heat exchanger arrangement. The coefficient of performance of absorption refrigeration is also improved by the combination of different refrigeration cycles (hybrid refrigeration cycle) such as compression–absorption and ejector–absorption.

Abbreviations: COP: coefficient of performance; GAX: generator absorber solution heat exchanger; ARS: absorption refrigeration system; ECOP: ecological coefficient of performance; CAHP: compression-assisted absorption heat pump     

A thermodynamic analysis of a transcritical cycle with refrigerant mixture R32/R290 for a small heat pump water heater

In this study, a thermodynamic analysis on the performance of a transcritical cycle using azeotropic refrigerant mixtures of R32/R290 with mass fraction of 70/30 has been performed. The main purpose of this study is to theoretically verify the possibility of applying the chosen refrigerant mixture in small heat pumps for high temperature water heating applications. Performance evaluation has been carried out for a simple azeotropic mixture R32/R290 transcritical cycle by varying evaporator temperature, outlet temperature of gas cooler and compressor discharge pressure. Furthermore, the effects of an internal heat exchanger on the transcritical R32/R290 cycle have been presented at different operating conditions. The results show that high heating coefficient of performance (COP_h) and volumetric heating capacity can be achieved by using this transcritical cycle. It is desirable to apply the chosen refrigerant mixture R32/R290 in small heat pump water heater for high temperature water heating applications, which may produce hot water with temperature up to 90 °C.     

Analysis on performance of a novel frost-free air-source heat pump system

Heating capacity of an air-source heat pump (ASHP) system often decreases due to frost on the air-side heat exchanger (evaporator) when the air temperature drops in winter. If the amount of frost accumulates to a certain value, performance of the system will degrade. Therefore, defrosting mode needs to be operated periodically. In order to solve the above problems, heat transfer enhancement or advanced defrosting methods should be adopted, but all these methods cannot solve the problems mentioned in essence. A novel frost-free air-source heat pump system is proposed, the new system can realize heating which does not need defrost in winter. In this new system, extracting heat process from environment includes two steps: the first one is extracting heat from the environment and then to the solution, the second one is releasing heat to the evaporator from the solution, avoiding frosting on the evaporator surface. A theoretical model is established to analyze the performance of the system. Results indicate that the novel system can operate more efficiently than the conventional air-source heat pump in winter. In addition, the new system does not need to run in defrosting mode periodically.     

污水源热泵制热工况的实际运行特性分析

通过对天津市一污水源热泵系统的监测,得到了冬季污水温度的变化范围、热泵系统的实际能效比与蒸发器和冷凝器的进出口水温.通过与热泵机组样本数据的比较,分析了普通水源热泵用作污水源热泵时的性能差异.指出了污水源热泵应用中存在的一些问题并给出了改进建议.