太阳能耦合地源热泵供暖系统的实验研究

太阳能耦合地源热泵系统的设计以太阳能为辅助、地源热泵为主,最大化地利用太阳能资源,在满足地板采暖制备的情况下,富裕的热量可以补充到生活用水当中。通过实验验证了太阳能耦合地源热泵供暖系统可以有效恢复土壤温度,提高机组性能系数,实现热泵长期稳定的运行。     

Comparison between design and actual energy performance of a HVAC-ground coupled heat pump system in cooling and heating operation

This work compares the experimental results obtained for the energy performance study of a ground coupled heat pump system with the design values predicted by means of standard methodology. The system energy performance of a monitored ground coupled heat pump system is calculated using the instantaneous measurements of temperature, flow and power consumption and these values are compared with the numerical predictions. These predictions are performed with the TRNSYS software tool following standard procedures taking the experimental thermal loads as input values. The main result of this work is that simulation results solely based on nominal heat pump capacities and performances overestimate the measured overall energy performance by a percentage between 15% and 20%. A sensitivity analysis of the simulation results to changes in percentage of its input parameters showed that the heat pump nominal coefficient of performance is the parameter that mostly affects the energy performance predictions. This analysis supports the idea that the discrepancies between experimental results and simulation outputs for this ground coupled system are mainly due to heat pump performance degradation for being used at partial load. An estimation of the impact of this effect in energy performance predictions reduces the discrepancies to values around 5%.     

土壤源热泵桩基埋管换热器的研究进展

近年来,作为可再生能源领域中一种新型的热泵组合形式,桩基埋管型土壤源热泵得到了广泛应用。总结归纳了桩基埋管换热器在国内外建筑领域的研究现状,包括其原理、结构、传热模型、数值模拟、试验研究等方面,特别是对该系统试验研究中,传热规律特性、地下土壤温度场及影响桩埋管传热因素等方面进行了阐述。     

基于全寿命周期成本的地埋管地源热泵系统间歇运行能效分析

间歇运行状态影响竖埋管地源热泵系统的换热性能,进而影响系统的全寿命周期成本(LCC)。利用DeST软件对某办公建筑进行了逐时负荷模拟分析,建立了地下换热器三维管群换热模型以及热泵系统各部分的能耗模型,通过对热泵系统在连续运行15年和间歇运行15年工况下的计算结果进行对比分析,间歇运行的LCC值相对于连续运行的LCC值降低了13.45%,间歇运行模式在热泵系统全寿命周期内的平均节能率为17.20%。间歇运行模式可以有效的提高系统能效和降低LCC值。     

Long term operation of a solar assisted ground coupled heat pump system for space heating and domestic hot water

This paper introduces a solar-assisted ground-coupled heat pump (SAGCHP) system with heat storage for space heating and domestic hot water (DHW) supply. The simulation results of the system's detailed operating performance are presented. The optimization of the system design is carried out by the TRNSYS and a numerical simulation is performed for continuous operation of 20 years under the meteorological conditions of Beijing. Different control strategies are considered and the operational characteristics of each working mode are studied. The simulating results show that the long term yearly average space heating efficiency is improved by 26.3% compared to a traditional ground coupled heat pump (GCHP) system because the solar thermal collecting system is used to elevate the thermal energy in the soil and to provide direct space heating with heat storage. At the same time, the underground heat load imbalance problem for a heating load dominated GCHP is solved by soil recharging during non-heating periods, while extra solar energy is utilized to supply DHW. The flexibility and high efficiency of the SAGCHP system could offer an alternative for space heating and DHW supply by heat pump technology and solar energy in cold winters of northern China.     

Three-years operation experience of a ground source heat pump system in Northern Greece

The paper presents the basic parameters and the energy flows of a ground source heat pump system (GSHP) used for air conditioning the New City Hall of Pylaia (Thessaloniki area—Northern Greece). The building is a typical public one, with an air-conditioned area of 1350 m². The ground source heat pump installation is the largest in Greece, and its operation is monitored with the aid of a DAQ system. The energy flows presented in the paper are based on DAQ recordings of the first 3 years of system's operation. It is proved that the energy demand of the system is significantly lower, compared to that of conventional heating and cooling systems. The seasonal COP of the system has not yet been stabilized, gradually increasing, as it is expected due to the operation of the ground heat exchanger.     

土壤源热泵地面辐射供暖系统测试分析

以河北某住宅小区为例,对土壤源热泵与低温地面辐射采暖系统进行测试,对系统性能、能耗及运行状况进行分析,分析采取该技术室内温度,地源热泵机组运行效率、节能性、环保减排与经济性,并对系统运行可行性、适宜地区、适宜建筑类型、系统形式、系统运行管理给出了建议。     

Performance study of underground thermal storage in a solar-ground coupled heat pump system for residential buildings

This paper is performed to analyze the performance of underground thermal storage in a solar-ground coupled heat pump system (SGCHPS) for residential building. Based on the experimental results, the system performance during a longer period is simulated by the unit modeling, and its parametric effects are discussed. The results show that the performance of underground thermal storage of SGCHPS depends strongly on the intensity of solar radiation and the matching between the water tank volume and the area of solar collectors. Compared with the solar radiation, the variations of the water tank temperature and the ground temperature rise lag behind and keep several peaks during the day time. For the case of Tianjin, the efficiency of underground thermal storage based on the total solar radiation and absorbed solar energy by the collectors can reach over 40% and 70%, respectively. It is suggested that the reasonable ratio between the tank volume and the area of solar collectors should be in the range of 20–40 L/m².     

太阳能-地源热泵串联复合式系统的性能研究

对于总热负荷与总冷负荷不平衡的建筑,单独采用土壤源热泵系统供暖或供冷时,系统运行末期土壤温度发生很大的变化,降低了系统的运行性能。针对此类建筑,搭建太阳能-土壤源串联复合式热泵系统,从集热器单位面积流量、存储水箱体积的影响因素出发,研究供暖期热泵机组蒸发器侧进水温度、系统运行性能和能耗的变化情况,为常规土壤源热泵系统引起的土壤热平衡问题提出解决方案,为今后的实际工程设计及应用提供参考依据。     

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%.     

地铁余热-地源热泵联合供暖系统研究进展

综述了利用地铁余热-地源热泵联合供暖系统的研究现状。提出了余热供暖以及地铁余热利用的相关方案。通过对地铁余热-地源热泵联合供暖的实验和应用情况进行概述,总结了地铁余热-地源热泵联合供暖的特点,即节能减排等优点和输送距离限制等缺点。阐述了地铁余热-地源热泵联合供暖冬夏季的运行方式,对余热回收方式进行分析,指出了地铁余热-地源热泵发展趋势,并对地铁余热-地源热泵联合供热系统的前景进行展望,以期为今后的研究提供理论参考和实验依据。     

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。     

太阳能与土壤源互补特性的实验研究

基于太阳能与土壤源的互补特性,建立了兼具实验研究和示范使用两种功能的太阳能-土壤源复合热泵系统。利用初步的实验运行结果,分析了跨季蓄热和即时采暖过程中太阳能与土壤源的互补情况。结果表明,蓄热结束时,埋管井和观测井不但恢复了初始平均温度,而且还分别比初始平均温度超出了0.73℃和0.8℃。在土壤源的配合或保证下,冬季太阳能产生的不同温度层次的热量完全可以即时利用于采暖,避免了太阳能的不稳定性,减轻了土壤源的取热负担,也体现了比较明显的节能效果。     

Numerical and experimental analysis of a horizontal ground-coupled heat pump system

The main objective of this work is to evaluate a heat pump system using the ground as a source of heat. A ground-coupled heat pump (GCHP) system has been installed and tested at the test room, University of Firat, Elazig, Turkey. Results obtained during experimental testing are presented and discussed here. The coefficient of performance (COP_sys) of the GCHP system is determined from the measured data. A numerical model of heat transfer in the ground was developed for determining the temperature distribution in the vicinity of the pipe. The finite difference approximation is used for numerical analysis. It is observed that the numerical results agree with the experimental results.     

Experimental study of a solar-assisted ground-coupled heat pump system with solar seasonal thermal storage in severe cold areas

This paper presents the experimental study of a solar-assisted ground-coupled heat pump system (SAGCHPS) with solar seasonal thermal storage installed in a detached house in Harbin. The solar seasonal thermal storage was conducted throughout the non-heating seasons. In summer, the soil was used as the heat sink to cool the building directly. In winter, the solar energy was used as a priority, and the building was heated by a ground-coupled heat pump (GCHP) and solar collectors alternately. The results show that the system can meet the heating-cooling energy needs of the building. In the heating mode, the heat directly supplied by solar collectors accounted for 49.7% of the total heating output, and the average coefficient of performance (COP) of the heat pump and the system were 4.29 and 6.55, respectively. In the cooling mode, the COP of the system reached 21.35, as the heat pump was not necessary to be started. After a year of operation, the heat extracted from the soil by the heat pump accounted for 75.5% of the heat stored by solar seasonal thermal storage. The excess heat raised the soil temperature to a higher level, which was favorable for increasing the COP of the heat pump.     

地源热泵夏季性能测试及传热模型

对50m深埋地下换热器地源热泵系统夏季间歇运行时的制冷性能进行了测试,分析了系统运行对地温的影响,提出采用混合系统来解决重庆地区冬夏季土壤中吸热、放热不平衡的问题,引入圆柱源理论建立了垂直U型管传热模型,模拟结果与实验结果吻合较好。     

高校区域能源站方案

以华北地区某大学校园区域能源站工程为例,根据不同类型热用户的供冷供热方式及供、回水温度,结合校园内有空旷用地的特点,进行能源站供能方案比选。设计了多种能源耦合的区域能源站供冷供热系统,进行主要设备选型,对地源热泵系统的地温平衡提出了运行建议。     

Experimental study of a ground-coupled heat pump combined with thermal solar collectors

This paper presents the experimental study of a ground-coupled heat pump used in a 180 m² private residence and combined with thermal solar collectors. This process, called GEOSOL, meets domestic hot water and heating–cooling building energy needs. Solar heat is used as a priority for domestic hot water heating and when the preset water temperature is reached, excess solar energy is injected into the ground via boreholes. This system has the advantage to contribute to the balance of the ground loads, increasing the operating time of the solar collectors and preventing overheating problems. After 11 months in operation, the power extracted and injected into the ground had average values of 40.3 and 39.5 W/m, respectively. Energy injected into the ground represents 34% of the heat extracted, and the heat pump's coefficient of performance (COP) in heating mode had an average value of 3.75. In addition, the domestic hot water solar fraction had an average value higher than 60% for the first 11 months in operation.     

Numerical simulation of ground heat and water transfer for groundwater heat pump system based on real-scale experiment

The groundwater heat pump (GWHP) system is an open-loop system that draws water from a well or surface water, passes it through a heat exchanger and discharges the water into an injection well or nearby river. By utilizing the relatively stable temperature of groundwater, GWHP system can achieve a higher coefficient of performance and can save more energy than conventional air-source heat pump (ASHP) system. The performance of the system depends on the condition of groundwater, especially temperature and depth, which affect performance of the heat pump and system. For the optimization of design and operation of GWHP systems, it is necessary to develop a simulation tool which can predict groundwater and heat flow and evaluate system performance comprehensively. In this research, 3D numerical heat-water transfer simulation and experiments utilizing real-scale equipment has been conducted in order to develop the optimization method for GWHP systems. Simulation results were compared with the experimental results, and the validity of the simulation model was confirmed. Furthermore, several case studies for the optimal operation method have been conducted by calculating the coefficient of performance on various groundwater and well conditions.     

污水源热泵中心能源站设计实例分析

本文所介绍项目以日排水量20万m3的污水处理厂处理后的污水作为热泵低位热源建立能源站,为周围公建及住宅集中供冷、供热.以项目一期为例,针对污水处理厂排水的特点,探讨了污水源热泵系统设计中的相关问题,并将该项目与传统电制冷加锅炉供热方式的经济性和环保性进行了比较,分析可知其节能环保效果十分显著.