北方地区应用地源热泵应注意的问题

介绍了地下土壤的热平衡问题 ,采用太阳能辅助加热的混合式地源热泵系统是有效的方法。土壤冻结对埋管换热器传热有利 ,设计时应考虑此影响。采用防冻液流体 ,由于其热物性参数不同 ,造成管内最小流速 ,换热系数和管内沿称阻力均与水不同 ,设计时需充分考虑。     

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.     

地源热泵系统的热响应测试的研究进展

近年来,地源热泵技术因其节能与环保优势得到广泛应用,地下岩土热物性参数是影响地源热泵系统设计与运行的重要因素,其参数的确定也是地源热泵技术领域的难点之一。本文综述地源热泵系统的热响应测试的理论基础、测试方法、实验数据处理及其研究发展现状,以期为地源热泵系统的热响应测试研究与应用提供借鉴与参考。     

群井地下换热系统初温和构造因素影响传热的研究

利用传热模拟计算,研究了地源热泵(GSHP)地能利用中群井系统初态因素对温变特性的影响规律。探讨地下初始温度、井群基本构造尺寸等对地下土壤温度场分布的影响。指出土壤初始温度是决定土壤源热泵运行的重要因素,初始温度提高1倍,系统运行时问和输出总热量增加约24倍。小井径对负荷因素影响更加敏感,相同的热负荷下,热流密度高,温度场变化剧烈。对于大井径而言,温度场变化相对平缓,但更易于发生井间传热交互影响。初态因素是强化地能利用中的重要因素之一,据此合理布置大区域群井意义重大。     

A spectral model for transient heat flow in a double U-tube geothermal heat pump system

This paper introduces a semi-analytical model based on the spectral analysis method for the simulation of transient conductive-convective heat flow in an axisymmetric shallow geothermal system consisting of a double U-tube borehole heat exchanger embedded in a soil mass. The proposed model combines the exactness of the analytical methods with an important extent of generality in describing the geometry and boundary conditions of the numerical methods. It calculates the temperature distribution in all involved borehole heat exchanger components and the surrounding soil mass using the fast Fourier transform, for the time domain; and the complex Fourier and Fourier-Bessel series, for the spatial domain. Numerical examples illustrating the model capability to reconstruct thermal response test data together with parametric analysis are given. The CPU time for calculating temperature distributions in all involved components, pipe-in, pipe-out, grout, and soil, using 16,384 FFT samples, for the time domain, and 100 Fourier-Bessel series samples, for the spatial domain, was in the order of 3 s in a normal PC. The model can be utilized for forward calculations of heat flow in a double U-tube geothermal heat pump system, and can be included in inverse calculations for parameter identification of shallow geothermal systems.     

一种新型的地源热泵与冰蓄冷空调联合运行系统

分析了目前国内外地源热泵与冰蓄冷空调系统的研究现状、技术优点及存在的问题.进而论述了两者联合运行的必要性,在此基础上构思出了一套以生态理念构建的复合式新型能源系统.最后结合目前国内在建的首个地源热泵及冰蓄冷中央空调系统工程,阐述了该工程冬季供暖,夏季制冷的控制策略,并对该新系统的经济性做了初步的分析.研究表明,该新型的复合式能源系统具有广阔的发展前景.     

岩土地下换热器热泵系统长期运行状况预测分析

在岩土地下换热器G函数理论的基础上,建立地源热泵热力系统模拟计算模型,提出了基于模型的系统长期运行状况分析方法。以严寒地区为例研究了近三年冬季供暖过程运行状况,模拟分析了地下换热器进、出口流体温度变化规律、热泵机组能效比和系统能耗特性,并与实测结果进行了对比。结果证明了模型及分析方法可行,可为进一步开展更广泛的预测分析提供有效途径。     

制冷工况下水平埋管换热器运行试验研究

通过夏季工况的地源热泵运行试验,对运行过程中水平埋管的换热性能参数、试验场地周围气象因素和换热过程中土体的温湿度变化等因素进行实时监测,探讨了地源热泵运行过程中水平埋管换热器热交换性能及其周围土壤的温、湿度场变化规律。研究结果表明,地源热泵间隙运行有利于土壤温度场的恢复,随着停机时间的增加,水平埋管与周围土壤的热交换能力明显提高;气候变化对水平埋管周围土壤的温度场分布具有显著影响,随着埋深的递减,土壤温度受气候变化的影响越明显;水平埋管周围土壤温度的变化幅度随着与埋管距离的增加呈递减趋势,其影响半径为1.0m左右;热交换对水平埋管周围土壤湿度场的影响不明显,但大气降雨引起的地表水入渗对土壤湿度场的分布具有显著影响。     

关于地源热泵发展的运行机制、管理模式和扩散模式的研究

在建筑领域规模化应用可再生能源是降低建筑能耗的重要途径之一。以地源热泵产业发展的运行机制和管理模式为研究对象,针对目前地源热泵系统在建筑中应用存在的成本高和市场规模小的问题,借鉴国外可再生能源发展的经验,分析促进其发展的目标机制和补偿机制,通过概算,预测符合国家可再生能源发展规划的地源热泵系统的发展目标,提出用于增量成本补偿的资金保障措施;探讨以政府主导为主、市场机制配合的管理模式,并对相关行政管理部门转变职能提出建议;探索具有中国特色的城市级示范的推广扩散模式。     

非寒冷地区土壤源热泵的改良研究

针对以夏季冷负荷为主的南方地区存在的冬、夏季冷热负荷不均的情况,在GSHP技术基础上探讨土壤蓄冷--地源热泵系统的可行性及其控制策略与其他土壤源耦合系统做了比较,发现了水蓄冷 套管垂直埋管模式下系统的优势明显.并综合考虑了土壤的短期及长期蓄冷作用,以蓄冷和土壤温度恢复过程的最佳结合点为目标进行了探讨.