外文翻译---气候条件对地源热泵系统性能的影响(编辑修改稿)

外文翻译---气候条件对地源热泵系统性能的影响(编辑修改稿)内容摘要：

lished through a ground heat exchanger (GHE). Heat transfer between the GHE and adjoining soil is primarily by heat conduction and to a certain degree by moisture migration [3].Therefore, it depends strongly on the soil type, temperature and moisture gradients. The entire process of heat extraction/deposition is a transient one. Heat is extracted/deposited from pipes laid horizontally or vertically in the ground. The thermal capacity of the soil varies with the moisture content and the climatic condition. Because the extraction/deposition of the heat will raise/reduce the ground temperature, plete temperature recovery may be possible. Vertical loop systems are known as operating better, especially in the cooling mode [4]. It was 气候条件对地源热泵系统性能的影响 8 found, however, that the effect of moisture content variation above 50% of saturation on ground heat pump performance is relatively insignificant [5]. The vertical ground heat exchangers are usually constructed by inserting one or two highdensity polyethylene Utubes into vertical boreholes to serve as the ground loops, which are referred to as single Utube, double Utube or cannula GHEs, respectively. The study reported here includes the performance analysis of three types of ground heat exchanger described above at cooling and heating mode. An experimental setup, described in the next section, is constructed and tested for the first time on the basis of a university study performed in city of Guangzhou. 2. System description A schematic diagram of the constructed experimental system is illustrated in Figure1. This system mainly consists of two separate circuits: (a) the water circuit, (b) the refrigerant circuit. A water tower is configured in the water circuit to supply enough water. The refrigerant circuit is built by the closed loop copper tubing. The working fluid of the heat pump is R22. The main characteristics of three ground heat exchangers (GHE) are given in Figure 3, which are marked with (a)Single Utube, (b)Double Utube, and (c) Cannula. These ground heat exchangers operate in parallel connection. The ground heat exchangers are configured in line as depicted in Figure 2. Ground source heat pump system Distribution of thermocouples around GHE The ground heat exchangers are 30m depth, and the space between GHEs is 5m. Six thermocouples are configured along the ground heat exchange vertically to obtain the temperature of soil. The distance between thermocouples are 10m、 8m、 6m、 3m and 3m from down to up(). The black dots in Figure 2 denote the position of the thermocouples. The output temperature of the thermocouples are transferred to a data logger and are recorded in a puter. Thermocouples are also used to measure the inlet and outlet temperature of water and refrigerant. To obtain the inlet and outlet water temperature of the ground heat exchanger or refrigerant temperature of condenser and evaporator, thermocouples are put inside the tube 9 at every tested position. Rotameters are used to obtain the flow rate of every ground heat exchanger as depicted in figure 1. Conversion from the heating cycle to the cooling cycle is obtained thtough a fourway valve. The laboratory will be conditioned during the summer and winter seasons. (a) (b) (c) Fig. 3. Schematic diagr。