不同地区土壤温度及建筑负荷特性对地源热泵系统的影响

本文以我国不同地区的地源热泵为研究对象,首先对地埋管系统建立了CFD模型,根据各地区的土壤初始温度和热物性进行模拟计算,讨论了几种工况下土壤换热能力及地埋管进、出口温差的变化。而后对某办公建筑匹配不同地区的围护结构参数,利用DeST软件进行模拟计算,得出了各典型城市建筑负荷特性,进一步分析了建筑负荷对地源热泵系统的影响。分析可知无论是从热泵机组效率角度考虑,还是从土壤热平衡角度考虑,低纬度地区均不宜单独使用地源热泵系统进行空调和采暖,应考虑采用辅助冷热源,构建复合型采暖空调系统。     

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.     

Modeling and performance evaluation of shallow ground water heat pumps in Beijing plain, China

The use of groundwater for cooling and heating purposes is of interest from both the economical and the ecological perspective. The groundwater heat pump (GWHP) system utilizes groundwater as alternative renewable and clean energy source for space heating and/or cooling, withdraws water from a production well, passes it through a heat exchanger and discharges the water into an injection well. By utilizing the relatively stable temperature of groundwater, GWHP system can achieve a higher coefficient of performance. Due to the utilization of groundwater stored in the aquifer, the assessment of the hydraulic capacity of the aquifer based on numerical groundwater models is always needed for the optimum design and the efficient performance of GWHP. In this paper, numerical methods of underground heat-water transfer, energy balance method and thermal storage method were presented to calculate the capacity of unit area of shallow groundwater aquifer. The model results indicate that the numerical method, which is based on performance efficiency of GWHP, represents the behaviour of groundwater pumping/recharging processes, and serves better than energy balance method and thermal storage method, in addition it has been proven itself that this method has the advantages of energy saving and environmental protection. The calculated capacity is positively related to aquifer thickness. It is found that it is easy for ground water recharge in alluvial and pluvial fan located at the piedmont, while the calculated capacity is relatively smaller compared with that of south-east plain where it is not easy for groundwater recharge.     

地源热泵系统工作井优化布设地下水热量运移模拟

针对地源热泵空调系统工作井优化布设问题,通过建立理想的＂对井抽-灌＂概念及数学模型,模拟拟建地下水源热泵系统特定水流及热源条件下抽水、回灌井不同间距夏季运行期间地下水热量运移过程,为抽、灌井合理间距确定等实际应用提供理论参考和依据。根据数值模拟结果,抽、灌井不同井间距对该热泵系统夏季运行期间地下水热量运移过程影响显著;...     

地下水源热泵运行模式对地温场效能影响研究

基于上海市某地下水源热泵工程项目,采用COMSOL Multiphysics有限元分析工具建立二维简化的热渗耦合数值模型,模拟采能区含水层多孔介质热量运移过程,并利用热泵运行3年的现场监测数据进行模型的识别与验证。探讨热泵系统冷、热负荷设计和抽、灌模式两个方面对采能区地温场效能的影响,分析和预测不同工况下热泵运行期间地温场的演变特征,最后对系统的运行效果进行评价。结果表明:该热泵系统按原设计方案运行时,抽灌井短期运行效果良好,但在第7个供暖期末将出现热贯通现象,长期运行将不利于热井的取热; 如果减小20%热负荷、增加20%冷负荷,会使冷影响区扩散速度降低46.3%,系统运行效果得到显著改善,在模拟的9个运行周期内并未出现热贯通现象,说明合理调节冷、热负荷有利于热泵系统的长期稳定运行; 当冷、热负荷恒定时,分别减小10%和20%的循环水量将会使冷影响区扩散速度分别降低9.3%和15.7%,有效地缓解了热贯通的发生,且仍能满足项目对于制冷供暖的需求,进一步阐明了地下水源热泵系统宜采用“大温差、小流量”的抽灌模式。     

A quasi-steady state mathematical model of an integrated ground source heat pump for building space control

This paper is concerned with the development of a mathematical model, capable of describing the quasi-steady state performance of an integrated ground source heat pump, which is used for heating and cooling of an institutional building located in a Mediterranean climate. The model is structured on functional basis according to the heat pump vapour compression or primary circuit, a secondary ground loop circuit and a secondary building loop circuit. Heat pump heating and cooling capacities, as well as COP, are considered to be dependent variables and are estimated in the model using performance fitted maps. Independent variables include: compressor speed, circulation pump speeds, ground loop return temperature and building circuit return temperature. The model is validated using data from a full-scale ground source heat pump installation. The validated model is used to examine system capacity and performance sensitivity to different control optimisation strategies, including set-point control of room air temperature, room air bandwidth temperature, building loop return water temperature and building loop return bandwidth temperature.     

地下水源热泵系统用于写字楼的经济性研究

基于莱工程实例,采用BIN法对其全年能耗进行了分析计算,以此为基础对比了地下水源热泵系统和常规水冷空调系统的费用年值,并分析了地下水源热泵系统的追加投资回收期.计算结果显示虽然地下水源热泵系统的初投资较高,但其费用年值仅为常规水冷空调系统的91.6％,且3.8年左右就可把追加投资完全收回,所以使用地下水源热泵系统不仅可...     

湖南平和堂商厦的空调设计

该商厦是一座功能齐全的商留建筑，中日合资兴建，简述了该工程的通风，空调，防排烟设计，重点介绍冷热源设计特点，根据环境和工程特点，选用2台水冷式离心机，另选4台风冷热泵式冷热水机组用于冬季供暖及夏季部分负荷时的调节，工程投入运行后效果良好，达到了设计要求。     

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%.     

天津市某绿色建筑暖通设计方案分析

以天津市某绿色建筑的计算负荷为基础,通过分析不同冷热源方案全寿命周期成本,确定采用地源热泵为系统的冷热源。对地源热泵系统地源侧的年吸、释热量进行计算和分析,确保系统长期运行的稳定性。结合建筑部分负荷运行时间和地源热泵机组部分负荷性能参数,对热泵机组的选型进行分析。此外,对水系统的运行策略和室内空气品质的调控性加以分析。     

某典型公共建筑地下水源热泵系统实际运行工况的测试评价研究

本文对赤峰地区某公共建筑地下水源热泵空调系统冬、夏季的运行情况进行了测试,分析了机组与系统的性能系数、室内温度情况以及机组进出口水温等参数的变化,并使用TRNSYS软件对该建筑进行了节能模拟研究。计算结果表明,在该地区此类公共建筑中使用地源热泵系统节能效果显著。     

基于全年动态负荷分析的冷热源方案设计

以北京某酒店为例,对该建筑进行全年逐时动态负荷计算分析。根据计算分析结果,确定制冷季梯级利用离心式冷水机组、螺杆机组和空气源热泵机组作为空调系统冷源,供热季利用板式换热器和空气源热泵机组作为空调系统热源,以达到系统节能的目的。     

对闭式环路水源热泵空调系统运行能耗影响因素的分析

运用闭式环路水源热泵空调系统运行能耗的计算机动态模拟程序，分析了气象条件，建筑特点，系统型式，热源形式等运行能耗影响因素，指出水源热泵空调系统面时有供冷和供热需求而两者热量相近时使用，才能发挥节能作用。     

郑州金苑小区地温中央空调工程的实际运用

地下浅层地能资源(地下水)的非开采利用,可以通过热泵装置实现供热和制冷的双重作用.地源热泵充分利用了地温逆变性(冬暖夏凉)和常年温变小以及蓄能的特点,实现了能量的再利用和良好的环保效能,使在北方冬季应用热泵供暖系统成为现实,并可实现供热制冷系统一体化.通过实际工程论述了该技术的可行性.     

大城市生活污水在建筑节能领域中的应用前景分析

文章通过对原生污水水处理设备的研发，污水源热泵应用水质水温变化规律，区域冷热源能源站供冷供热管网的敷设。污水源热泵与大城市办公、居住区已有空调杌组的对接，污水源氛泵集中制冷供暖系统的可靠性和运行维护安全稳定性研究的讨论，指出了城市污水在建筑节能领域中广阔的应用前景。     

电锅炉辅助空气源热泵干式车库发酵加温系统

干式发酵加温系统中存在着无法根据变工况提供相应的加温方式的问题,为此,针对200m。的车库式干式发酵池,根据不同的天气状况切换空气源热泵单独加温模式与电锅炉．空气源热泵联合加温模式[1],以满足沼气池内的加温需求。还针对最不利工况条件下空气源热泵可能存在的结霜问题,提出相应的除霜方案,保障空气源热泵在最不利工况下的正常运行。实验采取的干式发酵池内设计温度为35℃,原料体积占发酵池的73％,原料中固体占30％,水占70％,发酵池尺寸为12．5m×4m×4m,通过计算得到需要加热盘管总长度为125m。     

蓄热型空气式太阳能集热-空气源热泵复合供暖系统在寒冷地区的应用研究

设计了一种蓄热型空气式太阳能集热-空气源热泵复合供暖系统.该系统具有太阳能供热、太阳能辅助热泵供热和热泵供热3种运行模式,可根据环境工况及供暖负荷的变化自动切换运行模式,保证室内供暖的稳定性.在通辽市的实验研究结果表明:在整个供暖季内,该系统可持续提供42.6 ℃的热水,维持室内温度在21.3?24.1 ℃之间;平均C...     

A nomograph for estimating annual cooling and heating energy requirements in buildings dominated by internal loads

This paper describes a nomograph that can be used as a design tool for estimating annual cooling and heating coil loads in interior zones of office buildings. Based on simplified relationships between the heat load on an air-conditioning system, internal heat generation and outdoor air intake rate, the equations for normalized anuual cooling and heating coil loads in interior zones of office buildings are derived as a function of outdoor air enthalpy, two variables related to the intensity of internal cooling load, and the minimum and maximum outdoor air intake rates. Normalization of heat load on an ari-conditioning system made it possible to construct a design nomograph which can be used to calculate the energy-saving effects of an economizer cycle (passive cooling with ventilation air) and an exhaust air heat recovery unit on annual cooling and heating coil loads at the schematic design stage.Example calculations using the nomographs for three locations in Japan show that the energy-sacing effects of economizer cycle and exhaust air heat recovery units are heavily dependent on the profiles of regional weather conditions. A validation study showed that annual cooling and heating coil loads estimated from the nomographs were in good agreement with those from a detailed computer-based calculation.     

地源热泵系统的应用性分析

从建筑节能背景出发,结合相关工程实例,以传统空调系统为标准,分析地源热泵集中制冷供热空调系统的经济适用性,主要从初投资和年运行费用等方面进行了比较,得出地源热泵系统的优越性,继而展望了这项技术的发展前景。     

利用温频法对空调冷热源进行经济分析及选择

以天津某五星级酒店为例,采用温频法(BIN法)和费用年值法,比较土壤源热泵对传统型电制冷、集中供热组合和吸收式直燃机3种空调系统冷热源进行经济性分析。结果表明,虽然地源热泵初期投资最大,但是年运行费用在3种方案中最低,具有很好的经济性。