Ground source heat pump systems demonstrate significant potential for northern rural heating applications;however,the effectiveness of these systems is often limited by challenging geological conditions.For instance,i...Ground source heat pump systems demonstrate significant potential for northern rural heating applications;however,the effectiveness of these systems is often limited by challenging geological conditions.For instance,in certain regions,the installation of buried pipes for heat exchangers may be complicated,and these pipes may not always serve as efficient low-temperature heat sources for the heat pumps of the system.To address this issue,the current study explored the use of solar-energy-collecting equipment to supplement buried pipes.In this design,both solar energy and geothermal energy provide low-temperature heat to the heat pump.First,a simulation model of a solar‒ground source heat pump coupling system was established using TRNSYS.The accuracy of this model was validated through experiments and simulations on various system configurations,including varying numbers of buried pipes,different areas of solar collectors,and varying volumes of water tanks.The simulations examined the coupling characteristics of these components and their influence on system performance.The results revealed that the operating parameters of the system remained consistent across the following configurations:three buried pipes,burial depth of 20 m,collector area of 6 m^(2),and water tank volume of 0.5 m^(3);four buried pipes,burial depth of 20 m,collector area of 3 m^(2),and water tank volume of 0.5 m^(3);and five buried pipes with a burial depth of 20 m.Furthermore,the heat collection capacity of the solar collectors spanning an area of 3 m^(2)was found to be equivalent to that of one buried pipe.Moreover,the findings revealed that the solar‒ground source heat pump coupling system demonstrated a lower annual cumulative energy consumption compared to the ground source heat pump system,presenting a reduction of 5.31%compared to the energy consumption of the latter.展开更多
The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is...The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.展开更多
This article gives an overview of using the ground source heat pump (GSHP) and air-to-water heat pump (A&WHP) in cold climate areas for heating and for domestic hot water production of buildings. Computer simulati...This article gives an overview of using the ground source heat pump (GSHP) and air-to-water heat pump (A&WHP) in cold climate areas for heating and for domestic hot water production of buildings. Computer simulation and analysis were carried out for a typical detached house, with 200 m2 of living area, the heat demand of 9 kW and the average heat demand for DHW production of 1 kW. In heating period the average Coefficient of Performance (COP) of the A&WHP is considerably lower than COP of the GSHP.展开更多
This study introduces a novel artificial heating technique aimed at addressing frost heave issues in embankments on frozen ground,offering a sustainable solution.Initial evaluations assessed various heating systems,in...This study introduces a novel artificial heating technique aimed at addressing frost heave issues in embankments on frozen ground,offering a sustainable solution.Initial evaluations assessed various heating systems,including boilers,heat pumps,solar heaters,and electric heaters,focusing on their thermal performance and applicability.The study subsequently designed and implemented a direct-expansion ground source heat pump(DX-GSHP)system as the primary heat source for embankment warming.Rigorous testing confirmed the DX-GSHP system's ability to maintain a heat-supply temperature above 40℃ and a heat-absorption temperature below -3.5℃,effectively extracting geothermal energy for transfer to the topsoil layers.With a demonstrated coefficient of performance(COP)of 3.49,the DX-GSHP system not only proves its energy efficiency but also suggests a potential role in reducing the strain on electricity supply systems.Installation of DX-GSHPs,with heating capacities ranging from 1.0 to 2.0 kW and spaced at intervals of 2.0-4.0 m,provides a rapid thermal response to frost heave in singletrack railway embankments,thereby potentially mitigating frost-induced damage in cold climate regions.展开更多
The objective of the present paper is to describe a technical and economical visibility study of the application of ground source heat pumps （GSHP） in a supermarket in Portugal. The study was developed under the Eur...The objective of the present paper is to describe a technical and economical visibility study of the application of ground source heat pumps （GSHP） in a supermarket in Portugal. The study was developed under the European project ＂Integration of Geothermal Energy Into Industrial Application - IGEIA＂, project number EIE 06/001, supported by the Intelligent Energy for Europe, IEE, of EACI, European Commission. In general for supermarkets installed in single buildings, the building envelope has higher rates of envelope areas per indoor air volume. In Portugal this fact produces high need of heating during the winter season and high cooling needs during the summer season. Inside the building there are strong internal heat loads produced by high densities of lights and equipments. However these internal loads are not distributed uniformly. There are some areas with high production of heat but there are others with production of cooling. Therefore the acclimatization of this kind of buildings is not so easy and the balance of heating and cooling needs is depending of different parameters which should be well evaluated. The energy consummation of the cold display cases and deep freezers in market area and storage is also very high. The different energy needs could be studied in an integrated way and could be partially satisfied by geothermal energy using ground source heat pumps. At the same time the boreholes could be used as an energy reservoir increasing the efficiency of whole system. Four different climatic zones in Portugal were selected, （north coast, interior north, south coast and interior south） using the same system. The results of the study show that the all energy needs can by partially satisfied by geothermal energy but they need to be integrated to increase the global efficiency. The paper shows that the geothermal energy can be an attractive application for the supermarkets in Portugal if the energy solution is studied in an integrated way and if it is also considered as a cost the emissions of CO2 avoid by the new system.展开更多
According to the elements of hydrogeological conditions,lithology,stratigraphic thermal physical parameters,construction technology and economic rational elements,the evaluation system of ground source heat pump( GSHP...According to the elements of hydrogeological conditions,lithology,stratigraphic thermal physical parameters,construction technology and economic rational elements,the evaluation system of ground source heat pump( GSHP) were established in Baotou plain. The factor weights were determined by using analytic hierarchy process,and the comprehensive element method was selected to evaluate the region suitability of GSHP system. The results show that the suitable area is 559. 63 km2 for utilizing GSHP in the studied area,accounting for 62. 58% of the total area; while the unsuitable area is 334. 60 km2,accounting for37.42%. The evaluating results can provide not only a scientific basis for development and utilization rationally of shallow geothermal heat in Baotou,but also offer an important reference to the other areas.展开更多
Iraq is located in the Middle East with an area that reaches 437,072 km2 and a population of about 36 million. This country is suffering from severe electricity shortage problems which are expected to increase with ti...Iraq is located in the Middle East with an area that reaches 437,072 km2 and a population of about 36 million. This country is suffering from severe electricity shortage problems which are expected to increase with time. In this research, an attempt is made to minimize this problem by combining the borehole thermal energy storage (BTES) with a heat pump, the indoor temperature of a residential building or other facility may be increased or reduced beyond the temperature interval of the heat carrier fluid. Due to the relatively high ground temperature in Middle Eastern countries, the seasonal thermal energy storages (STES) and ground source heat pump (GSHP) systems have a remarkable potential, partly because the reduced thermal losses from the underground storage and the expected high COP (ratio of thermal energy gain to required driving energy (electricity)) of a heat pump, partly because of the potential for using STES directly for heating and cooling. In this research, groundwater conditions of Babylon city in Iraq were investigated to evaluate the possibility of using GSHP to reduce energy consumption. It is believed that such system will reduce consumed energy by about 60%.展开更多
According to the specific situation of a general hospital project, this paper analyzes the feasibility of the application of ground source heat pump air conditioning in the project from the conditions, one-time invest...According to the specific situation of a general hospital project, this paper analyzes the feasibility of the application of ground source heat pump air conditioning in the project from the conditions, one-time investment, energy consumption and operating costs of the implementation of ground source heat pump air conditioning, and comprehensively expounds several important technical measures of the implementation of ground source heat pump air conditioning. Combined with the characteristics of this project, the operation strategies of ground source heat pump air conditioning system under summer cooling condition, winter heating condition and over season condition are designed and put forward to ensure that the ground source heat pump air conditioning system can achieve the expected design effect and energy saving and emission reduction benefits.展开更多
Ground Source Heat Pump technique and its operating principle are described in this paper. Ground heat exchanger is the key technique of ground source heat pump and its patterns are discussed. Software is helpful to d...Ground Source Heat Pump technique and its operating principle are described in this paper. Ground heat exchanger is the key technique of ground source heat pump and its patterns are discussed. Software is helpful to design ground heat exchanger. A project of Chinese Ground Source Heat Pump is introduced and its market is more and more extensive.展开更多
In this paper, the operation strategy of an energy storage ground source heat pump project in Beijing is studied, and the heat balance of the ground source heat pump is analyzed and calculated under the existing opera...In this paper, the operation strategy of an energy storage ground source heat pump project in Beijing is studied, and the heat balance of the ground source heat pump is analyzed and calculated under the existing operation strategy. The research shows that after the ground source heat pump system has been in operation for one year, the temperature rise of geological body in the hole distribution area is about 0.34℃, considering the influence of formation lithology, scattered hole distribution, abundant site, groundwater runoff and other factors on the heat dissipation of geological body, and the intermission of the heat pump air conditioning system is also beneficial to the recovery of the temperature of geological body. It can be considered that the ground heat pump system has little impact on the temperature of the rock and soil mass, and the project has good sustainability.展开更多
Ground source heat pumps (GSHPs) are one of the renewable energy technologies with features of high efficiency, energy saving, economic feasibility and environmental protection. In China, GSHPs have been widely used f...Ground source heat pumps (GSHPs) are one of the renewable energy technologies with features of high efficiency, energy saving, economic feasibility and environmental protection. In China, GSHPs have been widely used for building heating and cooling in recent years, and have shown great potential for future energy development. This paper summarizes the classification, development history, and use status of shallow GSHPs. Several typical engineering cases of GSHP technology are also specified and analyzed. Finally, promising development trends and some advanced technologies are illustrated.展开更多
Energy piles have attracted increasing interest for application in ground source heat pumps,because it is environment-friendly,energy-efficient,and without additional drilling cost.However,when there is a large dif-fe...Energy piles have attracted increasing interest for application in ground source heat pumps,because it is environment-friendly,energy-efficient,and without additional drilling cost.However,when there is a large dif-ference between the heating and cooling loads,the system will suffer from a soil thermal imbalance which may further decline the system performance and even cause a system failure.A hybrid ground source heat pump sys-tem that integrates auxiliary equipment can solve the problem,however,it needs additional investment and a complicated control strategy.In this paper,the zoning operation of energy piles can effectively improve the tem-perature recovery ability of soil in the energy pile group and thus alleviate the soil thermal imbalance.Specifically,a heating-dominated residential building in Beijing is selected for a case study,with 144 energy piles arranged in a 12×12 layout.An analytical model of the spiral-coil energy pile group with seepage will be adopted,which can consider the groundwater flow,the geometry of spiral coils,and the thermal interaction among different energy piles,achieving high calculation accuracy and fast calculation speed.Based on this analytical energy pile model,a system model will be built to investigate the system performance influenced by different zoning operation strategies.Results show that intensive heat injection into the center of the pile group(Strategy 2 and Strategy 3)or heat extraction from the outer layer of the pile group(Strategy 4)can relieve the cold accumulation.Strategy 2 can relieve the outlet temperature decline from 5.54℃ to 4.46℃ and improve the heating COP from 3.297 to 3.423 compared to the conventional full operation strategy.Although the annual heat pump COP of Strategy 2 is a little lower than that of conventional full operation strategy,Strategy 2 has the shortest unmet heating or cooling time.Therefore,the proposed zoning operation strategy can achieve good system efficiency and excellent system reliability compared to the conventional strategy.展开更多
The borehole and total internal thermal resistance are both significant parameters in evaluating the thermal performance of the ground source heat pump.This study aimed to obtain the accurate correlation of the 3D bor...The borehole and total internal thermal resistance are both significant parameters in evaluating the thermal performance of the ground source heat pump.This study aimed to obtain the accurate correlation of the 3D borehole and total internal thermal resistance(R_(b,3D)and R_(a,3D))and analyze the impacts of parameters on the R_(b,3D)and R_(a,3D).Firstly,eight parameters affecting the R_(b,3D)and R_(a,3D),including the borehole diameter,pipe diameter,pipe-pipe distance,borehole depth,soil thermal conductivity,grout thermal conductivity,pipe thermal conductivity,and fluid velocity inside the pipe,were considered and an L-54 design matrix was generated.Then,the 3D numerical model,coupling with the four-resistance model,was proposed to calculate R_(b,3D)and R_(a,3D)for each case.After that,the response surface methodology was employed to obtain and verify the correlation of R_(b,3D)and R_(a,3D),which were compared with the existing resistance calculation methods.Lastly,analysis of variance was carried out to reveal parameters that have statistically significant impacts on the R_(b,3D)and R_(a,3D).Results show that the rationality and accuracy of the correlation of R_(b,3D)and R_(a,3D)can be verified by the determination coefficient and P value of regression model,as well as the P value of lack-of-fit.The existing resistance calculation methods are more or less inaccurate and the discrepancies in some cases can be up to 86.74%and 111.35%for the borehole and total internal thermal resistance.The pipe and grout thermal conductivity,pipe and borehole diameter,and the pipe-pipe distance can be seen as the significant contributory factors to the variation of R_(b,3D)and R_(a,3D).展开更多
Operation strategies of Ground Source Heat Pump System(GSHPS) such as continuous or intermittent approaches have been extensively studied. In this work, a novel strategy was proposed to maximize the energy efficiency ...Operation strategies of Ground Source Heat Pump System(GSHPS) such as continuous or intermittent approaches have been extensively studied. In this work, a novel strategy was proposed to maximize the energy efficiency of GSHPS. In this approach, the buildings was first air-conditioned by the preheating/precooling mode and the rest thermal load was covered by the heat pump(HP) mode. The system performance can then be optimized by considering the combination of these two operating modes. A case study was made to examine the thermal performance of a GSHPS installed in Nuremberg, Germany. Thermal performance of the HP and the preheating/precooling operating modes was examined. The system was optimized by deploying the assistant preheating/precooling approach and over one-year period monitoring showed that the seasonal Coefficient of Performance(COP) of the GSHPS was 4.12 in winter and 5.01 in summer. These COP values are higher than that of the conventional GSHPS. Thus, this proposed strategy could be an efficient way to improve the thermal performance of GSHPS.展开更多
Given the growing interest in ground source heat pump and distributed heating installations in general for the reduction of greenhouse gas emissions,technology implementation planning can benefit from the simultaneous...Given the growing interest in ground source heat pump and distributed heating installations in general for the reduction of greenhouse gas emissions,technology implementation planning can benefit from the simultaneous consideration of building renovations.Here,a method for identifying and evaluating scenarios based on cost and greenhouse gas emissions is presented.The method is demonstrated for a case study in Vaasa Finland.The case study considers the insulation of the walls,roof,and base floor and the replacement of windows based on 2003 and 2010 Finnish building codes simultaneously with the possible replacement of existing heat sources with ground source heat pumps.Estimates of changes in heat demand for consecutive renovations are combined with data on renovation,installation,heating costs,and life cycle greenhouse gas emissions data for the current and proposed heat sources.Preferred scenarios are identifi ed and evaluated by building type,construction decade,and current heating source.The results are then placed within the contexts of the Vaasa building stock and policy theory.展开更多
The orientation strategy of side pipe and the heat transfer performance of six ground heat exchangers(GHEs) were optimized by numerical simulation,with soil being treated as a porous medium.An experiment on the heat t...The orientation strategy of side pipe and the heat transfer performance of six ground heat exchangers(GHEs) were optimized by numerical simulation,with soil being treated as a porous medium.An experiment on the heat transfer of four GHEs was carried out in 2010.Results indicate that the velocity field is disturbed by GHEs.The optimal orientation strategy of side pipe is that the upward pipe is located upstream and the downward pipe downstream.The space between GHEs should be appropriately adjusted,depending on the direction and flow velocity.Groups of GHEs should be installed perpendicular to the mainstream in a single row,but if the acreage does not meet the requirements,GHEs should be installed in staggered multiple rows.Fewer GHEs parallel to the mainstream strengthen the heat transfer.Moreover,numerical results agree well with the test data,with the maximum relative error being less than 7.7%.展开更多
A simplified numerical model of heat transfer characteristics of horizontal ground heat exchanger (GHE) in the frozen soil layer is presented and the steady-state distribution of temperature field is simulated. Numeri...A simplified numerical model of heat transfer characteristics of horizontal ground heat exchanger (GHE) in the frozen soil layer is presented and the steady-state distribution of temperature field is simulated. Numerical results show that the frozen depth mainly depends on the soil′s moisture content and ambient temperature. The heat transfer loss of horizontal GHE tends to grow with the increase of the soil′s moisture content and the decrease of ambient temperature. Backfilled materials with optimal thermal conductivity can reduce the thermal loss effectively in the frozen soil. The applicability of the Chinese national standard “Technical Code for Ground Source Heat Pump (GB 50366-2005)” is verified. For a ground source heat pump project, the feasible layout of horizontal GHE should be determined based on the integration of the soil′s structure, backfilled materials, weather data, and economic analysis.展开更多
The effect of ground properties with heat conduction between soil and ground loop heat exchangers(GLHEs)has been analyzed.A finite line source model proposed by Cui,Yang,and Fang is used.Far field radius is defined.Th...The effect of ground properties with heat conduction between soil and ground loop heat exchangers(GLHEs)has been analyzed.A finite line source model proposed by Cui,Yang,and Fang is used.Far field radius is defined.The analyses for a 1.5m borehole line source in three kinds of soil conditions:damp and breeze(D.B.),damp and heavy(D.H.),and saturated and heavy(S.H.)are carried out.The results of the comparisons show that in the condition of continuous operation,the variation of the far field radius is related to soil thermal conductivity.The rate of heat transfer will decrease after long time operation.And then soil condition will not influence the far field radius obviously.展开更多
Natural energy use is important to reduce the energy consumption of buildings. However, further reducing energy consumption with traditional systems is difficult. Therefore, we proposed a MMHP （multi-source and multi...Natural energy use is important to reduce the energy consumption of buildings. However, further reducing energy consumption with traditional systems is difficult. Therefore, we proposed a MMHP （multi-source and multi-use heat pump） to achieve higher efficiency than traditional systems. The MMHP system connects multiple heat sources such as solar heat, the ground, and air and multiple heat uses such as cooling, heating, and a hot water dispenser with a water loop. Each type of heat use side can utilize heat efficiently. However, there is a distinct lack of highly efficient hot water dispensers available. Therefore, we developed the IHWD WS （instantaneous hot water dispenser based on a water source） heat pump. In this study, we developed a prototype of the IHWD WS heat pump. The coefficient of performance of the IHWD WS heat pump was 5.2-8.5 throughout a year. When it is improved, COP （coefficient of performance） is expected to be 9.3-9.9.展开更多
基金supported by 2024 Central Guidance Local Science and Technology Development Fund Project"Study on the mechanism and evaluation method of thermal pollution in water bodies,as well as research on thermal carrying capacity".(Grant 246Z4506G)Key Research and Development Project in Hebei Province:"Key Technologies and Equipment Research and Demonstration of Multiple Energy Complementary(Electricity,Heat,Cold System)for Solar Energy,Geothermal Energy,Phase Change Energy"(Grant 236Z4310G)the Hebei Academy of Sciences Key Research and Development Program"Research on Heat Transfer Mechanisms and Efficient Applications of Intermediate and Deep Geothermal Energy"(22702)。
文摘Ground source heat pump systems demonstrate significant potential for northern rural heating applications;however,the effectiveness of these systems is often limited by challenging geological conditions.For instance,in certain regions,the installation of buried pipes for heat exchangers may be complicated,and these pipes may not always serve as efficient low-temperature heat sources for the heat pumps of the system.To address this issue,the current study explored the use of solar-energy-collecting equipment to supplement buried pipes.In this design,both solar energy and geothermal energy provide low-temperature heat to the heat pump.First,a simulation model of a solar‒ground source heat pump coupling system was established using TRNSYS.The accuracy of this model was validated through experiments and simulations on various system configurations,including varying numbers of buried pipes,different areas of solar collectors,and varying volumes of water tanks.The simulations examined the coupling characteristics of these components and their influence on system performance.The results revealed that the operating parameters of the system remained consistent across the following configurations:three buried pipes,burial depth of 20 m,collector area of 6 m^(2),and water tank volume of 0.5 m^(3);four buried pipes,burial depth of 20 m,collector area of 3 m^(2),and water tank volume of 0.5 m^(3);and five buried pipes with a burial depth of 20 m.Furthermore,the heat collection capacity of the solar collectors spanning an area of 3 m^(2)was found to be equivalent to that of one buried pipe.Moreover,the findings revealed that the solar‒ground source heat pump coupling system demonstrated a lower annual cumulative energy consumption compared to the ground source heat pump system,presenting a reduction of 5.31%compared to the energy consumption of the latter.
基金Project(2012BAJ06B04)supported by"12th Five-Year Plan"National science and Technology,ChinaProject(2014-228)supported by Department of Housing and Urban Rural Development of Hebei,China
文摘The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.
基金supported by the Estonian Research Council,with Institutional research funding grant IUT1-15with the project“Development of efficient tech-nologies for air change and ventilation necessary for the increase of energy efficiency of buildings,AR12045”,financed by SA Archimedesby the project“Civil and Environmental Engineering PhD School,DAR9085”.
文摘This article gives an overview of using the ground source heat pump (GSHP) and air-to-water heat pump (A&WHP) in cold climate areas for heating and for domestic hot water production of buildings. Computer simulation and analysis were carried out for a typical detached house, with 200 m2 of living area, the heat demand of 9 kW and the average heat demand for DHW production of 1 kW. In heating period the average Coefficient of Performance (COP) of the A&WHP is considerably lower than COP of the GSHP.
基金supported by the National Natural Science Foundation of China(Grant Nos.42001059,52178340)the Natural Science Foundation of Hebei Province,China(Grant No.E2020210044)+1 种基金the Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei(Grant No.SZ 2022-03)the Overseas Expertise Introduction Project for Discipline Innovation("111 Project",Grant No.B21011).
文摘This study introduces a novel artificial heating technique aimed at addressing frost heave issues in embankments on frozen ground,offering a sustainable solution.Initial evaluations assessed various heating systems,including boilers,heat pumps,solar heaters,and electric heaters,focusing on their thermal performance and applicability.The study subsequently designed and implemented a direct-expansion ground source heat pump(DX-GSHP)system as the primary heat source for embankment warming.Rigorous testing confirmed the DX-GSHP system's ability to maintain a heat-supply temperature above 40℃ and a heat-absorption temperature below -3.5℃,effectively extracting geothermal energy for transfer to the topsoil layers.With a demonstrated coefficient of performance(COP)of 3.49,the DX-GSHP system not only proves its energy efficiency but also suggests a potential role in reducing the strain on electricity supply systems.Installation of DX-GSHPs,with heating capacities ranging from 1.0 to 2.0 kW and spaced at intervals of 2.0-4.0 m,provides a rapid thermal response to frost heave in singletrack railway embankments,thereby potentially mitigating frost-induced damage in cold climate regions.
文摘The objective of the present paper is to describe a technical and economical visibility study of the application of ground source heat pumps （GSHP） in a supermarket in Portugal. The study was developed under the European project ＂Integration of Geothermal Energy Into Industrial Application - IGEIA＂, project number EIE 06/001, supported by the Intelligent Energy for Europe, IEE, of EACI, European Commission. In general for supermarkets installed in single buildings, the building envelope has higher rates of envelope areas per indoor air volume. In Portugal this fact produces high need of heating during the winter season and high cooling needs during the summer season. Inside the building there are strong internal heat loads produced by high densities of lights and equipments. However these internal loads are not distributed uniformly. There are some areas with high production of heat but there are others with production of cooling. Therefore the acclimatization of this kind of buildings is not so easy and the balance of heating and cooling needs is depending of different parameters which should be well evaluated. The energy consummation of the cold display cases and deep freezers in market area and storage is also very high. The different energy needs could be studied in an integrated way and could be partially satisfied by geothermal energy using ground source heat pumps. At the same time the boreholes could be used as an energy reservoir increasing the efficiency of whole system. Four different climatic zones in Portugal were selected, （north coast, interior north, south coast and interior south） using the same system. The results of the study show that the all energy needs can by partially satisfied by geothermal energy but they need to be integrated to increase the global efficiency. The paper shows that the geothermal energy can be an attractive application for the supermarkets in Portugal if the energy solution is studied in an integrated way and if it is also considered as a cost the emissions of CO2 avoid by the new system.
基金Supported by project of Shallow Geothermal Energy Survey of Inner Mongolia Baotou Plain(No.2010-3-SK35)
文摘According to the elements of hydrogeological conditions,lithology,stratigraphic thermal physical parameters,construction technology and economic rational elements,the evaluation system of ground source heat pump( GSHP) were established in Baotou plain. The factor weights were determined by using analytic hierarchy process,and the comprehensive element method was selected to evaluate the region suitability of GSHP system. The results show that the suitable area is 559. 63 km2 for utilizing GSHP in the studied area,accounting for 62. 58% of the total area; while the unsuitable area is 334. 60 km2,accounting for37.42%. The evaluating results can provide not only a scientific basis for development and utilization rationally of shallow geothermal heat in Baotou,but also offer an important reference to the other areas.
文摘Iraq is located in the Middle East with an area that reaches 437,072 km2 and a population of about 36 million. This country is suffering from severe electricity shortage problems which are expected to increase with time. In this research, an attempt is made to minimize this problem by combining the borehole thermal energy storage (BTES) with a heat pump, the indoor temperature of a residential building or other facility may be increased or reduced beyond the temperature interval of the heat carrier fluid. Due to the relatively high ground temperature in Middle Eastern countries, the seasonal thermal energy storages (STES) and ground source heat pump (GSHP) systems have a remarkable potential, partly because the reduced thermal losses from the underground storage and the expected high COP (ratio of thermal energy gain to required driving energy (electricity)) of a heat pump, partly because of the potential for using STES directly for heating and cooling. In this research, groundwater conditions of Babylon city in Iraq were investigated to evaluate the possibility of using GSHP to reduce energy consumption. It is believed that such system will reduce consumed energy by about 60%.
文摘According to the specific situation of a general hospital project, this paper analyzes the feasibility of the application of ground source heat pump air conditioning in the project from the conditions, one-time investment, energy consumption and operating costs of the implementation of ground source heat pump air conditioning, and comprehensively expounds several important technical measures of the implementation of ground source heat pump air conditioning. Combined with the characteristics of this project, the operation strategies of ground source heat pump air conditioning system under summer cooling condition, winter heating condition and over season condition are designed and put forward to ensure that the ground source heat pump air conditioning system can achieve the expected design effect and energy saving and emission reduction benefits.
文摘Ground Source Heat Pump technique and its operating principle are described in this paper. Ground heat exchanger is the key technique of ground source heat pump and its patterns are discussed. Software is helpful to design ground heat exchanger. A project of Chinese Ground Source Heat Pump is introduced and its market is more and more extensive.
文摘In this paper, the operation strategy of an energy storage ground source heat pump project in Beijing is studied, and the heat balance of the ground source heat pump is analyzed and calculated under the existing operation strategy. The research shows that after the ground source heat pump system has been in operation for one year, the temperature rise of geological body in the hole distribution area is about 0.34℃, considering the influence of formation lithology, scattered hole distribution, abundant site, groundwater runoff and other factors on the heat dissipation of geological body, and the intermission of the heat pump air conditioning system is also beneficial to the recovery of the temperature of geological body. It can be considered that the ground heat pump system has little impact on the temperature of the rock and soil mass, and the project has good sustainability.
基金supported by“Key scientific issues in transformative technologies:intelligent evolution mechanism and design of distributed information energy system(2018YFA0702200)”.
文摘Ground source heat pumps (GSHPs) are one of the renewable energy technologies with features of high efficiency, energy saving, economic feasibility and environmental protection. In China, GSHPs have been widely used for building heating and cooling in recent years, and have shown great potential for future energy development. This paper summarizes the classification, development history, and use status of shallow GSHPs. Several typical engineering cases of GSHP technology are also specified and analyzed. Finally, promising development trends and some advanced technologies are illustrated.
基金The authors gratefully acknowledge the funding support from Sun Yat-Sen University(76140-18841230 and 2021qntd15)Guangdong Basic and Applied Basic Research Foundation(2021A1515011739,2020A1515110391 and 2020B1515120083).
文摘Energy piles have attracted increasing interest for application in ground source heat pumps,because it is environment-friendly,energy-efficient,and without additional drilling cost.However,when there is a large dif-ference between the heating and cooling loads,the system will suffer from a soil thermal imbalance which may further decline the system performance and even cause a system failure.A hybrid ground source heat pump sys-tem that integrates auxiliary equipment can solve the problem,however,it needs additional investment and a complicated control strategy.In this paper,the zoning operation of energy piles can effectively improve the tem-perature recovery ability of soil in the energy pile group and thus alleviate the soil thermal imbalance.Specifically,a heating-dominated residential building in Beijing is selected for a case study,with 144 energy piles arranged in a 12×12 layout.An analytical model of the spiral-coil energy pile group with seepage will be adopted,which can consider the groundwater flow,the geometry of spiral coils,and the thermal interaction among different energy piles,achieving high calculation accuracy and fast calculation speed.Based on this analytical energy pile model,a system model will be built to investigate the system performance influenced by different zoning operation strategies.Results show that intensive heat injection into the center of the pile group(Strategy 2 and Strategy 3)or heat extraction from the outer layer of the pile group(Strategy 4)can relieve the cold accumulation.Strategy 2 can relieve the outlet temperature decline from 5.54℃ to 4.46℃ and improve the heating COP from 3.297 to 3.423 compared to the conventional full operation strategy.Although the annual heat pump COP of Strategy 2 is a little lower than that of conventional full operation strategy,Strategy 2 has the shortest unmet heating or cooling time.Therefore,the proposed zoning operation strategy can achieve good system efficiency and excellent system reliability compared to the conventional strategy.
基金This work was supported by the National Natural Science Foundation of China(No.51708551).
文摘The borehole and total internal thermal resistance are both significant parameters in evaluating the thermal performance of the ground source heat pump.This study aimed to obtain the accurate correlation of the 3D borehole and total internal thermal resistance(R_(b,3D)and R_(a,3D))and analyze the impacts of parameters on the R_(b,3D)and R_(a,3D).Firstly,eight parameters affecting the R_(b,3D)and R_(a,3D),including the borehole diameter,pipe diameter,pipe-pipe distance,borehole depth,soil thermal conductivity,grout thermal conductivity,pipe thermal conductivity,and fluid velocity inside the pipe,were considered and an L-54 design matrix was generated.Then,the 3D numerical model,coupling with the four-resistance model,was proposed to calculate R_(b,3D)and R_(a,3D)for each case.After that,the response surface methodology was employed to obtain and verify the correlation of R_(b,3D)and R_(a,3D),which were compared with the existing resistance calculation methods.Lastly,analysis of variance was carried out to reveal parameters that have statistically significant impacts on the R_(b,3D)and R_(a,3D).Results show that the rationality and accuracy of the correlation of R_(b,3D)and R_(a,3D)can be verified by the determination coefficient and P value of regression model,as well as the P value of lack-of-fit.The existing resistance calculation methods are more or less inaccurate and the discrepancies in some cases can be up to 86.74%and 111.35%for the borehole and total internal thermal resistance.The pipe and grout thermal conductivity,pipe and borehole diameter,and the pipe-pipe distance can be seen as the significant contributory factors to the variation of R_(b,3D)and R_(a,3D).
基金the National Natural Science Foundation of China(NSFC)for providing financial support of this work(Grant No.41877200)supported by the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)No.CUGL150818 and No.CUGL180407。
文摘Operation strategies of Ground Source Heat Pump System(GSHPS) such as continuous or intermittent approaches have been extensively studied. In this work, a novel strategy was proposed to maximize the energy efficiency of GSHPS. In this approach, the buildings was first air-conditioned by the preheating/precooling mode and the rest thermal load was covered by the heat pump(HP) mode. The system performance can then be optimized by considering the combination of these two operating modes. A case study was made to examine the thermal performance of a GSHPS installed in Nuremberg, Germany. Thermal performance of the HP and the preheating/precooling operating modes was examined. The system was optimized by deploying the assistant preheating/precooling approach and over one-year period monitoring showed that the seasonal Coefficient of Performance(COP) of the GSHPS was 4.12 in winter and 5.01 in summer. These COP values are higher than that of the conventional GSHPS. Thus, this proposed strategy could be an efficient way to improve the thermal performance of GSHPS.
文摘Given the growing interest in ground source heat pump and distributed heating installations in general for the reduction of greenhouse gas emissions,technology implementation planning can benefit from the simultaneous consideration of building renovations.Here,a method for identifying and evaluating scenarios based on cost and greenhouse gas emissions is presented.The method is demonstrated for a case study in Vaasa Finland.The case study considers the insulation of the walls,roof,and base floor and the replacement of windows based on 2003 and 2010 Finnish building codes simultaneously with the possible replacement of existing heat sources with ground source heat pumps.Estimates of changes in heat demand for consecutive renovations are combined with data on renovation,installation,heating costs,and life cycle greenhouse gas emissions data for the current and proposed heat sources.Preferred scenarios are identifi ed and evaluated by building type,construction decade,and current heating source.The results are then placed within the contexts of the Vaasa building stock and policy theory.
文摘The orientation strategy of side pipe and the heat transfer performance of six ground heat exchangers(GHEs) were optimized by numerical simulation,with soil being treated as a porous medium.An experiment on the heat transfer of four GHEs was carried out in 2010.Results indicate that the velocity field is disturbed by GHEs.The optimal orientation strategy of side pipe is that the upward pipe is located upstream and the downward pipe downstream.The space between GHEs should be appropriately adjusted,depending on the direction and flow velocity.Groups of GHEs should be installed perpendicular to the mainstream in a single row,but if the acreage does not meet the requirements,GHEs should be installed in staggered multiple rows.Fewer GHEs parallel to the mainstream strengthen the heat transfer.Moreover,numerical results agree well with the test data,with the maximum relative error being less than 7.7%.
基金Supported by Tianjin Scientific Development Foundation (No.013112811-1) .
文摘A simplified numerical model of heat transfer characteristics of horizontal ground heat exchanger (GHE) in the frozen soil layer is presented and the steady-state distribution of temperature field is simulated. Numerical results show that the frozen depth mainly depends on the soil′s moisture content and ambient temperature. The heat transfer loss of horizontal GHE tends to grow with the increase of the soil′s moisture content and the decrease of ambient temperature. Backfilled materials with optimal thermal conductivity can reduce the thermal loss effectively in the frozen soil. The applicability of the Chinese national standard “Technical Code for Ground Source Heat Pump (GB 50366-2005)” is verified. For a ground source heat pump project, the feasible layout of horizontal GHE should be determined based on the integration of the soil′s structure, backfilled materials, weather data, and economic analysis.
基金Key Discipline Program of Donghua University,China
文摘The effect of ground properties with heat conduction between soil and ground loop heat exchangers(GLHEs)has been analyzed.A finite line source model proposed by Cui,Yang,and Fang is used.Far field radius is defined.The analyses for a 1.5m borehole line source in three kinds of soil conditions:damp and breeze(D.B.),damp and heavy(D.H.),and saturated and heavy(S.H.)are carried out.The results of the comparisons show that in the condition of continuous operation,the variation of the far field radius is related to soil thermal conductivity.The rate of heat transfer will decrease after long time operation.And then soil condition will not influence the far field radius obviously.
文摘Natural energy use is important to reduce the energy consumption of buildings. However, further reducing energy consumption with traditional systems is difficult. Therefore, we proposed a MMHP （multi-source and multi-use heat pump） to achieve higher efficiency than traditional systems. The MMHP system connects multiple heat sources such as solar heat, the ground, and air and multiple heat uses such as cooling, heating, and a hot water dispenser with a water loop. Each type of heat use side can utilize heat efficiently. However, there is a distinct lack of highly efficient hot water dispensers available. Therefore, we developed the IHWD WS （instantaneous hot water dispenser based on a water source） heat pump. In this study, we developed a prototype of the IHWD WS heat pump. The coefficient of performance of the IHWD WS heat pump was 5.2-8.5 throughout a year. When it is improved, COP （coefficient of performance） is expected to be 9.3-9.9.
