Thermal Modeling of a Geothermal Well Field for Ground Source Water Heat Pump Systems

Thermal Reservoir ◽

Geothermal Well ◽

Ground Source ◽

Well Model ◽

Single Well

Heat pumps are mechanical systems that provide heating to a space in the winter, and cooling in the summer. They are increasingly popular because the same system provides both cooling modes, depending on the direction of the cycle upon which they operate. For proper operation, the heat pump must be connected to a constant temperature thermal reservoir which in traditional systems is the ambient air. In ground source heat pumps however, subterranean ground water is used as the thermal reservoir. To access the subterranean groundwater, “geothermal” wells are drilled into the formation. Water from the building heating or cooling system is circulated through the wells thereby promoting heat exchange between the coolant water and the subterranean formation. The potential for higher efficiency heating and cooling has increased the utilization of ground source HVAC systems. In addition, their compatibility with a naturally occurring and very stable thermal reservoir has increased their use in the design of sustainable or green buildings and man-made environments. This paper is concerned with the development of a mathematical model describing the thermal processes that occur in a circulating geothermal well as the water thermally interacts with the surrounding formation. First principles are utilized to develop a general single well model that is able to predict the heating or cooling of a well with time. The single well model is then utilized to build a simulation for an infinite line of adjacent wells that thermally interact with each other over time. The behavior of a single isolated well and a line of evenly spaced wells is discussed and compared with recent experimental data for circulation in an isolated well.

ASME 2011 5th International Conference on Energy Sustainability, Parts A, B, and C ◽

A Model for a Geothermal Well in a Hydraulic Groundwater Flow for Ground Source Heat Pump Systems

10.1115/es2011-54679 ◽

2011 ◽

Author(s):

Kevin D. Woods ◽

Alfonso Ortega

Keyword(s):

Thermal Conductivity ◽

Analytical Solution ◽

Groundwater Flow ◽

Heat Pump ◽

Temperature Response ◽

Ambient Air ◽

Heat Pumps ◽

Thermal Reservoir ◽

Geothermal Well ◽

Heat pumps are mechanical systems that provide heating to a space in the winter, and cooling in the summer. They are increasingly popular because the same system provides both cooling modes, depending on the direction of the cycle upon which they operate. For proper operation, the heat pump must be connected to a constant temperature thermal reservoir which in traditional systems is the ambient air. In ground source heat pumps however, subterranean ground water is used as the thermal reservoir. To access the subterranean groundwater, “geothermal” wells are drilled into the formation. Water from the building heating or cooling system is circulated through the wells thereby promoting heat exchange between the coolant water and the subterranean formation. The potential for higher efficiency heating and cooling has increased the utilization of ground source heating ventilating and air conditioning systems. In addition, their compatibility with a naturally occurring and stable thermal reservoir has increased their use in the design of sustainable or green buildings and man-made environments. Groundwater flow affects the temperature response of thermal wells due to advection of heat by physical movement of groundwater through the aquifer. Research on this subject is scarce in the geothermal literature. This paper presents the derivation of an analytical solution for thermal dispersion by conduction and advection from hydraulic groundwater flow for a “geothermal” well. This analytical solution is validated against asymptotic analytical solutions. The traditional constant linear heat source solution is dependent on the ground formation thermal properties; the most dominant of which is the thermal conductivity. The results show that as hydraulic groundwater flow increases, the influence of the ground formation thermal conductivity on the temperature response of the well diminishes. The diminishing influence is evident in the Peclet number parameter; a comparison of thermal advection from hydraulic groundwater flow to thermal conduction by molecular diffusion.

Ground-Source Heat Pumps with Horizontal Heat Exchangers for Space Cooling in the Hot Tropical Climate of Thailand

Energies ◽

10.3390/en12071274 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1274 ◽

Cited By ~ 5

Author(s):

Arif Widiatmojo ◽

Sasimook Chokchai ◽

Isao Takashima ◽

Yohei Uchida ◽

Kasumi Yasukawa ◽

...

Keyword(s):

Economic Growth ◽

Heat Pump ◽

Heat Exchangers ◽

Life Cycle Cost ◽

Heat Pumps ◽

Ground Source Heat Pump ◽

Air Source Heat Pump ◽

Ground Source ◽

Space Cooling

The cooling of spaces in tropical regions, such as Southeast Asia, consumes a lot of energy. Additionally, rapid population and economic growth are resulting in an increasing demand for space cooling. The ground-source heat pump has been proven a reliable, cost-effective, safe, and environmentally-friendly alternative for cooling and heating spaces in various countries. In tropical countries, the presumption that the ground-source heat pump may not provide better thermal performance than the normal air-source heat pump arises because the difference between ground and atmospheric temperatures is essentially low. This paper reports the potential use of a ground-source heat pump with horizontal heat exchangers in a tropical country—Thailand. Daily operational data of two ground-source heat pumps and an air-source heat pump during a two-month operation are analyzed and compared. Life cycle cost analysis and CO2 emission estimation are adopted to evaluate the economic value of ground-source heat pump investment and potential CO2 reduction through the use of ground-source heat pumps, in comparison with the case for air-source heat pumps. It was found that the ground-source heat pumps consume 17.1% and 18.4% less electricity than the air-source heat pump during this period. Local production of heat pumps and heat exchangers, as well as rapid regional economic growth, can be positive factors for future ground-source heat pump application, not only in Thailand but also southeast Asian countries.

Sensitivity analysis using simulations for a ground source heat pump – implementation on a solar passive house

E3S Web of Conferences ◽

10.1051/e3sconf/201911101070 ◽

2019 ◽

Vol 111 ◽

pp. 01070

Author(s):

Gheorghe Ilisei ◽

Tiberiu Catalina ◽

Robert Gavriliuc

Keyword(s):

Sensitivity Analysis ◽

Heat Pump ◽

Fossil Fuels ◽

Electricity Consumption ◽

Heat Pumps ◽

Ground Source Heat Pump ◽

Passive House ◽

Modeling Tools ◽

Having in sight the need for a strong reduction in CO2 emissions and the fluctuation of the price of fossil fuels, the ground source resources alongside with the ground source heat pumps are becoming more and more widespread for meeting the heating/cooling demand of several types of buildings. This article targets to develop the thermal modelling of borehole heat storage systems. Trying to emphasize some certain advantages of a GSHP (ground source heat pump) with vertical boreholes, a case study analysing a residential solar passive house is presented. The numerical results are produced using different modelling software like DesignBuilder, EED (Earth Energy Designer) and a sizing method for the length of the boreholes (ASHRAE method). The idea of sizing the length of boreholes (main design parameter and good index in estimating the system’s cost) using two different methods shows the reliability of this modelling tool. The study shows that borehole’s length of a GSHP system can trigger a difference in electricity consumption up to 22%. Moreover, this sensitivity analysis aims to prove that the design of the whole system can be done beforehand just using modeling tools, without performing tests in-situ.

Selection and techno-economic analysis of hybrid ground source heat pumps used in karst regions

Science Progress ◽

10.1177/0036850420921682 ◽

2020 ◽

Vol 103 (2) ◽

pp. 003685042092168

Author(s):

Weisong Zhou ◽

Peng Pei ◽

Ruiyong Mao ◽

Haibin Qian ◽

Yanbing Hu ◽

...

Keyword(s):

Economic Analysis ◽

Heat Pump ◽

Groundwater Resources ◽

Heat Pumps ◽

Ground Source Heat Pump ◽

Pump System ◽

Ground Source ◽

Heat Buildup

In order to take advantage of different forms of heat pumps and to mitigate thermal imbalance underground caused by long-term operation of ground source heat pumps, hybrid ground source heat pump systems have received an increasing attention. In this research, based on the fact that abundant groundwater resources are commonly available in karst regions, a new strategy is introduced for selecting and determining hybrid ground source heat pump capacity. Five scenarios of hybrid ground source heat pump system coupling groundwater source heat pumps with other supplementary heat pumps are proposed in this article to provide appropriate options to eliminate heat buildup under different hydrogeologic conditions. Methodologies for sizing and selection are established. Then, a case study of techno-economic analysis was performed for a project in the karst region in South China. The results showed that these scenarios can effectively mitigate heat buildup, and under the hydrogeologic condition in the case study. Compared to the solo ground-coupled heat pump solution, the optimal solution (Solution 4 in this study) can reduce the annual costs by 16.10% and reduce the capital investment by 60%. Methodologies developed in this study are beneficial for selecting appropriate approaches to mitigate heat buildup and enhance competitiveness of ground source heat pumps.

A European Database of Building Energy Profiles to Support the Design of Ground Source Heat Pumps

Energies ◽

10.3390/en12132496 ◽

2019 ◽

Vol 12 (13) ◽

pp. 2496 ◽

Cited By ~ 7

Author(s):

Laura Carnieletto ◽

Borja Badenes ◽

Marco Belliardi ◽

Adriana Bernardi ◽

Samantha Graci ◽

...

Keyword(s):

Heat Pump ◽

Energy Demand ◽

Residential Buildings ◽

Building Energy ◽

Heat Pumps ◽

Climatic Conditions ◽

Heating And Cooling ◽

Energy Profiles ◽

The design of ground source heat pumps is a fundamental step to ensure the high energy efficiency of heat pump systems throughout their operating years. To enhance the diffusion of ground source heat pump systems, two different tools are developed in the H2020 research project named, “Cheap GSHPs”: A design tool and a decision support system. In both cases, the energy demand of the buildings may not be calculated by the user. The main input data, to evaluate the size of the borehole heat exchangers, is the building energy demand. This paper presents a methodology to correlate energy demand, building typologies, and climatic conditions for different types of residential buildings. Rather than envelope properties, three insulation levels have been considered in different climatic conditions to set up a database of energy profiles. Analyzing European climatic test reference years, 23 locations have been considered. For each location, the overall energy and the mean hourly monthly energy profiles for heating and cooling have been calculated. Pre-calculated profiles are needed to size generation systems and, in particular, ground source heat pumps. For this reason, correlations based on the degree days for heating and cooling demand have been found in order to generalize the results for different buildings. These correlations depend on the Köppen–Geiger climate scale.

Analysis of ground thermal potential reduction and thermal interaction between boreholes during operation of ground source heat pump in Moscow city environments

E3S Web of Conferences ◽

10.1051/e3sconf/202128902006 ◽

2021 ◽

Vol 289 ◽

pp. 02006

Author(s):

Elizaveta Tyabut ◽

Ivan Sokolov ◽

Artem Ryzhenkov

Keyword(s):

Heat Pump ◽

Mutual Influence ◽

Energy Resource ◽

Heat Pumps ◽

Geothermal Field ◽

Climatic Conditions ◽

Promising Alternative ◽

Ground Source ◽

Moscow City

Geothermal energy is a renewable energy resource. Nowadays it can be considered as a promising alternative to various fossil fuels. Ground source heat pumps are efficient installations enabling the intensive use of underground energy for heating and cooling of modern residential and commercial buildings. However, climatic conditions often limit the use of this type of installation to a certain extent. This paper presents a description of an existing system comprising a liquid-toliquid heat pump and a geothermal field consisting of 4 boreholes. The system is used to investigate the intensity of ground temperature potential decrease in winter and its recovery in summer in the Moscow city environment with a detailed study of the properties of individual soil layers, as well as to study the mutual influence of boreholes on each other, represented by the conditional radius of thermal influence of individual boreholes. Graphs of soil temperature changes at different depths are presented.

Analysis of the Heat Pump Market in Europe with a Special Regard to France, Spain, Poland and Lithuania

Environmental and Climate Technologies ◽

10.2478/rtuect-2021-0063 ◽

2021 ◽

Vol 25 (1) ◽

pp. 840-852

Author(s):

Agata Witkowska ◽

Dorota Anna Krawczyk ◽

Antonio Rodero

Keyword(s):

Heat Pump ◽

Energy Efficient ◽

Heat Pumps ◽

Hot Water ◽

Key Technology ◽

Technological Factors ◽

Special Regard ◽

Ground Source ◽

Social Environmental

Abstract Becoming the world’s first climate-neutral continent by 2050 is currently the most ambitious European goal. Heat pumps are the example of the key technology, which could help to achieve the aim by heating, cooling and domestic hot water (DHW) preparation in an ecological and energy-efficient way. This article characterized a heat pump market in Europe between 2009 and 2020 with a special regard to France, Spain, Poland and Lithuania, for which a more detailed study was presented. The analysis was performed primarily on the grounds of statistics data provided by the European Heat Pump Association (EHPA), which determined the number of heat pumps sold based on standard questionnaires from national heat pump associations, statistical offices and research institutes. The highest number of heat pump sold in analysed period of time was recorded in France, Italy, Sweden, Norway, Germany and Spain. Poland was in the middle of the list, while Lithuania was one of the last countries. Considering the number of heat pumps sold per 1000 households, Norway was the clear leader, followed by Estonia, Finland, Sweden and Denmark. Lithuania was placed 12th, while Poland was only 18th. In terms of the type of lower and upper heat source, air-to-water and air-to-air heat pumps were the most popular choices, while ground source heat pumps were the least popular. The development of the heat pump market has been influenced by social, environmental, economic and technological factors.

Measurement and Verification of Integrated Ground Source Heat Pumps on a Shared Ground Loop

Energies ◽

10.3390/en13071752 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1752 ◽

Cited By ~ 1

Author(s):

Jeong Soo Shin ◽

Jong Woo Park ◽

Sean Hay Kim

Keyword(s):

Heat Pump ◽

Air Conditioning ◽

Heat Pumps ◽

Hot Water ◽

Geothermal System ◽

Ground Source Heat Pump ◽

Pump System ◽

Water Service ◽

We propose an integrated geothermal system that consists of air-conditioning and hot water service ground source heat pumps, both of which share a ground water loop. The proposed system increases the COP of the service hot water ground source heat pump by recovering the condensation heat of the air-conditioning ground source heat pump as an evaporator heat source for the hot water service ground source heat pump. Eventually this integration expands the scope and capacity of the evaporator source in addition to the underground water of heat exchangers, which also leads to increase the COP of the air-conditioning ground source heat pump. The integrated geothermal heat pump system was installed in a hotel, and then data were measured for a limited period due to the hotel’s ongoing business activities. A TRNSYS simulation model has been developed as a baseline, and the baseline has been calibrated with the measured data. By running one-year simulations, it turns out that the annual electricity use for heating and cooling, and service hot water was reduced by 19.1% in the cooling season, and by 9.6% in the heating season, with respect to the conventional configuration in which the air-conditioning heat pump and hot water service heat pump work individually on their own ground loops.

KAJIAN TEORITIK PEMILIHAN HEAT PUMP DAN PERHITUNGAN SISTEM SALURAN PADA KANDANG PETERNAKAN AYAM BROILER SISTEM TERTUTUP

INFOMATEK ◽

10.23969/infomatek.v19i01.543 ◽

2017 ◽

Vol 19 (01) ◽

pp. 11

Author(s):

Evi - Sofia

Keyword(s):

Heat Pump ◽

Heat Pumps ◽

Kebutuhan daging ayam ras broiler (ayam pedaging) cenderung meningkat setiap tahun. Dengan terus meningkatnya konsumsi daging ayam tersebut diperlukan peternak-peternak ayam yang mampu memelihara ayam-ayam pedaging dengan baik. Salah satu penentu untuk menghasilkan ayam-ayam pedaging yang baik adalah sistem perkandangannya. Sistem perkandangan yang baik membutuhkan pengelolaan pengkondisian udara yang tepat. Karena ayam memerlukan temperatur ruangan yang berbeda-beda pada setiap masa pertumbuhannya. Penggunaan Heat Pump sebagai pemanas untuk kandang peternakan ayam broiler memang tidak lazim digunakan. Akan tetapi di beberapa negara penggunaan heat pump dengan fluida kerja air dari tanah (Ground Source Heat pumps/GSHP) banyak digunakan sebagai pemanas kandang ayam. Penggunaan heat pump dengan sistem kompresi uap masih belum ditemui. Kajian ini bertujuan untuk mencoba memanfaatkan Heat pump dengan sistem kompresi uap jika digunakan sebagai pemanas kandang ayam. Kajian diawali dengan menghitung energi yang dibutuhkan kandang, pemilihan heat pump dan perhitungan ducting. Dari hasil kajian ini menunjukkan bahwa penggunaan heat pump sebagai pemanas kandang ayam memungkinkan untuk digunakan

Experimental Study and Modeling of Ground-Source Heat Pumps with Combi-Storage in Buildings

10.20944/preprints201804.0183.v1 ◽

2018 ◽

Author(s):

Wessam El-Baz ◽

Peter Tzscheutschler ◽

Ulrich Wagner

Keyword(s):

Heat Pump ◽

Water Consumption ◽

Residential Buildings ◽

Heat Pumps ◽

Hot Water ◽

Space Heating ◽

Domestic Hot Water ◽

Ground Source ◽

And Control

There is a continuous growth of heat pump installations in residential buildings in Germany. The heat pumps were not only used for space heating and domestic hot water consumption but also to offer flexibility to the grid. the high coefficient of performance and the low cost of heat storages made the heat pumps an optimal candidate for the power to heat applications. Thus, several questions are raised about the optimal integration and control of the heat pump system with buffer storages to maximize its operation efficiency and minimize the operation costs. In this paper, an experimental investigation is performed to study the performance of a ground source heat pump (GSHP) with a combi-storage under several configurations and control factors. The experiments were performed on an innovative modular testbed that is capable of emulating a ground source to provide the heat pump with different temperature levels at different times of the day. Moreover, it can emulate the different building loads such as the space heating load and the domestic hot water consumption in real-time. The data gathered from the testbed and different experimental studies were used to develop a simulation model based on Modelica that can accurately simulate the dynamics of a GSHP in a building. The model was validated based on different metrics. Energetically, the difference between the developed model and the measured values was only 3.08\% and 4.18\% for the heat generation and electricity consumption, respectively.