scholarly journals Numerical Investigation of the Influence of Precooling on the Thermal Performance of a Borehole Heat Exchanger

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 151
Author(s):  
Shuiping Zhu ◽  
Jianjun Sun ◽  
Kaiyang Zhong ◽  
Haisheng Chen
Keyword(s):  
Numerical Simulation ◽  
Thermal Diffusivity ◽  
High Efficiency ◽  
Nonlinear Function ◽  
Energy System ◽  
Heat Pumps ◽  
Green Energy ◽  
Geothermal Resources ◽  
Ground Source Heat Pumps ◽  
Ground Source

Ground source heat pumps (GSHPs), a high-efficiency and energy-saving air-conditioning technology that utilizes shallow geothermal resources for both heating and cooling, are a vital green energy system for residential and commercial buildings. Improving the performance of such a system was the focus of the current research. As soil temperature and thermal radius are two important aspects that affect the performance of ground source heat pump systems, we conducted a new numerical simulation to capture the changes in sensitive factors and propose the optimized paths. The numerical simulation analyzed the thermal characteristics of a borefield under different pre-cooling times and soil types. The results indicated the following: (1) The rate of the ground temperature change with pre-cooling during the discharging period had a faster rise than in the case without pre-cooling. The longer the precooling time was, the smaller the thermal radius became. In particular, when the precooling time was longer than 14 days, the decrease in the thermal radius rate percentages was less than 4%. (2) Among the three kinds of soils compared, the soils with lower thermal conductivity and thermal diffusivity best suppressed the thermal interference effects. (3) Using a multivariate nonlinear function regression model, a simulation formula was proposed to predict- the thermal radius, which considered the factors of thermal diffusivity, precooling time, and discharging time. The prediction deviation was within 14.8%.

scholarly journals Optimal Operation Strategy of a Community Integrated Energy System Constrained by the Seasonal Balance of Ground Source Heat Pumps

2020 ◽  
Vol 12 (11) ◽  
pp. 4627
Author(s):  
Jianan Liu ◽  
Hao Yu ◽  
Haoran Ji ◽  
Kunpeng Zhao ◽  
Chaoxian Lv ◽  
...  
Keyword(s):  
High Efficiency ◽  
Energy System ◽  
Heat Pumps ◽  
Optimal Operation ◽  
Coefficient Of Performance ◽  
Operation Strategy ◽  
Ground Source Heat Pumps ◽  
Integrated Energy Systems ◽  
Ground Source ◽  
Integrated Energy System

Ground source heat pumps (GSHPs) are now widely used in community integrated energy systems (CIES) because of their high efficiency in energy conversion. However, the coefficient of performance (COP) of GSHPs is unstable if the soil temperature changes with seasonal imbalanced cooling and heating loads, thus downgrading the overall performance of CIES. In this paper, an annual optimization model for CIES that considers the seasonal balance of GSHPs is established. Then, a day-ahead operation strategy based on the pre-allocated load of the GSHP in the yearly balance is proposed while considering the uncertainties in daily conditions. The proposed strategy is validated on a practical CIES in China and assessed on a year-round time scale. The results show that the operation of CIES can be stable, economical and sustainable while ensuring the seasonal balance of the GSHP.

scholarly journals Research on Operation Optimization Strategy of Integrated Energy System Considering Ground Source Heat Pump

2020 ◽  
Vol 165 ◽  
pp. 01013
Author(s):  
Linfeng Wang ◽  
Kai Zhang ◽  
Nan Xu ◽  
Jingyan Wang ◽  
Danyang Zhang ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Energy System ◽  
Heat Pumps ◽  
Optimal Operation ◽  
Energy Prices ◽  
Operation Strategy ◽  
Ground Source Heat Pumps ◽  
Operation Optimization ◽  
Ground Source ◽  
Integrated Energy System

With the depletion of fossil energy and the popularity of renewable energy, a comprehensive energy system with the goal of improving system energy efficiency and consuming renewable energy is booming. Based on the combined heat, power, and heat generation, this paper builds a comprehensive energy system operation optimization model in conjunction with ground source heat pumps. It aims to find the optimal operation strategy based on the actual situation of the park’s load, equipment capacity, and energy prices. Using the linear programming method, a mathematical model with the best economic efficiency of the integrated energy system is established, the optimal operation strategy for a typical day is analyzed, and the annual operation is simulated. Finally, it compares with conventional energy supply methods and analyzes the contribution to the consumption of renewable energy.

scholarly journals Characterization of the Effects of Borehole Configuration and Interference with Long Term Ground Temperature Modelling of Ground Source Heat Pumps

2021 ◽  
Author(s):  
Ying Lam E. Law ◽  
Seth B. Dworkin
Keyword(s):  
Fast Food ◽  
High Efficiency ◽  
Separation Distance ◽  
Heat Pumps ◽  
Ground Temperature ◽  
Conventional Heating ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source

Ground source heat pumps (GSHPs) are an environmentally friendly alternative to conventional heating and cooling systems because of their high efficiency and low greenhouse gas emissions. The ground acts as a heat sink/source for the excess/required heat inside a building for cooling and heating modes, respectively. However, imbalance in heating and cooling needs can change ground temperature over the operating duration. This increase/decrease in ground temperature lowers system efficiency and causes the ground to foul—failing to accept or provide more heat. In order to ensure that GSHPs can operate to their designed conditions, thermal modelling is required to simulate the ground temperature during system operation. In addition, the borehole field layout can have a major impact on ground temperature. In this study, four buildings were studied—a hospital, fast-food restaurant, residence, and school, each with varying borehole configurations. Boreholes were modeled in a soil volume using finite-element methods and heating and cooling fluxes were applied to the borehole walls to simulate the GSHP operation. 20 years of operation were modelled for each building for 2x2, 4x4, and 2x8 borehole configurations. Results indicate that the borehole separation distance of 6 m, recommended by ASHRAE, is not always sufficient to prevent borehole thermal interactions. Benefits of using a 2x8 configuration as opposed to a 4x4 configuration, which can be observed because of the larger perimeter it provides for heat to dissipate to surrounding soil were quantified. This study indicates that it is important to carefully consider ground temperature during the operation of a GSHP. Borehole separation distances, layout, and hybridization should be studied to alleviate ground fouling problems.

scholarly journals BUILDINGS DESIGN INTEGRATION WITH GEOTHERMAL ENERGY SYSTEM TECHNOLOGIES AND AIR CONDITIONING APPLICATIONS

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Abeer Osama Radwan
Keyword(s):  
Geothermal Energy ◽  
Influence Factors ◽  
Energy System ◽  
Heat Pumps ◽  
Ground Source Heat Pumps ◽  
Human Thermal Comfort ◽  
Heating And Cooling ◽  
Ground Source ◽  
Modern Cities ◽  
Design Integration

Nowadays global warming and thermal islands in modern cities are spending much energy on heating and cooling spaces. Geothermal energy considered a renewable energy technology for space heating and cooling. The ground source heat pumps (GSHPs) are increasingly interested in their expressive potential to reduce fossil fuel consumption and hence reduce greenhouse gases. Geothermal energy used for both electricity generation and direct use, depending on the temperature and the chemistry of the resources. Recently, direct utilization has varied significantly, and there are several methods available for temperatures typically ranging from 4°C up to 80°C. (Lund J.W., 2012). This paper presents a comprehensive literature-based review of ground source heat pump technology, cooling, and heating applications buildings to achieve precisely human thermal comfort. Subsequently, propose the influence factors of the system components that would undoubtedly reflect on the optimal design of the building. As a result, achieve precisely an integrated building.

scholarly journals Characterizing Unggaran Geothermal Resource Potential in Central Java : Application of Gedongsongo Manifestations Evaluation

KnE Energy ◽  
2015 ◽  
Vol 2 (2) ◽  
pp. 1
Author(s):  
Adrian Rizki Sinuhaji ◽  
Yudha Herlambang
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Electrical Power ◽  
Heat Pumps ◽  
Electrical Power Systems ◽  
Geothermal Resources ◽  
Ground Source Heat Pumps ◽  
Central Java ◽  
Ground Source ◽  
Geothermal Power

<p>Geothermal power is extracted from heat stored in the earth. This paper discusses the use of geothermal energy in our electrical power systems and potential development in Central Java. Gedongsongo surface manifestations of the Ungaran geothermal prospect in Central Java have high temperature properties, (72 to 87) ºC, pH 2 to pH 6 and 770 g/kg of chloride. Geothermal power plant is very compatible built in Gedongsongo. At present, the development of geothermal resources as renewable energy have to be primarily focused on utilization of ground source heat pumps which can make good use of the enormous low temperature geothermal resources. </p><p><strong>Keywords</strong>: Central Java; Geothermal; renewable energy</p>

scholarly journals Characterization of the Effects of Borehole Configuration and Interference with Long Term Ground Temperature Modelling of Ground Source Heat Pumps

2021 ◽  
Author(s):  
Ying Lam E. Law ◽  
Seth B. Dworkin
Keyword(s):  
Fast Food ◽  
High Efficiency ◽  
Separation Distance ◽  
Heat Pumps ◽  
Ground Temperature ◽  
Conventional Heating ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source

Ground source heat pumps (GSHPs) are an environmentally friendly alternative to conventional heating and cooling systems because of their high efficiency and low greenhouse gas emissions. The ground acts as a heat sink/source for the excess/required heat inside a building for cooling and heating modes, respectively. However, imbalance in heating and cooling needs can change ground temperature over the operating duration. This increase/decrease in ground temperature lowers system efficiency and causes the ground to foul—failing to accept or provide more heat. In order to ensure that GSHPs can operate to their designed conditions, thermal modelling is required to simulate the ground temperature during system operation. In addition, the borehole field layout can have a major impact on ground temperature. In this study, four buildings were studied—a hospital, fast-food restaurant, residence, and school, each with varying borehole configurations. Boreholes were modeled in a soil volume using finite-element methods and heating and cooling fluxes were applied to the borehole walls to simulate the GSHP operation. 20 years of operation were modelled for each building for 2x2, 4x4, and 2x8 borehole configurations. Results indicate that the borehole separation distance of 6 m, recommended by ASHRAE, is not always sufficient to prevent borehole thermal interactions. Benefits of using a 2x8 configuration as opposed to a 4x4 configuration, which can be observed because of the larger perimeter it provides for heat to dissipate to surrounding soil were quantified. This study indicates that it is important to carefully consider ground temperature during the operation of a GSHP. Borehole separation distances, layout, and hybridization should be studied to alleviate ground fouling problems.

scholarly journals Application and development of ground source heat pump technology in China

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Chaofan Song ◽  
Yang Li ◽  
Taha Rajeh ◽  
Ling Ma ◽  
Jun Zhao ◽  
...  
Keyword(s):  
High Efficiency ◽  
Heat Pumps ◽  
Economic Feasibility ◽  
Ground Source Heat Pumps ◽  
Renewable Energy Technologies ◽  
Development History ◽  
Energy Technologies ◽  
Heating And Cooling ◽  
Ground Source ◽  
Promising Development

AbstractGround 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.

scholarly journals Modelling Ground Collectors and Determination of the Influence of Technical Parameters, Installation and Geometry on the Soil

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7153
Author(s):  
Ľubomíra Gabániová ◽  
Dušan Kudelas ◽  
Martin Prčík
Keyword(s):  
Climate Change ◽  
Water Content ◽  
Soil Type ◽  
High Efficiency ◽  
Heat Pumps ◽  
Heating Season ◽  
Ground Source Heat Pumps ◽  
Technical Parameters ◽  
Ground Source

The main objective of this work was to model ground collectors with different parameters and geometries in ANSYS R19.2 and to simulate their operation during the heating season in Slovakia in order to determine their impact on the soil. At the same time, four new geometries in the shape of vertical spirals with diameters of 6, 8 and 10 m were designed and simulated to occupy a smaller area while maintaining performance similar to classical geometries. Due to climate change, heat pumps are becoming an important proxy in the heating of buildings and are an important part of decarbonisation plans; thus, it is essential to adapt them to urban and metropolitan conditions. Ground source heat pumps possess high efficiency but require a lot of space for their collectors. The collector geometries proposed in this work are a combination of horizontal and vertical technologies and are feasible. Only one geometry achieved performance similar to classical geometries: spiral with 10 m diameter. Factors significantly influencing collector operation were confirmed, namely season, soil type, soil water content, geometry and collector placement.

scholarly journals Analysis of ground-source heat pumps in north-of-England homes

2017 ◽  
Vol 170 (3) ◽  
pp. 103-115 ◽  
Author(s):  
Alexis Ali ◽  
Mostafa Mohamed ◽  
Mohamad Abdel-Aal ◽  
Alma Schellart ◽  
Simon Tait
Keyword(s):  
Heat Pumps ◽  
Ground Source Heat Pumps ◽  
Ground Source
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