Energy demand reduction in the built environment using shallow geothermal integrated energy systems – A comprehensive review: Part I. Design consideration of ground heat exchanger

2021 ◽  
pp. 1-62
Author(s):  
Balaji Kumar
Keyword(s):  
Heat Exchanger ◽  
Built Environment ◽  
Energy Demand ◽  
Numerical Models ◽  
Thermal Response ◽  
Open Loop ◽  
Climatic Conditions ◽  
Heat Transfer Fluid ◽  
Ground Heat Exchanger ◽  
Comprehensive Review

Abstract The research collection aims at finding the various possible opportunities for the effective integration of shallow geothermal energy (SGE) to decrease the energy demand in the built environment and to reduce emission associated with it. The integration of SGE with heat pump using pipe network is extensively reviewed. The open loop and closed loop (vertical, horizontal, energy piles) pipe networks are the most common type of ground heat exchanging methods. The objective of the review is to improve the heat exchanger effectiveness through various design aspects according to the local climatic conditions. This comprehensive review part II contains the research details pertaining to the last two decades about ground heat exchangers (geometrical aspects, borehole material, grout material, thermal response test, analytical and numerical models). Also, the factors influencing the ground heat exchanger's performance such as heat transfer fluid, groundwater flow, and soil properties are discussed in detail. This paper highlights the recent research findings and a potential gap in the ground heat exchanger.

Energy demand reduction in the built environment using shallow geothermal integrated energy systems: Part II – Hybrid ground source heat pump for building heating

2021 ◽  
pp. 1-37 ◽  
Author(s):  
Balaji Kumar ◽  
Vishaldeep Sharma
Keyword(s):  
Built Environment ◽  
Heat Pump ◽  
Energy Demand ◽  
Climatic Conditions ◽  
Ground Source Heat Pump ◽  
Comprehensive Review ◽  
Integrated Energy Systems ◽  
Ground Source ◽  
Research Collection ◽  
Primary Focus

Abstract The research collection aims at finding the various possible opportunities for the effective integration of shallow geothermal energy (SGE) to decrease the energy demand in the built environment and to reduce emission associated with it. The direct utilization of SGE using a ground source heat pump (GSHP) has been reviewed in comprehensive review part I and part II. From the extensive review, it is found that the hybrid GSHP is needed to avoid ground thermal imbalance and peak demand. Hybrid GSHP can adopt various supplemental heat sources and sinks according to the local climatic conditions and the balance of energy demands. The primary focus on the integration of subsystems such as biomass, solar energy (PV, PVT, and collector), phase change material, micro gas turbine, and absorption heat pump with GSHP is presented for heating application. This comprehensive review part III highlights the recent research findings and a potential gap in hybrid GSHP for further research and developments

Optimum operation of open-loop ground heat exchanger considering subsurface temperature gradient

2015 ◽  
Vol 40 (5) ◽  
pp. 651-661 ◽  
Author(s):  
Hyun-Jun Choi ◽  
Sangwoo Park ◽  
Hyungi Lee ◽  
Khanh Linh Nguyen Pham ◽  
Hyungkyou Ryu ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Temperature Gradient ◽  
Open Loop ◽  
Ground Heat Exchanger ◽  
Subsurface Temperature ◽  
Optimum Operation

An Experimental Study on the Thermal Performance Evaluation of SCW Ground Heat Exchanger

2017 ◽  
Vol 25 (01) ◽  
pp. 1750006 ◽  
Author(s):  
Keun Sun Chang ◽  
Min Jun Kim ◽  
Young Jae Kim
Keyword(s):  
Thermal Conductivity ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Effective Thermal Conductivity ◽  
Thermal Performance ◽  
Thermal Response ◽  
High Heat ◽  
Injection Rate ◽  
Operating Parameters ◽  
Ground Heat Exchanger

In recent years, application of the standing column well (SCW) ground heat exchanger (GHX) has been noticeably increased as a heat transfer mechanism of ground source heat pump (GSHP) systems with its high heat capacity and efficiency. Determination of the ground thermal properties is an important task for sizing and estimating cost of the GHX. In this study, an in situ thermal response test (TRT) is applied to the thermal performance evaluation of SCW. Two SCWs with different design configurations are installed in sequence to evaluate their effects on the thermal performance of SCW using a single borehole. A line source method is used to derive the effective thermal conductivity and borehole thermal resistance. Effects of operating parameters are also investigated including bleed, heat injection rate, flow rate and filler height. Results show that the effective thermal conductivity of top drawn SCW (Type A) is 11.7% higher than that of bottom drawn SCW (Type B) and of operating parameters tested bleed is the most significant one for the improvement of the thermal performance (40.4% enhanced in thermal conductivity with 10.9% bleed).

scholarly journals Analysis on Thermal Performance of Ground Heat Exchanger According to Design Type Based on Thermal Response Test

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 651 ◽  
Author(s):  
Sang Bae ◽  
Yujin Nam ◽  
Jong Choi ◽  
Kwang Lee ◽  
Jae Choi
Keyword(s):  
Thermal Conductivity ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Thermal Resistance ◽  
Heat Pump ◽  
Thermal Performance ◽  
Thermal Response ◽  
Ground Heat Exchanger ◽  
Thermal Response Test ◽  
Borehole Thermal Resistance

A ground source heat pump (GSHP) system has higher performance than air source heat pump system due to the use of more efficient ground heat source. However, the GSHP system performance depends on ground thermal properties and groundwater conditions. There are many studies on the improvement of GSHP system by developing ground heat exchanger (GHX) and heat exchange method. Several studies have suggested methods to improve heat exchange rate for the development of GHX. However, few real-scale experimental studies have quantitatively analyzed their performance using the same ground conditions. Therefore, the objective of this study was to evaluate the thermal performance of various pipe types of GHX by the thermal response test (TRT) under the same field and test conditions. Four kinds of GHX (HDPE type, HDPE-nano type, spiral fin type, and coaxial type) were constructed in the same site. Inlet and outlet temperatures of GHXs and effective thermal conductivity were measured through the TRT. In addition, the borehole thermal resistance was calculated to comparatively analyze the correlation of the heat exchange performance with each GHX. Result of the TRT revealed that averages effective thermal conductivities of HDPE type, HDPE-nano, spiral fin type, and coaxial type GHX were 2.25 W/m·K, 2.34 W/m·K, 2.55 W/m·K, and 2.16 W/m·K, respectively. In the result, it was found that the average borehole thermal resistance can be an important factor in TRT, but the effect of increased thermal conductivity of pipe material itself was not significant.

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