Research on the Initial Operating Performance of Ground Heat Exchangers

2013 ◽  
Vol 448-453 ◽  
pp. 2897-2902
Author(s):  
Xue Ting Huang ◽  
Yan Ling Guan ◽  
Chao Jiang
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Cfd Simulation ◽  
Operating Performance ◽  
Operating Time ◽  
Three Dimensional ◽  
Ground Heat Exchanger ◽  
Initial Operation ◽  
Ground Heat Exchangers

Focus on the unfavorable effects of initial operation to the performance of ground heat exchangers, a three-dimensional CFD simulation of full-scale ground heat exchanger under dynamic load was established to investigate the heat transfer performance of a 120-meter vertical U-Tube ground heat exchanger under different initial operating time. The results show that initial operation has influence on the performance of ground heat exchangers.

scholarly journals Analysis of Yearly Effectiveness of a Diaphragm Ground Heat Exchanger Supported by an Ultraviolet Sterilamp

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2804
Author(s):  
Sławomir Rabczak ◽  
Paweł Kut
Keyword(s):  
Heat Exchanger ◽  
Ultraviolet Radiation ◽  
Heat Exchangers ◽  
Ground Heat Exchanger ◽  
Atmospheric Air ◽  
Ground Heat Exchangers ◽  
Air Handling Unit ◽  
Operational Costs ◽  
Uv C

Ground heat exchangers supplement ventilation systems and provide notable power gains by heating ventilated air during winter and cooling it in summer. Additionally, they prevent recuperator exchangers from freezing. In atmospheric air, there are many types of contaminants and microorganisms that significantly affect the quality of ventilated air. The air that flows through the system of pipes of the heat exchanger may also become contaminated. In order to remove contamination from ventilated air, ultraviolet radiation may be used. This article presents a concept of using a UV-C (ultraviolet with a wavelength of 200–280 nm) lamp in the air duct in front of the air handling unit connected to the ground heat exchanger. The UV-C lamp, apart from clearing the air, may also decrease operational costs thanks to eliminating contamination that forms bacterial jelly on heat exchanger elements.

Determination of Optimum Design Parameters of Horizontal Parallel Pipe and Vertical U-Tube Ground Heat Exchangers

2009 ◽  
Author(s):  
Hakan Demir ◽  
Ahmet Koyun ◽  
S¸. O¨zgu¨r Atayılmaz
Keyword(s):  
Thermal Conductivity ◽  
Energy Consumption ◽  
Heat Exchanger ◽  
Objective Function ◽  
Heat Exchangers ◽  
Ground Heat Exchanger ◽  
Ground Source Heat Pump ◽  
Soil Thermal Conductivity ◽  
Ground Heat Exchangers ◽  
Ground Source

The most important part of a ground source heat pump (GSHP) is the ground heat exchanger (GHE) that consists of pipes buried in the soil and is used for transferring heat between the soil and the heat exchanger of the ground source heat pump. Soil composition, thermal properties and water content affect the length of ground heat exchanger. Another parameter affects the size of the ground heat exchanger is the shape. There are two basic ground heat exchanger configurations: vertical U-tube and horizontal parallel pipe. There are plenty of works on ground source heat pumps and ground heat exchangers in the literature. Most of the works on ground heat exchangers are based on the heat transfer in the soil and temperature distribution around the coil. Some of the works for thermo-economic optimization of thermal systems are based on thermodynamic cycles. This study covers comparative thermo-economical analysis of horizontal parallel pipe and vertical u-tube ground heat exchangers. An objective function has been defined based on heating capacity, investment and energy consumption costs of ground heat exchanger. Investment and energy consumption costs were taken into account as total cost in the objective function. The effects of the soil thermal conductivity, number of pipes, thermal capacity of ground heat exchanger, pipe diameter and the burial depth on the objective function were examined. The main disadvantage of U-tube ground heat exchanger is higher borehole cost that makes installation cost higher than parallel pipe ground heat exchanger. To make reference functions equal for both type of ground heat exchangers, the borehole cost must be under 20 $/m (now 55 $/m) for a given heating or cooling capacity. The performance of ground heat exchangers depends on the soil characteristics especially the soil thermal conductivity.

scholarly journals “OPTIMIZATION OF GROUND SOURCE HEAT PUMP:A REVIEW”

2018 ◽  
Vol 4 (6) ◽  
pp. 9
Author(s):  
Anand Kumar Patel ◽  
Pankaj Mishra
Keyword(s):  
Heat Exchanger ◽  
Three Dimensional ◽  
Ground Heat Exchanger ◽  
System Study ◽  
Buried Pipes ◽  
One Dimensional ◽  
Ground Heat Exchangers ◽  
Hot Environment ◽  
Ground Source ◽  
Dimensional Models

To effectively exploit the heat capacity of the soil a heat-exchanger system has to be constructed. Usually an array of buried pipes running along the length of the building, a nearby field or buried vertically into the ground is utilized. A circulating fluid (water or air) is used in summer to extract heat from the hot environment of the building and dump it into the ground and vice versa in winter. A heat pump may also be coupled to the ground heat exchanger to increase its efficiency. In the literature several calculation models are found for ground heat exchangers. One-dimensional models were devised in the first stages of the system study which were replaced by two- dimensional models during the nineties and three-dimensional systems during the recent years.  The present study are further refined and can accept any type of grid geometry that may give greater detail of the temperature variation around the pipes and in the ground.

scholarly journals A Comprehensive Review of Backfill Materials and Their Effects on Ground Heat Exchanger Performance

2018 ◽  
Vol 10 (12) ◽  
pp. 4486 ◽  
Author(s):  
Hossein Javadi ◽  
Seyed Mousavi Ajarostaghi ◽  
Marc Rosen ◽  
Mohsen Pourfallah
Keyword(s):  
Heat Exchanger ◽  
Phase Change ◽  
Heat Exchangers ◽  
Phase Change Materials ◽  
Energy Systems ◽  
Ground Heat Exchanger ◽  
Comprehensive Review ◽  
Backfill Material ◽  
Ground Heat Exchangers ◽  
Backfill Materials

Geothermal energy systems can help in achieving an environmentally friendly and more efficient energy utilization, as well as enhanced power generation and building heating/cooling, thereby making energy systems more sustainable. The role of the backfill material, which fills the space between a pipe and the surrounding soil, is important in the operation of ground heat exchangers. Among the review articles on parameters affecting ground heat exchanger performance published over the past eight years, only two discuss types of backfill materials, even though the importance of these materials is significant. However, no review has yet been published exclusively on the kinds of backfill materials used in ground heat exchangers. This article addresses this need by providing a comprehensive review of a variety of types of backfill materials and their effects on ground heat exchanger performance. For organizational purposes, the backfill materials are divided into two categories: conventional backfill materials (pure and mixed materials) and modern backfill materials (improved phase change materials). Both categories are described in detail. It is shown that bentonite has been used considerably as a conventional backfill material in ground heat exchangers, followed by silica sand and coarse/fine sand. Moreover, acid and shape-stabilized phase change materials have been applied mostly as modern backfill materials in ground heat exchangers. It is observed, generally, that conventional backfill materials are used more than modern backfill materials in ground heat exchangers. It should be noted that the data covered in this study are not from all the articles published in the last eight years, but rather from a subset based on specific criteria (i.e., English-language papers published in reputable journals). These articles were published by authors from numerous countries. The results may, as a consequence, have some corresponding limitations, but these are likely to be minor.

The Analysis on the Effect of the Loading Capacity of the Pile with Buried Tubes

2011 ◽  
Vol 243-249 ◽  
pp. 2889-2892
Author(s):  
Wen Wang ◽  
Rui Han ◽  
Man Xia Wu ◽  
Chun Mei Zheng
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Engineering Practice ◽  
Loading Capacity ◽  
Tube Model ◽  
Ground Heat Exchanger ◽  
Engineering Applications ◽  
Spiral Tube ◽  
Energy Pile ◽  
Ground Heat Exchangers

The pile ground heat exchanger is devised to overcome the shortcomings in configuration of existing ground heat exchangers. In view of its engineering applications of the spiral tubes ground heat exchanger inside foundation piles, the effects of them on the loading capacity features of the pile are studied. Firstly, a spiral tube model is proposed for the energy pile system and the model is proved correctly compared with engineering practice of the piles.Then，in the FEM software the model is applied in the comparasion between the piles with and without buried tubes .As a result, the effects of buried tubes on the loading capacity features of the piles are found.

scholarly journals Geothermal Energy Use for the Additional Heat Supply of a Residential Building

2020 ◽  
Vol 28 (4) ◽  
pp. 15-22
Author(s):  
Oleksandra Kuzmenko ◽  
Kostiantyn Dikarev ◽  
Daniil Rodionov ◽  
Oleksandra Martysh ◽  
Anar Iskenderov ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Energy Use ◽  
Residential Building ◽  
Ground Heat Exchanger ◽  
Ground Heat Exchangers ◽  
Recovery System ◽  
Heat Recovery System ◽  
Building Ventilation

AbstractTo ensure low-energy consumption in new generation energy-efficient houses, the technology of a ground heat exchanger with a heat recovery system is used almost everywhere. However, this technology has not been widely disseminated in Ukraine. The work is aimed at presenting insights from research on the combination of ground heat exchangers with a heat recovery system for building ventilation by analyzing the operational and techno-economic indicators obtained. Current studies permit revealing the optimal configuration of a ground heat exchanger with a heat recovery system for ventilation in a residential building in order to analyze the efficiency of ground heat exchangers with a heat recovery system for ventilation of a residential building in comparison with several conventional ventilation options to assess the main price/ performance ration of the process of constructing a ground heat exchanger with a heat recovery system and to determine the duration of the technological process, the labor-intensive characteristics, and the estimated cost of the technology.

Soil Profile and Ground Properties Influence on Vertical Ground Heat Exchanger Efficiency

2017 ◽  
Author(s):  
Michał Chwieduk ◽  
Artur Rusowicz ◽  
Hanna Jędzrzejuk
Keyword(s):  
Heat Exchanger ◽  
Soil Profile ◽  
Heat Exchangers ◽  
Heat Pumps ◽  
Symmetric Model ◽  
Ground Heat Exchanger ◽  
Ground Heat Exchangers ◽  
Calculation Results ◽  
Vertical Ground ◽  
The Impact

Soil properties have a significant impact on the performance of ground heat exchangers. Exchangers cooperating with heat pumps are a reliable and efficient source of renewable energy. In the article concentric vertical ground heat exchanger is analysed, which is a common application cooperating with heat pumps. Soil and ground properties have great im-portance during sizing the system, i.e.: determining the length, configuration and deployment of ground heat exchangers. With the depth the soil/ground type and its properties can change significantly. In addition, occurrence of a ground water can influence physical and thermal properties. Determination of soil type present at different depths in a specific location is possible by performing a soil profile. The article presents an analysis of the impact of two soil profiles on the efficien-cy of the vertical ground heat exchanger. The analysis was performed based on the model of a single heat exchanger made using CFD (Computational Fluid Dynamics) program. The model is divided into two parts: model of heat ex-changer together with grout filling the borehole, second: axis-symmetric model of the ground surrounding the exchanger. Both models are coupled by first-type boundary condition. Simulations of ground heat exchanger work are made for a part of heating season period. The calculation results were compared to reference one with uniform ground profiles. Dif-ference in heat rejected form ground in two analysed does not show high influence of ground layers on ground heat ex-changer performance. On the other hand, results strongly depends on analysed soil profile.

scholarly journals A Three-Dimensional Numerical and Multi-Objective Optimal Design of Wavy Plate-Fins Heat Exchangers

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Chao Yu ◽  
Xiangyao Xue ◽  
Kui Shi ◽  
Mingzhen Shao
Keyword(s):  
Heat Exchangers ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Basis Functions ◽  
Approximation Model ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm ◽  
Colburn Factor ◽  
Heat Exchange Efficiency

This paper presents a method for optimizing wavy plate-fin heat exchangers accurately and efficiently. It combines CFD simulation, Radical Basis Functions (RBF) with multi-objective optimization to improve the performance. The optimization of the Colburn factor j and the friction coefficient f is regarded as a multi-objective optimization problem, due to the existence of two contradictory goals. The approximation model was obtained by Radical Basis Functions, and the shape of the heat exchanger was optimized by multi-objective genetic algorithm (MOGA). The optimization results showed that j increased by 17.62% and f decreased by 20.76%, indicating that the heat exchange efficiency was significantly enhanced and the fluid structure resistance reduced. Then, from the aspects of field synergy and tubulence energy, the performance advantage of the optimized structure was further confirmed.

Heat Transfer Performance of Different Nanofluids Flows in a Helically Coiled Heat Exchanger

2013 ◽  
Vol 832 ◽  
pp. 160-165 ◽  
Author(s):  
Mohammad Alam Khairul ◽  
Rahman Saidur ◽  
Altab Hossain ◽  
Mohammad Abdul Alim ◽  
Islam Mohammed Mahbubul
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Transfer Performance

Helically coiled heat exchangers are globally used in various industrial applications for their high heat transfer performance and compact size. Nanofluids can provide excellent thermal performance of this type of heat exchangers. In the present study, the effect of different nanofluids on the heat transfer performance in a helically coiled heat exchanger is examined. Four different types of nanofluids CuO/water, Al2O3/water, SiO2/water, and ZnO/water with volume fractions 1 vol.% to 4 vol.% was used throughout this analysis and volume flow rate was remained constant at 3 LPM. Results show that the heat transfer coefficient is high for higher particle volume concentration of CuO/water, Al2O3/water and ZnO/water nanofluids, while the values of the friction factor and pressure drop significantly increase with the increase of nanoparticle volume concentration. On the contrary, low heat transfer coefficient was found in higher concentration of SiO2/water nanofluids. The highest enhancement of heat transfer coefficient and lowest friction factor occurred for CuO/water nanofluids among the four nanofluids. However, highest friction factor and lowest heat transfer coefficient were found for SiO2/water nanofluids. The results reveal that, CuO/water nanofluids indicate significant heat transfer performance for helically coiled heat exchanger systems though this nanofluids exhibits higher pressure drop.

Heat Transfer Performance Analysis of Horizontal Ground Heat Exchanger under the Artificial Lake

2012 ◽  
Vol 516-517 ◽  
pp. 316-321
Author(s):  
Zhong Yi Yu ◽  
Yan Hua Chen ◽  
Xiao Liang Tang ◽  
Jian Ping Lei
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Performance ◽  
Simulation Method ◽  
Transfer Performance ◽  
Ground Heat Exchanger ◽  
Loop Formation ◽  
Artificial Lake ◽  
Pump System ◽  
Heat Pump System

According to the application conditions of horizontal ground heat exchanger(HGHE) under artificial lake, this paper uses numerical simulation method to do dynamic simulation research of the heat transfer performance of HGHE, analyzes the effect of connection mode and pipe flow velocity on heat transfer performance of HGHE in detail，puts forward efficient HGHE loop formation mode，and will provide effective technical support for ground-source heat pump system design with HGHE.

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