Analysis of Heat Transfer by Pile and Borehole Ground Heat Exchangers: Composite-Medium Line-Source Approach

2013 ◽  
pp. 55-62
Author(s):  
Min Li ◽  
Yi Yang
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Line Source ◽  
Composite Medium ◽  
Ground Heat Exchangers

scholarly journals Analysis and Comparison of Some Low-Temperature Heat Sources for Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1853 ◽  
Author(s):  
Pavel Neuberger ◽  
Radomír Adamovský
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Ambient Air ◽  
Heat Transfer Fluid ◽  
Heat Sources ◽  
Ground Heat Exchangers ◽  
Temperature Heat

The efficiency of a heat pump energy system is significantly influenced by its low-temperature heat source. This paper presents the results of operational monitoring, analysis and comparison of heat transfer fluid temperatures, outputs and extracted energies at the most widely used low temperature heat sources within 218 days of a heating period. The monitoring involved horizontal ground heat exchangers (HGHEs) of linear and Slinky type, vertical ground heat exchangers (VGHEs) with single and double U-tube exchanger as well as the ambient air. The results of the verification indicated that it was not possible to specify clearly the most advantageous low-temperature heat source that meets the requirements of the efficiency of the heat pump operation. The highest average heat transfer fluid temperatures were achieved at linear HGHE (8.13 ± 4.50 °C) and double U-tube VGHE (8.13 ± 3.12 °C). The highest average specific heat output 59.97 ± 41.80 W/m2 and specific energy extracted from the ground mass 2723.40 ± 1785.58 kJ/m2·day were recorded at single U-tube VGHE. The lowest thermal resistance value of 0.07 K·m2/W, specifying the efficiency of the heat transfer process between the ground mass and the heat transfer fluid, was monitored at linear HGHE. The use of ambient air as a low-temperature heat pump source was considered to be the least advantageous in terms of its temperature parameters.

scholarly journals Ground-Coupled Natural Circulating Devices (Thermosiphons): A Review of Modeling, Experimental and Development Studies

Inventions ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 14
Author(s):  
Messaoud Badache ◽  
Zine Aidoun ◽  
Parham Eslami-Nejad ◽  
Daniela Blessent
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Low Temperatures ◽  
Experimental Studies ◽  
Heat Transfer Fluid ◽  
Fluid Circulation ◽  
Ground Heat Exchangers ◽  
Additional Equipment ◽  
Different Types ◽  
Overall Efficiency

Compared to conventional ground heat exchangers that require a separate pump or othermechanical devices to circulate the heat transfer fluid, ground coupled thermosiphons or naturallycirculating ground heat exchangers do not require additional equipment for fluid circulation in theloop. This might lead to a better overall efficiency and much simpler operation. This paper providesa review of the current published literature on the different types of existing ground coupledthermosiphons for use in applications requiring moderate and low temperatures. Effort has beenfocused on their classification according to type, configurations, major designs, and chronologicalyear of apparition. Important technological findings and characteristics are provided in summarytables. Advances are identified in terms of the latest device developments and innovative conceptsof thermosiphon technology used for the heat transfer to and from the soil. Applications arepresented in a novel, well-defined classification in which major ground coupled thermosiphonapplications are categorized in terms of medium and low temperature technologies. Finally,performance evaluation is meticulously discussed in terms of modeling, simulations, parametric,and experimental studies.

Heat transfer characteristics of in-ground heat exchangers

1983 ◽  
Vol 7 (3) ◽  
pp. 265-278 ◽  
Author(s):  
O. J. Svec ◽  
L. E. Goodrich ◽  
J. H. L. Palmer
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Ground Heat Exchangers

Simplified heat transfer analysis method for large-scale boreholes ground heat exchangers

2016 ◽  
Vol 116 ◽  
pp. 593-601 ◽  
Author(s):  
Yu Mingzhi ◽  
Ma Tengteng ◽  
Zhang Kai ◽  
Cui Ping ◽  
Hu Aijuan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Large Scale ◽  
Heat Transfer Analysis ◽  
Analysis Method ◽  
Ground Heat Exchangers

Research on Heat Transfer and Environmental Impact of Horizontal Ground Heat Exchangers in Multi-Grooves

2012 ◽  
Vol 516-517 ◽  
pp. 395-400
Author(s):  
Zhong Yi Yu ◽  
Yan Hua Chen ◽  
Min Rui Zhou ◽  
Jian Ping Lei
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Temperature Drop ◽  
Heat Extraction ◽  
Maximum Temperature ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Heat Exchangers ◽  
Average Maximum ◽  
Average Maximum Temperature

This paper progresses to dynamically simulate and study the heat transfer process of horizontal ground heat exchangers in the multi-grooves by the use of numerical simulation based on the layout and heat extraction or rejection conditions of horizontal ground heat exchangers under the artificial lake. Effect of buried pipe type and groove spacing on the heat exchanger process is analyzed in detail. The influence of annual average water temperature change on the surrounding environment is evaluated with the introduction of parameters including summer weekly average maximum temperature rise and winter weekly average maximum temperature drop, in which can take the technical supports for the design of horizontal ground source heat pump system.

scholarly journals Heat Balance of Horizontal Ground Heat Exchangers

2018 ◽  
Vol 25 (4) ◽  
pp. 537-548
Author(s):  
Krzysztof Kupiec ◽  
Monika Gwadera
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Flux ◽  
Ambient Temperature ◽  
Heat Balance ◽  
Heat Exchangers ◽  
Ground Surface ◽  
Temporal Variations ◽  
Moisture Evaporation ◽  
Ground Heat Exchangers

Abstract This work refers to the modelling of heat transfer in horizontal ground heat exchangers. For different conditions of collecting heat from the ground and different boundary condition profiles of temperature in the ground were found, and temporal variations of heat flux transferred between the ground surface and its interior were determined. It was taken into account that this flux results from several different mechanisms of heat transfer: convective, radiative, and that connected with moisture evaporation. It was calculated that ground temperature at great depths is greater than the average annual ambient temperature.

Heat transfer in horizontal ground heat exchangers

2015 ◽  
Vol 75 ◽  
pp. 270-276 ◽  
Author(s):  
Krzysztof Kupiec ◽  
Barbara Larwa ◽  
Monika Gwadera
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Ground Heat Exchangers
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