Influence of Convalescence on Soil Temperature Field of Well Group around Vertical Single-U-Tube Ground Source Heat Exchangers

2012 ◽  
Vol 430-432 ◽  
pp. 1712-1715
Author(s):  
Zhen Yu Du ◽  
Yi Xing Zhang
Keyword(s):  
Temperature Field ◽  
Soil Temperature ◽  
Moisture Transfer ◽  
Three Dimensional ◽  
Thermal Response ◽  
Seepage Flow ◽  
Geological Structure ◽  
Temperature Fields ◽  
Tube Heat Exchanger ◽  
Ground Source

In this paper, the mathematical physical model of the heat and moisture transfer in the single-U-tube heat exchanger of a ground source heat pump(GSHP) on well group is established and validated using observed data from the practical rock-soil thermal response test for a resident district in Taiyuan, water in soil is three-dimensional seepage flow and the soil is layered according to the geological structure in the depth direction. The dynamic load of the district for one year is input into the model. The temperature fields of well group are simulated numerically in the two conditions which convalescence periods are omitted or not. It shows that it rather necessary to take the influence of convalescence periods into consideration while predicting the soil temperature field of a GSHP system running for a long term.

Influence of Convalescence on Soil Temperature Field around a Vertically Buried Single-U-Tube Ground Heat Exchanger

2011 ◽  
Vol 121-126 ◽  
pp. 1651-1655
Author(s):  
Zhen Yu Du ◽  
Yi Xing Zhang
Keyword(s):  
Temperature Field ◽  
Heat Exchanger ◽  
Soil Temperature ◽  
Moisture Transfer ◽  
Thermal Response ◽  
Geological Structure ◽  
Temperature Fields ◽  
Tube Heat Exchanger ◽  
Depth Direction ◽  
Single Well

The mathematical physical model of the heat and moisture transfer in the single-U-tube heat exchanger of a ground source heat pump (GSHP) is validated using observed data from the practical rock-soil thermal response test on a resident district in Taiyuan, the soil is layered according to the geological structure of an actual drill in the depth direction in this model. Inputting the dynamic design cooling and heating load of the district into the Realizable turbulent model in Fluent, the temperature fields of a single well in the GSHP project running for 1 year in 2 conditions in which convalescence is considered and not, are simulated numerically. It shows that it rather necessary to take the influence of convalescence into consideration while predicting the soil temperature field of a GSHP system running for a long term, or may not correspond to the reality and make a wrong theory guide to the practical engineering.

Simulation of Temperature Field of Soil Inside Drilling around a Vertically Buried Single-U-Tube Ground Heat Exchanger

2011 ◽  
Vol 393-395 ◽  
pp. 943-946
Author(s):  
Zhen Yu Du
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Soil Temperature ◽  
Moisture Transfer ◽  
Temperature Fields ◽  
Tube Heat Exchanger ◽  
Heat Transfer Efficiency ◽  
Ground Source ◽  
Practical Engineering ◽  
One Year

In this paper, the mathematical physical model of the heat and moisture transfer, which is about a vertical single-U-tube heat exchanger of a ground source heat pump (GSHP), is used to simulate the soil temperature fields inside drilling around a vertical single-U-tube ground source heat exchanger. The soil temperature fields inside drilling in the GSHP project running for one year are computed numerically. It shows that soil structure, cooling and heating load, cooling and heating period, and convalescence period have been determined by practical engineering conditions, the distance in the plane between drillings have a huge influence on heat transfer effect, only when the distance is designed reasonably, can it be possible to make sure normal heat transfer efficiency.

scholarly journals Impact of Tunnel Temperature Variations on Surrounding Rocks in Cold Regions

2019 ◽  
Author(s):  
Qingyang Yu ◽  
Chao Zhang ◽  
Zhenxue Dai ◽  
Chao Du ◽  
Mohamad Reza Soltanian ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Insulation Layer ◽  
Cold Regions ◽  
Ambient Temperatures ◽  
Temperature Conditions ◽  
Layer Control

Temperature is an important factor in designing and maintaining tunnels, especially in cold regions. We present three-dimensional numerical simulations of tunnel temperature fields at different temperature conditions. We study the tunnel temperature field in two different conditions with relatively low and high ambient temperatures representing winter and summer of northeast China. We specifically study how these temperature conditions affect tunnel temperature and its migration to surrounding rocks. We show how placing an insulation layer could affect the temperature distribution within and around tunnels. Our results show that the temperature field without using an insulation layer is closer to the air temperature in the tunnel, and that the insulation layer has shielding effects and could plays an important role in preventing temperature migration to surrounding rocks. We further analyzed how thermal conductivity and thickness of insulation layer control the temperature distribution. The thermal conductivity and thickness of insulation layer only affect the temperature of the surrounding rocks which are located at distances below ~20 m from the lining.

Influencing Degree of Star-Stop Frequency on Running Efficiency of Ground Source Heat Pump which Using Vertical Buried Pipe

2014 ◽  
Vol 508 ◽  
pp. 141-145
Author(s):  
Xian Fang Hu ◽  
Yu Yun Li ◽  
Yan Hua Chen ◽  
Zhong Yi Yu
Keyword(s):  
Heat Transfer ◽  
Energy Efficiency ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Three Dimensional ◽  
Buried Pipe ◽  
Tube Heat Exchanger ◽  
Ground Source ◽  
Unit Energy ◽  
Heat Pump Unit

Through the three-dimensional heat transfer simulation of different periodic running of 3×3 tube group during one running period, the article draw the influence of vertical buried tube heat exchanger heat transfer performance under the different start-stop times, when total time is certain, shortening the continuous time of intermittent operation (increasing the start and stop times) helps promote the unit energy efficiency as the outlet water temperature change of the heat exchanger is toward to the favorable direction, and the trend of the change showed first increased and then decreased with the increase of start-stop times. Increasing the number of start and stop times do more contribution to promote the energy efficiency of the heat pump unit under the Working condition of refrigeration.

Three-Dimensional Analytical Temperature Field Around the Welding Cavity Produced by a Moving Distributed High-Intensity Beam

1993 ◽  
Vol 115 (4) ◽  
pp. 848-856 ◽  
Author(s):  
P. S. Wei ◽  
M. D. Shian
Keyword(s):  
Temperature Field ◽  
Power Density ◽  
High Power ◽  
Three Dimensional ◽  
Second Law Of Thermodynamics ◽  
Temperature Fields ◽  
Momentum Balance ◽  
High Power Density ◽  
Depth Of Penetration ◽  
Confluent Hypergeometric Functions

An analytical solution for the three-dimensional temperature field in the liquid and heat-affected zones around a welding cavity produced by a moving distributed low- or high-power-density-beam is provided. The incident energy rate distribution is assumed to be Gaussian and the cavity is idealized by a paraboloid of revolution in workpieces of infinite, semi-infinite, or finite thicknesses. The present study finds that temperature fields can be described by the Laguerre and confluent hypergeometric functions. By satisfying a momentum balance at the cavity base and utilizing a consequence of the second law of thermodynamics, the depth of penetration is uniquely determined. The results show that the predicted depths and temperatures of the cavity agree with available experimental data. Some crucial factors affecting the transition from low- to high-power-density-beam welding are presented.

Analysis of Transient Heat Conduction in Complex Shaped Composite Materials

1988 ◽  
Vol 110 (2) ◽  
pp. 110-112 ◽  
Author(s):  
Seiichi Nomura ◽  
A. Haji-Sheikh
Keyword(s):  
Temperature Field ◽  
Heat Conduction ◽  
Composite Materials ◽  
Analytical Procedure ◽  
Three Dimensional ◽  
Transient Heat Conduction ◽  
Temperature Fields ◽  
Finite Region ◽  
Symbolic Algebra ◽  
The Galerkin Method

This paper addresses a generalized analytical procedure for transient heat conduction in composite materials of two- and three-dimensional finite region. The Galerkin method is employed to obtain temperature field in closed form with the utilization of symbolic algebra software such as REDUCE or MACSYMA. It is found from illustrative examples that the proposed method yields accurate and effective predictions of temperature fields for which purely numerical methods such as finite element or finite difference are not suitable.

Research on Characteristics of the Soil Temperature Field around Vertical Double U-Tube Group of the Heat Exchangers

2012 ◽  
Vol 170-173 ◽  
pp. 2558-2563
Author(s):  
Jun Yang ◽  
Xiao Ping Miao ◽  
Xiao Feng Zhou ◽  
Xin Ping Wu
Keyword(s):  
Temperature Field ◽  
Soil Temperature ◽  
Heat Exchangers ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Tube Wells ◽  
Tube Well ◽  
Temperature Rate ◽  
One Year ◽  
Increasing Temperature

Based on the temperature monitoring for the double U-tube wells with thermal resistance , numerical simulation researching on two-dimensional temperature field and three-dimensional temperature field was carried out for vertical double U-tube group. Under the condition of 6.5m for horizontal spacing of tube well, the Soil temperature around inner tube wells increases 0.4°C in one year, and 0.24°C for the surrounding tube wells. The paper calculates the increasing temperature of the tube wells, 7.95°C for inner tube wells and 4.70°Cfor surrounding tube wells. The soil temperature of tube wells is rising with the running time increasing, however,the temperature rate of the soil around inner tube wells is larger than the surrounding tube wells’.

Dependence of the Shape of the Temperature Field around Basement Structures on the Properties of Surrounding Soils

2016 ◽  
Vol 824 ◽  
pp. 503-510
Author(s):  
Petr Kacálek ◽  
Jan Plachý ◽  
Radim Smolka ◽  
Tomáš Petříček
Keyword(s):  
Temperature Field ◽  
Soil Temperature ◽  
Statistical Evaluation ◽  
Temperature Fields ◽  
Basement Structure ◽  
Individual Effects ◽  
3D Simulation Model ◽  
Soil Temperatures ◽  
Basement Structures ◽  
The Individual

This paper exams the dependence of soil temperature fields of basement structures of buildings on the type of the surrounding soil. The 3D simulation model is based on data from real measurements of soil temperatures during the winter over a period of two years. The measured data were incorporated into the model on the basis of statistical evaluation. The basic aim of this paper is to approach, as closely as possible, the individual effects of basement structure construction on the soil temperature field on the basis of real measured values.

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