scholarly journals Heating system with vapour compressor heat pump and vertical U-tube ground heat exchanger

2010 ◽  
Vol 31 (4) ◽  
pp. 93-110 ◽  
Author(s):  
Małgorzata Hanuszkiewicz-Drapała ◽  
Jan Składzień
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Mutual Influence ◽  
Heating System ◽  
Calculation Model ◽  
Ground Heat Exchanger ◽  
Heating Season ◽  
Residential House ◽  
Time Parameters ◽  
Heated Object

Heating system with vapour compressor heat pump and vertical U-tube ground heat exchangerIn the paper a heating system with a vapour compressor heat pump and vertical U-tube ground heat exchanger for small residential house is considered. A mathematical model of the system: heated object - vapour compressor heat pump - ground heat exchanger is presented shortly. The system investigated is equipped, apart from the heat pump, with the additional conventional source of heat. The processes taking place in the analyzed system are of unsteady character. The model consists of three elements; the first containing the calculation model of the space to be heated, the second - the vertical U-tube ground heat exchanger with the adjoining area of the ground. The equations for the elements of vapour compressor heat pump form the third element of the general model. The period of one heating season is taken into consideration. The results of calculations for two variants of the ground heat exchanger are presented and compared. These results concern variable in time parameters at particular points of the system and energy consumption during the heating season. This paper presents the mutual influence of the ground heat exchanger subsystem, elements of vapour compressor heat pump and heated space.

Comparison of Borehole Thermal Resistance Values of Ground Heat Exchanger Obtained by Several Methods

2013 ◽  
Vol 732-733 ◽  
pp. 103-108 ◽  
Author(s):  
Han Byul Kang ◽  
Seok Yoon ◽  
Gyu Hyun Go ◽  
Seung Rae Lee
Keyword(s):  
Heat Exchanger ◽  
Thermal Resistance ◽  
Heat Pump ◽  
Heating System ◽  
Geothermal System ◽  
Ground Heat Exchanger ◽  
Ubiquitous System ◽  
Borehole Thermal Resistance ◽  
Quantity Of Heat ◽  
Emission Of Greenhouse Gases

The Ground-Coupled or Source Heat Pump (GCHP/GSHP) system is increasingly being considered as an alternative to traditional cooling/heating system because it can reduce the emission of greenhouse gases. The GCHP/GSHP system uses sustainable ground temperature to emit heat during the summer and to extract heat during the winter. It is a ubiquitous system because it can be used at any time or place and semi-permanent energy. The geothermal system is composed of Ground Heat Exchanger (GHE), heat pump and load facilities. The GHE is embedded in a borehole, which is made up of GHE and grout. The borehole thermal resistance is the most important parameter in designing the geothermal system because it shows the quantity of heat transfer in the borehole. There are many methods to estimate the borehole thermal resistance. Thermal Performance Tests (TPTs) were conducted to directly measure the borehole thermal resistance of several kinds of GHEs. Then the experiment results and analytical results were compared in order to select the most accurate methods to evaluate the borehole thermal resistance.

scholarly journals Heating of external surfaces by means of heat pumps

2018 ◽  
Vol 44 ◽  
pp. 00128
Author(s):  
Krzysztof Nowak
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Financial Analysis ◽  
Negative Impact ◽  
Heating System ◽  
Heat Pumps ◽  
Ground Heat Exchanger ◽  
Heating Installation ◽  
Manual Methods ◽  
Snow And Ice

In winter we are forced to eliminate or mitigate the disadvantages associated with the accumulation of snow and ice on sidewalks, steps, driveways, roofs, squares, sports fields. There are many ways to remove snow and ice from the considered surfaces, including chemical, mechanical or use of a heating installation. Mechanical or manual methods do not always allow to completely remove snow and ice, while chemicals often have a negative impact on the environment. The most effective is the use of an electric or liquid heating installation. The article presents the results of technical analysis for a maneuver area heating system for driving training lesson using a heat pump with a ground heat exchanger, as well as financial analysis of its application in the established conditions. The literature lacks information on this subject, so it was interesting to investigate whether the proposed installation is technically and economically feasible.

scholarly journals OPTIMAL WORKING CONDITIONS OF THE GROUND SOURCE HEAT PUMP FOR HEAT SUPPLY

2017 ◽  
pp. 19-26
Author(s):  
M.K. Bezrodnyi ◽  
N.A. Prytula ◽  
M.A. Gobova
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Working Conditions ◽  
Heat Carrier ◽  
Heating System ◽  
Ground Heat Exchanger ◽  
Heat Exchanger Tube ◽  
Vertical Ground ◽  
Optimum Velocity ◽  
Exchanger Tube

The method of determination of optimal working conditions of vertical ground heat exchanger for heat pump low temperature water heating system, providing minimum energy cost for heat production is presented in this article. It was determined that there is an optimum speed of a heat carrier to which minimum total cost of electricity for heating system in a whole corresponds when using vertical probes for heat pump heating system. The correlation between the characteristics of vertical ground heat exchanger (depth of the well, the intensity of selection of heat from the soil pipe diameter, the velocity of a heat carrier) in its optimal working conditions was found. It is shown that the optimum velocity of a heat carrier in the lower circuit depends on the depth of the well, the heat exchanger tube diameter, and is almost independent of temperature conditions works of heat pump systems. It is found that the higher velocity observed at the beginning of the heating period in view of energy storage in the ground. Optimum coolant velocity should decrease until the end of the heating season to ensure minimum specific energy expenditure at HPS. Also noted that an optimum velocity increases with increasing depth of the well and with decreasing diameter of the heat exchanger tube. The established correlation may be used when determining the optimum operating conditions of the vertical ground heat pump heat exchanger low-temperature heating systems with a plan to maximize their energy efficiency. Bibl. 8, Fig. 7.

scholarly journals Analysis of Heat Exchange Rate for Low-Depth Modular Ground Heat Exchanger through Real-Scale Experiment

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1893
Author(s):  
Kwonye Kim ◽  
Jaemin Kim ◽  
Yujin Nam ◽  
Euyjoon Lee ◽  
Eunchul Kang ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Pump ◽  
Heat Extraction ◽  
Ground Heat Exchanger ◽  
Pump System ◽  
Heat Pump System ◽  
Scale Experiment ◽  
Real Scale

A ground source heat pump system is a high-performance technology used for maintaining a stable underground temperature all year-round. However, the high costs for installation, such as for boring and drilling, is a drawback that prevents the system to be rapidly introduced into the market. This study proposes a modular ground heat exchanger (GHX) that can compensate for the disadvantages (such as high-boring/drilling costs) of the conventional vertical GHX. Through a real-scale experiment, a modular GHX was manufactured and buried at a depth of 4 m below ground level; the heat exchange rate and the change in underground temperatures during the GHX operation were tracked and calculated. The average heat exchanges rate was 78.98 W/m and 88.83 W/m during heating and cooling periods, respectively; the underground temperature decreased by 1.2 °C during heat extraction and increased by 4.4 °C during heat emission, with the heat pump (HP) working. The study showed that the modular GHX is a cost-effective alternative to the vertical GHX; further research is needed for application to actual small buildings.

Thermodynamic Analysis of a Central Heating System Combing the Urban Heat Network With Geothermal Energy

2013 ◽  
Author(s):  
Xiao Wang ◽  
Lin Fu ◽  
Xiling Zhao ◽  
Hua Liu
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Pump ◽  
Geothermal Energy ◽  
Heating System ◽  
Heat Network ◽  
Pump System ◽  
Absorption Heat Pump ◽  
Central Heating ◽  
Exchange Unit

In recent years, with the continuous urban expansion, the central heating sources are commonly insufficient in the areas of Northern China. Besides, the increasing heat transfer temperature difference results in more and more exergy loss between the primary heat network and the secondary heat network. This paper introduces a new central heating system which combines the urban heat network with geothermal energy (CHSCHNGE). In this system, the absorption heat exchange unit, which is composed of an absorption heat pump and a water to water heat exchanger, is as alternative to the conventional water to water heat exchanger at the heat exchange station, and the doing work ability of the primary heat network is utilized to drive the absorption heat pump to extract the shallow geothermal energy. In this way, the heat supply ability of the system will be increased with fewer additional energy consumptions. Since the water after driving the absorption heat pump has high temperature, it can continue to heat the supply water coming from the absorption heat pump. As a result, the water of the primary heat network will be stepped cooled and the exergy loss will be reduced. In this study, the performance of the system is simulated based on the mathematical models of the heat source, the absorption heat exchange unit, the ground heat exchanger and the room. The thermodynamic analyses are performed for three systems and the energy efficiency and exergy efficiency are compared. The results show that (a) the COP of the absorption heat exchange unit is 1.25 and the heating capacity of the system increases by 25%, which can effectively reduce the requirements of central heating sources; (b) the PER of the system increases 14.4% more than that of the conventional co-generation central heating system and 54.1% more than that of the ground source heat pump system; (c) the exergy efficiency of the CHSCHNGE is 17.6% higher than that of the conventional co-generation central heating system and 45.6% higher than that of the ground source heat pump system.

Performance Evaluation of a Vertical U-Tube Ground Heat Exchanger Using a Numerical Simulation Approach

2013 ◽  
Vol 724-725 ◽  
pp. 909-915
Author(s):  
Ping Fang Hu ◽  
Zhong Yi Yu ◽  
Fei Lei ◽  
Na Zhu ◽  
Qi Ming Sun ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Transfer Process ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Ground Heat Exchanger ◽  
Ground Source Heat Pump ◽  
Ground Source

A vertical U-tube ground heat exchanger can be utilized to exchange heat with the soil in ground source heat pump systems. The outlet temperature of the working fluid through the U-tube not only accounts for heat transfer capacity of a ground heat exchanger, but also greatly affects the operational efficiency of heat pump units, which is an important characteristic parameter of heat transfer process. It is quantified by defining a thermal effectiveness coefficient. The performance evaluation is performed with a three dimensional numerical model using a finite volume technique. A dynamic simulation was conducted to analyze the thermal effectiveness as a function of soil thermal properties, backfill material properties, separation distance between the two tube legs, borehole depth and flow velocity of the working fluid. The influence of important characteristic parameters on the heat transfer performance of vertical U-tube ground heat exchangers is investigated, which may provide the references for the design of ground source heat pump systems in practice.

scholarly journals Efficiency and area demand of multi-layer ground heat exchanger using phase change of water

2019 ◽  
Vol 282 ◽  
pp. 02027
Author(s):  
Hauke Hirsch ◽  
Hans Petzold ◽  
John Grunewald
Keyword(s):  
Heat Exchanger ◽  
Numerical Simulations ◽  
Heat Pump ◽  
Simulation Software ◽  
Passive Cooling ◽  
Ground Heat Exchanger ◽  
Pump System ◽  
Heat Pump System ◽  
German Standard ◽  
The Impact

We conducted numerical simulations of a heat pump system connected to a horizontal ground heat exchanger (HGHX), using a coupling of the hygro-thermal simulation software DELPHIN with Modelica. The aim was to study the influence of different HGHX sizes and assemblies as well as the impact of passive cooling on the systems efficiency. We found that the required ground area could be reduced by up to 70 % compared to the recommendation of German standard when the pipes are placed in multiple layers. Passive cooling is possible but has a negligible effect on the systems efficiency.

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