Ground Source Heat Pump Modeling: Accounting of Ground Moisture Freezing-Melting in a Model of Heat Transfer outside Deep Borehole

2014 ◽  
Vol 704 ◽  
pp. 102-112 ◽  
Author(s):  
G.P. Vasilyev ◽  
N.V. Peskov ◽  
A.A. Burmistrov ◽  
N.A. Timofeev ◽  
P.E. Zakharov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Latent Heat ◽  
Heat Pump ◽  
Melting Process ◽  
Heating System ◽  
Source Model ◽  
Cold Climate ◽  
Ground Source Heat Pump ◽  
Ground Source

This paper contains the results of research, carried out with financial support from the Ministry of Education and Science of the Russian Federation (contract ID RFMEFI57914X0026). For the ground source heat pump (GSHP) used as a heating system in regions with cold climate the thermal effects of ground moisture freezing-melting processes can make an essential long-term impact on GSHP performance. However, widely known models of heat transfer inside and outside GSHP borehole do not take into account such effects. In this paper we propose a method of engineering estimation of freezing-melting latent heat in the frame of modified cylindrical source model. The key feature of the method is the definition of effective thermal conductivity of ground to "convert" the latent heat of phase transition into equivalent heat flux from outer ground. The method is validated by laboratory measurements of ground thermal conductivity during the freezing-melting process.

Accounting for “Zero Curtain” Effect in GSHP Simulation

2014 ◽  
Vol 664 ◽  
pp. 243-249 ◽  
Author(s):  
G.P. Vasilyev ◽  
V.F. Gornov ◽  
N.V. Peskov ◽  
M.V. Kolesova ◽  
A.A. Burmistrov ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Latent Heat ◽  
Melting Process ◽  
Heating System ◽  
Source Model ◽  
Cold Climate ◽  
Ministry Of Education ◽  
Ground Source ◽  
Definition Of ◽  
Long Term Impact

This paper contains the results of research, carried out with financial support from the Ministry of Education and Science of the Russian Federation (contract ID RFMEFI57914X0026). For the ground source heat pump (GSHP) used as a heating system in regions with cold climate the thermal effects of ground moisture freezing-melting processes can make an essential long-term impact on GSHP performance. However, widely known models of heat transfer inside and outside GSHP borehole do not take into account such effects. In this paper, we propose a method of engineering estimation of freezing-melting latent heat in the frame of modified cylindrical source model. The key feature of the method is the definition of effective thermal conductivity of ground to "convert" the latent heat of phase transition into equivalent heat flux from outer ground. The method is validated by laboratory measurements of ground thermal conductivity during the freezing-melting process.

A Study on the Calculation Model of Rock Soil Thermal Conductivity in the Design of the Ground Source Heat Pump System

2014 ◽  
Vol 889-890 ◽  
pp. 1347-1352
Author(s):  
Hong Wen Jin ◽  
Qing Shen Fang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Pump ◽  
Soil Layer ◽  
Heat Extraction ◽  
Ground Source Heat Pump ◽  
Soil Thermal Conductivity ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Source

The rock soil thermal conductivity is the most important design parameter for the ground source heat pump system. Based on the equation applied for the heat transfer between the geothermal heat exchanger and its surrounding rock soil, a quasi-three dimensional heat conduction model showing the heat transfer inside the borehole of the U-tube was established to determine the thermal conductivity of the deep-layer rock soil. The results obtained show that the average thermal conductivity got through calculation and actual determination in a tube-embedding region of the ground source heat pump engineering were 1.895 and 1.955W/(m·°C), respectively. The soil layer, which has a great thermal conductivity and a strong integrated heat transfer capability, is suitable for the use of the ground source heat pump system with the tubes embedded underground. The soil layer, with a body temperature of 19 °C and a higher initial temperature, is suitable for the heat extraction from underground in winter. The deviation between the calculation and the determination of the average thermal conductivity in the abovementioned region was 0.06, which could meet the required precision, indicating that the results from the calculation could be used for design.

scholarly journals The thermal behavior of a novel wall radiator panel coupled with horizontal ground source heat pump heating system: improve indoor environment to reduce the airborne transmission of infectious diseases

2020 ◽  
Vol 5 ◽  
pp. 11
Author(s):  
Sabrin Korichi ◽  
Bachir Bouchekima ◽  
Nabiha Naili ◽  
Messaouda Azzouzi
Keyword(s):  
Infectious Diseases ◽  
Thermal Comfort ◽  
Heat Pump ◽  
Heating System ◽  
The Novel ◽  
Ground Source Heat Pump ◽  
Radiation Heating ◽  
Geothermal Heat ◽  
Ground Source ◽  
Geothermal Heat Pump

Motivated by the rapid spread of the novel pandemic disease (COVID-19) that swept the most countries in the world, a new radiation heating system consists of wall radiator panel system connected to a reversible geothermal heat pump (GHP) coupled with horizontal ground heat exchanger (HGHX) was proposed as fast and permanent solution to the risks of the dispersion of airborne infectious diseases in air-conditioned enclosed spaces. An experimental system was installed and tested in the laboratory of thermal process of Research and Technology Center of Energy (CRTEn), Tunisia, in order to achieve the two main goals of this work: developing a new radiation heating system with quick and inexpensive implementation while ensuring high efficiency and environment-friendly performance for the entire system. The results obtained show that it is feasible to use the novel RPHs as heat rejecter of the horizontal ground source heat pump system (HGSHPs) for heating buildings with limited surface land areas epically those located in the Mediterranean regions such as Tunisia, the average performance coefficients of the geothermal heat pump COPhp and the overall system COPsys are found to be 6.3 and 3, respectively. The thermal comfort analysis indicates that there is only a small vertical temperature fluctuation in the test room that would not produce any negative effect on thermal comfort.

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.

Ground source heat pump performance in case of high humidity soil and yearly balanced heat transfer

2013 ◽  
Vol 76 ◽  
pp. 956-970 ◽  
Author(s):  
Luigi Schibuola ◽  
Chiara Tambani ◽  
Angelo Zarrella ◽  
Massimiliano Scarpa
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
High Humidity ◽  
Ground Source Heat Pump ◽  
Pump Performance ◽  
Ground Source
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