Analysis of Ground Massif Temperatures with Slinky Horizontal Heat Exchanger

2015 ◽  
Vol 752-753 ◽  
pp. 1035-1039 ◽  
Author(s):  
Michaela Šeďová ◽  
Pavel Neuberger ◽  
Radomír Adamovský

The article is describing a ground massif with a Slinky heat exchanger as a heat source for a heat pump, which is used for cold water warming and a heating of an administration building. The object of the research is to analyse the influence of the heat exchanger on the ground massif temperature while extracting heat energy at the beginning and during the heating season 2012 - 2013, as well as beyond it. Based on executed measurements the process of the ground massif temperatures near the exchanger is described. Also described is temperature process of the ground massif on a reference lot in a burial depth of the heat exchanger, and also subsurface temperatures in a depth of 0.2 m. The energy potential of the ground massif was evaluated using the difference of temperatures of the ground massif in the area of the Slinky heat exchanger at the beginning and at the end of the heating season.

2021 ◽  
Vol 42 (3) ◽  
pp. 333-348
Author(s):  
Zhenpeng Bai ◽  
Yanfeng Li ◽  
Jin Zhang ◽  
Alan Fewkes ◽  
Hua Zhong

This study investigated the optimal design of a capillary heat exchanger device for the heat pump system and its innovative engineering application in a building. The overall aim was to use a capillary heat exchanger to obtain energy in coastal areas for promoting renewable energy in low-carbon building design. Initially, the main factors affecting the efficiency of the capillary heat exchanger were identified, a mathematical model was then established to analyse the heat transfer process. The analysis showed the flow rate and the capillary length are the key factors affecting the efficiency of the capillary heat exchanger. Secondly, to optimize the structural design of the capillary heat exchanger, the heat energy transfer is calculated with different lengths of the capillary under various flow rates in summer and winter conditions, respectively. Thirdly, a typical building is selected to analyse the application of the capillary heat exchanger for extracting energy in the coastal area. The results show the performance of the selected capillary heat exchanger heat pump system, in winter, the heat energy transfer rate is 60 W/m2 when the seawater temperature is 3.7 °C; in summer, the heat energy transfer rate is 150 W/m2 when the seawater temperature is 24.6 °C. Finally, the above field test results were examined using a numerical simulation model, the test and simulation results agree with each other quite well. This paper is conducive in promoting the development of the capillary heat exchanger heat pump as an innovative sustainable technology for net-zero energy and low carbon buildings using renewable energy in coastal areas. Practical application: A recently proposed capillary heat exchanger is used as an energy extraction and utilisation device to obtain energy in coastal areas for promoting renewable energy in low-carbon building design. This paper explores the application of a capillary heat exchanger as both cold and heat sources for application in typical low-rise buildings. The analysis of the heat energy transfer rate of a typical low-rise building located in a coastal area in summer and winter provides guidance for the application of capillary heat exchangers.


Author(s):  
Shuichi Umezawa ◽  
Haruo Amari ◽  
Hiroyuki Shimada ◽  
Takashi Matsuhisa ◽  
Ryo Fukushima ◽  
...  

This paper reports application study of newly developed turbo heat pump for 130 degrees Celsius (°C) water for an industrial process in an actual factory. The heat pump is characterized by high efficiency and large heat output, by using a state-of-the-art turbo compressor. The heat pump requires a low temperature heat source in order to achieve high efficiency. The heat demand is for several drying furnaces in the factory, which requires producing hot air of 120 °C. The heat exchanger was designed to produce the hot air. Experiments were conducted to confirm the performance of the heat exchanger under a reduced size of the heat exchanger. Low temperature heat sources are from both exhaust gas of the drying furnaces and that of an annealing furnace. The heat exchangers were also designed to recover heat of the exhaust gas from the two types of furnace. A thermal storage tank was prepared for the low temperature heat source, and for adjusting the time difference between the heat demand and the low temperature heat source. The size of the tank was determined by considering the schedule of furnaces operations. As a result of the present study, it was confirmed that the heat pump was able to satisfy the present heat demand while retaining high efficiency. Primary energy consumption and CO2 emission of the heat pump were calculated on the basis of the present results in order to compare them with those of the boilers.


2012 ◽  
Vol 58 (No. 2) ◽  
pp. 57-65 ◽  
Author(s):  
R. Adamovský ◽  
L. Mašek ◽  
P. Neuberger

The goal of the article is to analyze the distribution and changes of temperatures in boreholes with the rock mass/fluid tubular heat exchangers used as an energy source for the heat pump. It also aims at documenting changes of temperatures in the rock mass during stagnation and heat extraction, and to compare the temperatures in the active and referential borehole. The testing results showed that temperatures of the rock mass reached a minimal value of 1.3°C at depths of 9 m and 20 m with maximal heat extraction corresponding to minimal air temperatures. The temperatures of the rock mass increased near the end of the heating season to values which correspond to the initial values. The temperature differences of the rock mass between the reference borehole and active boreholes increased to up to 10.5 K during the heating season. However, the temperature differences at the end of the heating season between the reference and active boreholes dropped back to 0.5–1.1 K.  


2017 ◽  
Vol 8 (2) ◽  
pp. 141-144
Author(s):  
M. Zheng ◽  
Y. Tian ◽  
H. Teng ◽  
J. Hu ◽  
F. Wang ◽  
...  

In this paper, the wind energy resource in China’s oilfields is analyzed, the difference between China’s energy consumption structure and that of the world in average is analyzed as well, and the application prospect of wind heating technology in China’s oilfields is discussed as an example to reform China’s energy consumption structure. It shows that it is possible to use wind energy as an appropriate heat resource or supplementary heat source in some oilfields to supply heat energy for oil heating and living, more room to improve the energy resource utilization in various fields in China remain. It is a benefit to both oilfield and society to improve energy saving and environments.


1996 ◽  
Vol 118 (4) ◽  
pp. 300-305 ◽  
Author(s):  
M. T. Kangas

In this study, the use of the ground as the heat source for a heat pump was studied by computer simulation. The heat extraction system consisted of vertical pipes drilled into the ground where groundwater was present. Along with available thermal energy, potential environmental effects, such as freezing and thermal pollution, were examined. It was found that the presence of groundwater enhances system performance by decreasing the possibility of freezing but, on the other hand, increases the range of thermal effects in the ground. The temperature of the ground as well as extraction arrangements also have a significant effect on system performance.


2013 ◽  
Vol 59 (No. 3) ◽  
pp. 91-97 ◽  
Author(s):  
M. Šeďová ◽  
R. Adamovský ◽  
P. Neuberger

The paper is aimed at specification of ground massif temperatures in the horizontal heat exchanger area in both the heating season and during heat exchanger stagnation. The energetic potential of the ground massif was evaluated using the difference of temperatures of the ground massif in the area of the heat exchanger at the beginning and at the end of the heating season. Specific heat rates of the ground heat exchanger were also determined, and the influence of the ground massif thermal resistance and coefficient of heat transfer between the inner wall of the heat exchanger pipe and the heat-carrying liquid were analysed.  


2021 ◽  
Vol 9 ◽  
Author(s):  
Rui Tang ◽  
Feng Wang ◽  
Zhihao Wang ◽  
Weibo Yang

The frosting type and frosting degree of the outdoor heat exchanger of air source heat pump (ASHP) in the heating season are greatly affected by the local environmental temperature and humidity. China has a vast territory, and the climate varies greatly in different regions. Therefore, when the ASHP is running in different climate zones for heating in winter, there are significant differences in the frosting type and frosting degree. In order to achieve deeper understanding of frost formation and provide more accurate guidance for the suitability application of antifrosting and defrosting technologies, a study on the division of frosting type and frosting degree was performed in this work. Based on the three-phase diagram of water and combined with the theory of phase change dynamics, the outdoor heat exchanger of the ASHP in the heating season was divided into four states: neither frosting nor condensation, condensation, condensation frosting, and sublimation frosting, and the proportion of each state in a typical city in different climate zones was calculated. The results showed that more than 80% of the heating seasons in Nanjing, Shanghai, Wuhan, Changsha, Xi’an, and Harbin had the frosting phenomenon. Sublimation frosting was the main frosting type in Xi’an, Beijing, and Harbin, while Chongqing was all condensation frosting. Moreover, a frosting model was developed and the frosting degree was divided into mild frosting, moderate frosting, and heavy frosting, according to the performance attenuation of the ASHP under frosting conditions. The proportion of each frosting degree in a typical city was achieved. About 50% of the heating seasons in Nanjing and Changsha were distributed in the heavy frost area and 100% in Chongqing.


2010 ◽  
Vol 31 (4) ◽  
pp. 93-110 ◽  
Author(s):  
Małgorzata Hanuszkiewicz-Drapała ◽  
Jan Składzień

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.


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