scholarly journals THE THERMODYNAMIC PROCESS OF AGGREGATE-THERMAL CONVERSION TEPLOPOTERJAH SYSTEMS

2020 ◽  
pp. 123-132
Author(s):  
S. V. Fedosov ◽  
V. N. Fedoseev ◽  
V. A. Emelin
Keyword(s):  
Heat Exchange ◽  
Heat Pump ◽  
Closed System ◽  
Thermodynamic Cycle ◽  
Thermal Conversion ◽  
Thermodynamic Process ◽  
Evaporation Temperature ◽  
Technological Characteristics

The performed study shows the result of comparing the technological characteristics of the thermodynamic process of heat exchange of a closed system with the environment of an air heat pump (VTN) with a power of 7 kW obtained experimentally and the work of a recirculation air heat pump (RVTN) with the same power at the same parameters, on the basis of a thermodynamic cycle, at the evaporation temperature of the 100C and three condensation temperatures 300C, 400C, 500C. The result showed that the technological characteristics of the heat pump systems are almost the same.

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.

Evaluation of heat exchange rate of GHE in geothermal heat pump systems

2009 ◽  
Vol 34 (12) ◽  
pp. 2898-2904 ◽  
Author(s):  
Liu Jun ◽  
Zhang Xu ◽  
Gao Jun ◽  
Yang Jie
Keyword(s):  
Exchange Rate ◽  
Heat Exchange ◽  
Heat Pump ◽  
Geothermal Heat ◽  
Geothermal Heat Pump

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.

scholarly journals Prospect for the using of heat pumps for heating of buildings in enterprise

2020 ◽  
Author(s):  
Z. Sirkо ◽  
◽  
V. Korenda ◽  
I. Vyshnyakov ◽  
O. Protasov ◽  
...  
Keyword(s):  
Water Supply ◽  
Heat Pump ◽  
Thermal Energy ◽  
Alternative Energy ◽  
Thermodynamic Cycle ◽  
Heat Pumps ◽  
The State ◽  
Hot Water ◽  
Alternative Energy Sources ◽  
Hot Water Supply

Heat pump - a device for transferring thermal energy from a source of low potential thermal energy to a consumer with a higher temperature. The thermodynamic cycle of a heat pump is similar to a refrigerating machine. Depending on the principle of operation, heat pumps are divided into compression and absorption. The most commonly used compression heat pumps. In recent years, numerous publications on the use of heat pump technology in heating and hot water supply facilities of various spheres - from individual homes to residential neighborhoods have appeared in various media. The authors of the publication have many years of experience in joint scientific and technical cooperation with leading technical universities and industrial organizations in the field of development and practical use of heat pump technology. The authors analyze the possibilities of introducing heat pumps at enterprises and organizations of the State Reserve System of Ukraine. It has been shown that the amount of expenses in comparison with central heating or operation of gas and electric boilers of similar power is several times smaller. It is noted that the implementation of heat pumps is a promising direction in the use of alternative energy sources to meet the heating, ventilation and hot water supply needs of buildings. The payback period from the introduction of heat pumps at enterprises is 4-9 years, depending on the location of the object and the type of source of low-temperature heat. The article meets the requirements of the State Tax Code of Ukraine and can be recommended for publication.

Graphical Interpretation of Exergy

2011 ◽  
Author(s):  
Daisie D. Boettner ◽  
James Bluman ◽  
Matthew Rowland ◽  
Jonathan Bodenhamer ◽  
A. O˝zer Arnas
Keyword(s):  
Thermodynamic Property ◽  
Heat Pump ◽  
Closed System ◽  
Abstract Concept ◽  
System State ◽  
Power Cycle ◽  
Graphical Interpretation ◽  
Dead State ◽  
The Dead

Exergy is a system thermodynamic property defined only with respect to the system’s surroundings. For a specified system state, exergy is the maximum potential useful work available from the system as it achieves equilibrium with the surroundings. For students exergy can be a very abstract concept. This paper presents a graphical means to clarify the concept of exergy for a closed system, demonstrating exergy at any state i corresponds to the sum of the net work of a power cycle that incorporates a process from system state i to the dead state and the net work of a refrigeration/heat pump cycle required to move the system from the dead state to state i.

scholarly journals Evaluation of Suitable Areas to Introduce a Closed-Loop Ground Source Heat Pump System in the Case of a Standard Japanese Detached Residence

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4294
Author(s):  
Gaurav Shrestha ◽  
Mayumi Yoshioka ◽  
Hikari Fujii ◽  
Youhei Uchida
Keyword(s):  
Heat Exchange ◽  
Heat Pump ◽  
Closed Loop ◽  
Ground Source Heat Pump ◽  
Standard Size ◽  
Pump System ◽  
Heat Pump System ◽  
The North ◽  
Ground Source ◽  
Suitability Map

Evaluation of appropriate areas to introduce a closed-loop ground-source heat pump (GSHP) system in the case of a standard detached residence was conducted in Akita Plain, Japan. Depth of borehole heat exchanger (BHE) required to use a GSHP system was taken as the suitability index, which is simpler for the general public to understand and to promote the system. Heating and cooling loads of the standard size detached residence were calculated based on the 2013 Energy Conservation Standard. To estimate BHE depths and estimate a suitable area, identical 3D BHE models were constructed at 30 points in the plain. Required BHE depths were determined by performing heat exchange simulations at each location using the calculated loads and heat exchange rates. A suitability map showing distribution of the required BHE depths was prepared. BHE depths were shorter in the north-western area compared to the other parts, implying that the coastal lowlands in this area are more suitable for closed-loop system in the standard detached residences in terms of heat exchange performance as well as the cost reduction. Thickly distributed Quaternary System with higher thermal conductivity is contributing to shorter BHE depths. The suitability map is effective to adopt potential areas for the system installation in the standard detached Japanese residences.

scholarly journals Theoretical and Experimental Cost–Benefit Assessment of Borehole Heat Exchangers (BHEs) According to Working Fluid Flow Rate

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4925
Author(s):  
Borja Badenes ◽  
Miguel Ángel Mateo Pla ◽  
Teresa Magraner ◽  
Javier Soriano ◽  
Javier F. Urchueguía
Keyword(s):  
Exchange Rate ◽  
Heat Exchange ◽  
Heat Pump ◽  
Flow Rate ◽  
Cost Benefit ◽  
Operating Costs ◽  
Working Fluid ◽  
Geothermal Systems ◽  
Operational Parameters ◽  
Pumping Rate

In ground-source heat-pump systems, the heat exchange rate is influenced by various design and operational parameters that condition the thermal performance of the heat pump and the running costs during exploitation. One less-studied area is the relationship between the pumping costs in a given system and the heat exchange rate. This work analyzes the investment and operating costs of representative borehole heat-exchanger configurations with varying circulating flow rate by means of a combination of analytical formulas and case study simulations to allow a precise quantification of the capital and operational costs in typical scenario. As a conclusion, an optimal flow rate minimizing either of both costs can be determined. Furthermore, it is concluded that in terms of operating costs, there is an operational pumping rate above which performance of geothermal systems is energetically strongly penalized.

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