scholarly journals Study on Heat Transfer Calculation Method of Ground Heat Exchangers Based on Heat Pump Unit Operation Characteristics

2016 ◽  
Vol 146 ◽  
pp. 450-458 ◽  
Author(s):  
Wenxin Li ◽  
Yong Wang ◽  
Yitao Jin
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Calculation Method ◽  
Heat Exchangers ◽  
Unit Operation ◽  
Pump Unit ◽  
Ground Heat Exchangers ◽  
Heat Pump Unit ◽  
Operation Characteristics ◽  
Heat Transfer Calculation

scholarly journals Analysis and Comparison of Some Low-Temperature Heat Sources for Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1853 ◽  
Author(s):  
Pavel Neuberger ◽  
Radomír Adamovský
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Ambient Air ◽  
Heat Transfer Fluid ◽  
Heat Sources ◽  
Ground Heat Exchangers ◽  
Temperature Heat

The efficiency of a heat pump energy system is significantly influenced by its low-temperature heat source. This paper presents the results of operational monitoring, analysis and comparison of heat transfer fluid temperatures, outputs and extracted energies at the most widely used low temperature heat sources within 218 days of a heating period. The monitoring involved horizontal ground heat exchangers (HGHEs) of linear and Slinky type, vertical ground heat exchangers (VGHEs) with single and double U-tube exchanger as well as the ambient air. The results of the verification indicated that it was not possible to specify clearly the most advantageous low-temperature heat source that meets the requirements of the efficiency of the heat pump operation. The highest average heat transfer fluid temperatures were achieved at linear HGHE (8.13 ± 4.50 °C) and double U-tube VGHE (8.13 ± 3.12 °C). The highest average specific heat output 59.97 ± 41.80 W/m2 and specific energy extracted from the ground mass 2723.40 ± 1785.58 kJ/m2·day were recorded at single U-tube VGHE. The lowest thermal resistance value of 0.07 K·m2/W, specifying the efficiency of the heat transfer process between the ground mass and the heat transfer fluid, was monitored at linear HGHE. The use of ambient air as a low-temperature heat pump source was considered to be the least advantageous in terms of its temperature parameters.

Experiment Study on Ground Temperature Recovery and Operating Performance of Intermittent Heat Storage in GSHP System

2010 ◽  
Author(s):  
Sufen Li ◽  
Lanhua Dai ◽  
Yan Shang
Keyword(s):  
Soil Temperature ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Heat Storage ◽  
Borehole Wall ◽  
Pump Unit ◽  
Pump System ◽  
Heat Pump System ◽  
Heat Pump Unit ◽  
The Impact

The ground source heat pump system (GSHP) continuous operation will result in heat accumulation of the soil around the underground heat exchangers leading the descend operation performance of heat pump system. Based on experiment of GSHP system in summer season, the temperature distribution of humid soil around the vertical boreholes, the power consumption of the heat pump unit, the water temperature in the inlet and outlet of the underground heat exchangers, the heat release rate of per unit length of the buried pipes in humid soil and the cooling coefficient of performance (COP) for the heat pump unit were acquired during the different intermittent heat storage modes. This study investigated the impact of soil temperature change around the borehole wall on the performance of heat pump operation, the influence of intermittent heat storage on the soil temperature near the borehole wall and the performance of heat pump unit, and the effect of intermittent heat storage process on the recovery rate of soil temperature. The results showed that proper control of the operation and interval time of GSHP can effectively improve the soil temperature field around the underground heat exchangers and enhance the performance of GSHP system, thus achieving high efficiency operation of heat pump units.

Operation Characteristics of Heat Pump Systems With Ground Heat Exchangers

2012 ◽  
Vol 33 (7) ◽  
pp. 629-641 ◽  
Author(s):  
Małgorzata Hanuszkiewicz-DrapaŁa ◽  
Jan Składzień
Keyword(s):  
Heat Pump ◽  
Heat Exchangers ◽  
Ground Heat Exchangers ◽  
Operation Characteristics

Study on the Adjustment Law of Supply Water Temperature of the Fan Coil Unit Based on Daily Air-Conditioning Load

2011 ◽  
Vol 374-377 ◽  
pp. 538-542 ◽  
Author(s):  
Zhi Jie Gao ◽  
Zhi Wei Wang ◽  
Ji Feng Zhao
Keyword(s):  
Heat Transfer ◽  
Water Temperature ◽  
Heat Pump ◽  
Air Conditioning ◽  
Heat Transfer Performance ◽  
Residential Buildings ◽  
Transfer Performance ◽  
Pump Unit ◽  
Heat Pump Unit ◽  
Supply Water

A new adjustment law of supply water temperature of heat pump unit was presented by analyzing heat transfer performance and computing supply water temperature of fan coil unit (FCU) in this paper. The paper established the energy equations for air side, water side and FCU in dry and wet conditions, respectively. And the heat transfer performance of FCU was obtained by analyzing the manufacturers’ performance data. According to an actual central air-conditioning system of residential buildings, we calculated the daily inlet water temperature of FCU and proposed the adjustment law for supply water temperature. The results show that the supply water temperature of cooling design day is 9.3°C, the daily supply water temperature of cooling season is higher than 7°C; the supply water temperature of heating design day is 36.4°C, the highest in heating season is 38.5°C, which is below the rated supply water temperature of heat pump unit, 45°C.

scholarly journals Air-to-water heat pump assessment: Part 1 – Experimental setup

2021 ◽  
Vol 327 ◽  
pp. 01009
Author(s):  
Nadezhda Doseva ◽  
Daniela Chakyrova ◽  
Svetoslav Stoianov ◽  
Ilia Hadhidimov
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Transfer Rate ◽  
Cost Allocation ◽  
Experimental Tests ◽  
Experimental Setup ◽  
Ambient Conditions ◽  
Pump Unit ◽  
Heat Pump Unit ◽  
The Cost

This paper is part 1 of the investigation on the exergetic and exergoeconomic parameters of an existing system with an air-to-water heat pump unit as a heat source. Part 1 presents the used experimental setup. The main aim of the conducted experimental tests is to develop a model of produced heat transfer rate and energetic COP at different ambient conditions. The obtained data is used in Part 2 of the study where the exergetic and exergoeconomic assessment is carried out. The performance of the considered system is evaluated using Seasonal Exergy Efficiency. Moreover, Part 2 of the study has presented the formulation of the cost of the product, and cost allocation within the heat pump unit based on exergy.

Technical Note. Influence of Material Used for the Regenerator on the Properties of a Thermoacoustic Heat Pump

2013 ◽  
Vol 38 (4) ◽  
pp. 565-570 ◽  
Author(s):  
Bartłomiej Kruk
Keyword(s):  
Heat Transfer ◽  
Temperature Gradient ◽  
Acoustic Wave ◽  
Heat Pump ◽  
Sound Wave ◽  
Heat Exchangers ◽  
Heat Pumps ◽  
Technical Note ◽  
New Materials ◽  
Modern Technologies

Abstract Research in termoacoustics began with the observation of the heat transfer between gas and solids. Using this interaction the intense sound wave could be applied to create engines and heat pumps. The most important part of thermoacoustic devices is a regenerator, where press of conversion of sound energy into thermal or vice versa takes place. In a heat pump the acoustic wave produces the temperature difference at the two ends of the regenerator. The aim of the paper is to find the influence of the material used for the construction of a regenerator on the properties of a thermoacoustic heat pump. Modern technologies allow us to create new materials with physical properties necessary to increase the temperature gradient on the heat exchangers. The aim of this paper is to create a regenerator which strongly improves the efficiency of the heat pump.

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