scholarly journals Performance and Exergy Transfer Analysis of Heat Exchangers with Graphene Nanofluids in Seawater Source Marine Heat Pump System

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1762 ◽  
Author(s):  
Zhe Wang ◽  
Fenghui Han ◽  
Yulong Ji ◽  
Wenhua Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Transfer Model ◽  
Enhanced Heat Transfer ◽  
Pump System ◽  
Heat Pump System ◽  
Tube Heat Exchanger ◽  
Exergy Transfer

A marine seawater source heat pump is based on the relatively stable temperature of seawater, and uses it as the system’s cold and heat source to provide the ship with the necessary cold and heat energy. This technology is one of the important solutions to reduce ship energy consumption. Therefore, in this paper, the heat exchanger in the CO2 heat pump system with graphene nano-fluid refrigerant is experimentally studied, and the influence of related factors on its heat transfer enhancement performance is analyzed. First, the paper describes the transformation of the heat pump system experimental bench, the preparation of six different mass concentrations (0~1 wt.%) of graphene nanofluid and its thermophysical properties. Secondly, this paper defines graphene nanofluids as beneficiary fluids, the heat exchanger gains cold fluid heat exergy increase, and the consumption of hot fluid heat is heat exergy decrease. Based on the heat transfer efficiency and exergy efficiency of the heat exchanger, an exergy transfer model was established for a seawater source of tube heat exchanger. Finally, the article carried out a test of enhanced heat transfer of heat exchangers with different concentrations of graphene nanofluid refrigerants under simulated seawater constant temperature conditions and analyzed the test results using energy and an exergy transfer model. The results show that the enhanced heat transfer effect brought by the low concentration (0~0.1 wt.%) of graphene nanofluid is greater than the effect of its viscosity on the performance and has a good exergy transfer effectiveness. When the concentration of graphene nanofluid is too high, the resistance caused by the increase in viscosity will exceed the enhanced heat transfer gain brought by the nanofluid, which results in a significant decrease in the exergy transfer effectiveness.

Key Problem Analysis and Solution on Intake Water and Heat Transfer of Sewage-Source Heat Pump System

2014 ◽  
Vol 1070-1072 ◽  
pp. 1799-1802
Author(s):  
Hai Yang Bi ◽  
Yong Mao Shang ◽  
Xiang Hong Gu
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Waste Heat ◽  
Problem Analysis ◽  
Pump System ◽  
Heat Pump System ◽  
Technology Application ◽  
Tube Heat Exchanger ◽  
Sewage Source

Changing "high consumption energy, low temperature heat to the indoor, waste heat to the environment", and turning the HVAC harmoniously into the natural ecological cycle, conform to the trend of the development of ecological architecture. Heat pump technology is a way of HVAC energy saving the most practical. Although low heat and cold source of the city sewage is ideal, but the quality is very unstable, can not meet the operation requirements of heat exchange equipment. This paper analyzes the key problems of the sewage side in sewage source heat pump technology application in the present: hair dirt clog sewage heat exchanger; fouling in heat surface reduces the heat transfer performance, and results in large heat-transfer equipment in the practical application. According to the key problems of sewage side, this paper prevents hair clogged with large tube heat exchanger; reduces the fouling thermal resistance, and enhances heat transfer process using the heat exchanging technology of circulating fluidized bed.

Study on heat transfer model of capillary exchanger in subway source heat pump system

2020 ◽  
Vol 150 ◽  
pp. 1074-1088 ◽  
Author(s):  
Guodan Liu ◽  
Chuanrui Li ◽  
Songtao Hu ◽  
Yongming Ji ◽  
Zhen Tong ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Pump System ◽  
Heat Pump System

Simulation Study on Heat Transferring Performance of Vertical T-Tube Ground Heat Exchangers

2013 ◽  
Vol 805-806 ◽  
pp. 547-551
Author(s):  
Shao Wen Shang ◽  
Pei Pei Li ◽  
Dong Wen Fang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Common Ground ◽  
Inlet Temperature ◽  
Ground Heat Exchanger ◽  
Pump System ◽  
Heat Pump System ◽  
Tube Heat Exchanger ◽  
Ground Heat Exchangers ◽  
Ground Source

In the Ground Source Heat Pump system, the vertical U-tube is the most common ground heat exchanger. The heat transfer between the U-tube and the soil is affected by many factors. For analyzing the influence of these factors on heat transfer of the U-tube, I use GAMBIT software to establish a physical model who is used to simulated the heat exchanging of single U-tube heat exchanger and the surrounding soil physical. and mesh it. On the base, we take advantage of FLUENT software to make numerical simulation. After finishing analysis, we got some conclusions as follows: Under different tube wells depths and different inlet water temperature conditions, with the pipe inlet velocity increases, the heat exchanger performance improves, but the temperature difference between the import and the export will decreases. In addition to improve the inlet temperature of the U-tube, we can significantly increase the transferring heat of the ground heat exchanger.

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