Characteristics Study of Sewage Source Heat Pump System Based on Heat Transfer Enhancement and Acoustic Cavitation Decontamination

2014 ◽  
Vol 665 ◽  
pp. 607-610
Author(s):  
Jian Feng Qian ◽  
Ya Yuan Liu

Put forward an application of ultrasonic cavitation technology of the sewage source heat pump system to solve the problem of controlling pollution and emphatically discusses the principle of acoustic cavitation and the effect, to conduct a feasibility analysis of Anti-fouling in sewage source heat pump sewage side. Through analysis principle of ultrasonic cavitation and heat transfer enhancement for carrying the experiment, study the pattern of scaling in heat exchange tube for different velocity and viscosity, effect in flow rate on the ultrasonic cleaning wastewater, Effect in ultrasonic treatment time on the descaling result. Obtain that it can enhancement transfer for 48%.

2014 ◽  
Vol 525 ◽  
pp. 603-606
Author(s):  
Jian Feng Qian ◽  
Ya Yuan Liu ◽  
Ying Xu ◽  
Yan Kun Tan

sewage heat exchanger is important to collect heat energy in sewage source heat pump system. Heat transfer enhancement effect is not obvious while the chemical methods and manual cleaning is applying to remove the heat exchangers fouling in the long-term operation. Here sets an ultrasonic incrustation removal physical model in heat exchanger structure to antiscaling and descaling simultaneously. The acoustic cavitation technology can be used in sewage source heat pump systems for the experimental results and decontamination rate reaches 50%.


2014 ◽  
Vol 1070-1072 ◽  
pp. 1799-1802
Author(s):  
Hai Yang Bi ◽  
Yong Mao Shang ◽  
Xiang Hong Gu

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.


Author(s):  
Chaobin Dang ◽  
Eiji Hihara

Understanding the heat transfer characteristics of supercritical fluids is of fundamental importance in many industrial processes such as transcritical heat pump system, supercritical water-cooled reactor, supercritical separation, and supercritical extraction processes. This chapter addresses recent experimental, theoretical, and numerical studies on cooling heat transfer of supercritical CO2. A systematic study on heat transfer coefficient and pressure drop of supercritical CO2 was carried out at wide ranges of tube diameter, mass flux, heat flux, temperature, and pressure. Based on the understanding of temperature and velocity distributions at cross-sectional direction provided by the numerical simulation, a new prediction model was proposed, which agreed well with the experimental results. In addition, the effect of lubricating oil was also discussed with the focus on the change in flow pattern and heat transfer performance of oil and supercritical CO2.


Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1762 ◽  
Author(s):  
Zhe Wang ◽  
Fenghui Han ◽  
Yulong Ji ◽  
Wenhua Li

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.


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