Adiabatic capillary tube flow of carbon dioxide in a transcritical heat pump cycle

2007 ◽  
Vol 31 (11) ◽  
pp. 1016-1030 ◽  
Author(s):  
Neeraj Agrawal ◽  
Souvik Bhattacharyya
Keyword(s):  
Carbon Dioxide ◽  
Heat Pump ◽  
Capillary Tube ◽  
Tube Flow

Prediction of Adiabatic Capillary Tube Length of Heat Pump Using Carbon Dioxide

2011 ◽  
Vol 35 (5) ◽  
pp. 576-581
Author(s):  
Hoo-Kyu Oh ◽  
Kwang-Hwan Choi ◽  
Min-Ju Jeon ◽  
Chang-Hyo Son
Keyword(s):  
Carbon Dioxide ◽  
Heat Pump ◽  
Capillary Tube ◽  
Tube Length

A Study on the Performance of Drinking Fountain Using CO2 Heat Pump under Different System Pressures

2010 ◽  
Vol 44-47 ◽  
pp. 2433-2437 ◽  
Author(s):  
Yu Lieh Wu ◽  
Yu Dai Shiue ◽  
Kuo Hsiang Chien ◽  
Chiu Li Wang
Keyword(s):  
Carbon Dioxide ◽  
Heat Source ◽  
Heat Pump ◽  
Air Conditioning ◽  
High Performance ◽  
High Efficiency ◽  
Electric Heating ◽  
Alternative Refrigerant ◽  
Saving Effect ◽  
Natural Refrigerant

To avoid continuous damage of ozone layer and deterioration of global warming, many countries have devoted to the development and application of natural refrigerant. Although CO2, an alternative refrigerant in the area of air conditioning is not the best all-temperature refrigerant, it has the lowest operating risk as compared to hydrocarbon (HCs) and ammonia.Traditional drinking fountain provides heat source through secondary energy source - electric heating; however, the heating effect is limited. Since heat pump has a high performance, this study used a carbon dioxide heat pump, which has energy-saving effect and high efficiency, to provide heat source to drinking fountains. It further assembled the drinking fountain system with carbon dioxide heat pump and analyzed its performance.

Experimental Investigation on Flow Characteristic of Stepped Capillary Tube for Heat Pump Type Air Conditioner with R410A

2014 ◽  
Vol 960-961 ◽  
pp. 643-647
Author(s):  
Yan Sheng Xu
Keyword(s):  
Mass Flow Rate ◽  
Heat Pump ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Tube ◽  
Coefficient Of Performance ◽  
Tube Length ◽  
Air Conditioner ◽  
Capillary Tubes ◽  
Tube Assembly

A stepped capillary tube consisting of two serially connected capillary tubes with different diameters is invented to replace the conventional expansion device. The mass flow rate of refrigerant R410A in stepped capillary tubes with different size were tested. The model of stepped capillary tube is proposed, and its numerical algorithm for tube length and mass flow rate is developed. The experimental results show that the performance comparing between stepped capillary tube system and capillary tube assembly system, the cooling capacity is reduced by 0.3%, the energy efficiency ratio (EER) is equal to each other, the heating capacity is increased by 0.3%, the coefficient of performance (COP) is decreased by 0.3%. That is to say, the performance index of the two kinds of throttle mechanism is almost identical. It indicates that the stepped capillary tube can replace the capillary tube assembly in the R410A heat pump type air conditioner absolutely. The model is validated with experimental data, and the results show that the model can be used for sizing and rating stepped capillary tube.

Study on Cooling Heat Transfer of Supercritical Carbon Dioxide Applied to Transcritical Carbon Dioxide Heat Pump

2021 ◽  
pp. 451-493
Author(s):  
Chaobin Dang ◽  
Eiji Hihara
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Heat Pump ◽  
Supercritical Co2 ◽  
Lubricating Oil ◽  
Cross Sectional ◽  
Pump System ◽  
Heat Pump System ◽  
Transcritical Carbon Dioxide ◽  
Supercritical Water Cooled Reactor

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.

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