Vortex Tube Expansion Transcritical CO2 Heat Pump Cycle

2012 ◽  
Vol 190-191 ◽  
pp. 1340-1344 ◽  
Author(s):  
Ying Fu Liu ◽  
Chun Jing Geng ◽  
Guang Ya Jin
Keyword(s):  
Heat Pump ◽  
Ozone Depletion ◽  
System Performance ◽  
Vortex Tube ◽  
Outlet Temperature ◽  
Throttle Valve ◽  
Refrigerant Alternatives ◽  
Natural Refrigerant ◽  
Tube Expansion ◽  
Better Than

The application of natural refrigerant CO2 is of great significance to reduce the greenhouse effect and ozone depletion. Transcritical CO2 heat pump cycle is presently an important aspect of natural refrigerant alternatives research. In this paper, a vortex tube expansion transcritical CO2 heat pump cycle is established and compared to that of the transcritical CO2 refrigeration cycle with throttle valve. Thermodynamic analysis results indicate that the system performance of vortex tube expansion transcritical CO2 heat pump cycle is better than the transcritical CO2 heat pump cycle with throttle valve, and the COPh improvement is 5.8%~13.9% at given conditions. The gas-cooler outlet temperature has a great impact on the system performance, there is a higher COPh improvement when the cycle at lower evaporation temperature or higher gas-cooler outlet temperature.

Experimental Investigation on Transcritical CO2 Refrigeration System

2012 ◽  
Vol 516-517 ◽  
pp. 1156-1159 ◽  
Author(s):  
Ying Fu Liu ◽  
Peng Yu Shen ◽  
Guang Ya Jin
Keyword(s):  
High Pressure ◽  
Ozone Depletion ◽  
Refrigeration Cycle ◽  
Outlet Temperature ◽  
Heat Rejection ◽  
Evaporation Temperature ◽  
Cycle System ◽  
Refrigerant Alternatives ◽  
Exit Temperature ◽  
Natural Refrigerant

The application of natural refrigerant CO2 is of great significance to reduce the greenhouse effect and ozone depletion. Transcritical CO2 refrigeration cycle is presently an important aspect of natural refrigerant alternatives research. In this paper, the transcritical CO2 refrigeration cycle system is experimentally studied, effect on performance of heat rejection pressure, gas-cooler outlet temperature and evaporation temperature is analyzed. The experimental results show that there is an optimum high pressure to achieve the maximum COP, the evaporation temperature and gas-cooler exit temperature have great impact on the COP. Increase of gas-cooler outlet temperature led to a rapid increase in the optimal high pressure, but effect of evaporation temperature is not obvious. So in order to obtain the optimum performance, the influence of heat rejection pressure, evaporating temperature and gas-cooler outlet temperature should be considered during the designing and operating CO2 refrigeration cycle system.

Performance Analysis of Refrigerants R1234yf Single Stage Compression Cycle with a Throttle Valve and an Expander

2013 ◽  
Vol 753-755 ◽  
pp. 2790-2793
Author(s):  
Jing Rui Tian ◽  
Hong Li Wang ◽  
Gui Jun Xue ◽  
Qing Hua Zhang
Keyword(s):  
High Pressure ◽  
Performance Analysis ◽  
Pressure Ratio ◽  
Single Stage ◽  
Cycle Performance ◽  
Outlet Temperature ◽  
Throttle Valve ◽  
Compression Cycle ◽  
Increasing Trend ◽  
Better Than

In range of high pressure, the performance of single stage cycle with an expander (SCE) is better than the cycle with a throttling valve (SCV). With increasing of the evaporating temperature or decreasing outlet temperature of condenser, the performance of the two cycles is an increasing trend. With increasing of pressure ratio, the performances of all cycles are decreased. Under the same comparison conditions, expander cycle performance superior to the throttle valve performance.

Performance Analysis of Single Stage Compression Cycle with a Throttle Valve, an Expander and an Internal Heat Exchanger

2012 ◽  
Vol 602-604 ◽  
pp. 1064-1067
Author(s):  
Jing Rui Tian ◽  
Hong Li Wang
Keyword(s):  
Heat Exchanger ◽  
Internal Heat ◽  
Single Stage ◽  
Cycle Performance ◽  
Outlet Temperature ◽  
Internal Heat Exchanger ◽  
Throttle Valve ◽  
Compression Cycle ◽  
Increasing Trend ◽  
Better Than

In range of high pressure, the performance of single stage cycle with an expander (SCE) is better than the cycle with a throttling valve (SCV) and an internal heat exchanger (SCV+IHX). With increasing of the evaporating temperature or decreasing outlet temperature of condenser, the performance of the three cycles is an increasing trend. Under the same comparison conditions, expander cycle performance superior to the throttle valve performance.

Performance Analysis of Coupled System of CO2 Transcritical Heat Pump and Rankine Cycle

2011 ◽  
Vol 291-294 ◽  
pp. 1860-1865
Author(s):  
Hong Li Wang ◽  
Jing Rui Tian ◽  
Yi Tai Ma ◽  
Xiu Juan Hou
Keyword(s):  
Heat Pump ◽  
Waste Heat ◽  
Coupled System ◽  
Rankine Cycle ◽  
Coupled Systems ◽  
Feed Water ◽  
Outlet Temperature ◽  
Throttle Valve ◽  
Optimal Efficiency ◽  
Discharge Pressure

Based on thermodynamic principles, the coupled systems performance of the Rankine cycle and the transcritical CO2compression cycles with a throttle valve and the cycle with an expander were analyzed, respectively. The results show that the corresponding maximum performance in transcritical CO2heat pump, there is an optimal efficiency of the coupled system. With the temperature increasing of boiler feed water, the efficiency of the two coupled system showed an increasing trend; with increasing of discharge pressure of condenser or outlet temperature of gas cooler, both of the two kinds coupled system efficiency showed a downward trend. Under the same conditions, the efficiency of the coupled system with an expander is better than the system with a throttle valve. This paper can provide the fundamental datum for the power plant waste heat recovery.

Vortex Tube Expansion Two-Stage Transcritical CO2 Refrigeration Cycle

2012 ◽  
Vol 516-517 ◽  
pp. 1219-1223 ◽  
Author(s):  
Ying Fu Liu ◽  
Guang Ya Jin
Keyword(s):  
Mass Fraction ◽  
Vortex Tube ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Outlet Temperature ◽  
Two Stage ◽  
Evaporation Temperature ◽  
Optimum Heat ◽  
Tube Expansion ◽  
Cold Mass

Use of vortex tube as an expansion device in transcritical CO2 cycle could reduce the throttle loss and improve the coefficient of performance. In this paper, a vortex tube expansion two-stage transcritical CO2 refrigeration cycle(VTTC) is established and compared to that of the two-stage transcritical CO2 refrigeration cycle with throttle valve(TVTC). Thermodynamic analysis results indicate that there is also an optimum heat rejection pressure for the vortex tube cycle, and the COP improvement is 2.4%~16.3% at given conditions. Decrease in evaporation temperature or increase in gas-cooler outlet temperature decrease the COP, but the COP improvement will increase. The effect of cold mass fraction on the COP is negligible, but the COP improvement will increase fast with the increase of cold mass fraction.

BER performance analysis of FSO using hybrid-SIM technique with APD receiver over weak and strong turbulence channels

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rajat Kumar Giri
Keyword(s):  
Performance Improvement ◽  
System Performance ◽  
Avalanche Photodiode ◽  
Free Space Optical ◽  
Error Performance ◽  
Strong Turbulence ◽  
Meijer G Function ◽  
Hermite Approximation ◽  
Ber Performance ◽  
Better Than

Abstract In this paper, a hybrid-subcarrier-intensity-modulation (hybrid-SIM) technique for the performance improvement of free-space-optical (FSO) communication system has been proposed. Subsequently, for further error performance improvement, avalanche photodiode (APD) based receiver is used in the proposed system. The system performance is analyzed at various atmospheric turbulence levels over weak and strong turbulence channels. The bit error rate (BER) is theoretically derived using Gauss–Hermite approximation and Meijer-G function and it is simulated in the MATLAB environment. The simulation result shows that the BER performance of hybrid-SIM is better than BPSK-SIM technique irrespective of the channel types and also the significant BER performance improvement is observed by APD receiver.

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.

scholarly journals Experiment Study on Performance of Air Source Heat Pump

2013 ◽  
Vol 805-806 ◽  
pp. 645-648
Author(s):  
Wei Xiu Shi ◽  
Li Sheng Pan
Keyword(s):  
Heat Pump ◽  
Temperature Difference ◽  
Heat Pumps ◽  
Outlet Temperature ◽  
Exhaust Temperature ◽  
Air Source Heat Pump ◽  
And Performance ◽  
Save Energy ◽  
C 30 ◽  
Set Up

Under the situation of energy crisis, air source heat pumps are paid more attention recently. In order to save energy, the feasibility and performance of air source heat pump are studied by experiment, and variation laws of exhaust temperature, evaporator outlet temperature and outlet presser of compressor were analyzed in this paper. Air source heat pump apparatus were set up and the experiment was during 10°C, 20°C, 30°C and 40°C. The results were as follows: exhaust temperature of compressor increases gradually with the increase of tank temperature, but the temperature difference between exhaust temperature of compressor and tank temperature becomes little; temperature difference in evaporator decreases; Compressor outlet pressure increases obviously.

Study on Ground Source Heat Pump System of Combined Office and Residential Building in Hot Summer and Warm Winter Region

2013 ◽  
Vol 732-733 ◽  
pp. 564-570 ◽  
Author(s):  
Ying Ning Hu ◽  
Ya Zhao Liu ◽  
Jun Lin ◽  
Yan Wang
Keyword(s):  
Heat Pump ◽  
Heat Balance ◽  
System Performance ◽  
Residential Buildings ◽  
Residential Building ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Warm Winter ◽  
Ground Source

A ground source heat pump system of combined office and residential buildings in hot summer and warm winter region is introduced. The system performance is studied through the experiment, and the performance of underground heat balance is analyzed by TRNSYS. The results show the superiority and applicability of the ground source heat pump system.

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