Effect of working fluids on the performance of a novel direct vapor generation solar organic Rankine cycle system

In this paper, three typical working fluids were selected for the near-critical ORC and subcritical ORC. The difference of performance between the near-critical ORC and subcritical ORC was analyzed by establishing the thermodynamic model. The reason for difference was analyzed in terms of the thermophysical properties. The results indicate that the performance of the near-critical ORC is better than the subcritical ORC. The net absorbed heat, net power and efficiency of the near-critical ORC vary slowly with the vapor generation temperature, which means that the near-critical ORC has good off-design performance. The dry working fluid R236fa is best adapted for the near-critical ORC among the three working fluids. The singular performance of the near-critical ORC depends on the properties of latent heat and type of working fluid in near-critical region.

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Effect of Phase Change Material Storage on the Dynamic Performance of a Direct Vapor Generation Solar Organic Rankine Cycle System

Energies ◽

10.3390/en13225904 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5904

Author(s):

Jahan Zeb Alvi ◽

Yongqiang Feng ◽

Qian Wang ◽

Muhammad Imran ◽

Lehar Asip Khan ◽

...

Keyword(s):

Phase Change ◽

Phase Change Material ◽

Storage Tank ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Thermal Storage ◽

Working Fluid ◽

Vapor Generation ◽

Cycle System ◽

Change Material

Solar energy is a potential source for a thermal power generation system. A direct vapor generation solar organic Rankine cycle system using phase change material storage was analyzed in the present study. The overall system consisted of an arrangement of evacuated flat plate collectors, a phase-change-material-based thermal storage tank, a turbine, a water-cooled condenser, and an organic fluid pump. The MATLAB programming environment was used to develop the thermodynamic model of the whole system. The thermal storage tank was modeled using the finite difference method and the results were validated against experimental work carried out in the past. The hourly weather data of Karachi, Pakistan, was used to carry out the dynamic simulation of the system on a weekly, monthly, and annual basis. The impact of phase change material storage on the enhancement of the overall system performance during the charging and discharging modes was also evaluated. The annual organic Rankine cycle efficiency, system efficiency, and net power output were observed to be 12.16%, 9.38%, and 26.8 kW, respectively. The spring and autumn seasons showed better performance of the phase change material storage system compared to the summer and winter seasons. The rise in working fluid temperature, the fall in phase change material temperature, and the amount of heat stored by the thermal storage were found to be at a maximum in September, while their values became a minimum in February.

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Selection of Working Fluids for Different Temperature Heat Source Organic Rankine Cycle

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.614-615.195 ◽

2012 ◽

Vol 614-615 ◽

pp. 195-199

Author(s):

Guang Lin Liu ◽

Jin Liang Xu ◽

Bing Zhang

Keyword(s):

Power Generation ◽

Heat Source ◽

Flue Gas ◽

Thermal Power ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Source Power ◽

Working Fluids ◽

Cycle System ◽

Temperature Heat

In the current paper, under the condition of different flue gas temperatures and constant flue gas thermal power, the influence of different organic working fluids on the efficiency of sub-critical organic Rankine cycle system were studied. The efficiency and other parameters of the simple system were calculated. The results show that the efficiency of sub-critical organic Rankine cycle system could reach maximum when the parameters of the working fluids in the expander inlet are dry-saturation. Flammability, toxicity, ozone depletion and other factors of the working fluids should be considered in the organic Rankine cycles. R245fa is considered a better choice for low-temperature heat source power generation, and the efficiency of the system is about 10.2%; for the high-temperature heat source, R601a can be considered; however, due to its high flammability, novel working fluids should be further discovered for power generation.

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Thermophysical capability of ozone-safe working fluids for an organic rankine cycle system

Heat Recovery Systems and CHP ◽

10.1016/0890-4332(93)90042-t ◽

1993 ◽

Vol 13 (5) ◽

pp. 409-418 ◽

Cited By ~ 33

Author(s):

M.J. Lee ◽

D.L. Tien ◽

C.T. Shao

Keyword(s):

Organic Rankine Cycle ◽

Rankine Cycle ◽

Working Fluids ◽

Cycle System ◽

Safe Working

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Selection of Working Fluids for Low-Temperature Power Generation Organic Rankine Cycles System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.557-559.1509 ◽

2012 ◽

Vol 557-559 ◽

pp. 1509-1513 ◽

Cited By ~ 2

Author(s):

Zhong He Han ◽

Yi Da Yu

Keyword(s):

Low Temperature ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Working Fluid ◽

Heat Sources ◽

Working Fluids ◽

Cycle System ◽

Organic Rankine Cycles ◽

Organic Fluids ◽

Cycle Efficiency

A Rankine cycle using organic fluids as working fluids, called organic Rankine cycle (ORC), is potentially feasible in recovering low enthalpy containing heat sources. The choices of fluids should meet the requirement of environment, safety, critical pressure and critical temperature etc. Under the proposed working conditions, R600a, R245fa, R236fa, R236ea, R227ea are chosen as the working fluids of the low-temperature Rankine cycle system, then those fluids are investigated and compared from cycle efficiency, work ratio, exergy efficiency, irreversible loss. The results show that R245fa is an available and effective working fluid for low-temperature Rankine cycle.

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