Thermodynamic analysis and comparison between CO 2 transcritical power cycles and R245fa organic Rankine cycles for low grade heat to power energy conversion

Li, Liang; Ge, Y.T.; Luo, Xianglong; Tassou, S.A.

doi:10.1016/j.applthermaleng.2016.06.132

Cited by 46 publications

(15 citation statements)

References 25 publications

(24 reference statements)

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“…Furthermore, authors [8] performed a parametric optimization by taking some parameters including the relative cost of the system as performance pointers. Li et al [9] theoretically compared and studied CO 2 transcritical power cycle and R245fa Organic Rankine cycle both with low grade heat sources. They proposed that using a recuperator in both systems would improve their exergy efficiency.…”

Section: Introductionmentioning

confidence: 99%

Exergy analysis of a hydrogen and water production process by a solar-driven transcritical CO 2 power cycle with Stirling engine

Naseri

Bidi

Ahmadi

et al. 2017

Journal of Cleaner Production

112

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 A novel cogeneration plant including Stirling engine to produce water and hydrogen. A dynamic RO model including recovery turbine for different permeate flow rate. About 8% reduction in exergy destruction in the system using ideal Stirling engine. More electrical power production, higher than both LNG and CO 2 power cycle. Electrolyzer-based ZLD approach by employing electrolyzer beside RO desalination. ACCEPTED MANUSCRIPT AbstractThis study attempts to go beyond the conventional framework of the integrated solar transcritical CO 2 power cycle works, aimed at further utilization of available exergy as much as possible. This paper proposed a novel system for hydrogen and fresh water production in which a Stirling engine used instead of a condenser, for the places with abundant access to solar radiation and sea, and least to freshwater sources. This proposal leads to further utilization of streams' exergy through the system instead of wasting to the environment, and further power production by the engine followed by the higher products. The electrolyzer employed beside Reverse Osmosis (RO) desalination system, and takes full advantages of highly concentrated brine stream of desalination, eliminating the wastewater rejection through proposed system leading to attaining a near-ZLD approach in fresh water and hydrogen production. This reduces the adverse impacts of desalination's wastewater on the environment. A thermodynamic and exergy analysis is carried out to compare the superiority of this study and investigate the effect of some key parameters on the overall performance of the system as well. The results showed that replacing the condenser by a Stirling engine reduces the exergy destruction through heat transfer from CO 2 to an LNG unit. Exergy destruction was reduced from 16.7% to 8.8% for the above configuration for an ideal Stirling engine that exploits it to produce extra power which its minimum is at least 9 kW and 15 kW higher than CO 2 and LNG power productions.Moreover, Entering RO brine stream, wasting 2.58 kW exergy, to the electrolyzer leads toNaClO and H 2 production besides removing brine stream. In a power plant, sodium hypochlorite is used for disinfection of cooling systems and hydrogen can be used as a source of energy in fuel cells. An examination of some thermodynamic factors showed that higher ACCEPTED MANUSCRIPT 2 CO 2 turbine inlet pressure has an optimum value in producing fresh water and hydrogen, while the higher CO 2 turbine inlet temperature slightly reduces the productions rate. The more recovery ratio also causes a sharp reduction in hydrogen production, whereas it has an optimum amount of fresh water production at recovery ratio equals to 0.47.

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Section: Introductionmentioning

confidence: 99%

Exergy analysis of a hydrogen and water production process by a solar-driven transcritical CO 2 power cycle with Stirling engine

Naseri

Bidi

Ahmadi

et al. 2017

Journal of Cleaner Production

112

View full text Add to dashboard Cite

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“…The Table 6 to Table 10 provide the thermodynamic properties of different cycle components, mass discharge of the cycle's working fluid, results of economic analysis of the cycle, results from thermodynamic analysis of cycle, and total cost of investment in Damavand geothermal power plant, respectively. The results of the written code were compared to those of reference number 50 and the maximum error value was obtained around 5.7% (Li et al, 2016). The Fig.…”

Section: Resultsmentioning

confidence: 99%

Energy, exergy, and economic analysis of a geothermal power plant

Kazemi

Ehyaei

2018

Adv. Geo-Energy Res.

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Citation:Kazemi, H., Ehyaei, M.A. Energy, exergy, and economic analysis of a geothermal power plant. Advances in Geo-Energy Research, 2018, 2(2): 190-209, doi: 10.26804/ager.2018.07.Corresponding author: *E-mail: aliehyaei@yahoo.com Keywords:Geothermal cycle Organic Rankine Cycle exergy Abstract:The current study aimed at designing a geothermal power plant in the Nonal area in Damavand district for simultaneous generation of thermal energy the electric power in the network of Damavand City and a part of Tehran province, the organic working fluid for the above cycle is R245fa which is a non-flammable fluid of dry type. The values of energy efficiency, exergy, the net rate of entropy change, and the specific output power were calculated as 18.2%, 21.3%, 172.97 kW/K, and 31.43 kJ/kg, respectively. The cost of drilling a well, as well as designing and construction of Damavand's geothermal power plant, were calculated to be 4.2 and 521.5 million (USD), respectively. Also, the cost per generation of each kW/h of power in Damavand power plant was 17 cents. The estimated payback time is calculated as 15 years. The analysis of the cycle in different months of the year showed that exergy efficiency has little change. The only significant effect of temperature changes was on the exergy efficiency as approximately a change of 2% can be seen during a year.

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“…The high pressure ratio between the evaporator and the cooler necessarily requires double stage compression for reasonable performance, for instance. However, proven technology exists for all devices [3], and other solutions could be studied, for example using CO 2 blends, as is being done for power cycles [4].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Transcritical CO2 and Conventional Refrigerant Heat Pump Water Heaters for Domestic Applications

et al. 2019

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Although CO 2 as refrigerant is well known for having the lowest global warming potential (GWP), and commercial domestic heat pump water heater systems exist, its long expected wide spread use has not fully unfolded. Indeed, CO 2 poses some technological difficulties with respect to conventional refrigerants, but currently, these difficulties have been largely overcome. Numerous studies show that CO 2 heat pump water heaters can improve the coefficient of performance (COP) of conventional ones in the given conditions. In this study, the performances of transcritical CO 2 and R410A heat pump water heaters were compared for an integrated nearly zero-energy building (NZEB) application. The thermodynamic cycle of two commercial systems were modelled integrating experimental data, and these models were then used to analyse both heat pumps receiving and producing hot water at equal temperatures, operating at the same ambient temperature. Within the range of operation of the system, it is unclear which would achieve the better COP, as it depends critically on the conditions of operation, which in turn depend on the ambient conditions and especially on the actual use of the water. Technology changes on each side of the line of equal performance conditions of operation (EPOC), a useful design tool developed in the study. The transcritical CO 2 is more sensitive to operating conditions, and thus offers greater flexibility to the designer, as it allows improving performance by optimising the global system design.

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Thermodynamic analysis and comparison between CO 2 transcritical power cycles and R245fa organic Rankine cycles for low grade heat to power energy conversion

Cited by 46 publications

References 25 publications

Exergy analysis of a hydrogen and water production process by a solar-driven transcritical CO 2 power cycle with Stirling engine

Exergy analysis of a hydrogen and water production process by a solar-driven transcritical CO 2 power cycle with Stirling engine

Energy, exergy, and economic analysis of a geothermal power plant

Comparison of Transcritical CO2 and Conventional Refrigerant Heat Pump Water Heaters for Domestic Applications

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