Binary-objective optimization of latest low-GWP alternatives to R245fa for organic Rankine cycle application

Yang, Jenny; Gao, Lei; Ye, Zhenhong; Hwang, Yunho; Chen, Jiangping

doi:10.1016/j.energy.2020.119336

Cited by 36 publications

(7 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The drop-in assessment is performed considering potential drop-in replacements with VCC and COP values within 25% of the reference refrigerant to be replaced. It should be mentioned that for R1336mzz(Z) and R1224yd(Z), the COP is predicted as an average based on available experimental data under similar conditions, , due to the nonavailability of isothermal ideal gas entropies needed to compute the TS-diagrams involved in the COP calculations. The COP values for these refrigerants are within those obtained for highly efficient refrigerants R1233zd(E) and R245fa.…”

Section: Resultsmentioning

confidence: 99%

Assessment of Low Global Warming Potential Refrigerants for Drop-In Replacement by Connecting their Molecular Features to Their Performance

Albà

Alkhatib

Llovell

et al. 2021

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

The use of hydrofluorocarbons (HFCs) as an alternative for refrigeration units has grown over the past decades as a replacement to chlorofluorocarbons (CFCs), banned by the Montreal’s Protocol because of their effect on the depletion of the ozone layer. However, HFCs are known to be greenhouse gases with considerable global warming potential (GWP), thousands of times higher than carbon dioxide. The Kigali Amendment to the Montreal Protocol has promoted an active area of research toward the development of low GWP refrigerants to replace the ones in current use, and it is expected to significantly contribute to the Paris Agreement by avoiding nearly half a degree Celsius of temperature increase by the end of this century. We present here a molecular-based evaluation tool aiming at finding optimal refrigerants with the requirements imposed by current environmental legislations in order to mitigate their impact on climate change. The proposed approach relies on the robust polar soft-SAFT equation of state to predict thermodynamic properties required for their technical evaluation at conditions relevant for cooling applications. Additionally, the thermodynamic model integrated with technical criteria enable the search for compatibility of currently used third generation compounds with more eco-friendly refrigerants as drop-in replacements. The criteria include volumetric cooling capacity, coefficient of performance, and other physicochemical properties with direct impact on the technical performance of the cooling cycle. As such, R1123, R1224yd(Z), R1234ze(E), and R1225ye(Z) demonstrate high aptitude toward replacing R134a, R32, R152a, and R245fa with minimal retrofitting to the existing system. The current modeling platform for the rapid screening of emerging refrigerants offers a guide for future efforts on the design of alternative working fluids.

show abstract

Section: Resultsmentioning

confidence: 99%

Assessment of Low Global Warming Potential Refrigerants for Drop-In Replacement by Connecting their Molecular Features to Their Performance

Albà

Alkhatib

Llovell

et al. 2021

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

show abstract

“…In this study, the thermodynamic and economic performance of the system is investigated considering the three organic working fluids selected. The following working fluids are studied and compared, R245fa, R1234yf, and R1234ze, which were found to be appropriate fluids for low-temperature waste heat recovery (Yang et al, 2021) and are suitable fluids according to the criteria mentioned above. Some physical properties of the studied working fluids (e.g., boiling and critical temperature, specific heat of liquid and vapor, GWP and ODP) are collected in published article (Dokl et al, 2021).…”

Section: Description Of Orc Systemmentioning

confidence: 99%

Techno-Economic Optimization of a Low-Temperature Organic Rankine System Driven by Multiple Heat Sources

Dokl

Kravanja²,

Čuček³

2022

Front. Sustain.

View full text Add to dashboard Cite

This study presents the optimization of organic Rankine cycle (ORC) which utilizes low temperature waste heat from the aluminum production process and two low temperature renewable energy sources, solar thermal energy and geothermal energy. As geothermal energy is present at lower temperature level compared to the other two heat sources, two separate ORC cycles are considered. Optimization of the proposed system is performed based on a non-linear programming (NLP) formulation by maximizing the thermodynamic and economic performance of the system. The main variables considered in the model include temperature, pressure, flowrate, mass enthalpy, and energy flows of all the streams in the system. To optimize the variables in the system, correlations were developed, which were formulated as NLP models and optimized by minimizing the sum of least squares. The results show that most of the generated power output can be provided by the waste heat, while the lowest by the solar energy due to the relatively low average solar irradiance at considered location. When monthly time periods are considered, the highest electricity production is generated by the working fluid R1245fa in June, and amounts to 830.4 kW from waste heat, 246.5 kW from geothermal energy and 149.4 kW from solar energy. The proposed system is economically feasible for all three studied working fluids and the discount rates of 2% and higher. The final conclusions indicate that the proposed ORC system utilizing waste heat, geothermal and solar thermal energy, can generate power in a more sustainable way.

show abstract

“…The final preferred solution is then determined by the concept of ‘weight’, which reflects the preference of the decision-maker. Yang et al [ 23 ] carried out the binary-objective optimization of low-GWP alternatives to R245fa for the ORC system. The results showed that both the cycle thermal efficiency and the LECT (total savings of levelized electricity cost) are sensitive to evaporator outlet temperature.…”

Section: Introductionmentioning

confidence: 99%

Multi-Objective Optimization of the Basic and Regenerative ORC Integrated with Working Fluid Selection

Zhou

Ruan

Hong

et al. 2022

Entropy

View full text Add to dashboard Cite

A multi-objective optimization based on the non-dominated sorting genetic algorithm (NSGA-II) is carried out in the present work for the basic organic Rankine cycle (BORC) and regenerative ORC (RORC) systems. The selection of working fluids is integrated into multi-objective optimization by parameterizing the pure working fluids into a two-dimensional array. Two sets of decision indicators, exergy efficiency vs. thermal efficiency and exergy efficiency vs. levelized energy cost (LEC), are adopted and examined. Five decision variables including the turbine inlet temperature, vapor superheat degree, the evaporator and condenser pinch temperature differences, and the mass fraction of the mixture are optimized. It is found that the turbine inlet temperature is the most effective factor for both the BORC and RORC systems. Compared to the reverse variation of exergy efficiency and thermal efficiency, only a weak conflict exists between the exergy efficiency and LEC which tends to make the binary objective optimization be a single objective optimization. The RORC provides higher thermal efficiency than BORC at the same exergy efficiency while the LEC of RORC also becomes higher because the bare module cost of buying one more heat exchange is higher than the cost reduction due to the reduced heat transfer area. Under the heat source temperature of 423.15 K, the final obtained exergy and thermal efficiencies are 45.6% and 16.6% for BORC, and 38.6% and 20.7% for RORC, respectively.

show abstract

Binary-objective optimization of latest low-GWP alternatives to R245fa for organic Rankine cycle application

Cited by 36 publications

References 21 publications

Assessment of Low Global Warming Potential Refrigerants for Drop-In Replacement by Connecting their Molecular Features to Their Performance

Assessment of Low Global Warming Potential Refrigerants for Drop-In Replacement by Connecting their Molecular Features to Their Performance

Techno-Economic Optimization of a Low-Temperature Organic Rankine System Driven by Multiple Heat Sources

Multi-Objective Optimization of the Basic and Regenerative ORC Integrated with Working Fluid Selection

Contact Info

Product

Resources

About