Thermo-economic optimization of superheating and sub-cooling heat exchangers in vapor-compressed refrigeration system

SUMMARYIn this study, a novel, renewable energy based, multigeneration energy system is introduced, and solar energy is, in this regard, used to produce electricity for a multi-unit building utilizing a Kalina cycle. For cooling a four-stage absorption chiller running on excessive or recovered heat is used. An electrolyzer is employed to produce hydrogen from the unused portion of electricity. In addition, domestic hot water is obtained from the system. In the analysis, a comprehensive thermodynamic model of the system is developed; the exergy efficiencies of the overall system and its components are determined; and the effects of varying configurations and operating conditions on the system performance are investigated. The number of suites that the system can satisfactory meet the demands is determined. Finally, an environmental impact assessment is conducted to determine the reductions in the amount of greenhouse gases, which can easily be achieved here by this solar energy based multigeneration system. The highest energy efficiency of the system is 57%, while the maximum exergy efficiency is 36%. It produces a maximum power of 92 kW and has a maximum cooling effect of 128 kW. It saves 1398 t of CO 2 per year compared with a conventional system to produce the same amounts of outputs, which can sufficiently meet the demand of 94 suites, respectively.

Section: Discussionmentioning

confidence: 99%

Analysis and evaluation of a new solar energy-based multigeneration system

Ozlu

Dinçer

2016

“…Ozkaymak et al [95] made a thermo economic optimization of a vapour compression refrigeration system integrated with sub cooling and super-heating based on energy and exergy analysis. This method involves complexity due to more theoretical calculations and assumptions.…”

Section: Cost Analysis Associated With Refrigerant Replacementmentioning

confidence: 99%

A review on recent developments in new refrigerant mixtures for vapour compression-based refrigeration, air-conditioning and heat pump units

Mohanraj

Muraleedharan

Jayaraj

2010

133

SUMMARYIn the present paper, an attempt has been made to review the performance of new refrigerant mixtures employed in vapour compression-based refrigeration, air-conditioning and heat pump units. The studies reported with refrigerant mixtures are categorized into six groups as follows: (i) hydrocarbon (HC), (ii) hydroflurocarbons (HFC), (iii) HFC/HC, (iv) hydrochloroflurocarbons (HCFC), (v) carbon dioxide (R744) and (vi) ammonia (R717). This paper explores the studies reported with new refrigerant mixtures in domestic refrigerators, commercial refrigeration systems, air conditioners, heat pumps, chillers and in automobile air conditioners. In addition, the technical difficulties faced with new refrigerant mixtures, further research needs in this field and future refrigerant options for new upcoming systems have been discussed in detail. This paper concludes that HC based refrigerant mixtures are identified as a long-term alternative to phase out the existing halogenated refrigerants in the vapour compression-based systems.

“…The same conclusions would be conceptually drawn by comparing the environomic and the threeobjective (energetic, economic, and environmental) approaches. The thermoeconomic objective function to be minimized expresses the total cost rate as the sum of fuel and investment (equipment/maintenance) cost rates [22,23]:…”

Section: Evolutionary Algorithmsmentioning

confidence: 99%

“…On the other hand, in a single-objective approach considering both the thermodynamic and economic objectives (C w and C tot ), the overall single-objective function (to be maximized) would be constructed by combining the two functions through appropriate weights as follows [22,23]:…”

Section: Evolutionary Algorithmsmentioning

confidence: 99%

“…MOEAs have been developed over the past decade [22,23]; severe tests on complex mathematical problems and on real-world engineering problems have shown that they can eliminate the above-cited difficulties of classical methods. An evolutionary algorithm is a hybrid stochastic/deterministic optimization tool that imitates the natural evolution of biological organisms, i.e.…”

Section: Evolutionary Algorithmsmentioning

confidence: 99%

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Optimization of the coupling of pressurized water nuclear reactors and multistage flash desalination plant by evolutionary algorithms and thermoeconomic method

Manesh

Amidpour

Hamedi

2009

SUMMARYThermodynamic simulation programs are widely used for designing complex thermal systems, but most of them do not incorporate second law optimization techniques. In this study, an efficient optimization strategy is presented, which integrates three optimization techniques with a professional power plant and a cogeneration simulator so as to perform exergoeconomic optimization of complex thermal systems and generate combined pinch and exergy representations. This paper deals with the application of an evolutionary algorithm based on NSGA-II to multi-objective thermoeconomic optimization of coupling desalination plant with pressurized water reactor (PWR). In addition, one-objective thermoeconomic optimization through genetic algorithm and mixed integer non-linear mathematical programming methods has been applied for evaluation of multi-objective optimization. The thermodynamic simulation of this plant has been performed in the THERMOFLEX simulator. An Excel Add-in called THERMOFLEX link has been developed to calculate the exergy of each stream from THERMOFLEX simulation results. In addition, a computer code has been developed for thermoeconomic and improved combined pinch-exergy analysis in the MATLAB environment. Also, multi-objective and one-objective evolutionary algorithm optimization has been performed in MATLAB and one-objective mathematical programming has been performed in LINGO software. Both the design configuration and the process variables are optimized simultaneously. The optimization algorithm can choose among several design options included in a superstructure of the feed water heaters and multistage flash desalination in a dual-purpose plant. For the assumptions and simplifications made in this study, a 3000 MWh PWR power plant similar to Bushehr power plant has been considered.