Comparison of absorption refrigeration cycles for efficient air-cooled solar cooling

Xu, Z.Y.; Wang, R.Z.

doi:10.1016/j.solener.2018.04.004

Cited by 32 publications

(9 citation statements)

References 26 publications

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“…For comparison, a base case has been selected. The base case system is designed for 10 kW of refrigeration effect at the evaporator temperature of 5 • C and a condenser temperature of 45 • C, while the heat source temperature is characterized by the generator temperature of 90 • C which is same as used by Yingjie Xu et al [4] for their ejection-compression system (ECS). For the base case, the performance comparison of the proposed system with various other systems reported in the literature is given below in Table 2.…”

Section: Performance Comparisonmentioning

confidence: 99%

“…Additionally, low-temperature heat energy (60-100 • C) is abundantly available from the sources like solar energy and geothermal energy. Non concentrating solar collectors can provide heat with temperatures 75-100 • C [4]. Therefore, low-temperature heat recovery can lead to increased efficiency and the share of sustainable energy in the global energy mix.…”

Section: Introductionmentioning

confidence: 99%

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Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

et al. 2020

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Low-grade heat is abundantly available as solar thermal energy and as industrial waste heat. Non concentrating solar collectors can provide heat with temperatures 75–100 °C. In this paper, a new system is proposed and analyzed which enhances the electrical coefficient of performance (COP) of vapour compression cycle (VCC) by incorporating low-temperature heat-driven ejectors. This novel system, ejector enhanced vapour compression refrigeration cycle (EEVCRC), significantly increases the electrical COP of the system while utilizing abundantly available low-temperature solar or waste heat (below 100 °C). This system uses two ejectors in an innovative way such that the higher-pressure ejector is used at the downstream of the electrically driven compressor to help reduce the delivery pressure for the electrical compressor. The lower pressure ejector is used to reduce the quality of wet vapour at the entrance of the evaporator. This system has been modelled in Engineering Equation Solver (EES) and its performance is theoretically compared with conventional VCC, enhanced ejector refrigeration system (EERS), and ejection-compression system (ECS). The proposed EEVCRC gives better electrical COP as compared to all the three systems. The parametric study has been conducted and it is found that the COP of the proposed system increases exponentially at lower condensation temperature and higher evaporator temperature. At 50 °C condenser temperature, the electrical COP of EEVCRC is 50% higher than conventional VCC while at 35 °C, the electrical COP of EEVCRC is 90% higher than conventional VCC. For the higher temperature heat source, and hence the higher generator temperatures, the electrical COP of EEVCRC increases linearly while there is no increase in the electrical COP for ECS. The better global COP indicates that a small solar collector will be needed if this system is driven by solar thermal energy. It is found that by using the second ejector at the upstream of the electrical compressor, the electrical COP is increased by 49.2% as compared to a single ejector system.

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Section: Performance Comparisonmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

et al. 2020

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“…Systems providing both cooling and heating ( Table 3 ) are primarily solar-based, and the interest in solar thermal cooling has been recently growing for HVAC applications [ 62 , 63 , 64 ]. The most common is sorption cooling, and one of the examples is the study done by Behi et al [ 65 ], who carried out a numerical and experimental evaluation of a novel solar-collector-integrated sorption module for the cogeneration of cold and heat.…”

Section: Review Of Thermal Storages With Pcm In Building’s Hydronimentioning

confidence: 99%

Phase-Change Materials in Hydronic Heating and Cooling Systems: A Literature Review

et al. 2020

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When considering the deployment of renewable energy sources in systems, the challenge of their utilization comes from their time instability when a mismatch between production and demand occurs. With the integration of thermal storages into systems that utilize renewable energy sources, such mismatch can be evened out. The use of phase-change materials (PCMs) as thermal storage has a theoretical advantage over the sensible one because of their high latent heat that is released or accumulated during the phase-change process. Therefore, the present paper is a review of latent thermal storages in hydronic systems for heating, cooling and domestic hot water in buildings. The work aims to offer an overview on applications of latent thermal storages coupled with heat pumps and solar collectors. The review shows that phase-change materials improve the release of heat from thermal storage and can supply heat or cold at a desired temperature level for longer time periods. The PCM review ends with the results from one of the Horizon2020 research projects, where indirect electrical storage in the form of thermal storage is considered. The review is a technological outline of the current state-of-the-art technology that could serve as a knowledge base for the practical implementation of latent thermal storages. The paper ends with an overview of energy storage maturity and the objectives from different roadmaps of European bodies.

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“…Various thermal refrigeration systems, reviewed in Sleiti et al, [ 8 ] can be powered with low‐temperature heat sources such as absorption/adsorption systems, [ 9–11 ] ejector systems, [ 12,13 ] organic Rankine cycle (ORC) systems, [ 12,14–16 ] and Stirling engine systems. [ 17,18 ] Nevertheless, these systems have their own technical problems that limit their applications.…”

Section: Introductionmentioning

confidence: 99%

Isobaric Expansion Engines Powered by Low‐Grade Heat—Working Fluid Performance and Selection Database for Power and Thermomechanical Refrigeration

Sleiti

2020

Energy Tech

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A database is developed for the most suitable working fluids for Worthington‐type and Bush‐type isobaric engines based on their performances for a wide range of heat source temperature, from 40 to 300 °C, and operating pressures from 1 to 100 bar. Thermodynamics models are developed and simulated to study the effects of different operating temperatures and pressures on the efficiency and back work ratio of both engines. Results show that in temperature range from 40 to 60 °C, the achieved efficiency is less than 4% for most cases, suggesting that practical applications in this range are very limited. Ammonia and R32 show the highest efficiencies (≈11%) at high pressure of 50 bar for the temperature range of 100–300 °C. The refrigerant R161 has high performance for pressures between 10 and 50 bar for the full range of temperatures from 80 to 300 °C, which makes R161 the choice fluid for a wide range of applications. Novel applications are introduced, which integrate these isobaric engines with vapor compression refrigeration systems. The thermodynamic cycles of the heat driven compressor with the selected working fluids as in the current study and the simplified technological solutions are crucial components of the study novelty.

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Comparison of absorption refrigeration cycles for efficient air-cooled solar cooling

Cited by 32 publications

References 26 publications

Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

Phase-Change Materials in Hydronic Heating and Cooling Systems: A Literature Review

Isobaric Expansion Engines Powered by Low‐Grade Heat—Working Fluid Performance and Selection Database for Power and Thermomechanical Refrigeration

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