The Refrigeration Cycle

Hundy, G.F.; Trott, A.R.; Welch, T.C.

doi:10.1016/b978-0-08-100647-4.00002-4

Cited by 15 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[30] In particular, residential heat pumps are often equipped with scroll, screw, or rotating piston compressors besides reciprocating-piston compressors. [46] All these compressor types are positive displacement compressors based on the same physical principle and are affected by similar losses: friction, flow, and electrical losses. In practice, these positive displacement compressors also show similar trends in isentropic and volumetric efficiency.…”

Section: Transferability Of Findingsmentioning

confidence: 99%

“…In practice, these positive displacement compressors also show similar trends in isentropic and volumetric efficiency. [46] Furthermore, Roskosch et al [30] identified the ratio of isentropic compressor power (refrigerant-dependent) and refrigerant-independent compressor losses (e.g., friction losses) as the main drivers for the refrigerant dependency of compressor efficiencies. We expect these effects to occur with all positive displacement compressors, making our results qualitatively transferable to heat pumps equipped with other types of positive displacement compressors.…”

Section: Transferability Of Findingsmentioning

confidence: 99%

See 1 more Smart Citation

Refrigerant Selection for Heat Pumps: The Compressor Makes the Difference

et al. 2023

View full text Add to dashboard Cite

Increasingly stringent regulations and new applications require selecting improved refrigerants for heat pumps. The selected refrigerants should be environmentally friendly and maximize the performance of the heat pump process. Systematic refrigerant selection methods usually model the compressor with one fixed isentropic efficiency identical for all refrigerants. However, compressor studies indicate that the isentropic efficiency may be highly refrigerant‐dependent. Herein, the need for a refrigerant‐dependent compressor model for refrigerant selection is investigated. For this purpose, a refrigerant‐dependent compressor model is combined with an integrated design of refrigerant and heat pump process. To guarantee a comparable nominal heating power among refrigerants, the compressor design is tailored to the refrigerant by expanding the refrigerant‐dependent compressor model toward compressor sizing. Integrating compressor design into systematic refrigerant selection is enabled by a computationally efficient model implementation. Accounting for refrigerant‐dependent compression substantially changes the resulting refrigerant ranking compared to the widely used assumption of identical isentropic efficiencies for all refrigerants: The best‐performing refrigerant is not even identified among the best ten refrigerants when assuming identical isentropic efficiencies. Consequently, compression is identified as the main driver for differences in refrigerant performance. Therefore, integrating refrigerant‐dependent compressor models is crucial for systematic refrigerant selection.

show abstract

Section: Transferability Of Findingsmentioning

confidence: 99%

Section: Transferability Of Findingsmentioning

confidence: 99%

Refrigerant Selection for Heat Pumps: The Compressor Makes the Difference

et al. 2023

View full text Add to dashboard Cite

show abstract

“…The analysis of the case study is carried out under the following considerations, all the components operate in steady state and the kinetic and potential energy and the kinetic and potential exergy of the components are omitted for calculations. The heat flow from the heat source to the evaporator Q̇e va and the heat flow from the condenser to the heat sink Q̇c ond can be expressed as in equation 1and (2) respectively, The real power in the compressor is given as in equation 3And the electrical power input for the compressor is determined as in equation 4, as shown in Table 1. Table 1.…”

Section: Energy and Exergy Analysismentioning

confidence: 99%

“…Cooling systems are one of the main areas of application of thermodynamics, these systems can be defined as the heat transfer from a lower to a higher temperature zone, this process is determined as cooling cycles [1]. The focus of this paper is about one of the most used cooling cycle, which is the vapour compression cycle or VCR [2]. For the refrigeration systems use conventional refrigerants, which are one of the responsible of the depletion of the ozone layer, the Montreal protocol (UNEP, 1997) wants to eliminate all the conventional refrigerant which are considered ozone depleting substances within CFCs and HCFCs…”

Section: Introductionmentioning

confidence: 99%

Application of a genetic algorithm to optimize the exergy performance of a vapor compression refrigeration system

Valencia¹,

Castro²,

Narvaez³

2018

ces

View full text Add to dashboard Cite

This paper presents a theoretical performance study of a vapour compression refrigeration (VCR) system using R134a, R22, R32, and R40. The VCR system was modeled and simulated in Aspen HYSYS® through the selection of the proper fluid package to compare the Coefficient of Performance (COP) and the exergy of four different conventional refrigerants against different temperatures values. The results obtained have been compared through graphics that allow to identify the most proper refrigerant for the VCR. Finally, the use of genetic algorithm allowed to obtained the optimal operational condition.

show abstract

“…As mentioned previously, there are cooling systems that use thermal energy as an energy input such as the absorption cooler (AC). It uses a pair of working fluids, and the most commonly used pair for air conditioning applications is LiBr‐H 2 O with a COP of about 0.7 for a single effect unit 12 . One of the most common heat sources used to drive an AC is solar energy.…”

Section: Introductionmentioning

confidence: 99%

A novel hybrid cooling system combining vortex tube with absorption cooler

Mugdadi

Al‐Nimr

2022

Intl J of Energy Research

View full text Add to dashboard Cite

In this study, a novel cooling system that combines a vortex tube with an absorption cooler is presented. The system produces cooling effects from both devices. The compressed air enters the vortex tube to produce a cooling effect, and the hot air escaped from the vortex tube is used to drive the absorption cooler. The theoretical model has been built and employed to study the performance of the hybrid cooling system, in terms of the specific cooling load and the coefficient of performance, under the effect of different parameters (feed air pressure, feed air temperature, and cold/hot mass fractions). Further, the hybrid system performance is compared to the performance of the vortex tube alone. The results showed that the cooling capacity of the system increases with an increase of both the feed air temperature and the feed air pressure. The maximum coefficient of performance of the system under current design points is 29.3% greater than the maximum coefficient of performance of the standalone vortex tube.

show abstract

The Refrigeration Cycle

Cited by 15 publications

References 0 publications

Refrigerant Selection for Heat Pumps: The Compressor Makes the Difference

Refrigerant Selection for Heat Pumps: The Compressor Makes the Difference

Application of a genetic algorithm to optimize the exergy performance of a vapor compression refrigeration system

A novel hybrid cooling system combining vortex tube with absorption cooler

Contact Info

Product

Resources

About