Theoretical study on a novel R32 refrigeration cycle with a two-stage suction ejector

Yu, Jianlin; Song, Xin; Ma, Ming

doi:10.1016/j.ijrefrig.2012.09.017

Cited by 43 publications

(12 citation statements)

References 9 publications

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“…The evaporating temperature of the evaporator t e varies from À30 to 5°C, and the superheating degree for the evaporator Dt e is set at zero; The isentropic efficiency of the compressor is assumed to be g s ¼ 0:75 [31]. For the simplicity, the ejector isentropic efficiencies are assumed to be g n ¼ 0:9, g m ¼ 0:85 and g d ¼ 0:8 [32]. It should be noted that in the following simulations the cycle performances are evaluated on per unit of mass at the compressor suction inlet.…”

Section: Resultsmentioning

confidence: 99%

Performance analysis of a new ejector enhanced vapor injection heat pump cycle

Wang

Xing

2015

Energy Conversion and Management

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Section: Resultsmentioning

confidence: 99%

Performance analysis of a new ejector enhanced vapor injection heat pump cycle

Wang

Xing

2015

Energy Conversion and Management

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“…No improvement was found under extreme cooling and heating conditions. Yu et al [63] proposed a new ejector enhanced vapour compression refrigeration cycle ( Figure 7) operating with refrigerant R32, which improves the COPh and volumetric capacity by more than [8.8, 9.3]% and [13.6, 9.7]%, respectively. Finally, the use of an internal heat exchanger (IHX) is not recommended for R32 because it reduces the COPc and increases the discharge temperature, even though this component can enlarge the energy efficiency for some of its mixtures, as with R407C or R410A [64].…”

Section: Performance and Discharge Temperature Concern Of Pure R32mentioning

confidence: 99%

Refrigerant R32 as lower GWP working fluid in residential air conditioning systems in Europe and the USA

Mota-Babiloni

Navarro-Esbrí

Makhnatch

et al. 2017

Renewable and Sustainable Energy Reviews

110

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Because air conditioning and heat pump systems contribute greatly to greenhouse gas emissions, equipment with both lower global warming potential (GWP) working fluids and a higher level of performance should be used. R32 (difluoromethane) has been proposed to substitute R410A, particularly in residential air conditioning (RAC) systems. This study collected the most relevant and recent researches into R32 as a refrigerant so as to assess its viability in RAC systems in both Europe and the USA, as compared to R410A and other lower GWP RAC alternatives.The R32 value of GWP is 677, which is below the F-gas regulation limit in RAC equipment (750). According to ASHRAE standard 34, R32 is less flammable than hydrocarbons, and the amount of charge permitted for R32 is above the necessary level in RAC equipment. It can be concluded that R32 has significantly good heat transfer characteristics and a level of performance that make it acceptable at low condensing temperatures, thereby avoiding overly high compressor discharge temperatures. Its performance is very similar to that of R410A across the entire operating range, and it is therefore believed that R32 will be utilized in RAC systems in the remaining countries that prioritize lower GWP fluids but are less strict in their security regulations.To replace R410A under extreme conditions, some system modifications can be conducted, or R32 mixtures with hydrofluoroolefins (HFOs) can be used. Such mixtures achieve a lower performance than R32, but are acceptable replacements when considering their lower GWP compared to that of R32, and similar level of flammability. Finally, other (R32-based) alternative mixtures have also been developed and their behaviours studied under a wide range of operating conditions.

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“…Under stable primary and secondary flow conditions and optimum geometrical parameters, a pressure recovery of over 32.8% was achieved with the adjustable ejector (Lino et al, 2012). Yu et al (2013) presented a cycle operating with an ejector system with two suction inlets to recover the expansion losses. MEJ 3 in Table 5 illustrates the developed cycle.…”

Section: Multiple Ejector Cyclesmentioning

confidence: 99%

Multi-temperature heat pumps: A literature review

Arpagaus

Bless

Schiffmann

et al. 2016

International Journal of Refrigeration

107

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Please cite this article as: Cordin Arpagaus, Frédéric Bless, Jürg Schiffmann, Stefan S. Bertsch, Multi-temperature heat pumps -A literature review, International Journal of Refrigeration (2016), http://dx.doi.org/Highlights (3-5 bullets, max. 85 characters including spaces):  A review on multi-temperature heat pumps and refrigeration systems is given.  Design strategies for multi-temperature heat pumps are presented.  Application examples in refrigeration, air-conditioning and heating are discussed.  First Law and Second Law efficiencies of the cycles are calculated based on thermodynamic models. AbstractThis review highlights the major advantages and challenges of mechanically driven heat pumps and refrigeration systems with focus on multi-temperature applications. Different design strategies are presented, including cycles with multi-stage compressors, ejectors, expansion valves, cascades, and separated gas coolers. Most multitemperature heat pump cycles use two heat sources and one heat sink. In supermarket applications, multi-stage compressor cycles with transcritical CO2 is an established key technology. Cascades with secondary loops are another frequently applied type of system. Expansion valve cycles are applied in household refrigeration and air conditioning. Cycles with ejectors seem to be a promising modification for system performance improvement. Separated gas coolers for space heating and hot water production have recently attracted attention due to the possible combination with supercritical CO2 cycles. Thermodynamic simulations reveal that multi-stage compressor cycles have the highest COPs and Second Law efficiencies, followed by cascade, ejector, and expansion valve cycles. The baseline cycle consisting of two single-stage heat pumps in parallel shows lower Second Law efficiency than the multi-stage compressor and cascade cycles, and higher efficiency than the ejector and expansion valve cycles.

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Theoretical study on a novel R32 refrigeration cycle with a two-stage suction ejector

Cited by 43 publications

References 9 publications

Performance analysis of a new ejector enhanced vapor injection heat pump cycle

Performance analysis of a new ejector enhanced vapor injection heat pump cycle

Refrigerant R32 as lower GWP working fluid in residential air conditioning systems in Europe and the USA

Multi-temperature heat pumps: A literature review

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