Two-stage air-source heat pump for residential heating and cooling applications in northern U.S. climates

Bertsch, Stefan S.; Groll, Eckhard A.

doi:10.1016/j.ijrefrig.2008.01.006

Cited by 268 publications

(84 citation statements)

References 2 publications

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“…Equation (6) is equivalent to the limit given for the equation (3). In this system, as the restrictions (2) and (3) are fixed, the only independent parameter is the intermediate working pressure.…”

Section: Description Of Vapour Injection Cyclesmentioning

confidence: 99%

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Analysis and optimization of subcritical two-stage vapor injection heat pump systems

et al. 2014

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ElsevierRedon Climent, A.; Navarro-Peris, E.; M. Pitarch; José Gonzálvez-Maciá; José M. Corberán (2014). Analysis and optimization of subcritical two-stage vapor injection heat pump systems. Applied Energy. 124:231-240. Analysis and optimization of subcritical two-stage vapor injection heat pump systems AbstractTwo of the major problems of heat pump systems working in extreme conditions are the loss of efficiency of the system and the high compressor discharge temperatures which can even impede the correct performance of the machine. One possibility in order to overcome these issues is to perform the compression in two stages. In this frame the use of vapor injection two stage cycles represent an economic and effective solution. The results of using this kind of cycles are the reduction of the pressure ratio of each compression stage, the reduction of the discharge temperature due to the cooling effect provided by the intermediate cooling and the increase of theoretical cycle efficiency. This study analyzes two vapor injection cycles, in terms of the injection conditions for three different refrigerants (R407C, R290 and R22). The work considers the efficiencies of each component and their sensibility to the working conditions. From all the analysis, guidelines for the optimum design and control of such systems are obtained in terms of capacity, COP and discharge temperature criteria.Keywords: Heat pump, vapor injection, efficiency, simulation, Two-stage.

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Section: Description Of Vapour Injection Cyclesmentioning

confidence: 99%

“…Variable speed compressors allows a better coupling of this kind of systems to external conditions and the like. Table 1 summarizes the main alternatives found in literature to increase the application range of refrigeration equipment [3].…”

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confidence: 99%

Analysis and optimization of subcritical two-stage vapor injection heat pump systems

et al. 2014

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“…However, there a main problem with the heating performances of AHPWHs, i.e. their heating capacity and coefficients of performance (COPs) are degraded when they operate at low ambient temperature conditions [Bertsch and Groll, 2008]. In order to solve this problem, lots of methods to improve the heating performance of vapor compression based heat pump systems (including AHPWHs) have been proposed over the past years, such as the refrigerant injection technique, ejector enhanced heat pump systems, multistage and hybrid systems [Heo et al, 2011;Chua et al, 2010;Sarkar, 2012;Wang et al, 2009].…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of a thermoelectric-assisted vapor compression cycle for air-source heat pump applications

Zhu

2015

International Journal of Refrigeration

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“…In contrast, economization uses the injected refrigerant to absorb the heat of compression. Previous researchers have demonstrated the potential to reduce power consumption through economization with multi-stage compression both experimentally and analytically (Bertsch and Groll, 2008;Cho et al, 2009;Torrella et al, 2009;Wang et al, 2009;Winandy and Lebrun, 2002). One common configuration for achieving economization with a two-stage compressor is shown schematically in Figure 2.…”

Section: Introductionmentioning

confidence: 99%

“…Wang et al (2009) experimentally investigated the performance of a vapor-injected scroll compressor with both flash tank and IHX economization, and observed similar performance improvements for both configurations in heating and cooling modes. Other studies have focused on the performance of the vapor compression cycle in the heating mode, including an experimental and theoretical evaluation of a low-temperature heat pump with economization by Bertsch and Groll (2008).…”

Section: Introductionmentioning

confidence: 99%

Performance limit for economized cycles with continuous refrigerant injection

Mathison

Braun

Groll

2011

International Journal of Refrigeration

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The cost of multi-stage compressors has traditionally limited the implementation of economization to larger-scale applications. However, the development of compressors with ports for refrigerant injection, which can be added at relatively low cost, introduces new opportunities for economizing in small-scale applications. Injecting economized refrigerant provides cooling during the compression process, and thus reduces the work required for compression and improves the cycle's coefficient of performance (COP) despite a slight decrease in cooling capacity. A simple model is developed to show that increasing the number of injection ports improves COP, approaching a performance limit defined by continuous injection. In the case of continuous injection, refrigerant in the compressor remains saturated vapor throughout the compression process due to the cooling provided by the injected refrigerant. The model predicts that continuous injection will improve the COP between 18% and 51% for common air-conditioning and refrigeration applications, benefiting higher temperature lift cycles most significantly.

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Two-stage air-source heat pump for residential heating and cooling applications in northern U.S. climates

Cited by 268 publications

References 2 publications

Analysis and optimization of subcritical two-stage vapor injection heat pump systems

Analysis and optimization of subcritical two-stage vapor injection heat pump systems

Theoretical study of a thermoelectric-assisted vapor compression cycle for air-source heat pump applications

Performance limit for economized cycles with continuous refrigerant injection

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