Experimental investigation on the performance of a transcritical CO 2  heat pump with multi-ejector expansion system

Boccardi, G.; Botticella, Francesco; Lillo, Gianluca; Mastrullo, R.; Mauro, A.W.; Trinchieri, R.

doi:10.1016/j.ijrefrig.2017.06.013

Cited by 50 publications

(27 citation statements)

References 16 publications

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“…The acronym EERC refers to refrigeration, but also to air-conditioning applications and heating. Depending on the working fluid, two types of EERC cycles are reported in the published literature: subcritical cycles [30,80] and transcritical CO 2 cycle [48,81]. The performances of the transcritical CO 2 cycles are generally superior to the other refrigerants.…”

Section: Applications Potential Of the Two-phase Ejectormentioning

confidence: 99%

“…The multi-ejector approach used by Hafner et al [173] was later employed by Boccardi et al [81] to conduct experiments on an air-to-water CO 2 heat pump for space heating under partial and full-load conditions. The authors evaluated individual components and overall heat pump performance, varied the ejector area ratio and the compressor frequency to adjust to ambient conditions from −15 to 12 • C. Optimal COP was possible by varying the ejector area, regulated to match with the pressures at the inlet and outlet of the compressor.…”

Section: Eerc Experimental Studiesmentioning

confidence: 99%

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Current Advances in Ejector Modeling, Experimentation and Applications for Refrigeration and Heat Pumps. Part 2: Two-Phase Ejectors

et al. 2019

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Two-phase ejectors play a major role as refrigerant expansion devices in vapor compression systems and can find potential applications in many other industrial processes. As a result, they have become a focus of attention for the last few decades from the scientific community, not only for the expansion work recovery in a wide range of refrigeration and heat pump cycles but also in industrial processes as entrainment and mixing enhancement agents. This review provides relevant findings and trends, characterizing the design, operation and performance of the two-phase ejector as a component. Effects of geometry, operating conditions and the main developments in terms of theoretical and experimental approaches, rating methods and applications are discussed in detail. Ejector expansion refrigeration cycles (EERC) as well as the related theoretical and experimental research are reported. New and other relevant cycle combinations proposed in the recent literature are organized under theoretical and experimental headings by refrigerant types and/or by chronology whenever appropriate and systematically commented. This review brings out the fact that theoretical ejector and cycle studies outnumber experimental investigations and data generation. More emerging numerical studies of two-phase ejectors are a positive step, which has to be further supported by more validation work.

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Section: Applications Potential Of the Two-phase Ejectormentioning

confidence: 99%

Section: Eerc Experimental Studiesmentioning

confidence: 99%

Current Advances in Ejector Modeling, Experimentation and Applications for Refrigeration and Heat Pumps. Part 2: Two-Phase Ejectors

et al. 2019

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“…Typical operational strategies of such systems are full storage and partial storage strategies, as shown in Figure 1 [31]. Boccardi et al [20], instead, evaluate the performance improvement due to an ejector in a HVAC system working with CO₂ as refrigerant. The optimal configuration of the system is determined.…”

Section: Energy Storagementioning

confidence: 99%

“…Boccardi et al [20], instead, evaluate the performance improvement due to an ejector in a HVAC system working with CO 2 as refrigerant. The optimal configuration of the system is determined.…”

mentioning

confidence: 99%

Assessing the Demand Side Management Potential and the Energy Flexibility of Heat Pumps in Buildings

Arteconi

Polonara

2018

Energies

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Abstract:The energy demand in buildings represents a considerable share of the overall energy use. Given the significance and acknowledged flexibility of thermostatically controlled loads, they represent an interesting option for the implementation of demand side management (DSM) strategies. In this paper, an overview of the possible DSM applications in the field of air conditioning and heat pumps is provided. In particular, the focus is on the heat pump sector. Three case studies are analyzed in order to assess the energy flexibility provided by DSM technologies classified as energy efficient devices, energy storage systems, and demand response programs. The load shifting potential, in terms of power and time, is evaluated by varying the system configuration. Main findings show that energy efficient devices perform strategic conservation and peak shaving strategies, energy storage systems perform load shifting, while demand response programs perform peak shaving and valley filling strategies.

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“…Studies on implementation of the ejectors with converging-diverging nozzles in refrigeration, airconditioning and heat pumps demonstrated significant improvement of the energy efficiency of the discussed systems [1][2][3]. As a result, a growing interest in studying an operation and design of the ejector in mentioned systems can be observed [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Application of a fast transonic trajectory determination approach in 1-D modelling of steady-state two-phase carbon dioxide flow

2019

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An original generalised procedure of determination of the transonic trajectory has been proposed. The procedure is much faster than the commonly used Newton Critical Point approach. The approach was applied in modelling of a carbon dioxide transonic two-phase flow through the converging-diverging nozzle by means of the Homogeneous Equilibrium Model and Delayed Equilibrium Model (DEM). The simulations concern flows that were experimentally and theoretically investigated in the literature. DEM was prev ously used only in choked water flow simulations. Its application in CO2 flow modelling and the supersonic trajectory part determination is a novel contribution. The adjusted for CO2 version of the closurelaw was proposed. The investigation revealed that the applied Darcy friction factor determination approach has a significant influence on the results. Moreover, the models are unable of producing physically acceptable solutions until theLockhartMartinelli approach is utilised. It was shown that the Friedel approach might be considered more proper for CO2 flows.

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Experimental investigation on the performance of a transcritical CO 2 heat pump with multi-ejector expansion system

Cited by 50 publications

References 16 publications

Current Advances in Ejector Modeling, Experimentation and Applications for Refrigeration and Heat Pumps. Part 2: Two-Phase Ejectors

Current Advances in Ejector Modeling, Experimentation and Applications for Refrigeration and Heat Pumps. Part 2: Two-Phase Ejectors

Assessing the Demand Side Management Potential and the Energy Flexibility of Heat Pumps in Buildings

Application of a fast transonic trajectory determination approach in 1-D modelling of steady-state two-phase carbon dioxide flow

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