Analysis of Two-Phase Flow Solar Collectors With Application to Heat Pumps

Chaturvedi, Sushil K.; Chiang, Yuan-Ching; Roberts, A. S.

doi:10.1115/1.3266330

Cited by 33 publications

(15 citation statements)

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“…The concept of DX-samp was first considered by Sporn and Ambrose (1955) in West Virginia. Following the same line work, many theoretical and experimental studies have been reported (Chaturvedi et al, 1982;Morgan, 1982;O'Dell et al, 1984;Chaturvedi and James Shen, 1984;Chaturvedi and Abazeri, 1987;Morrison, 1994;Chaturvedi et al, 1998;Axaopoulos et al, 1998;Hawlader et al, 2001;Huang and Chyng, 2001). A review on such field of work has indicated that the COP values of the DX-SAHP systems range from 2 to 9 and the collector efficiencies vary between 40 and 75% under different climatic conditions, experimentally.…”

Section: Introductionmentioning

confidence: 91%

Study on a direct-expansion solar-assisted heat pump water heating system

Kuang

Sumathy

Wang

2003

Int. J. Energy Res.

123

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SUMMARYAnalytical and experimental studies were performed on a direct-expansion solar-assisted heat pump (DX-SAHP) water heating system, in which a 2 m 2 bare flat collector acts as a source as well as an evaporator for the refrigerant. A simulation model was developed to predict the long-term thermal performance of the system approximately. The monthly averaged COP was found to vary between 4 and 6, while the collector efficiency ranged from 40 to 60%. The simulated results were used to obtain an optimum design of the system and to determinate a proper strategy for system operating control. The effect of various parameters, including solar insolation, ambient temperature, collector area, storage volume and speed of compressor, had been investigated on the thermal performance of the DX-SAHP system, and the results had indicated that the system performance is governed strongly by the change of solar insolation, collector area and speed of compressor. The experimental results obtained under winter climate conditions were shown to agree reasonably with the computer simulation.

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Section: Introductionmentioning

confidence: 91%

Study on a direct-expansion solar-assisted heat pump water heating system

Kuang

Sumathy

Wang

2003

Int. J. Energy Res.

123

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“…Based on our review, in 1980, Chaturvedi et al [3] were possibly the first ones to set out a comprehensive model describing a two-phase flow solar collector with application to heat pumps; they found that a large pressure drop might occur if the refrigerant is passed through a small number of parallel serpentine tube panels. The results suggested that a high COP and collector efficiency are feasible with bare collectors and that a higher collector area improves COP and additionally reduces the electrical energy input, however, reducing the efficiency of said collector due to a higher energy availability, hence, a higher collector temperature that results in higher back losses.…”

Section: Analysis Of the Solar Collectorsmentioning

confidence: 99%

Mathematical Thermal Modelling of a Direct-Expansion Solar-Assisted Heat Pump Using Multi-Objective Optimization Based on the Energy Demand

León-Ruiz

Carvajal-Mariscal

2018

Energies

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An analytical model is proposed to evaluate the performance of a Direct Expansion Solar-Assisted Heat Pump under a given environmental condition. These thermal machines commonly employ uncovered flat plate solar collectors, and given this, the convection phenomenon is taken into account as well as the effect of the diffuse and reflected solar radiation in addition to the normal beam radiation absorbed by the tilted surface of the collectors. The heat pump cycle is modelled through a first law of thermodynamics approach in order to compute the heat yielded through condensation and the minimum heat required by the volume of water in the thermal storage unit. Consequently, the thermal capacity of the heat pump, the ratio at which the system yields heat to a given load of water, is calculated and discussed. The results of the model proposed are compared with the experimental data provided by three research papers with experiments conducted in different geographic coordinates and test rigs operating during diverse atmospheric conditions. A maximum relative error of 20% was obtained and furthermore, a statistical analysis of the data was conducted having found that there is no significant statistical difference between the analytical and experimental data samples within the 95% confidence interval. Finally, based on the thermal capacity, the performance of the heat pump is evaluated and a multi-objective optimization technique is implemented to obtain the best possible combination of factors to further enhance the performance of the heat pump.

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“…However, an inverter compressor is able to make an SAHP system operate under a better condition by changing the frequency of the system as the solar radiation differs. Through a full-year forecast of SAHP system that applied an inverter compressor, researchers like Chaturvedi suggest that not only the COP of a heat pump and thermal efficiency of its collectors, but also the system premium operating performance can be guaranteed by converting the frequency of the compressor to an optimal performance according to weather status in different seasons throughout the whole year [1]. Targeting better heat pump performance and collector efficiencies, temperature of collectors should be 5~10˝C higher than environment temperature [2].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Influence of the Stability Factors of PV/T-SAHP on the Performance of the System

et al. 2015

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Abstract:The integrated photovoltaic/thermal collector (PV/T) with solar assisted heat pump (SAHP) often operates under an undesigned condition. Against the backdrop of heat pump system oscillation resulting from the mismatching between collectors area and compressor capacity, this work explores the dynamic performance of heat pump system at a fixed compressor frequency when the condensing water temperature and electronic expansion valve (EEV) opening are variable or invariable. We also consider why the system is unstable and propose the theory of SAHP system stability. Also, a preliminary performance analysis is made on SAHP system that is respectively influenced by an inverter compressor and EEV. The MSS(Minimum Stable Signal) line theory is proposed to account for system unstabilty in the research of the match between EEV and evaporators, that is to say, the critical problem of keep the system stability is to find out how evaporators superheat under the circumstance of specified loads and its corresponding EEV opening, in other words, to find the MSS line.

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Analysis of Two-Phase Flow Solar Collectors With Application to Heat Pumps

Cited by 33 publications

References 0 publications

Study on a direct-expansion solar-assisted heat pump water heating system

Study on a direct-expansion solar-assisted heat pump water heating system

Mathematical Thermal Modelling of a Direct-Expansion Solar-Assisted Heat Pump Using Multi-Objective Optimization Based on the Energy Demand

Analysis of the Influence of the Stability Factors of PV/T-SAHP on the Performance of the System

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