Influence of Parameters on the Estimation of Coefficient of Performance for R410a Refrigerant

Moritani, Shigeoki; Akahira, Akira

doi:10.1007/s10765-020-02699-4

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…In this system configuration, the air-source heat pump works on the vapor compression cycle, and it is utilized to heat the water that is circulated to the storage tank. The refrigerant of the heat pump is compressed in the compressor with a pressure ratio of 3.5, where the expansion pressure is 6.5 bar, and this is within the typical operation ranges of the refrigeration cycle [32,33]. In addition, the isentropic and mechanical efficiencies of the compression work are 75% and 95%, respectively.…”

Section: Process Modelling Approachmentioning

confidence: 99%

A Comprehensive Technoeconomic and Environmental Evaluation of a Hybrid Renewable Energy System for a Smart Farm in South Korea

Rabea

Michailos

Udeh

et al. 2023

International Journal of Energy Research

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The farming sector like any other industry needs to be decarbonized. Hence, it is essential to meet the energy demands of the farms by adopting energy systems with a low-carbon footprint. Depending on the weather conditions, heating or cooling is needed. Within this context, this study presents a new hybrid renewable decentralized energy system that is designed to satisfy the requirements for heating, cooling, and electricity of a smart farm in South Korea. The under-investigation energy system comprises solar PV arrays, heat pumps, thermal energy storage tanks, and a wood pellet boiler. This study is the first to conduct an inclusive techno-enviroeconomic assessment of such a hybrid energy system by utilizing actual meteorological data on an hourly basis. This enables the model to be dynamic and facilitate accurate and reliable assessments. The modelling efforts have been performed in Aspen Plus and MATLAB to investigate the thermodynamic behaviour of the system. The investigation shows that the proposed system has achieved a daily average temperature of around 23.9°C inside the farm throughout the year with a standard deviation of 2.16°C. For the economic assessment, the levelized cost of energy has been selected as the main economic indicator, and this has been estimated at $0.218/kWh. It is found that the PV panels and the biomass boiler dominate the capital expenditures, and the biomass feedstock is the major contributor to the operating expenditures. Further, the proposed energy system reduces CO2 emissions, by up to 88.94%, when compared to conventional fossil-based energy systems. The outcomes of this study represent a holistic evaluation for such a low-carbon hybrid energy system when applied to greenhouses in Korea and in similar locations.

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Section: Process Modelling Approachmentioning

confidence: 99%

A Comprehensive Technoeconomic and Environmental Evaluation of a Hybrid Renewable Energy System for a Smart Farm in South Korea

Rabea

Michailos

Udeh

et al. 2023

International Journal of Energy Research

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“…In 1959, Martin and co‐workers achieved a further improvement on the accuracy of the 55 M–H EOS in higher densities region 16 . The 55 M–H EOS has been applied to many various systems, especially for refrigeration technology design, 17–22 no matter mixture system or pure substance, but the applications of the 55 M–H EOS were still limited to the gaseous phase. However, the modern industrial design demands that EOS not only be accurate in the gaseous phase but also be applicable to the liquid phase.…”

Section: Introductionmentioning

confidence: 99%

An improvement on Martin–Hou equation of state for more precise prediction in the liquid region

Yao

Yang

et al. 2022

AIChE Journal

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A modified Martin–Hou (M–H) equation of state (EOS) for the accurate representation of thermodynamic property data of some pure substances in liquid phase is presented in this work. The improvement is achieved by substituting a new parameter η into the original M–H EOS. Eighteen pure substances are chosen to construct the dependency relationship of η on reduced temperature Tr and acentric factor ω. Furthermore, to verify the effectiveness and improvement of the modified M–H EOS, the calculated values of the saturated vapor and liquid molar volumes are compared with the literature data in the reduced temperature ranging from approximately 0.6 to 1.0. The results show that the modified M–H EOS perform a good prediction in gaseous phase for pure substances with the average absolute deviation (AAD) generally less than 1%, and more precise liquid molar volume values can be obtained with the modified equation. In liquid phase, the AAD of the modified M–H EOS is 3.71%, which is much lower than 6.16% of the original M–H EOS.

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Heating and cooling methods for the subirrigation of strawberry plants using air and geothermal heat pumps

Moritani

Nanjo²,

Atsushi³

et al. 2023

Environ Dev Sustain

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Influence of Parameters on the Estimation of Coefficient of Performance for R410a Refrigerant

Cited by 3 publications

References 14 publications

A Comprehensive Technoeconomic and Environmental Evaluation of a Hybrid Renewable Energy System for a Smart Farm in South Korea

A Comprehensive Technoeconomic and Environmental Evaluation of a Hybrid Renewable Energy System for a Smart Farm in South Korea

An improvement on Martin–Hou equation of state for more precise prediction in the liquid region

Heating and cooling methods for the subirrigation of strawberry plants using air and geothermal heat pumps

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