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RISS 인기검색어
- 검색키워드
- 저자 : Kadhim Hakim T. (검색결과 2 건)
- 무료
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- 유료
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Al-Chlaihawi Kadhim K. Idan,Kadhim Hakim T.,Yousif Ahmad Hashim 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.4
In this study, the performance of ejector-expansion refrigeration cycle (EERC) with R134a alternative refrigerants (R152a, R1234yf, R404A, R407C, R507A and R600a) for automobile air-conditioning application is investigated numerically. The ejector is modeled with a constant mixing-pressure assumption taking into consideration the friction effect in the ejector mixing section. The studied refrigerants are compared based on the optimum area ratio, discharge temperature, compressor input power, volumetric cooling capacity, exergy destruction, COP, exergy efficiency and COP improvement. The results show that R152a and R1234yf have the closest performance to R134a and can be considered the most suitable alternative refrigerants for R134a. The COP and exergy efficiency are improved by 2.26% and 2.27%, respectively, using R152a compared to the use of R134a, whereas they are reduced by 2.89% and 2.88% using R1234yf. The volumetric cooling capacity is reduced for both R152a and R1234yf by 6.14% and 6.8%, respectively. In addition, the effect of compressor rotational speed on the performances is reported.
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Theoretical investigation of combining cooling tower and cooling coil with direct evaporative cooler
Aldamaad Munadhil A. H.,Kadhim Hakim T. 대한설비공학회 2023 International Journal of Air-Conditioning and Refr Vol.31 No.1
A theoretical study is developed to examine the feasibility of using the cooling tower and the cooling coil with the direct evaporative cooler in the highest summer temperature in Karbala/Iraq. This is due to the inability of the direct evaporative cooler in reducing the outside air temperature and efficiency reduction in the mechanical vapor compression systems despite its high electrical energy consumption at high temperatures. The water in the cooling tower is cooled to a temperature higher than the outdoor wet-bulb temperature by (3.9 $$^\circ$$ ∘ C). The water then passes through the cooling coil where the outdoor air is pre-cooled through it, and the outdoor air temperature decreases by (17 $$^\circ$$ ∘ C) without an increase in humidity. Then the pre-cooled air passes through the direct evaporative cooler where its temperature decreases by (10 $$^\circ$$ ∘ C) and humidity increases. The temperature of the air leaving this combining system is reduced by (27 $$^\circ$$ ∘ C). The results showed that the temperature of the air leaving this combining system is adequate and passes through the comfort zone in the psychrometric chart. The results presented that the cooling tower and the cooling coil alone were unable to reduce the air temperature to reach the comfort zone. A similar observation is noted with the direct evaporative cooler. Therefore, the combining system is considered a more effective alternative to the direct evaporative cooler, and its effectiveness reaches more than 100%. Additionally, it is clean, environmentally friendly, energy efficient, and does not add heat to the surrounding environment in comparison with mechanical vapor compression systems.
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