Effects of sub-cooler on cooling performance of variable refrigerant flow air conditioning system

Tu, Qiu; Zhang, Lina; Cai, Wei; Guo, Xuerang; Deng, Chenmian; Zhang, Jie; Bingjun, Wang

doi:10.1016/j.applthermaleng.2017.08.112

Cited by 16 publications

(3 citation statements)

References 25 publications

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“…Tu dkk. [32] melakukan eksperimen untuk menganalisis efek sub-pendingin pada kapasitas pendinginan, rasio efisiensi energi, derajat sub-pendinginan, dan derajat/tingkat pelepasan superheating dalam sistem VRF dengan siklus bypass. Dari hasil eksperimen, mereka menemukan bahwa pembukaan EEV sub-pendingin yang optimal dapat meningkatkan kinerja sistem VRF multisplit dengan mengadopsi siklus bypass.…”

Section: Pendahuluanunclassified

“…Dari hasil eksperimen, mereka menemukan bahwa pembukaan EEV sub-pendingin yang optimal dapat meningkatkan kinerja sistem VRF multisplit dengan mengadopsi siklus bypass. Rasio efisiensi energi maksimum dari sistem dengan sub-pendingin meningkat hingga 3,3%, 3,1%, dan 3,0%, ketika satu, dua, dan empat unit dalam ruangan, masing-masing dioperasikan pada mode termo-on, [32]. Wang dkk.…”

Section: Pendahuluanunclassified

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Overview of Variable Refrigerant Flow Air Conditioning System

Rachman

2021

JTM

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Variable refrigerant flow air-conditioning (VRF) systems are important and widely used in building energy systems around the world. The system is gradually gaining popularity in commercial and residential buildings due to its satisfactory partial load performance, flexible control, ease of installation and maintenance. Variable refrigerant flow air-conditioning (VRF) is a multi-split Heating, Ventilation and Air Conditioning (HVAC) system that controls refrigerant flow to control separate zones for the needs of residential consumers and commercial buildings. The objective of this review is to identify VRF systems that affect various aspects of operation and performance. Special VRF components regulate refrigerant volume control for system performance and reliability. The findings show that specific testing through different compressor settings, electronic expansion valve (EEV) position, and airflow operation affects performance, thermal comfort and potential energy savings. The main conclusions drawn from this detailed review provide a comprehensive overview of VRF and inspire new insights and viable solutions for relevant researchers, product developers, practitioners and policy makers in this field. Previous experimental investigations will be more helpful in the future direction of progress as the development of an extensive VRF system is still in the main stages.

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Section: Pendahuluanunclassified

Overview of Variable Refrigerant Flow Air Conditioning System

Rachman

2021

JTM

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“…The CVI was found to be more effective to improve the Q h , but the AVI could decrease the T d and increase both Q h and COP slightly under the condition of high compressor frequency. Tu et al 20 studied the AVI injection style in the variable refrigerant flow air conditioning system. Chul et al 21 applied the SCRI technique in a cascade heat pump system.…”

Section: Introductionmentioning

confidence: 99%

Effects of injection styles on heating performance of a heat pump with sub-cooler refrigerant injection: Experimental and thermodynamic analysis

Zhang

Yuan³

et al. 2022

Indoor and Built Environment

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The performance improvement of heat pump depends on the appropriate injection style such as liquid injection, vapour injection and two-phase injection. In this work, experimental and theoretical investigation on the heat pump with R410A refrigerant reveals three kinds of injection styles can be selectively achieved in the same injection device by suitable control of the sub-cooling electronic expansion valve. Liquid injection and vapour injection improve the heating capacity (Qh), mainly due to the increase of heat exchange in the sub-cooler and compressor compression work, respectively. Two-phase injection lifts the Qh owing to these two effects. Subsequently, the effect of two-phase injection on improving the heat pump performance is superior to the other two injection styles. For instance, the maximum Qh were 14.4 kW at 60 rps with the liquid injection, 12.5 kW and 13.4 kW at 85 rps with vapour injection and two-phase injection, and 8.1%, 7.0% and 18.3% higher than those without injection, respectively. The corresponding coefficient of performance was improved by 10.4%, 4.5% and 10.6%, respectively. Furthermore, the model based on the pressure-enthalpy diagram has been developed to analyze the experimental results and expound the main factors affecting the heat pump performance under different ambient temperatures.

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