Variable Refrigerant Flow in Air Conditioning of Buildings: System Configuration and Energy Efficiency

Mohammad Arif Kamal^1, and Sahil Ali Khan²

¹Architecture Section, Aligarh Muslim University, Aligarh, India

²Department of Architecture, Jamia Millia Islamia, New Delhi, India

Cite this paper:
Mohammad Arif Kamal and Sahil Ali Khan. Variable Refrigerant Flow in Air Conditioning of Buildings: System Configuration and Energy Efficiency. American Journal of Civil Engineering and Architecture. 2021; 9(2):42-51. doi: 10.12691/ajcea-9-2-1

Abstract

Variable Refrigerant Flow (VRF), also known as Variable Refrigerant Volume (VRV) refers to the ability of an air-conditioning (AC) system to control the amount of refrigerant flowing to multiple evaporators (indoor unit). This study evaluates the VRF system to its core, and how the system is more beneficial in terms of built environment than the traditional air-conditioning system. This type of type of system consists of a number of air handling units (possibly up to 48) connected to a modular external condensing unit. The refrigerant flow in the VRF system is varied using either an inverter-controlled variable speed compressor or multiple compressors of varying capacity in response to changes in the cooling or heating requirement within the air-conditioned space. With the help of these advanced compressor like the twin rotary compressor the metering device can be closed to controls the flow of refrigerant between the indoor and outdoor unit which helps in avoiding the overheating or overcooling of the space. VRF system also helps in covering the duct losses which is impossible to cover in traditional system as VRF system is ductless or minimum duct are used in the process.

Keywords:
air conditioning buildings variable refrigerant flow energy efficiency compressor

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References:

[1]	A. Bhatia, HVAC Variable Refrigerant Flow System, Continuing Education and Development Inc., New York.
[2]	William Goetzler, “Variable Refrigerant Flow System,” American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc, ASHRAE Journal, April 2007.
[3]	Qian, M., Yan, D., Hong, T., & Liu, H., “Operation and performance of VRF systems: Mining a large-scale dataset.,” Energy & Buildings, Volume 230, January 2021.
[4]	Aynur, T. N., “Variable refrigerant flow systems: A review,” Energy & Buildings, Volume 42, Issue 7, July 2010.
[5]	I.E. Agency, The Future of Cooling, IEA, Paris, 2018.
[6]	K.J. Chua, S.K. Chou, W.M. Yang, J. Yan, Achieving better energy-efficient air conditioning – A review of technologies and strategies, Appl. Energy 104 (2013) 87–104.
[7]	Xinqiao Yu, Da Yan, Kaiyu Sun, Tianzhen Hong, Dandan Zhu, Comparative study of the cooling energy performance of variable refrigerant flow systems and variable air volume systems in office buildings, Appl. Energy 183 (2016) 725-736.
[8]	Zhang, R., Sun, K., Hong, T., Yura, Y., & Hinokuma, R., “A Novel Variable Refrigerant Flow (VRF) Heat Recovery System Model: Development and Validation,” Energy and Buildings, Volume 168, 1 June 2018, Pages 399-412.
[9]	ANSI/AHRI, 2010 Standard for Performance Rating of Variable Refrigerant Flow (VRF) Multi-split Airconditioning and Heat Pump Equipment, AHRI, Arlington, VA. (2010).
[10]	L.E. Southard, X. Liu, J.D. Spitler, Performance of HVAC Systems at ASHRAE HQ: Part One, ASHRAE J. (2014).
[11]	L.E. Southard, X. Liu, J.D. Spitler, Performance of HVAC Systems at ASHRAE HQ: Part Two, ASHRAE J. (2014).
[12]	Kang, D., Jeong, J. H., & Ryu, B. “Heating performance of a VRF heat pump system incorporating double vapor injection in scroll compressor.” International Journal of Refrigeration, Volume 96, December 2018, Pages 50-62.
[13]	ANSI/ASHRAE, ASHRAE Guideline 14-2014 Measurement of Energy and Demand Savings, ASHRAE. (2014).
[14]	Carrier, Variable Refrigerant Flow (VRF) Systems, Carrier Corporation Syracuse, New York, January 2013.
[15]	Ramez Afify, Designing VRF Systems, ASHRAE Journal, June 2008.