Engineering Economics of Variable Refrigerant Flow Systems Using a Case Study

10:00AM - 6:00PM
Mohammed Hameeduddin Haqqani, C.E.M.

Line of Business Manager for Replacement and Rental
Johnson Controls Saudi Arabia

Asharudheen Kunnathodi, MASHRAE & MSCE | Sales & Application Engineer
Johnson Controls
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The constant flow of refrigerant is allowed in conventional systems to maintain the constant requirement of cooling load. This have forced the industry to use high efficient energy consuming and GHG which is threat to ozone layer when a leak is confronted and further environmental hazards. The conventional HVAC system have been employing various refrigerants developed over time to time which have been serving the industries since the inception of the revolutionary idea of air conditioning. Scientists and engineers have been worried about the environmental hazards and have been trying to mitigate this risk. The perseverance of enthusiasts and engineers have developed systems which caters variable needs of cooling requirements according to the demand.

The most prominent among them is variable refrigerant flow system in direct expansion HVAC systems and since its inauguration it has portrayed impressive results. Since then various manufactures have tried their efforts in this revolutionary HVAC system and successfully implemented the quality parameters it delivers.

This paper addresses the practical case of such VRF systems and its various benefits from the conventional DX systems and reduces the carbon foot prints thereby enhancing overall economic benefits to the customer and contributes to the community. This is further extended to space savings in buildings which helps architects to design the building in a better way and reduce the façade area. The VRF system predominantly covers about the air side space savings and when compared with conventional one to one direct expansion system. The thermal energy losses have been able to mitigate by the application of VRF system by induction of less number of supports and minimal use of heavy pipe structures unlike in chilled water system.

The VRF system doesn’t require any chemical cleaning for periodic maintenance unlike chilled water systems and this contributes much to environmental safeguarding and awareness. VRF systems contribute a drastic improvement in life cycle cost analysis when compared with conventional DX system which is elaborated in the paper. Detailed contribution of VRF in terms of power consumption, life cycle cost, reducing carbon foot prints sustainability is elaborated at different sub sections of this paper.

Further the paper elaborates the importance of environmental hazards of conventional HAVC system and contribution of VRF to counter it taking various factors of VRF installations system including hydronic pipe supports, refrigerant charges, space savings, and maintenance free from chemical de scaling. Moreover this paper elaborate the precise temperature controls and enhances personnel comfort levels as well.

This paper envisages the savings in a commercial building by running a simulation in comparison with actual power bills and highlighting the hidden savings in VRF systems and its contribution for a sustainable future for the community.