Conserve Green Building & MEP Solutions Conserve Green Building & MEP Solutions WLL Office No: 6, 6th Floor, Building Number: 24, Al Khalidiya Street, Najma, Doha, Qatar. P.O. Box: T: | F: |

Initial and Operational Cost of different Air Conditioning Systems in GCC: A supporting case for VRF Systems  In one of our recent projects targeting GSAS Certification, we have advised the client to change the HVAC system from Split to VRF.  The client asked us about the return of investment and payback period. We have worked out on the initial and operational cost for different AC systems.  We are publishing the basis of calculation, so that it can guide other projects pursuing LEED or GSAS Certification to choose the right system. GSAS Certification

In this article we will discuss 1.Installation cost of different AC systems 2.Energy Performance of different AC systems 3.Financial analysis of VRF over air cooled central system and split/package system 4.In what cases the projects can go for VRF systems Air Conditioning System TypePrice in QAR per Nominal TR Ductless Wall mounted/Ceiling mounted split system Ducted split units Package Units VRF Units Air Cooled chilled water systems Water cooled chilled water systems Installation cost of different AC systems: LEED Certification

Note:  The prices can vary based on the manufacturer, project specifications, Air distribution system etc.  The prices mentioned here only approximate based on interview with different manufacturers and contractors. In the absence of much literature on Energy performance of different AC systems in the region, the study recently conducted by RSB Dubai appears to be very close and hence we will consider the same for our calculation 2.Energy Performance of different AC Systems:

Energy Audit

It is very clear that district cooling plants are the most efficient followed by water cooled central cooling system. S.NoSystem typekW/TRInstallation Cost QR 1Split/Window Ducted Split/Package Package VRF Air cooled chiller Water cooled chiller District Cooling VRF Vs. Split System Cost Vs. Benefit

Equivalent full load hours3750 Installed Nominal TR500 Electricity Tariff0.35 Energy Consumption of split units kwh Energy Cost of split units QAR/annum Initial Cost of split units in Million QAR1.375 Initial cost of VRF Units Million QAR2.9 Additional Investment in VRF Million QAR1.525 Energy Consumption of VRF system kwh/annum Savings in kwh/annum in VRF Savings in Million QAR/Annum in VRF Simple payback period4.225

1.Financial analysis of VRF over air cooled central system and split/package system Air cooled Central AC System:  The prices of Air cooled system and VRF systems are very much similar hence there is no incremental capital cost for the project.  The operational cost VRF system is lesser resulting in significant reduction in Life cycle cost of the AC system Energy Conservation

Let us do the math for 500 TR building,  Energy Consumption in Central Air Cooled System per annum = 500 TR * 3750 Equivalent Full load operational Hrs. * 1.42 KW/TR = kWh  Energy Cost = kWh * 0.35 QAR/kwh =  Energy Consumption in VRF System per annum = 500 TR * 3750 Equivalent Full load operational Hrs. * 1.07 KW/TR = kWh

 Energy Cost per annum = kWh * 0.35 QAR/kwh =  Savings per annum = kWh  Considering the life of the equipment to be 10 years, the life cycle cost savings shall be 2.3 Million QAR. Split Air Conditioning System:  The prices of split or package shall be around lesser by QR 2500/TR compared to VRF systems.  Let us do the math again for 500 TR building,  Incremental Cost = 500 TR * QR 2500/TR = QAR 1.25 Million

 Energy Consumption in split or ducted AC system per annum = 500 TR * 3750 Equivalent Full load operational Hrs. * 1.62 KW/TR = kWh  Energy Cost = kWh * 0.35 QAR/kwh =  Energy Consumption in VRF System per annum = 500 TR * 3750 Equivalent Full load operational Hrs. * 1.07 KW/TR = kWh  Savings per annum = kWh  Simple payback period = Energy Consumption

In the next article we will discuss more about commercial aspects of Energy Conservation Measures like Life cycle cost, Net Present Value (NPV) and Internal rate of Return (IRR) which is useful in Energy Audit.Energy Audit. Factors to be taken care when going for VRF System: 1.Limitation in refrigerant pipe length 2.Integration with conventional BMS system 3. Skilled maintenance.

Summary and conclusion:  If the project is evaluating VRF against Air Cooled chilled water system and if there is feasibility of VRF systems.  The straight choice would be to go for VRF system  If the project is evaluating VRF against split units the decision has to be taken based on financial priorities. Thank You

Conserve Green Building & MEP Solutions WLL Office No: 6, 6th Floor, Building Number: 24, Al Khalidiya Street, Najma, Doha, Qatar. P.O. Box: T: | F: |