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: 31718
T: +974 4442 7968 | F: +974 4437 4210
www.conservesolution.com | bazeeth@conservesolution.com
GSAS Certification
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.
LEED 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
1.
Installation cost of different AC systems:
Air Conditioning System Type
Price in QAR per Nominal TR
Ductless Wall mounted/Ceiling mounted split system
1800-2000
Ducted split units
2500-3000
Package Units
3500- 4000
VRF Units
5000-6000
Air Cooled chilled water systems
6500-7000
Water cooled chilled water systems
8000-9000
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.
2.
Energy Performance of different AC Systems:
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
Energy Audit
It is very clear that district cooling plants are the most efficient
followed by water cooled central cooling system.
VRF Vs. Split System Cost Vs. Benefit
S.No
System type
kW/TR
Installation Cost QR
1 Split/Window
1.73
1800
2 Ducted Split/Package
1.62
2750
3 Package
1.62
3800
4 VRF
1.07
5800
5 Air cooled chiller
1.42
7000
6 Water cooled chiller
0.93
9000
7 District Cooling
0.92
9000
Equivalent full load hours
3750
Installed Nominal TR
500
Electricity Tariff
0.35
Energy Consumption of split units kwh
3037500
Energy Cost of split units QAR/annum
1063125
Initial Cost of split units in Million QAR
Initial cost of VRF Units Million QAR
Additional Investment in VRF Million QAR
1.375
2.9
1.525
Energy Consumption of VRF system kwh/annum
2006250
Savings in kwh/annum in VRF
1031250
Savings in Million QAR/Annum in VRF
0.360938
Simple payback period
4.225
Energy Conservation
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
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
=2662500 kWh
Energy Cost = 2662500kWh * 0.35 QAR/kwh = 931875
Energy Consumption in VRF System per annum = 500 TR *
3750 Equivalent Full load operational Hrs. * 1.07 KW/TR
=2006250kWh
Energy Cost per annum = 2006250kWh * 0.35 QAR/kwh =
702187
Savings per annum = 656250 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
Energy Consumption in split or ducted AC system per annum =
500 TR * 3750 Equivalent Full load operational Hrs. * 1.62 KW/TR
=3037500kWh
Energy Cost = 3037500kWh * 0.35 QAR/kwh = 1063125
Energy Consumption in VRF System per annum = 500 TR * 3750
Equivalent Full load operational Hrs. * 1.07 KW/TR
= 2006250 kWh
Savings per annum =1031250 kWh
Simple payback period = 4.225
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.
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: 31718
T: +974 4442 7968 | F: +974 4437 4210
www.conservesolution.com | bazeeth@conservesolution.com