42
Technical
A CASE FOR GAS ENGINE VRF SYSTEMS
By Patrick Burke , SAIRAC Fellow
A gas heat pump ( GHP ) air-conditioning system is a conventional VRF system where the compressor is driven by a gas engine using natural gas .
The capacity is controlled by the engine speed , thereby matching the varying load to suit the required conditions . This gas-powered heating , ventilation and air conditioning ( HVAC ) system is available in both heat pump and heat recovery versions to suit a broad range of design applications .
The benefits of GHP are – inter alia – lower CO 2 emission , reduced electrical power consumption and more effective heating .
FINDINGS AND OBSERVATIONS In search of some general information on the internet recently , an industry white paper titled Gas Heat Pump Technology caught my attention . Sponsored by some 14 US and Canadian gas distribution companies , the paper identifies opportunities and strategies to accelerate the market acceptance of GHPs in North America .
In effect , the paper claims that GHPs have the potential to reduce energy use and greenhouse gas emissions across various climates for both the residential and commercial markets in North America . As such , these sponsor companies are eager to accelerate and advance the commercialisation of GHP technologies for HVAC .
Given South Africa ’ s electrical power supply issues , could this type of technology be a solution ( or even a partial solution ) to our problems in this regard , at the same time addressing the issues surrounding climate change ?
As we know , the VRF technology itself is well understood in South Africa since first introduced way back in the 1980s . With many role players and suppliers of quality equipment serving our local market , VRF is probably the most dominant category of comfort cooling options currently on offer .
So why the lack of market development for VRF gas heat pump technology in South Africa ? While there is probably a call locally ( albeit small ) for this type of VRF system , no one to my knowledge is actively marketing their product even though several leading HVAC companies manufacture this type of product . One would think that this would receive serious consideration given our crippling electrical power situation .
Not so ! Obtaining any information on the subject is like pulling teeth . From all accounts , even the local guys have no marketing strategy from their principals in this regard .
• Could it be the availability of LNG / LPG gas ? Surely not ! This is currently produced in Mozambique , Mossel Bay and elsewhere , and piped and / or transported into
Patrick Burke , SAIRAC Fellow . our major cities and commercial centres , apparently without any major issues .
• Could it be a matter of running costs , LNG versus electrical power ? Maybe it ’ s simply not economically viable locally at today ’ s comparative rates . By the way , LNG is substantially cheaper than electrical power in the US .
• Could it be the cost of setting up the required site infrastructure and safety requirements ? In this regard , many local commercial buildings and shopping malls are already piped for LNG to serve their restaurant kitchens , hot water boilers and more .
• Capital equipment costs : Gas engine VRF versus standard electric powered VRF equipment . What is the difference in rands and cents ?
• Operational costs including maintenance and repairs : Regarding gas engine versus standard electric VRF equipment , suppliers of this equipment claim 10 000 hours of maintenance-free operation , or as long as five years .
In weighing up the pros and cons , my scrutiny has yielded the following prognosis , based on the information at my disposal .
As already stated , LNG / LPG is available in bulk supply in all major centres .
© RACA Journal
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RACA Journal I April 2024 www . refrigerationandaircon . co . za