When you look at purchasing or installing anything in your home or business you want the designer and installing contractor to follow industry accepted quality standards. Why should that be any different when considering a solar and/or geothermal renewable energy system. These are long term investments.
Air conditioning Research Institute (ARI) – The ARI is the performance testing organization for the air conditioning industry. This also includes any refrigerant type of unit used for heating too. Now known as AHRI ( to include HEATING ). The AHRI can be reached at their web site at www.arinet.org.
ARI sets the standards for the geothermal equipment manufacturers by naming standards and publishing major manufacturers equipment as they are tested to these standards. This in not a one time deal,but a continuing thing for the geothermal equipment member manufacturers. Not all geothermal manufacturers are members of ARI, and not all geothermal equipments meet ARI’s stringent requirements. Without those standards you could be buying “Bob’s Horsepower” or “Fred’s Peak” Power, whatever that means.
The geothermal standards set for the United States market are:
ARI-320 – This is not a geothermal standard, but water source heating and cooling units operated on a boiler and cooling tower closed loop. The performance numbers do not include the required pumping energy costs to supply the units with water or fluid, nor the fuel energy of the boiler or high fan horsepower of the cooling tower. In effect, it gives you false performance figures, because there are hidden extra operating costs you don’t see..
ARI-325(70) – This is predominantly for geothermal units operated in the South where average ground water temperatures vary around 70’F. These performance figures do include pumping energy costs to supply the units with water.No hidden operating costs .
ARI-325(50) – This is predominantly for geothermal units operated in the North where average ground water temperatures vary around 50’F.These performance figures do include pumping energy costs to supply the units with water. No hidden operating costs .
ARI-330 – This is for heating and cooling outputs of geothermal equipments operated on a closed loop installation. These performance figures do include pumping energy costs to supply the units with antifreeze fluid. The standard input for heating is 32’F, and for cooling is 77’F Entering Fluid Temperature. With hidden operating costs .
In the Northeast, over the past 40 some years Smart-Energy has found geothermal units operating under ARI-325(50) to be significantly more efficient, and have higher output capacities, than their counterparts operating on ARI-330.
The argument that closed loops are more efficient in ARI-330 because they use circulators where in ARI-325(50) we use pumps has been proven wrong consistently by ARI standard tests.
A geothermal unit running on ARI-325 produces higher levels of both heating and cooling than the same unit operating on ARI-330, thereby requiring less run time to satisfy space temperature requirements. Given the advantage of the clean water ( fuel ) source and the high density bedrock we have throughout the Northeast why would anyone throw away this clear performance advantage and opt for a closed loop vs.an open ( or VSWC) system.
A good case in point is a real geothermal unit with the following data. The manufacturer is one of the four best in the industry, as follows.
Unit Size – 3 Tons ( this is the same exact piece of equipment in both cases )
Under ARI-330 Operating Conditions
Heat Output … 28,000 BTUH … COP 3.0
Cooling Output … 36,000 BTUH …EER 11.2
Heat Output … 35,000 BTUH … COP 3.2
Cooling Output … 42,500 BTUH … EER 14.5
( now remember that both ARI-330 & ARI-325(50) include pumping energy costs )
Of the over 770 geothermal systems we have put in since 1975, only 6 are closed loops operating on ARI-330. The rest are Water Well VSWC systems operating on ARI-325(50).