EcoRenovator - View Single Post - What would be more efficient cheapest to run

stevehull · 02-28-14, 10:28 AM

The unit that has the higher SEER (seasonal EER) or HSPF will be the most efficient. Most new geothermal units are in the SEER range for AC of about 30-35 (some as high as 45-50). Mini splits typically have a SEER in the upper teens to low 20's. But at a lot less cost.

For example, let's compare an AC unit that has a EER of 15 and compare it to another with a EER of 30.

The second unit (higher EER) will put out twice the amount of cold BTUs for a dollar of electricity. Or, the second will put out the same amount of cold BTUs for half that amount of electricity. Think of EER (or SEER) as 'gasoline mileage" on a car/truck.

The EER is simply the quotient of the BTU output and the electrical power to run the heat pump.

With an open loop geothermal system, you need about 2-3 gallons per minute of water per ton to get an adequate temperature difference (10 F) across the unit. A 2 ton unit will need about 4-6 gallons per minute when the geothermal compressor is on.

Inside every geothermal heat pump is a relay and a set of 24 V AC wires that controls a 24 V AC electric water valve (open loop water). When the compressor turns on, these wires are energized and the electric water valve opens allowing water flow to go through the unit. When the compressor turns off, the value is closed.

It is not as simple as just putting the mini split evaporator in a running stream of water - sure wish it was!

Hope this helps,

Steve

02-28-14, 10:28 AM	#2
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	The unit that has the higher SEER (seasonal EER) or HSPF will be the most efficient. Most new geothermal units are in the SEER range for AC of about 30-35 (some as high as 45-50). Mini splits typically have a SEER in the upper teens to low 20's. But at a lot less cost. For example, let's compare an AC unit that has a EER of 15 and compare it to another with a EER of 30. The second unit (higher EER) will put out twice the amount of cold BTUs for a dollar of electricity. Or, the second will put out the same amount of cold BTUs for half that amount of electricity. Think of EER (or SEER) as 'gasoline mileage" on a car/truck. The EER is simply the quotient of the BTU output and the electrical power to run the heat pump. With an open loop geothermal system, you need about 2-3 gallons per minute of water per ton to get an adequate temperature difference (10 F) across the unit. A 2 ton unit will need about 4-6 gallons per minute when the geothermal compressor is on. Inside every geothermal heat pump is a relay and a set of 24 V AC wires that controls a 24 V AC electric water valve (open loop water). When the compressor turns on, these wires are energized and the electric water valve opens allowing water flow to go through the unit. When the compressor turns off, the value is closed. It is not as simple as just putting the mini split evaporator in a running stream of water - sure wish it was! Hope this helps, Steve __________________ consulting on geothermal heating/cooling & rational energy use since 1990 Last edited by stevehull; 02-28-14 at 10:34 AM..