Better Than Geo - VRV
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Last edited by HeyBob; 04-28-2010 at 09:20 PM.
That ought to make those GEO boys take notice.
I wonder if they could put that in a GEO unit.
Geo thermal water conditioning
Geothermal water conditioning can and is used in commerical applications with VRV systems. Our office has a geothermal system installed on VRV.
Unfortunately the VRV systems are not ARI rated and cannot receive rebates or incentives.
Unless i am wrong, in which case you can correct me.
ARI is in the process of creating the standard for VR(X) systems to come out this year. (VR(X) is generic term for VRV which is owned by Daikin.) There will be a seperate rating named IEER or something along this line for VRV systems. As will other ARI certifications the equipment will have to undergo ARI testing before becoming certified.
As with any product there are differences between manufacturers. One major difference is the method of defrosting of the system during sub freezing outside air temperature days. Most systems require a shutdown period to deice the condensing coil. Although heat is produced it is difficult if not impossible for this type system to keep up with heating the building. Daikin has developed a system that defrosts while the unit is continuing to run. The condensing unit is able to keep up with the heating loads even in subzero outside air temperature. Unlike water source heat pumps the critical load for equipment sizing becomes the heating load instead of the cooling load. Proper equipment selection is very important.
Not as great as one might think
I went to class to learn what we needed to know to bid a local project, the equipment cost was more than the engineers buget for the entire mechanical part of the contract. On original bid only one vendor could supply numbers. I like the theory and am excited that it may be coming to geo. But it doesn,t have a proven trac record, we have no data to truley compare it to geo. Oh did anyone forget our country is in turmoil and Daiken or Sanyo are both made in JAPAN!!!
Is'nt Comparing to geo missing the point? Apples and oranges.
Vrv efficiency is due to variable speed dc motors. Moving the heat THROUGH the system efficiently, not the absorption/transfer efficiency.
Given all else equal its easier to pull heat fro 40f than 0f. So if applied to geo, vrv would make Geo technology even more efficient also!
Some GEO manufacturers are working with VRV and I suspect you'll see one in the next 1 - 2 years.
GEO vs VRV
The primary issue in discussing GEO versus VRV is that the same or better efficiencies can be acheived with air cooled condensers thus eliminating the upfront and maintenance cost associated with Geothermal. Daikin does have VRV systems that are working with geothermal condensing systems. The efficiencies of this system are very high. It then becomes a return on investment question. With standard WSHP versus geothermal there is enough of an energy savings to justify the additional cost of installing and maintaining a geothermal system. Can the cost of adding geothermal to a VRV system be justified? That all depends on the geographical location, the installation cost, and the energy cost. If you have low energy cost like we do in the St. Louis area $0.07/kwh it becomes more difficult to justify the cost differential. Other areas like California at $0.22/kwh would be easier to justify. Also using cooling ponds instead of wells will lower the cost. Also some customers want the most energy efficient product available and are willing to pay more for the system to reduce their impact on the environment.
Guess I'll try explaining this another way.
Originally Posted by Steve Cornish
Clearly there are variables of home tightness and insulation effectiveness, alternative energy sources and cost, and scale that all come into play. Generally the two largest factors determining Geo's return on incremental investment are:
- heating and cooling load (house size - geo has a fair base capital investment that a small house is unlikely to overcome)
- alternative energy source cost (Nat Gas = looong payback no matter what size house)
Still, the argument should not be geo vs vrv because they are not apples to apples. Geo can utilize vrv so it is really a nonsensical argument. The type of compressor or "refrigerant" technology should be the same in both technologies in order to get an accurate measure of the incremental cost/benefit of going to ground.
The analysis is geo vs air source. Vrv may be the best current technology, the efficiency of which makes the added capital of the geo argument harder to make.
Which makes more sense to you?
- turning your thermostat back and being uncomfortable. Maybe saving 5-10%
- leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org
, or RESNET
, and find an auditor near you.
All very good arguments and I agree they are apples and oranges, loads and insulation are key. Utility costs are the biggest factor in payback. I guess what I have been trying to compare is the vrv cost to produce 100,000 BTU. We use this as our benchmark when comparing gas, oil, air source, dual fuel and geo so when a customer askes it is black and white to produce 100,000 BTU for 1 hour ( a therm ) it costs x.
Originally Posted by Steve Cornish
I have some questions about using the vrv-w series for a large project. Could you PM me or respond to this thread? Thanks.
Last edited by Senior Tech; 04-29-2010 at 12:11 AM.
Steve, I have left the rest of the posts here, your first post has been edited. Please remember that unless you purchase an ad, you can't advertise, which is what your fist post essentially was.
I was IGSHP certified and put in one loop and strained my shoulder badly sealing well holes with Bentonite and fusing joints. I spent time recooping with visits to the doctor. I didn't enjoy the mud to much either. I have also put in Daikin systems. From an installation point of view instead of efficiency, I like the air to air VRV systems. I have also serviced both extensively. Daikin is much more specialized.
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