Geotherm AC

[halifax]

Well looking into the future, my future house that is, I've been looking into the "new" Geo therm Heat pumps. Its funny how everything goes around. These new Heat pumps, in one variation or another have been around, at least since my Dad was in the started in the AC&R back in the late 50's.
Back to the subject.
I've studied the different variants available now, and they all look to have promise, but not at the current price tag. True, 3 times the cost initially, but they last 2 to 3 times longer.

Well in the mean time I decided to conduct a little test on our current AC unit. Our outside temp was 94F so I measured the temp of the air from a register, (64F). Well I went back outside and turned on the hose and sprayed it onto the coils for the AC, not full blast but enough to cover as much of the coils as possible. Waited a while, well about 2 cigarettes, and measured the air temp again at the register. It went down to 57F! Now I'm not one to say I know everything about AC units, not even close, but if the temp of the air was decrease down, then the unit should reach the set temp quicker, hence run less, maybe not much, but run less. Maybe I'm just dreaming Well I went one step further, since I have a fountain in front of the unit (Brownie points for the wife) I used a small fountain pump to pump water into a make shift manifold that leads to 3 separate sprayers aimed at the AC coils. The wife always turns the water fountain on, so I have it on the same circuit. Right now, I'm only out, $15, so if I don't have any benefit, then, oh well... I think I might need to make a pan and place it under the AC unit to return the water back to the fountain.

Well, any ideas out there, or does all of this sound like I've had too many Beam and cokes?

Aubrey

[red]

Aubrey-
The "Beam" is fine and what you're talking about with A/C is usually used on commerical size jobs because of the expense of a water tank to hold and recycle the water. My brother had a customer that use to use city water until they raised the water rates and he went thru the roof when the water bill came in. Check this post out on geothermal
www.tractorbynet.com/forums/rural-living/74680-geothermal-heat-pump-project.html for your future home -Ed

[3RRL]

Aubrey,
I think that is a "cool" idea.
I do the same thing here at the Rancho home when it gets really hot. Seems to work for me too? Thanks for the reminder, I'll be sure to set something up like a fine sprayer for my unit up at 3 Rivers.
I stopped drinking many many moons ago. Still smoke the old Pall Malls though... Out here we used to drink Seagram's 7 and coke, brandy and coke ... heck everything and coke except now I just the drink the coke part.
Rob-

[mariner]

Hi Halifax,

I have only just seen your posting on the Geo A/C.

I bought my place just three years ago. The previous owner installed a geo A/C - heat unit. My unit is a 5ton Waterfurnace and is used to heat and cool a 2300sq.ft. home plus basement.

Where I live, winter temps. dip down to -35C (common, sometimes to -40C) and summer can go to 35C or 94F. The geo unit handles these extremes very well. I have three fan speeds and the high speed seems to be used only when heating up after a power outage and the house temps have dropped quite low.

I have a large mercury amp on outside, all nite to give some light. The house is on 150 acres with nerest neighbour 1/4 mmile away and the road nearly 400 yds away and it is really black on a cloudy night without the light. Anyway, my heaviest winter billing is $360 for two months - that is heat light etc, Summer billing is around $240 for two months. So I am getting a range from $120 a month to $180 for the year. To me that is very reasonable for heat, hot water, light etc.

These units have their pro's and con's - just like everything else.

Initial cost is way above conventional systems. My unit has horizontal loop system.

Repairs can be expensive. The circuclating fan motors are 3 or 4 speed dc motors. These motors are around $800 plus controllers - say $1000 to replace. Mine is playing up and looks like I need to replace the motor

One thing you must have is a very reliable electrical supply. I am out in the boonies (40+ miles to nearest city/town) and power outages are known to happen - usually during the winter time due to high snowfall conditions. I am lucky in that I have an emergency power source - a 12kW diesel genset I fire up and put on line. If you loose power you loose heating/cooling otherwise. I also have a med. efficiency propane fired heating unit next to the geo heat one - shared air ducts, that can be used if the geo unit goes down.

There is no question that these units are very efficient. The payback time can be quite a bit now that all prices have increased. Depending on the house setup and location, a different heating system might actually be better. And, of course, having an alternative source during poweroutages is a big plus - especially when temperatures can go down to -40F/C.

Other than the fan motor going, I have had no problems with my system. When I first moved in I spent time cleaning the evaporator fins to get the accumulated dust out - same with ducting. I installed blue filter media on all of the air returns registers and have cleaned up the dust problem the previous owers had. The filters are slowly getting cleaner for the two month cycles I use for replacement.

I digress - these units are great, but expensive. Don't know if I was any help to you. Warmer parts of the country you might find othe alternatives. Another big factor is the electricity charges per kW hour - these vary widely and the power cost for me is a lot less than say New York or California.

HTH

mariner

[halifax]

Well, as in the first post, I'm looking to the future when I build the house to retire (goof Off) in. Trying to come up with a system that is reliable, and efficient. My current house, has a traditional A/C with a extra coil in the air handler, since my heat comes from the hot water tank through the air handler and back to the hot water heater. Actual bills are fairly reasonable, however, my air handler is placed in the attic, not a good location, hot in the summer when using the A/C and cold in the winter when using the heat. I do cheat in the winter, and use a wood stove.

While I'm at this house, I've insulated the air handler with foam, haven't increased the insulation to the ducts yet, I have a mist of water spraying on the A/C evaporator outside to help dissipate the heat. Overall I've lowered the air temp out the ducts by 6 degrees so far. Not a great amount, but I reason that cooler air out the air ducts would decrease the time the A/c would run, (maybe only save 5 minutes worth). However 5 minutes of 30A 220V, is less I have to pay the electric company. I use wood in the winter so I don't have to pay the gas company much. I measured the temp of the supply pipe to the air handler to be 47F but the air out of the register is 59. I'm still trying to get that closer.

Back to the GEOtherm type. If the unit is placed in a better location, and I'm more efficient in cooling and heating, the end result should be better. I'm also looking at the fact that I might not want to cut wood all my life so I would need efficient heat, vice sore backs.

Thanks for the response

Aubrey

[mariner]

Hi Aubrey,

I am sure that one could be almost as efficient with better design of a house and it's insulation. I am sure that going to 8" walls instead of 6" would make a big difference, as would improvements on/around the windows. If you are building a house from scratch, the extra money in this, would be a worthwhile investment.

With the high cost of fuel and energy now, I would also contemplate what you use for heating and cooling. Rob (3RRL) has gone to off grid for power source for his new millionaire home. He has not said too much about the battery bank, solar panels etc., that are installed. I bet though, that they were not too terribly expensive. A lot would depend on where you live and the type of weather you would typically see on a regular basis.

If I were to rebuild and I had a wood fuel source for free, I would use wood heat. That would easily be taken care of in a power outage using small generator (diesel,gas or propane) or battery bank to power the small circulating fans. Running a wood stove circulating fan is a lot cheaper if your fuel source is free. Why pay for a trip to the gym for a workout, when you get one at home for free ;D ;D ;D

Even the house design plays a major factor into how energy efficient your home could be. For me personally, I would consider looking into geodysic dome homes. They are far more energy efficient, cheaper to construct for given living area, stronger and fare far better in inclmental weather conditions. Not everybody's cup of tea I grant you. Still, looking outside of the box as they say, can give surprising results sometimes.

mariner

[tuffytractor]

In my new house I am planning on using radiant heat, but was looking for a way to get cooling running through the same system. I didn't want the added expense of a traditional Geo thermal system, so I talked with a few people and came up with the idea of stringing Pex lines through the footings. As addition, I'm also placing a Slinky line in the back of one of the retaining walls between the split levels. I'm hoping to get from this heat dissipation source over 6 tons of cooling. I've heard that 200' feet of Pex line is equivalent to 1 ton of cooling. I have about 500 feet in the footings and another 750' or so behind the split level retaining wall. I have a shop that is about 1000 sq ft but I don't want to use AC to cool it, so I'm trying this with an additional pump to circulate the cooling water through the same Pex that will carry the Radiant heat in winter.



Slinky coil geothermal ground loops are gaining popularity, particularly in residential geothermal system installations. Slinky coil ground loops are essentially a more economic and space efficient version of a horizontal ground loop. Rather than using straight pipe, slinky coils, as you might expect, use overlapped loops of piping laid out horizontally along the bottom of a wide trench. Depending on soil, climate and your heat pumps’ run fraction, slinky coil trenches can be anywhere from one third to two thirds shorter than traditional horizontal loop trenches.