Brock
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| 06/27/2008 2:30 PM |
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Here is our situation. We have a 16k gallon indoor pool and some in floor radiant heating that is heated with our 4 ton geothermal heat pump. The cold side of the heat pump can either go out to the field or to our furnace to cool the house. They are connected in parallel with a valve that opens with the furnace calls for cooling and even if the compressor isn’t running it circulates the field coolant through the furnace, right now about 52F. This is our first summer with this system. In the last three days we have been 85+ and really humid outside and not dropping below 70 at night. Our problem the pool doesn't need any more heat, but the house needs more cooling. It is much better then outside but sitting about 78F, at least it's dry.
My first thought was to get a window AC unit to take the peak off cooling, maybe eventually get regular central AC installed, again to take the over what cooling we don't get from heating the pool.
My second thought was to dump excess heat to the radiant heating system in the garage floor. I tried it and it seems to work, of course the garage is really warm, but I can leave windows open and the access to the above garage storage which lets the heat out the ridge vents open as well. It creates a pretty good draft.
My question is which is more efficient? The regular AC would be more straight forward, but I am thinking heating the garage floor and cooling the house might be more efficient. The 3 1/2 stall garage has four 1/2 inch 250 foot loops and is about 1200 sq ft. It runs in parallel with the pool heater taking about half of the heat (a guess). We do also have a desuper heater as well. |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1kw solar PV setup, 3400 sq ft |
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geo fan
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| 06/27/2008 3:09 PM |
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| whats heating you hot water. geo thermal systems can heat up domestic water to 110 very effeciently. the next best thing dump it into the garage floor . but the hot water possibley multiple tanks with a 3rd as a second stage and the first 2 as a heat sink and to warm the water so the heater doesnt work as hard |
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Brock
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Posts:257
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| 06/27/2008 3:16 PM |
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| That is another option, to get a larger de super heater tank. Right now it is only 40 gallons, but that tank stays pretty warm as it is (130F range), even adding more I don't think that will use enough extra heat to cool the house, unless we left the hot water running. |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1kw solar PV setup, 3400 sq ft |
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geo fan
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| 06/27/2008 4:33 PM |
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I recomend giving the manufacturer a call it may be an option to increase the cooling coil size . and make sure the fan speed is increased for cooling . if you are at wits end maytag makes the most eff. traditional ac system called the iq drive 23seer in all sizes |
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geodean
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| 06/27/2008 9:33 PM |
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| Can you run the heat out to the ground loop? |
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Dewayne Dean
PalaceGeothermal.com
Why settle for 90% when you can have 400%
We heat and cool with dirt!
visit- http://welserver.com/WEL0114/- to see my system |
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Brock
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Posts:257
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| 06/28/2008 12:45 AM |
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Yes and yes.
I set the fan speed up to four (highet), the default is two, the temps coming out of the heat pump are about 45F and returning back to the heat pump at 55F, with about 55F air leaving the furnace as well. Obviously as I slow the fan down those temps drop, but I am assuming I am actually getting less cooling with a slower fan speed. The numbers with the fan on high speed are actually warmer then the ground loop, which comes back about 52F.
Yes my heat pump is reversible, but that is the catch. Since we have time of use power it cost $.22 a kw during the day ($.05 at night), what I have been doing is leaving one circulation pump on and the fan in speed 2 (normal cooling). This uses about 350w total (I have 625w of solar panels) and it does help with cooling, basically circulating the field through the furnace coils with no compressor running. Those numbers run about 52 out of the field to the furnace then about 58 out of the furnace back to the field with an air temp leaving the furnace of about 62. So if I reverse the heat pump it will warm the field and I will have no "cheap" cooling or cooling from the field during the day during on peak times.
It still comes back to whether a 23seer unit is more efficient or whether dumping that heat to the garage floor is more efficient.
And now you all know I am crazy. |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1kw solar PV setup, 3400 sq ft |
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geo fan
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| 06/28/2008 10:12 PM |
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Not a soul thinks you are insane. If any thing Im impressed sounds like calling in a consult would be a waste of time considering your extensive knowlege . and balancing comfort with eff is a tough game to play . please post back if you come to a conclusion and how it turns out |
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gregj
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| 06/30/2008 4:32 PM |
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| Sounds like you are doing a lot of creative thinking. Have you considered adding another ground loop just for dumping heat so you don't have to heat the garage or warm your daytime cooling loop? Seems like long term an extra ground loop would cost less than another cooling unit. |
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Brock
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Posts:257
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| 06/30/2008 7:55 PM |
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Hey now that’s an idea. I was even thinking of a small pond or pool with a fan blowing on it, sort of like cooling towers use, but on a smaller scale. I also thought about leaving the covers off the pool and hot tub and leave the exhaust fan on high bypassing the HRV. It is noticeable when we have a pool party that the pool needs more heat then it usually does. I am guessing I would consume more water as well since I would loose it in the warm humid air being exhausted.
Honestly beside those three days last week we have been fine again. I think the kicker is if it doesn't get cool at night. If it turns out to be 10 days this summer I will either live with the heat or maybe get a single window AC unit for the peak cooling days. If it's 20+ days I will have to come up with another solution.
I like the thinking outside the box ideas though! |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1kw solar PV setup, 3400 sq ft |
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engineer
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| 07/02/2008 2:41 PM |
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I like the idea of just leaving the cover off the pool if the problem is in fact intermittent. Every pint / pound of water evaporated is 1000 Btu - not a bad trade.
There are of course issues of the pool getting dirtier from airborne debris as well as extra chemicals, particularly chlorine, which dissipates quickly from uncovered pools. |
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Without data, you only have an opinion. |
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louiee
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| 07/02/2008 3:29 PM |
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| Matag is manufactured by Nordyne. I would consider a small mini split vs. a window unit. You can put the evaps in just the rooms you need to drop the temp and moisture. |
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Brock
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| 07/02/2008 4:17 PM |
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Since the pool is inside we don't have a problem with dirt / pollen or really anything getting in the pool, it does consume more water and a bit more chlorine with the cover off. The biggest problem is if the room is wet it would never dry out with the cover off, with the cover on it takes about 8 hours to dry out. I still have to seal the concrete deck which should help that a lot since right now the floor just sucks up any water the kid’s splash on it. The added advantage is if I do add water it is at 50F which would require more heating and give us more cooling
I think I will try uncovering the hot tub when it’s warm and the room is dry.
I actually brought this up with our HVAC guy, he said either dumping the heat to the garage or leaving the cover off, as long as the high humidity didn't affect the rest of the home (which it doesn't) would be fine. He said to think of it like running the AC, it has to run "x" hours to cool, it doesn’t matter if you dump the heat in the pool or the garage or even outside as long as you can get rid of it. He said it is still more efficient then regular AC would be since it's water to water and we get the added bonus of even more hot water from the de-super heater. |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1kw solar PV setup, 3400 sq ft |
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geo fan
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Posts:143
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| 07/02/2008 5:32 PM |
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| yes and no they use nordyn parts but not on the iq drive . the compressor is the brand new panasonic which with inverter's and reverters operates at 23 seer with a standard foot print at full load. The ductless mini ( which I 'm a fan of) also use inverter tech. but only the mxz series ( mitsubishi) and operate at 13 seer full load . except the new mxz36 4head which operates full load at 16 seer . again neither system operates at full load for long so the actual eff are both much higher and the mit. units are much cheaper . but the maytag is more eff and a ducted system which is prefered by some . My apologies for going off topic just thought I would respond. And it sounds like a mitsubishi would be a better fit anyway |
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dmaceld
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| 07/04/2008 12:23 AM |
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You're heating your home with the GSHP during the winter, right? How about dumping the excess summer heat into the ground using the ground as a heat reservoir from which to draw from during the winter? If you can warm up the ground your system will be a bit more efficient in the winter.
One idea I kicked around for a while was using solar panels to collect summer heat and putting it into the ground for winter use.
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Building house - what a way to spend retirement! |
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Brock
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Posts:257
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| 07/04/2008 12:53 AM |
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Not really heating the house with the geo in winter, the system was primarily installed to heat the pool, but we did talk about watching the run time is on just the pool and if it's only 6 hours a day adding a heating coil in the furnace as well.
But yes dumping the heat to the field would make heating later more efficient. Already we went from about 9 hours a day of run time to 6 hours a day to maintain the pool and hot tub as the ground started at 30F (the geothermal ran 2 weeks straight to take the pool from 40F to 80F) and is now 50F. I wish I had the temp sensor on the field when we started, I put it on after about a week of running.
Again the down side is I could run the field coolant through my furnace to cool. Although gaining 2 degrees a week in field temps I soon won't ahve any cooling left anyway. I am imaging once it hits the ground temp it will start to stay there so I might get coling all summer, I hope. |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1kw solar PV setup, 3400 sq ft |
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Brock
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| 08/08/2008 12:03 AM |
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Just an update. The garage has worked ok for dumping heat and keeping the house cool. I just have to run two window fans at night to cool the garage back down.
I just found another heat dump. My wife bought a 1000 gallon "kiddie" pool for outside. It make a perfect radiator ;) It takes about 3 hours to run it up from 88F to 104F, but we use it like an outside hot tub at night and just leave the cover off and by the next afternoon it's back down to 88 again.
It a little bit of a pain because I have to run two 1 1/2 inch lines through a window and in to the pool room and tap off the hot tub intake an return. It radiates more heat then the garage floor and we can actually use the heat, a win win. Now I hope she won’t want to keep it warm once we don’t need the cooling… |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1kw solar PV setup, 3400 sq ft |
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engineer
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Posts:585
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| 08/08/2008 9:00 AM |
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| I regularly divert open loop water into a kiddie pool - works well, kids love it. Happy kids become tired kids ===> happy parents |
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Without data, you only have an opinion. |
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Brock
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Posts:257
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| 08/08/2008 10:14 AM |
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| For sure :) |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1kw solar PV setup, 3400 sq ft |
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