POTD- PROJECT OF THE DAY: What Did You Make In Your Shop Today?

[dkemppai]

The manufacturer ? Not sure , I just looked and saw Carrier books along with Beckett . The one installed in my place is a pump with oil backup. The one down the other house is a pump with electric backup .

These are air to air heat pumps?

When we built, I did cost analysis on heat pump vs. other heat source. Running a water to air heat pump was literally the cheapest option to operate. (If natural gas was available, that would have been the same cost as a heat pump to operate).

I love ours. We went from a small house with oil heat to a 4x bigger house, and our energy bills dropped by a third.

 

[woodchucker]

LMAO ! Just had both houses done Jeff . The one basement is pretty cleared out at this point . 3 roll arounds , a radial arm saw and a Diacro shear is left . And a 30 ton hydraulic press , and tons of wood . I have a 2 year old AirTemp/Goodman AC unit down here that I have to get rid of now also . Re-arranged the garage yesterday in hopes of some things leaving this summer . My basement ? We won't go there . I like the heat pumps so far . Bills are higher but no longer a slave to the oil delivery company .

Bills are higher? I thought these things were more efficient? My oil delivery was always great. That's not the problem. I needed a new AC, and was convinced here that Heat pump and backup were the way to go. damn

 

[woodchucker]

Mine will be a carrier. With a propane backup. The electric backup seems way too expensive, and would not work with our generator. well it seems the new heat pump won't work with the generator either, it's a bit more amperage. They are going up in size because they felt we were undersized currently, being a 1/2 ton under. So going up another 10amps. But for less money than the other bids for a 3ton, we are getting a 4 ton. We had 2 bids higher, and 2 bids lower..

 

[mmcmdl]

Bills are higher?

My electric bills went up this winter by approx $50 a month . My oil bills were way over a grand every winter . When they came and filled the tank it took 8 gallons . The rancher is only 1000 or so square foot and is a rental . I went with electric backup because I got tired of dealing with the oil burner in the middle of the nights . The service calls were always ended up being $700 or close to it . Being a rental , I got the entire system replaced for $6700 and can write the entire thing off , plus a $2000 gubmint credit for effeciency savings . There is still about 175 gallons of diesel in the tank which Ill use in the Kubota , truck or my house before I can yank the tank . I might be able to sell the 2.5 ton AC unit as it was new 2 years ago . I'll say both are a lot cleaner than the oil fired systems .

 

[mmcmdl]

I pulled the trailer down the other house yesterday after trying to cut the grass for the first time this year . Got more friggin limbs and sticks down from those damn maple trees that fell . That's today's chore . I have to load up 4 or 5 6 x 6s for making some horseshoe pits also . The yards are looking pretty good for this time of year so far , but alot more work is planned . I'll post a pic of the fire this evening as we all like pics !

 

[dkemppai]

Mine will be a carrier. With a propane backup. The electric backup seems way too expensive, and would not work with our generator. well it seems the new heat pump won't work with the generator either, it's a bit more amperage. They are going up in size because they felt we were undersized currently, being a 1/2 ton under. So going up another 10amps. But for less money than the other bids for a 3ton, we are getting a 4 ton. We had 2 bids higher, and 2 bids lower..

Any idea what the COP numbers are for these units?

Running water to air, the COP is pretty much constant, and quite high. Despite our low ground temperature and high electricity cost (nearly the highest in the country from what I've been told). It still equates to a fairly good cost per million BTU. (My FIL 250 miles south has an electric cost that's half of ours.)

Twiddling with the water flow rate (to balance pumping cost vs. efficiency) yielded a cop a bit over 4.3 or so.

For perspective cost wise, propane would have to hit 45 or 50 cents per gallon to match that. That's at 20+ cents per KWh.

 

[woodchucker]

I am not doing geothermal. At my age, it just doesn't pay. My son did, still spending a lot, but he think it has to do with a bad control board, that was not showing what was running (it was calling for backup but not showing that from the upstairs unit, he has resistive elements) and was doing some other things. He installed a monitoring system on his electrical panel to find what was causing high electric. So this season (1st) was a bust, as they are still working out the bugs.

 

[dkemppai]

I am not doing geothermal. At my age, it just doesn't pay. My son did, still spending a lot, but he think it has to do with a bad control board, that was not showing what was running (it was calling for backup but not showing that from the upstairs unit, he has resistive elements) and was doing some other things. He installed a monitoring system on his electrical panel to find what was causing high electric. So this season (1st) was a bust, as they are still working out the bugs.

That's unfortunate. A lot of contractors don't understand the systems. Very few people around here do geothermal heat pumps. Actually had HVAC contractors swearing at me for wanting a heat pump! I found a contractor to work with me, and I did part of the install/commissioning myself. Bought the few odd tools/programmers needed, because it's nice to have access to those for settings/monitoring.

Cost wise, the payback for the new install over propane/AC was only about 2 or 3 years. That said, I skipped the electrical backup element and put propane in also. Wanted a completely independent backup I can run on a small Honda EU generator.

My one gripe is that in AC mode the AC is too big. This is a two stage unit (35K/65K BTU/hr). AC is better done with a lower rated AC, that runs longer. Bigger AC makes cold wet air as opposed to cool dry air from something smaller.

Edit: Had to look up COP of air/air units. COP of 2.0 might be reasonable according to google. So, yeah power could add up in that case.

 

[woodchucker]

I was aware of lower A/C but they told me do to the variable speed, 16 speeds, I was told that I will be fine in this case. I'm hoping they are right. And if they are right about my needing 1/2 ton more than 3 tons, that will be fine. They told me the a/c will run most all the time, just at a lower rate, enough to keep it dry.

edit: and I now should be able to cool the basement without a problem, which was a problem in the past, robbing the house. I want to dry the basement out, not really cool it.

The heat doesn't get in the basement because the T's I put in are on the bottom of the duct, and the hot air doesn't get there. I don't divert. I run 3 electric oil radiators in the basement to keep the temp at 65 to 68 depending on what I am doing. When finishing (wood) I bring it up a few days before to 68 or 70 depending on what type of finishing I am doing.

 

[dkemppai]

I was aware of lower A/C but they told me do to the variable speed, 16 speeds, I was told that I will be fine in this case. I'm hoping they are right. And if they are right about my needing 1/2 ton more than 3 tons, that will be fine. They told me the a/c will run most all the time, just at a lower rate, enough to keep it dry.

Variable compressor should help a bunch in that case. An extra half ton isn't a huge difference. Air to Air, guessing you'll pay an efficiency penalty on the hottest and coldest days of the year. But those will be offset by gains during more moderate days on both ends.

There was a fully variable unit available when I did this 2 stage unit. Efficiency improvements while better were small, so cost wise it didn't pay. Knowing what I know now, I might have gone that path for variable speed during cooling.

The one downside I've heard of for a heat pump over propane/oil, is combustion would tend to disinfect air. Blowing that air over hot tubes kills microbes, etc. No evidence to back that up, however. Just something someone mentioned to me once.