Wood boiler tank minus the boiler with a heat pump

[tom in maine]

Even though I manufacture unpressurized tanks for a living, it has taken me six months to finally put together one of our tanks in my basement.
The wood boiler will show up later. It is a 345 gallon tank that is rectangular. We do not normally produce this type of tank, but the floor space is limited and even though it takes me a while, I can do custom tanks.
The 345 gallon size is based on upon our heat load of about 6000 btus/hr at -10F. The house is mostly R-65 foam and I have a tiny Jotul QT100, which always overheats the house when I use it.

So, the concept is to use a small wood boiler with the tank to buffer the heat load.

The summertime plan (for now) is to use a Nyle Corp. heat pump water heater to heat the tank. This dehumidifies the basement and also air conditions the
first floor of the house. A solar system we are working on will go in next year.

We have our regular DHW heat exchanger in the tank to feed the household. We used it for testing this week at the shop. It was in a 150 gallon tank that was heated to 180F and then delivered 224 gallons of hot water(110F) at 3 gallons per minute. Once the testing was done, I got it.

It will take 28 hours to heat the tank since the heat pump only puts out about 6,000 btus/hr.

BUT the basement is drying out and it is already cooler upstairs! Great news since the rainy season is over and the several days of summer are upon us!

Tom

 

[Fred61]

Tom,
Is that Nyle Corp water heater a standard product or is it some kind of prototype? I brought up Nyle on the web and what I saw was industrial units with industrial prices for dehumidifying kilns.

 

[daleeper]

Tom,
Is that Nyle Corp water heater a standard product or is it some kind of prototype? I brought up Nyle on the web and what I saw was industrial units with industrial prices for dehumidifying kilns.

I'm interested in Tom's response and continued updating on this project. Nyle did some domestic hot water heaters in the past, and looks like they have spun this off to another group or sold off that part of the business.

This is the current web site for their residential water heaters. They claim Nyle as an affiliate. I had just done a new search on heat pump water heaters this morning, and ran across it.

(broken link removed)

Tom, have you had experience with these heat pumps? If so, please elaborate on your experiences. I find this project as an interesting mix of wood heat and heat pump for domestic hot water, along with your plans for solar heat. I'm even wondering if solar is really worth it, as you are gaining the dehumidifying that you would have to do with a dehumidifier anyway. Keep us posted on this project please.

 

[tom in maine]

The Nyle unit I have is their older one. It runs on 220V and was engineered to interface with the controls on an electric hot water heater.

The new unit, The Geyser, is 110V and is simpler to control. It does the same thing heat wise.

I have also used the Airtap on a TV program, but it is not quite as versatile and I think it would not be able to be easily moved from one installation to another (like if an electric tank sprung a leak).

I am very impressed with Nyle's engineering. The unit sells for about $1,000. There is a lot of hardware there for the money.

Right now I am more interested in the dehumidification more than anything else, although it does produce cheaper hot water than my Toyotomi OM 148
water heater does.

The solar project is based on work we did for NREL (National Renewable Energy Labs) about 9 years ago. It is an all polymer cold climate solar collector.
It is just waiting for either time or money, maybe both. Should have some prototypes tested this summer. Solar is a lot easier to get into the markerplace than wood boilers!

BTW, the tank is now about 90F after running about 15 hours(remember, it is 345g). AND the house is a lot drier. We live on the coast and it is wet and rainy today. The basement is also very nicely air conditioned.

Past experience is that the unit costs $20-30 a month to run. That was with an Amtrol 80 gallon stainless steel foam insulated tank.
I think it was 1.5-2 inches of foam insulation. The big tank, even though it is 4x bigger is better insulated with few thermal breaks.

We'll see.

 

[Wallyworld]

Nyles old website for the heat pump Hot water heater was (broken link removed), that goes to Geyser now. The Nyle unit works great but looks totally different than the Geyser unit. The payback claims are right on and mine will pay off before guarantee runs out. Pretty good deal if you ask me. Keeps my walk out basement dehumidified and I ducted mine to the living room so it cools that off also

I use my heat pump for backup for my solar system, good thing I had it this summer

 

[red247dog]

Tom,

I see you are in Maine as am I. I have an 80 gal storage tank that is connected to an undersized solar collector, with an on demand propane heater to pick up the slack. I also run a dehumidifier in the basement in the summer, but not in the winter. The basement gets down to the high 30's in the coldest days of winter.

In your opinion would the type of heat pump you are running be a worthwhile investment for me? I have a second coil in the storage tank I could run it through and assume I could somehow wire it into the tank thermostat associated with the solar system.

I see the savings calculator they have on their website, but I have to assume that it is based on running 365 days a year and that I wouldn't realize those savings since I would run it at most 6 months of the year.

When you talk about payback, are you planning to run it all year, even if you don't need the dehumidification in the winter?

I'd be curious to hear your thoughts. It certainally looks like a slick system, don't know if the 1K investment would be worth it though. Thanks.

Chris

 

[tom in maine]

Hi Chris,
I think the investment is worth it. If you consider the cost of running the dehumidifier, that cost now creates enough hot water for your home, while keeping the basement dry. The COP is usually at least 2 and is usually closer to 3.

I have not been running it all year, but still feel pretty good about it saving me at least $150 a year over the oil I was running.
Might run it more once we get the wood system online. Will be posting more on this in the autumn.

Tom

 

[Wallyworld]

I had to shut mine off in dec. last year. Started it again in May.

 

[pybyr]

I had to shut mine off in dec. last year. Started it again in May.

Was the reason for the shut-down that the basement became too cool for the heat pump to readily extract much heat? This technology seems really promising, but I have heard that it may struggle during cold months in cooler cellars of older buildings.

 

[tom in maine]

Basement was cool, but in my case, the first floor of the house was cooled off too much.
My basement walls are spray foamed on the inside, so it steals heat from the living space.
IF, the basement is large enough and not insulated, it works year-round. Probably better in states other than Maine.

 

[red247dog]

Tom,

When you say it saved you $150 over the oil you were using do you mean that you used to use $150 worth of oil in the summer but no longer need to? Does that added $150 include the added electrical cost. Any elaboration would be appreciated.

I guess a 6.5 year payback isn't so bad (assuming it costs $1000 and you save $150 a year).

 

[Wallyworld]

In my case it was getting to cold in the house. I could have kept running it but either oil or wood would have been the heat source for the pump. I originally(still do in winter) used electric resistence for my back up hot water. I saw my electric bills drop 30 bucks a month once I had the heat pump online. I also saw the tank on my water softener stop sweating as much( used to have a wet floor because of this) as the pump did such a good job pulling the moisture out of my basement

 

[tom in maine]

The $150 is what I figured I would've used in oil. The additional electric cost is what a dehumidifier would've cost, so in one sense that is a wash.
The air conditioning that it affords me is free.

The house is a lot drier than it was with the dehumidifer.

 

[fabguy01]

where are you getting these units ? what is the cost? Thanks.

 

[tom in maine]

They sell them at (broken link removed).

I have a first generation unit. My unit runs on 220v. The new one works on 110v and is simpler to install.

I believe they are going for about $1,000.

 

[fabguy01]

What happens in the winter when this unit is removing heat and dehumidifying the area that you are trying to heat? :roll: I would think it leads to more wood usage.

 

[tom in maine]

I shut it off and heat with wood or oil.