Water to Air Heat Exchanger Coil???

What I have is a heat pump with a 140,000 BTU water to air heat exchanger, plenum mounted into the trunk line of my forced hot air system. Clearly I only use the heat pump for the blower, supply/return air and filtering. This exchanger was once fed by an outdoor wood boiler that is no longer in service, instead, I am using a 85,000 BTU Alaska Stoker Stove 2 to handle the heating duties. This year I would like to utilize the exchanger coil, I would like to install a coil (or coil's) in my stoker to handle the water heating duties, but don't know how to go about it exactly?? Pressurized system?? Non-pressurized with a storage tank?? Seems like pressurized would be the way to go, but not sure of what or which parts/components are needed to make this happen?? I am a very good pipefitter, did industrial fitting for many years, problem is most all of the piping I did was from piping Iso's, from point a-b-c-d-etc. and I never had a chance to really learn the why's and how's of what I was doing, all that was done long before it ever got into my hands, so, I'm looking for some help with this process and any input/advice is more than welcome and appreciated.. I can provide any measurements etc. that may be needed to assist..

Thanks, Adam

MURDOC1 wrote:This year I would like to utilize the exchanger coil, I would like to install a coil (or coil's) in my stoker to handle the water heating duties, but don't know how to go about it exactly??

Get a boiler to replace your existing stoker stove, you can sell it to defray the cost of conversion. What you want to do is not going to be practical or efficient unfortunately. A coil cannot hold a massive reserve of heat like a boiler can with it's 20-50 gallon capacity. The exchanger coil would be sipping from a boiler, one gulp from a stove coil and your latent heat is gone.

coaledsweat wrote:Get a boiler to replace your existing stoker stove, you can sell it to defray the cost of conversion. What you want to do is not going to be practical or efficient unfortunately. A coil cannot hold a massive reserve of heat like a boiler can with it's 20-50 gallon capacity. The exchanger coil would be sipping from a boiler, one gulp from a stove coil and your latent heat is gone

Thanks for the relpy, I was affraid I was gonna read that at some point.. So now I must ask this- What would the likley outcome be if I were to heat water with multiple stove coils, send it from there through the water-to-air exchanger, return it to a 40 gallon insulated hot water storage tank then do it all again running the circulator constant. Could I manage to generate 180 Degree water to send through the w-a??? How cool could the return water get?? And how difficult could it be to reheat say 140 Degree water back to 180 Degrees?? The stove to be used is downstairs in my garage and serves the purpose of heating only that area, a Harman Mag Stoker is upstairs in the living space for those duties, I would prefer to not use the Mag Stoker and handle it all from the garage downstairs instead, a boiler would be nice, but not exactly cost effective to heat this 1600 s.f. space not to mention I couldn't rely on it to then heat the garage as well. Plus, I was also thinking of building a hot air jacket around the Alaska to be ducted into the cold air return of the heat pump in conjunction with using the water-air, maximum usage of efficiency from the Alaska. In other words, the setup would be exactly that of a outdoor wood boiler, just using a stoker stove instead.. Any thoughts??? And just for kicks, what boiler would be recommended for a job like this, keep in mind I will NOT be heating any DHW with it nor can I vent through a chimney, none there, powervent only...

A boiler would be the way to go. Their is no reason you could not heat your garage with it, you could heat your neighbors garage with it if you run the pipes . If you install the boiler in the garage, like an axeman anderson without the insulated jacket the heat radiated might be enough to heat the area. If you install in the basement, you could always run pipe to the garage and heat with a modine heater. With a boiler the possabilities are endless, you could run lines under your driveway and never shovel snow again.

I missed the part of not having a chimney, could you use the pipes from the old wood boiler and install the unit outside in a small shed where the wood boiler was ? I would not feel safe powerventing a solid fuel appliance.

AA130FIREMAN, thank you for the reply, I can appreciate the wisdom behind a boiler and really wish I could go that route, truth is, my place is a rental and landlord is pretty cool with just about anything I do here, hey he let me put in not just 1 but 2 stoker stoves to heat through the winter ... I just am not sure if I want to go to the expense of a boiler install even though it does make perfect sense what you are saying... By chance, what is the approx cost of a AA-130??? If you don't mind me asking that is... As far as the wood boiler piping, the boiler is still here in use for the property owners home across the driveway, but, the pex piping into my place has been removed ... I would almost have to place the boiler in the garage, not to mention the brand spankin' new 4 ton bin that I just built is sitting right there next to the concrete slab I poured last year for the Alaska... Maybe if the price is right I can go the boiler route and install a class-a chimney, just more money though, ya know...

Thanks for your thoughts

Adam

Forget about class a chimney unless it is a short run, it will rust, yes the stainless will rust, I have it in my house. Masonary is the best way and if I have to redue mine that is the way I will go. A new aa130 runs about $7000. Look for a used unit, but I WOULD NOT spend the money if you are in a RENTAL unit. I had bought a second used aa130 out of the classifieds for $400/got to be fast, he had over 20 calls in 2 days. Are you shure they removed all the pex, I would think it's still underground just waiting to be unearthed.