Smitty,
Captain Michael wrote:Hey everyone, I have a question. I currently have a keystoker 90 with a coal trol and 6 inch collar for the blower piped into the cold air return. Works great! The stove is in the basement of a 1040 ft. split entry. It works so well I ripped out the oil furnace and replaced it with an electric heat pump figuring to only use the electric if I was out of town. I have not had to use the electric yet this winter.
Now the question. We are building a new home this spring. 2600 square foot 1.5 story. It will be well insullated and tight. My property does not have access to natual gas so the primary HVAC system will need to be something else. I was dumb once but not twice so oil is out. Propane is also out. I have decided to go back to the well and install an electric heat pump. Of course it will not get much use because I also be putting in a coal unit. I am thinking Koker with a coal trol ducted into the HVAC system. What do you guys think? Am I thinking right? Also I will be building a new chimney. The Koker has 6 inch flue. What would be the optimum size flue liner? I am not going to do anything with a boiler lets just stay with forced air.
To this CK replied
coalkirk wrote:Just because you want you use forced air doesn't mean you cant take advantage of the efficiency of a coal boiler. I would do the heat pump and have a water to air heat exchanger installed in the duct work. The benefits are more efficiency AND it can do your domestic hot water.
heat exchanger.jpg
Here's what it would look like. Also this will heat your home very evenly and not dry it out as much as a radiant stove would.
To that I added
waldo lemieux wrote:Cap'n
As CK pointed out , using a stoker boiler and an heating coil is absolutely the way to go. As he pointed you can use a indirect for your DHW .Too if down the line the need arises for say heat in your garage or detached workshop or studio or whatever , running a couple of pipes is way easier and you couldn't even use hot air in a garage as an air return from a garage is a large no no
Bottom line is putting heat where you want it is way easier with hot water. Put a stoker in your garage or a separate room off your garage and keep in mind coal delivery, storage and ash removal disposal, all much eaiser when your starting with a blank slate.... you dawg
Regards ,
Waldo
The term "indirect dhw" means a tank with a water to water heat exchanger. There is no such term as "indirect boiler". Of COURSE you cant use any type of forced air system to make hot water nor do you need to use a coal boiler to make heat for a heat pump. The idea here is to use the ductwork from the heatpump/ac system to distribute heat made by a coal boiler ( via a heating coil in said ductwork) and using the same coal boiler to also make Dhw with a INDIRECT DHW tank. Essentially you wind up with ground source cooling in the summer, coal boiler for heat and hot water and the same ground source unit for backup heat in the winter. There is no way anyone would go to the expense of installing a coal stoker just for dhw. Its not that complicated,
SMITTY wrote:Your not understanding what I'm trying to say here. YOU DO NOT NEED ANYTHING hooked to forced hot air to run an INDIRECT BOILER for DHW. Your making this waay more complicated than it needs to be. I'm talking about DOMESTIC HOT WATER - nothing to do with heating your home.
YES - you need the water-to-air exchanger in a forced air system for HEAT, to heat your house - that has NOTHING to do with DHW. One, or more zones are for HEAT, other zone is for the indirect.
CM asked about using coal a FURNACE or Some coalburing thing hooked to the ductwork of a electric heatpump, as a backup for his new house. He went on to say he didnt want to get involved with a boiler. Ck pointed that boilers and forced air are not mutually exclusive; saying that you could use a stoker boiler and a coil in your ductwork for heat and get dhw to boot .I was merely agreeing that said system works great for people that want ac which requires ductwork. The other option ( which is what CM was driving at) would be to use a coal FURNACE to make heat for your house using the heatpump /ac ductwork to distribute the heat made by the coal FURNACE. The point I was making here is that while you can make hot air you CANT MAKE DHW WITH A COAL FURNACE. With a COAL BOILER , AN INDIRECT DHW TANK and an HEATING COIL you can while using your heatpump as backup heat in the winter and ac in the summer.
Waldo
I am the good one. 
