retrofitting an old farm house....questions.

[redryder2006]

Located in CT. 1890's era early farm house with a small field stone foundation with the rest of the basement crawl space. I only have one flue available to me.

I would like to replace my aging oil boiler (steam heat) two pipe system with a wood boiler with a propane burner backup. Looking at the BioMass 40 wood gasification boiler with propane backup. (finished the propane retrofit last year. I have a few questions regarding the best way to deliver the heat. I attached a word doc. with a basic layout of how I would like to set this up.

1: Reading about hot water heat delivery options...Radiant floor heat is not an option right now since I am not going to rip up the floors. If I add water storage at about 190F then I would want a hot water delivery system that is about 100-110F to maximize the amount of BTU's stored correct? As I understand hot water baseboard usually operates at about 180F? please correct me if this is incorrect. What would be the best hot water delivery option in this case?

2: Thermal Storage. I plan on doing this retrofit in stages. I would first like the remove the old system (oil tank, boiler, pipes & radiators; and replace with the biomass boiler and new delivery system. Because of the small basement I do not have room for water storage, However in the next few years I plan on building a detached garage with a separate heated shop area that I could incorporate hot water storage tanks into. Can the storage tanks be piped into the system through underground insulated pipes?

3: Gravity vs circulator pump system. We had a pretty bad ice storm that left us without power last year and with having unlimited access to firewood, I would like the system to run without electricity for emergency situations. Can someone explain how a system like this works? I asked my boiler guy about them and he said he has serviced them but never installed such as system. Is it possible to run a gravity system (with expansion tank in attic) inline with a circulation pump to increase pressure for DHW?

Thanks for the advice.

 

[mikefrommaine]

Welcome.

Are the existing radiators in good shape? I'd suggest converting the existing radiators to hot water and leave them in place.

Re thermal storage. I don't see why you can't do remote storage in an outbuilding. Many have done the opposite with the boiler outside and storage in the basement. I have the tanks in the far end of my basement away from the boiler. I used 1.5" lines to reduce pump head and keep the circulator as small as possible. But still ended up needing a 26-64 grundfos. The farther away the tanks are the more money you will spend.

My last house had a gravity based system. Originally with a coal boiler. The piping was all exposed and a work of art in its own right. Can't help on designing it but know that it worked quite well. But may be very hard to retrofit. Much easier to run some pex and pump it.

I'd consider running a pair of 1/2" pex from a central manifold to each radiator retrofitted with trv's. And use a single alpha pump?
http://www.pmengineer.com/PME/Home/Images/PME-dec-2012-fig-2_lg.jpg

 

[redryder2006]

the radiator's seem to be in decent shape (need to be blasted and repainted) but I worry about the condition of the pipes inside the walls. Some of them are in exterior walls and when I re-sided the house sections of the pipes were very scaled and rusted. I have already had to replace several sections of the existing steam pipe due to water leaks, I would not feel comfortable circulating hot water though them.

Also, attached the doc. to my original post. I replaced the hot water heater when I first bought the house so it is in new condition and works very well. I would like to keep this plumbed in the system so that I can shut the boiler down in the summer until I get a storage system in place.

 

[NHFarmer]

I did the very same retrofit in my 1850 farm house with steam heat. I ripped out all the old piping and ran 1/2" pex to each rad. The nice thing about the pex is that you can fish it in the walls just like you would electrical wires.I went to a manifold for each zone. You can carry plenty of BTUs in 1/2" pipe as long as you have a separate run for each rad. They do an excellent job of providing a nice even heat. You will need to make sure the rads are set up for a two pipe system. If you want to go with a gravity system I am afraid I can't help

 

[redryder2006]

have not thought of running pex to the radiators...I suppose that would probably be the most cost effective. But I would still have to remove 15 radiator's from the house, restore then re-install them...better get back in the gym to get ready.

What is the most common or most efficient heat delivery system? it seems that radiant floors are popular, but I am looking at all possible options.

 

[maple1]

The most common delivery system might be plain hot water baseboard radiators (e.g. Slant Fin). What is best for you likely comes down to what is the easiest to install in your situation. Hot water baseboard is often thought to need significantly hotter water, but it will output heat at lower temps than lots of people give it credit for. I'd say that if you want to make full use of lower water temps, just put more radiators in. My storage usually gets down to 140 or so (the odd time 120) before I light a fire, and the house is still warm when I do that (I have the Slant Fin). In floor or under floor will work better with lower temps than baseboard, yes - but if you can't install it it's not the end of the world.

My system will heat without electricity - the boiler generates the heat without a fan (it uses natural draft, no fan), and the system will distribute the heat by gravity. The fundamental requirements for gravity flow are quite simple - heat goes up, so your heat supply &/or storage needs to be at the bottom (i.e. basement), and your zones above it. There may be other ways to have some of that work by gravity, say if you can pump the heat to a low spot, like from an outside boiler/storage to a smaller buffer tank in the basement (using a generator or battery powered pump), and letting it flow the rest of the way by gravity. Mine is not strictly a gravity system, I don't think - it still relies on electrically operated zone valves when the power is on, and uses a circulator pump. When the power goes out, a normally open zone valve opens to allow gravity flow without the circulator running, but it is uncontrolled since the thermostats & zone valves need power to control how warm the house gets.

 

[redryder2006]

Thanks for the reply maple. This is my first home ownership and my first time considering a wood burner boiler. Previous locations had open floor plans and I could beat with primarily a wood stove insert but with this closed floor plan in a bigger house the heat does not circulate well. I also have more wood here than I could burn in 3 lifetimes. :dance:

Your system sounds like what I am aiming for, comfortable and modern with separate zones while still able to function in a simple form during a power outage.

Won't be starting this project until July at the earliest so I'm trying to get my options worked out now.

 

[maple1]

Another hint from experience: don't put off starting it thinking you still have months to do it.

I started 'way early' in early May when I bought & brought home my tanks (after months of reading on here & other places).

I was scrambling in October getting fired up as the weather was getting colder each day. That was in just swapping out my heat supply & having the main distribution system already in place.

Summer distractions can really throw the schedule off - along with simply underestimating how long it will take to get things done.

 

[SmokeyTheBear]

Another hint from experience: don't put off starting it thinking you still have months to do it.

I started 'way early' in early May when I bought & brought home my tanks (after months of reading on here & other places).

I was scrambling in October getting fired up as the weather was getting colder each day. That was in just swapping out my heat supply & having the main distribution system already in place.

Summer distractions can really throw the schedule off - along with simply underestimating how long it will take to get things done.

LOL x a very large number.