Seeking Engineer for Off-Grid Religious Facility Heating in the Mountain States

Firewood warms you twice once in the process of obtaining it, then when you combust it.

I live in the city now, so I head to the mountains or desert to burn wood to heat and cook, in the camper, with a Cubic mini wood stove.

Timber companies allowed folks to take branches. Stack them into piles and then haul piles out in winter on sleds. Preferable to attending church or Sunday school? In addition to drying time there's the advisability of having years' supply on hand.

I think a two-pipe district steam might be the easy way. The boilers can be in an outbuilding, depending on how your customer feels, you might be able get away with modern controls in the outbuilding, and TRVs or manual controls in the main buildings. Even if that's not viable, consolidating the boilers in one location should make managing them easier. Or orifices in the radiators and manage the output by controlling pressure. Might even be able to find a steam-powered vacuum pump for a vapor system.

Time for a mental reset.

Gravity hot water, once installed PROPERLY , is elegant.

It is ideal for a solid fuel heating system. The simpler am more old timey the better , including the open system design.

One of the elegant features is that because it is temperature difference that drives the system the coldest room draws the most water from the system until that room is warm, then the preference moves to the next coldest radiator.

Another elegant feature is that the large thermal mass in water and radiation makes for very slow and flat bounces in the temperature.

The only disadvantages come with sudden need for more heat and having to tend the fire.

How are you going to address the Outside Air requirements in a new tight structure?

Yep. Poroton structural tile. Awesome stuff. Cousin in Germany built his new house using it and couldn't be happier. Place is a fortress. Link to manufacturers below. Juwo and Wienerberger are the big ones

https://www.juwoe.de/en/index.php

https://www.wienerberger-building-solutions.com/Products/Wall.html

They have a US distributor in Wyoming.

I did preliminary work on this project a few years ago. We were talking about hydronic radiant floor heat and utilizing PV powered circulators (With battery backup) that were mounted outside the facility. We also talked of using a wood gasification boiler to utilize all of the beetle kill pine. I am happy to discuss our initial design ideas, and to see if we can be of any help! Ferguson Hydronics 303-942-8102

With district steam they'd only need 24v at the boiler house for controls. Way smaller load than pumps of any sort. if the land has a slope they may be able to do gravity condensate return.

If in the building, with no electricity allowed, better to do gravity HW . There are a number of thermostatic damper controls for wood fired HW boilers on the market.

Gravity air is really a non-starter.

VENTILATION: I once saw an old school in Chicopee, MA that used steam piping in a chimney structure to provide ventilation - sort of a "whole building" fan idea with 5 rows of 2.5" piping around the inside of the 6x6 "chimney", heating air drawn in by infiltration which then rose and exhausted the building…Not the most efficient but it worked!

That story reminds me of an innovative office building in Zimbabwe that was designed to mimic the passive ventilation in termite mounds, which have a central "stack" through which warmed air rises, and the termites regulate the temperature by digging vents at the base of the mound to admit varying amounts of air.

The office building design is more complicated and does involve fans and electricity, but the principle is similar. The building has 48 air stacks on the roof through which building air is expelled, after it passes through the hollow floors of the building and is distributed through the office spaces. The building mass also serves as a thermal battery, so that the cool night air cools the building's interior mass, which then absorbs the heat from the warmer daytime air during working hours. The building has no air conditioners and relies only on this passive cooling.

https://www.mickpearce.com/Eastgate.html

Mebbe, if Dennis is comfortable with the type of system required. Definitely not your usual duck.

"Some creative architecture that integrates passive ventilation, passive heating and cooling, and smart use of thermal mass and glazing, is definitely called for."

I've never seen a building that claimed to use "thermal mass" that was actually engineered. As in, here's a predictive, quantitative model that we'll use to map out the performance of the building and guide our choices of materials and their quantities. There have been plenty of buildings that attempt to use "thermal mass" and passive solar guided by guesswork. The results tend to be exactly what you would expect from guesswork.

The passive solar houses and other structures my late father0in-law and I did back forty plus years ago were completely engineered, including thermal mass effects. A couple of the early ones we didn't get quite right, but later we usually came pretty close. Architecture wasn't our thing, so we worked mostly the The Architects Collaborative or Mies van der Rohe on that.

I know that question was directed at Jamie, but I'll offer a few thoughts.

An electrical analogue of thermal mass is, say, a rechargeable battery. A rechargeable battery can store a given number of amp-hours, as a "thermal mass" like a drum full of water can store a certain number of BTU's for a given delta T. So the BTU storage capacity of, say, a drum full of water is:

BTU's stored = Mass x specific heat capacity (BTU/unit mass/degree F) x delta T (degrees F)

So that's the first "unit" of "thermal mass," its total BTU storage capacity.

And the rechargeable battery can supply that stored charge at a certain rate, in units of amperes, which is Coulombs/second. Just as the drum full of water can release those stored BTU's at a certain rate, which will depend on a number of factors including surface area of the drum, emissivity, convective airflow, delta T, etc. So the release rate is not as easy to determine as the discharge rate of a battery, but the analogy is there.

So the second "unit" of thermal mass is the release rate in BTU's/unit time, which will depend on a number of factors.

The third "unit" is the rate at which the mass can absorb BTU's, which again will depend on a numer of factors.

So that's all we would care about for a given "thermal mass:"

1. How many BTU's it can store
2. The rate at which those BTU's are released
3. The rate at which it absorbs BTU's (from the sun, etc)

The first is easily calculated. The other two are more difficult, but can be derived from known heat transfer laws. And the basic units are BTU's stored per unit mass, and the rate of BTU release or absorption.

Solar is a potential option, however, the design of the structure was not set up for passive. Active solar has its own power challenges and more importantly, this building is being built in an area that sees minus 20 or more on many winter days. Solar will only be helpful during the shoulder seasons and there are complications in doing solar thermal without power.

The initial design we proposed involved Danfoss non- electric thermostats and zone valves, radiant floor heating in concrete, heated by a gasification wood boiler to use the abundant beetle kill pine, and two PV powered circulators backed up by battery that were mounted outside with the boiler. Super simple and effective.

Well @Jamie Hall , you win the prize for being the first person I've asked that question of to give a coherent answer. Honorable mention to @jesmed1 . Normally a conversation goes something like this:

"My building has lots of thermal mass."

Me: "Oh really. How much?"

"It has 4" concrete floors"

Me: "How many units of thermal mass is that?"

"It has 4" concrete floors."

The property of matter you describe is more properly called "heat capacity."

I tried to find out as much as I could about that building, I couldn't really find anything that wasn't written by the designer. They say it was engineered but they don't say anything about what they engineered. On their website they include temperature data for one month, April. They note that they have 32 banks of fans and they're set for 10 air changes per hour at night and two during the day.

The temperature data for April shows outdoor temperature ranging from about 14C to 28C (57F to 82F) and indoor temperatures ranging from 19C to 26C (66F to 79F). So basically the same kind of weather we get in April here in Washington and in many places. I wouldn't consider it an accomplishment to keep a building in that range, especially with that much ventilation.

It seems to me that it's more about the ventilation than the concrete. Ten air changes per hour is a lot. A small house might be 20,000 cubic feet, ten of those an hour is 3333 CFM. That's an enormous fan going all the time.