RMH/Air Conditioner/Trombe Wall/Exhaust Fan

     I intend to build my rocket mass heater about 6 feet from a bank of south facing windows. I'm in a perfect spot for solar gain and expect that the sun alone will provide for much of my heat and light requirements.

     Trombe walls are usually solid masonry structures meant to intercept sunlight in solar homes and store that heat for nighttime use. This should work fine for me on Vancouver Island except for the dullest rainy season which lasts from November to February. My intent is to build the rocket stove within this Trombe wall. This will give me the option of topping up the available heat within this wall.

     During the hottest part of the summer this wall will absorb unwanted heat from the surrounding room during the day. By opening the feed door and baffle to allow full draft at night the chimney effect will turn the RMH into a powerful exhaust fan which will suck heated air out of the house. Even on the hottest summer days my building site has cool nights. With cool air sucking through the system all night my RMH/Trombe wall will be quite cool by morning at which point the feed door and baffle will be closed and the Trombe wall will act as a passive air conditioner. I've tested all of this on a large stone chimney with good results.

    In another posting labeled "rocket mass heater converts to cooler/air conditioner"I talk about condensation, ducting in cold air, thermal blankets and other issues.  I welcome any input from others who have any insights or those who have constructed hybrid systems for both heating and cooling.

     

I almost missed this thread and then, as I had already clicked on another thread, i read your title before the other thread came up. I said, 'hey that is what i've been planning.' 

You are on the right track for getting the most out of your rocket mass configuration.

I have just recently been thinking of the summer air flow though the unit for cool. I had already planned that the mass would be cooled from a deep connection to the cool shady earth beneath the structure..

I am a couple years away from building, so keep me posted of your design and any other thoughts you have on this.

Way to go Dale.

A common thread I've been seeing and experiencing first hand is LOTS of thermal mass.  When I put up a 14 ton granite stone fireplace/Trombe wall in the middle of my solar+passive home with large SW glass walls, I saw a [glow=red,2,300]12F[/glow] change in temperature indoors both summer and winter. 

Although insulated envelopes are good, indoor thermal mass is also good (maybe better).

So I would advise anyone doing an indoor RMH or other things, if you get the chance, haul more thermal mass indoors... as much as you can without compromising floor + foundation psf loading.

      My rocket mass heater will be the center of energy consumption and dispersal for the entire home.  I use the term RMH quite loosely. My initial plans for this called for a Russian fireplace looking contraption but one that required very little masonry skills since it would be basically a jumble of used firebrick and granite piled inside a large recycled propane tank stood vertically like a huge chimney. One of the really big ones like they have at gas stations  will hold 20 tons of this material which may be overkill. A firebrick tube would completely combust the material before the exhaust gases reach the thermal mass.

     I only learned about rocket mass heaters about two months ago and immediately realized that all of my plans for heating, cooling, cooking, water heating, hot tub, trombe wall, exhaust fan and dehumidification with one appliance was transferable from my modified Russian fireplace to RMH instead. My building plans are quite extensive and I'm not going into this broke, so I will probably still build some version of the Russian fireplace but I will include an insulated heat riser as in an RMH.

    In a far-flung corner of the bed-and-breakfast portion of my home I will build a more standard RMH but will still use it as a trombe wall, air-conditioner, and exhaust fan. I will seek design advice on this secondary unit since I intend it to be a prototype multipurpose device but still within the technical abilities of your average owner builder. I'm transitioning from my demolition business to two other businesses that are related. I own a bus which holds 24 people and will be using it part time to haul people to green building events. My other business will be constructing green buildings which incorporate large quantities of recycled materials(16 years in recycling building materials). I've already done quite a bit of building but the bus thing is new.

      My primary unit built around a large tank is fine for me since I'm involved in demolition, I own a crane and I'm building from scratch and can thus place the big tank before the roof goes on. But for most homes that are already built this sort of system would obviously be impractical and prohibitively expensive.

      So I will post much more information as time goes on about the simpler unit which does not require a new house being built with a crane but still incorporates hot water and hot tub heating, cooling, dehumidification, exhaust fan, and solar heat storage in the form of a Trombe wall along with the normal heating qualities of a thermal mass heater.

That is a lot bigger than I'm building, but very interesting... It would be a BnB that many energy conscious folk might flock to. You may have to get a bigger bus.

Winsol3 -  do you mean that you got 12 F higher in winter and 12 F cooler in summer?

     You're a mind reader ronie. I plan to turn my place into a destination for those who want to learn and experience living in a green building. People will be able to pay the daily rate as in any other B and B or if they have useful skills they can work it off. Since my bus is set up for camping I'll be able to accommodate quite a crowd at my building site and at other workshops where I will be the transportation, accommodation, entertainment provider, head cook and bottle washer. Actually I always delegate things like bottle washing .

      Although I have limited experience in cob and other hippie building styles, I've recycled approximately 15,000 tons of building materials over the years and will be  incorporating materials which are free or which I get paid to remove. When I added 1100 ft.² to my ex-wife's home it cost me nine dollars per square foot and that includes lots of hired labor. I hope to move to a 60 passenger bus within two years at which point I hope to occasionally show up at building sites with an eager army of workers who wish to learn something while providing some labor on larger projects.

     This is an ambitious undertaking but certainly within the realm of possibility and not unlike other things I've done. 16 years ago I announced to my family that I have figured out how to get a free house. They all laughed at me. 18 months later we were living in a house that had been in the way of a new bridge. I got paid $4000 to clear that site. It cost $14,500 to move the house so my out of pocket was $10,500.oo    . I signed that house over to my ex-wife several years ago and she sold it last year for $293,000.  Almost all of the work I have ever done has involved getting paid to remove valuable resources and then finding a use for those resources. Green building is a natural fit for me because of this ability to convert unwanted items to buildings and cash. 

        I think we need a separate forum section on how to source valuable resources without paying for them. I could write a book on that subject and I'm sure there are other members who have carried scrounging to great heights . The frugality section has lots of neat ideas but I seldom see postings that clearly explain how to get your hands on thousands of dollars worth of materials for free. At some point I'll create a free e-book detailing my own experience as a recycler and professional cheapskate . Demolition materials make up approximately 30% of North America's waste stream and I believe they represent a huge untapped potential for anyone who is looking for greater self reliance. If you're looking to live lightly on the planet taking a free resource which is destined for the landfill and converting it into something useful makes a lot of sense socially, morally and financially. If I live to be 10,000 years old I will never consume as much as I have already withdrawn from the scrap heap of this incredibly wasteful society.

Some people make money on everything they do others lose on everything they try. I wouldn't want all the hassle of having the public around all the time, but there was a time that I thought of a similar buisness aventure.. My farm is named Camp NewLife (was planning of having likeminded folk around )- but things change... after getting close to the dirt, air and sky in the country, I wouldn't want a bunch of people around anymore.

I want to enjoy the peace and not have people running off blue snakes and stepping on wild mint and other things.
If you enjoy the company, I'm all for it for you.

You can start a new thread if you want. I am hoping to see some pics or drawings on this thread...since it took me years of planning (still planning) to arrive at an idea that fits in this thread.

ronie wrote:
That is a lot bigger than I'm building, but very interesting... It would be a BnB that many energy conscious folk might flock to. You may have to get a bigger bus.

Winsol3 -  do you mean that you got 12 F higher in winter and 12 F cooler in summer?

yes... the thermal mass alone (without any other source) had 12F improvement... empirical observation over years.

There's an entire field called 'DeConstruction'  involving salvaging, reusing, recycling, etc.  It's a growing business. 

Many construction RFPs (request for proposals) give extra points for reused materials.  In many locales the deconstruction people are overwhelmed and 'cherry picking'.

I built my own place out of 80% salvaged/reused materials from Restore (Habitat f.Humanity places - there's probably one close to everyone) and other places. 
http://www.habitat.org/cd/env/restore.aspx

The only BIG hassle is waiting for the right materials to show up.  most mainstream contractors can't do this unless they have a large storage facility. 

Maybe a new thread under the Green Building Forum here with deconstruction/salvage would be good.

      I've made my living from deconstruction for 16 years and have hired approximately 500 guys in the process. Most of them are street types who only work for a short time but there are a few who I've known for a dozen years or more. This is a perfectly viable business in any market where dumpage rates  approach $100 per ton.

      The viability of this business in any given city is determined by dumpage rates and demographics. If you live somewhere where lots of people are into recycling and where it costs quite a bit to get rid of junk then there is good money to be made. The West Coast is good because the quality of wood is generally higher than in the East. Houses from the 1940s and earlier are usually good candidates for recycling unless they have experienced extensive, shoddy renovations. The poorest quality houses for deconstructing are those built in the 1970s and more recent buildings which contain lots of OSB/Aspenite or whatever they call glue impregnated crap board in your region. Newer buildings also use lots of glue and any sheeting materials are generally destroyed if you try to pop them apart.

     This is a good job for fit individuals who are not accident prone. Fortunes have been won and lost in this business. Failure is more common than success in the deconstruction field. The most common causes of failure are that people grossly underestimate the time and labor costs associated, they failed to put in key clauses in contracts which deal with who owns any toxic substances found, huge safety or environmental fines bankrupt the business or the new contractor injures himself.

    I have watched all of these things happen to people who got into this when they shouldn't have. But if you have your head screwed on straight you can avoid the pitfalls and access vast quantities of resources that you are paid to remove. I was just over one year into this business when a free house fell into my lap and I moved it to a nice lot. My family lived in it for 14 years

For individual DIY builders and homesteaders, how does one find houses, buildings, etc. to reclaim, tear-down, deconstruct... AND reuse these materials for one's own projects?  ... without all the hassles of city/county permits, etc.    Like, having a friendly neighbor?

Dale:  There's a new thread going under green building... 'DeConstruction...

winsol3 wrote:
For individual DIY builders and homesteaders, how does one find houses, buildings, etc. to reclaim, tear-down, deconstruct... AND reuse these materials for one's own projects?  ... without all the hassles of city/county permits, etc.    Like, having a friendly neighbor?

It sounds like someone like Dale will be known and people probably call him... for the rest of us - try craigs list.

      City hall should be your first stop. Most municipalities require you to get a demolition permit and these things are a matter of public record. Go to the building department. Some places just list the property address and owners name but others even include phone numbers. I've found dozens of jobs this way even when I was brand-new at it. The City Hall thing also works if you're a drywaller, electrician, plumber or whatever yet I don't see many people doing it.

    I found that Craigs list and other Internet sites have ads by owners who are deluded. They think they have a salable resource when in fact your average three-bedroom demo house in this city is a $10,000 liability. Remember you can almost always find a way to get paid to harvest the resources you need.

Well we really went off topic with all the deconstruction talk. It's been over a year since the RMH/Trombe wall discussion.

A few things have developed for me since then.

1. I learned how to use a Bobcat and did several test mixes of cob and of a wood chip impregnated cob which will form exterior walls.

2. Three people have moved to my property and one was born there.

3. The first tennant owns an excavator and has done so many improvements that I have never charged him the agreed upon rent. He has graded the road, cut down steep banks that were in danger of sliding onto the road, fixed some drainage issues and cleared building sites. His excavator will be used for cob mixing and many other heavy tasks.

4. The other tennants are a young couple who have fixed up a half built cottage in exchange for a years rent. We'll probably come up with another job for them next year and extend it until they can afford their own place. No rent is a good first step for young people trying to save. They produce their own food as well and do some off farm work, so are in a better position than most to get ahead financially.

5. I cleared thousands of small trees from the edge of the road and a building site and the excavator piled them into 4 large hugelkultur beds covering a couple thousand sq. ft. and averaging 5ft. in depth. Then I got busy and didn't return all summer and fall.

--------------- So now we have the right machine for cob mixing and a built in labour force. They are ready, willing and able, so it's all up to me to find the time and money to continue.

I didn't know how to post links when this thread was started. This is a closely related one entitled Rocket mass heater converts to cooler/air conditioner https://permies.com/t/9580/rocket-stoves/Rocket-mass-heater-converts-cooler.

Horribly useless tenants didn't work out and they were afraid to have a RMH in the cottage. They also had an aversion to electricity and spent 20 months in the dark. The other tenant conducted all cottage improvements while they watched.

I've amassed some materials and when the cottage is vacated in early March, I'll build some sort of RMH. This one won't be a Trombe wall. The cottage is in a shaded area. Finances force the postponement of the big unit.

I do plan to put together the greenhouse/spa building this summer. A wood fired bathing unit will be in the sun and will act as a Trombe wall.

This link goes to some drawings of Trombe walls. http://sustainabilityworkshop.autodesk.com/buildings/trombe-wall-and-attached-sunspace

After reading both this and the other thread, I am wondering what keeps a Trombe wall from gathering radiating heat into the living space during the summer months? Is it just shaded by a carfully built roof overhang?

William Bronson wrote:After reading both this and the other thread, I am wondering what keeps a Trombe wall from gathering radiating heat into the living space during the summer months? Is it just shaded by a carefully built roof overhang?

The wall will absorb any heat that it is exposed to. If the sun shines on it, it will heat up. The windows need to be managed just as they should be if there were no Trombe wall. This includes a proper overhang, shutters, curtains etc. that are used to prevent excess heating.

Suppose we want to turn it into an exhaust fan for night cooling. Once the outside temperature has cooled in the evening, the vent could be opened, which would allow warm air to rise up the chimney. Cool air would be sucked in to replace it. This chimney effect would continue until morning when the vent is closed. The wall will have cooled off quite a bit. Once the house warms up, the Trombe wall will begin absorbing heat from the room and will continue to do so until night.

In areas where night temperatures are too low, the wall would simply moderate the temperature by storing daytime heat and releasing it at night.