Remy Fils

Thanks again guys for your help.

Cristobal, today I'll try to remake the simulation with the new website, as there are some things to be changed:
- Climate data you put is too cold, it's the climate we had here 30 years ago
- I have triple glass windows
- I'll put 40cm mineral wool insulation on ceiling + insulation on main floor + wooden floor this summer

With those new inputs, I guess we could lower by 40% at least the heat loss you obtained in the simulator.

If RMH doesn't provide a significant advantage over my actual system (like -75% wood consumption), it won't be interesting because my actual system provides better heat distribution and warm water for bathroom use. But I'm almost sure it will do, because I'm throwing a lot of heat to the chimney and I don't have the radiant heat of an RMH system.

Central heater's gas exhaust is 200°C (392°F).

Edit: with new input data: (I didn't change climatic data though because although I have higher temperature, there are strong winds here in winter that directly impact wall heat loss) I obtain:
- 15,5 kw peak and 9,7 kw average (uninsulated)
- 12,7 kw peak and 7,9 kw average (40 cm mineral wool on roof and 7 cm mineral wool on ground floor - which are short term work I'll do this year)
- 4,5 kw peak and 2,1 kw average :O  (all above + 36 cm straw insulation on walls - longer term as it is a bigger work)

So as you said, insulation first!!

Cristobal Cristo wrote:Remy,
For the area have you used the area of exterior walls?

Yes

Cristobal Cristo wrote:Remy,
Are the exterior walls over a meter thick (42")?

Conversion error...Used metric system. Let me change it

Cristobal Cristo wrote:
Are the concrete or hollow blocks or bricks?

I guess hollow blocks. No bricks for sure.

Cristobal Cristo wrote:
You put 35" for the ceiling thickness. Is it some conversion error? The same for the floor.

My mistake

Cristobal Cristo wrote:
Please provide house dimensions: length, width and height, and I will play with it myself.

Ok let me get back to you shortly. Thank you!

Edit: correcting metric system error gave me even worse numbers: 70 kW heat loss!

For insulation, maybe I should put in the calculator what my intentions are (on roof and main floor short term), instead of how is the house today (uninsulated)..?

Dimensions:
Floor surface: 737 square feet
Height: 19 ft
I know floor surface, but not exact length and width (I'm not there at the moment to take the measures). So to calculate wall surface, I took square (737)*19*3+square (737)*19*0.3. I didn't multiply *4 walls because the fourth wall is adjacent to another wall (barn's wall), so it's not fully exposed to outside temp. To take in account this, I considered 1/3 of the heat loss of a normal wall instead of 1.

Thank you again for your kind help.

Hi guys!

Here it is: https://jmp.sh/s/HvO2r8Y4CnpNZOjsnOVf

It's even worse, last calculations give a 35 kW result.

And yeah I did put "unheated" both for the room up the ceiling and under the main floor.

In any case, what Cristobal said is right. Before building the RMH, i may insulate correctly the house and see what happens in terms of wood consumption with my actual system. Oh, i forgot to mention that I have a solar panel for hot water that covers our hot water needs for whole summer and for sunny  spring days.  Question about main floor insulation: is it a good idea to put thermal insulation + wood floor on living room, knowing that I will probably destroy part of it to put my RMH there?

thomas rubino wrote:Hi Remy;
Support columns are a good idea.
Have you chosen a build design yet?  
A J-Tube with piped mass?
A J-Tube into a stratification chamber? (Bell)
A Batchbox into a bell?
Single wall bell or double wall bell?
All these choices will weigh differently and spread the weight over different areas of size.

Yes, you could continue with this thread.
However, I would start a new thread for your next questions.

Here is why: Your current thread addresses a very common question from prospective builders.
Any new questions you ask may be just as important, but they will be buried under a thread header of weight restrictions.

So, any perspective builder will bypass this thread, looking for one that covers their question on, say, the transition area (another common worry).


 

Hi Thomas!

Sorry I just saw I missed your answer. Meanwhile, I continued posting...I will rename the title, for it to include also the other thematics.

I still have to keep on doing research on RMHs, but from what I've read, batchbox is the better option for my house configuration. Single or double wall bell, I still don't know at the moment!

Cristobal Cristo wrote:Remy,

I would recommend to start the journey with estimating the heat loss of your house:

https://kalk.pro/en/heating/heat-loss-calculator/

I like this calculator, because it has a list of various masonry building materials that can be assigned any thickness.
It would help if you provided a plan for each floor.
With masonry interior walls, the placement of the heater is crucial.

Cristobal,

Just made the calculation with all the measures taken. We obtain this:


If needed, I can try to share the input data.

Please note that this summer I will insulate the ceiling and the floors, which should increase house thermic performance by 40%.

John C Daley wrote:As a Civil Engineer, I am confident 100mm steel columns will work.
Have a base plate at the bottom to spread the load around, say 300 x 300mm x 10mm thick.
Using 100mm diameter pipe will ensure the L/ R ratio will ensure the column is not too slender.
A steel or timber beam at the top will spread the protection across the floor.
I consider Cristobal's suggestion of 4 / 400 mm brick columns overkill

Thank you for your input John, much appreciated!

Cristobal, so I understand that a good proportion of houses in the rural US have thin wood framed interior walls? That would explain a lot of things! On my side, when the small wood stove is fully heating the living-room, you can get a comfy 70°F but when you pass the living room door, it can easily go down to 60°F just in the room next door so what you say makes complete sense.
And what you are telling on historical evolution of Italian rural houses is true: my house had individual wood stoves until I think, 2012, when the old owner installed the centralized wood stove system in the basement, that heated hot water both for tap hot water and for newly installed radiators that ensured house heating. But what you can see is that this system is not adapted to my humid conditions and mold tends to develop quite fast on walls if you don't respect strict window opening rituals everyday. So I really think that RMH will change the house, not only for temperature, but also for air quality and interior humidity.

As you were saying, the RMH positioning will be key. Dunno if it helps, I tried to sketch the house interior. Only the livable parts. Under living room, as I was saying, there is the ground floor with technical room + cheese laboratory. Over the second floor (over the 4 rooms), there is lost roof space that I will insulate this summer. Please note that it's not at scale! Some specifications:
- All rooms are separated by 40 cm concrete walls
- A key element of the house are the stairs. It is an open point of connexion between floor 1 and floor 2. So there is not clear separation between the 2 floors, which can allow hot air to go upstairs, provided there is air circulation.
- All rooms and livable spaces are closed by doors (that we can open but not all the time for privacy reasons)
- I did put, in the sketch, the RMH in the living room. Maybe a work is to be done on satellite thermal masses to allow heat to go on other parts of the house.


As soon as I have the possibility, I make the measurements for the heat loss calculator.

As an image is worth a thousand words, here are some photos to help understanding the house:

What you see when you enter the house. Right door gives access to living-room + kitchen; Left to room 1 and bathroom. And the stairs could give the possibility to hot air to go up.


Some views of the kitchen + living room. The RMH would replace the small wood stove, extending its heat mass towards right.



What you see when you arrive upstairs. This corridor is separated to each room by a door. So the heat would eventually arrive upstairs but then wouldn't enter in each individual room + bathroom 2.


Our actual wood boiler + 2000 liter how water tank for house heating:

Hi Cristobal,

Too bad I'm not there at the moment to take all measurements. I'll ask some people that are there now to help me on this. I keep you informed! Thank you for your help!!

Hi Cristobal,

Yes I'm in seismic zone. I take note for columns specs and measurements, thank you. Floor is reinforced already in technical room at ground level.

The 2 chimneys you see:
- On the left, is the chimney coming from the living room, where a conventional, small wood stove is connected to as of today. I will precisely use this one and replace the wood stove with the RMH there.
- On the right (small one): this one is the exhaust of a modern wood boiler located in the technical room, connected to a closed-circuit hydraulic heating system (2000L hot water tank, pump, expansion vessel, radiators in all rooms of the house) that ensure house heating + domestic hot water. The system is quite sophisticated and built with top quality materials, etc.,  but in the end, what is the result? 9 tons (I think approx 25 cords) of wood consumption/year for a 1500 sq. ft house in USDA zone 6a/b (poorly insulated I must admit), for a house that barely struggles to get to 63°F and that gets colder at night.

Hence my thoughts:
- 1. I need to insulate the house correctly, and the process has begun (but that will make another post in the appropriate section)
- 2. My so-called modern heating system, which surely pleases “conventional” plumbers, in fact generates no radiant heat and struggles to bring the house up to a stable temperature and dehumidify it (we get 80 inches of rain a year here). So RMH makes so much sense! But my house has constraints:
-> 2 floors
-> Quite small, separated spaces (5 bedroom, living room+ kitchen and 2 bathrooms).

What could be the weak points of RMH in my configuration? I noted:
- Difficulty heating upstairs and remote rooms
- How can I produce hot water? At present, my wood boiler system is energy-intensive but it works well. Electricity is expensive here, so switching to this for hot water once i have the RMH is not an option.

Browsing the forum, I think the ideal would be to opt, in my case, for a Batch RMH + satellite upstairs for heat, coupled with a water heating system on the RMH barrel, connected to my current circuit. I manage to find more information on RMH + hot water systems in the European forums. I was wondering whether in the USA hydraulic heating of rooms by radiators was a common thing? In fact, these systems can both produce domestic hot water and heat radiators in remote rooms from an RMH.
In Italy also, connecting a traditional wood stove to the radiator hydraulic system of the house is quite common.

Lots of questions, but one thing I'm sure of: my actual config is not energy efficient at all!

Hi guys and thank you for your ideas! This morning I checked the house configuration and yes, ground floord and first floor (where the RMH will be) match perfectly in terms of measures. so I think the easiest should be to build a few columns downstairs as suggested by John.

Edit: Sorry guys I'm a bit new to the forum, I have other questions related to a RMH-heated multi-floor house (not on weight stuff), can I ask here or it's better if I open a new topic? Thank you!

Hi Guys.

I'm just discovering the incredible potential of RMH by browsing this forum. Thank you for all the information you made available! I am planning to put one on my 140 sq meter 2 floors house.

Before digging into technical specs, I have a preliminary question about the weight that the RMH and its cob bench can exert on the concrete slab: my living room is on the first floor. However, a total RMH weight of 2-3 tons is often reported, for a floor area of ​​approximately 3m2 (32 sq ft). This is 850 kg/m2 (170 pounds per sqf), while the standard in Italy is to build concrete slabs that can theoretically support 250 kg/m2 (50 pounds per sqft).

While browsing the forum, I did not find any topic mentioning this constraint, except in the case of people who have a wooden floor, which is not my case.

Is it because this type of configuration (placing the RMH on the first floor) is automatically a bad idea and thus, the concern does not emerge in the questions, or is it because a concrete slab can in fact support much more than what is announced? In other words, is it a NO-GO for the RMH project in the configuration of my house or not?

I specify that I cannot put the RMH on the ground floor, because it is not a living room (it is a kind of basement with technical room, but not buried. Particular configuration probably due to our terraced land which pushed the previous owner to build the house in this way I guess). An image can help understanding:

Ground floor: tecnical room
First windows: living room + kitchen
Second floor: bedrooms

I know, there are some missing shutters. I'm in the process of rebuilding them


The entrance of the house is made laterally. On the left side, I guess the house is constructed on plain ground. On the right side, it is the living room.

Thank you all for your enlightenment!

All the best

Remy

PS: recently bought the farm. The entrance will evolve progressively, definitely too much concrete!