Mark Roelofs

I was also thinking "why is the slope of the house opposite of the hill". Entry of Sun sounds like a good reason, but for the water it is not handy. Gutters sounds nice, but what happens in the case of a 10 or 100 year event? At this moment we have been in a 2 month long storm with a lot of water. The stone walls and roof have been saturated with water for at least a month and water is appearing in many unwanted places. You never know when such an event strikes, because this is our second winter here. I would thing very hard about this for your house. Your water system should be design for the 10 or 100 year event, else your entire house might be destroyed. In this case, with the questions about foundation, maybe making the house off the floor with wooden beams sitting on (very) big stones. Maybe with enough height of the house, you could even plant something like vetiver underneath the house to hold everything together when there is water racing of the slope.

What would be the reason to connect the roof to the slope? Collecting all the water of the roof would make it more accesible for storage and use.

I have made a more detailed layout of the core. I'm shooting for 35cm, 70cm and 105cm for the woodfeed, burn tunnel and riser. The layout I have now is pretty close (37cm, 70cm, 114cm)

The surface area of the burn tunnel is a bit less than needed. The height is 15cm, the width 18cm, which is 270cm2 instead of 314cm2 for the 8" system. Would this be a big problem? I have ordered the book of the Wisner's (assuming they will discus this topic), but Amazon says it is only going to be here in May...... i do not want to wait with the design untill then. I could add another layer of bricks at the bottom, but that would make the dimensions of the whole core a bit bigger, which would become tricky with the space I have inside the bell.

The measurements of the bell are 165x155x50cms. The purple areas I want to insulate to reduce heat transfer. Heat going out the top will not really warm the room and the heat against the outside wall will just heat up a very thick stone wall (~infinite heat sink). The ISA of the bell will be ~5,4m2 (not counting the insulated areas) which is a bit over the recommend ISA for a 8" J-tube (5,3m2). The ISA might change a little depending on the thickness of the brick I will be able to find here. Would adding a column of bricks for extra mass inside the bell change anything about the ISA calculation? Since the the column would not radiate heat outside of the bell.

I have also added a clean out in the left lower corner, right underneath the exhaust. Although I have read many times on these forums that a clean-out is not really needed with a bell system, because blockage is very unlikely. Eventhough ash will build up somewhere in the system, so over many many years there might be a big layer of ash on the bottom of the bell right?

I'm thinking about also adding a 45degree downwards T just above the bell on the exhaust pipe for chimney sweeping. But i feel that that should never be needed in this type of system, so i'm not sure i want to spend money on it.

Anybody has any thougths on overall weight? With the regular bricks i'm finding here the weight of the bell is about 600 kg. The core about 100 kgs. The weight would be a thermal mass, but the prolonged heat would be more because of the hot air in the bell. Are there any general guidelines about this? Or is the weight not really import, but the material (and how fast it radiates the heat) is?

Any inputs are welcome

Hello rocket people,

After spending 2 winters (in our new house) burning a lot of wood and still not being very warm i have decided to put the rocket mass heater project higher on the prio list. So i'm working on a design at the moment with the intention to build it this summer.

I have an open living room with high sloped ceilings and a loft that takes all the heat. At the moment we have 2 ceiling fans blowing the warm air down. Total volume of the salon is about 150m3, with heighest point of the ceiling almost 5m. The heater will be placed in this living room, but the bell will be attached to a divinding wall of the kitchen.  My plan is to heat both the living room and the kitchen. The kitchen has a way lower ceiling (it is below the loft), so that helps. Ideally the kitchen would get so toasty warm that we can open the door to our bedroom and bathroom and also heat those a little.

In the picture you have the layout (not the entire living room or kitchen depicted in the floor surface, i just drew up the corner of interest), with the heater in the middle of the livingroom, the wooden frame is the opening to the kitchen, with above the black beam which is where the opening of the loft starts (the ceiling fans are in front of this opening).  The big brick column is not the end of the living room, but it is the end of the seating area. Before the brick column is a desk/workspace. I have chimey on the roof which is about 1,5m height of bricks and 2,5 meters of black steel pipe. I want to have the exit pipe of the bell more or less straight underneath it giving me about 9m of straight pipe. We live in a mountain house with 80cm thick stone walls, so we have quite some mass to warm up

2nd picture is the current setup. We have a huge open fire place that will only warm you because of all the tree trunks you have to haul into the house. So we put a simple stove/fire box in front of it. The entire open fire place including the chimey up will be torn down. We do not really like it, and it serves very little purpose and takes up a lot of space. Somewhere in that chimey is the tubing, which is 25cm diameter.

After some iterations I think a 8" J tube with a bell is easiest and gives us freedom to arrange the seating area with sofas etc, instead of having fixed benches. Although a batchbox looks nice as well, i would like to start with a more easy build. Also I like that the J tube has a higher woodfeed, so my 1 year old is less tempted to have a look at/meddle with the fire.

I will document my design and progress here.

I have some questions so far, if anybody would be so kind to chime in, that would be much appreciated:
- Having the cold air exhaust and heat riser close together: Would that cause any issues regarding draft? Only thing that I can think of is that the exit would be warmed immediatly upon firing and therefore draft would increase.
- I heard Glenn talk about his system which has already a very strong draft with a 8" system and a 6" exit. I'm thinking that in my case, because of my straight chimey, I might also have good draft with a 6" pipe. I have space for a 8" also, so reducing would only save me some money. I wouldn't want to get a too strong draft either, that is why i'm thinking of 6".  
- I'm taking the ISA of a 6" batch rocket system, I believe Glenn's build had the same and that worked nicely. Does anybody have any experience with 8" J tubes and corresponding ISA? I could not find a lot of details for this in the forums.
- With the current measurement of my bell the ISA is a bit to large: 5.77m2. I would like to insulate the bell at least on one side (which is an outer wall of 80cm stone, that feels a bit like an infinite heat sink), and maybe even on the top. Could I disregard these insulated surfaces in the calculation of the ISA, because they will radiate a lot less heat?

Thanks so far for reading. I'm really looking forward to this build, I have read about the these heaters and everything makes sense on paper. So i'm really curious to see what they can do, they sound too good to be true

Nancy Reading wrote:Like other people with a suitable climate I usually get volunteer potatoes popping up. I don't tend to encourage them, since the surprise appearance isn't always convenient for me. It is easy enough to overwinter the tubers indoors... I think if you do leave them in the ground then having a good polyculture is a reasonable defence against pest and diseases.

Yes, my plan is to let the potatoes grow during spring/summer. Then after harvest plant a winter covercrop. I do not have very harsch winters, and I can grow cold loving plants for quite some months after the potatoe harvest. Then maybe every year add some manure and plant some perrenials around the plots to see if i can have some sort of barrier or the potatoes to keep the potatoe plot the same size every year.

Anybody has an update about their experiments? I have seen my forgotten last year potatoes pop up this year. Soon i will harvest, but i already had a sneak peek and the potatoes looked pretty good. So i will start intentionally leaving potatoes in a plot as well starting after next years planting.

Just wondering whether somebody has some years of experience to share what to think about/look out for =)

Hi John,

Not sure if your questions are for me or for the thread owner, but i'll answer for me anyway.

I bought this house 1,5 years ago and everything is already in place regarding water. My collection point is very shallow, especially in the dry summer when i need the water. My plan is not to capture the silt and extract water from it. I'm capturing a lot a silt now because of the shallow collection point, and i want to have less silt in my water. Now my filters are full of silt very quickly, especially when i'm irrigating. So firstly i'm thinking about reducing the amount of silt in my collection point, although I think there is not much to do there...

I was watching the videos in the thread and i saw the 3 components of the water system: collection, silttrap, storage. I was just wandering what the function of the gravel is in the collection part of the system, and whether this would not fill up with silt and other debris over time.

My silt trap at the moment is my storage tank, but this is not very pratical. Also my irrigation line is connected before the tank (to have pressure at the upper part of my land), but it is very dirty. My storage tank also gets very dirty now.

I'm thinking of making a silt trap in between the collection and storage, because there is none now.

I'm also working on improving my water catchment system for my house. At the moment i'm hooked up to a river (that is going down the mountain), but in summer the flow is pretty low. (I live in the south of Spain) So at the moment i'm gathering a lot of silt in my tubes. More down below (~90m) from my catchment i have a big tank that settles all the silt, but i would prefer to not catch it in the first place.

I'm seeing 2 videos here about catchment systems that are holding the water and are filled with gravel. A tube is placed at a certain height (to avoid catching the silt im guessing) the gather the water. But to me, this catchment filled with gravel would, over time, completely fill with silt right? I feel that i'm missing something about this design. Can somebody explain this?