So those are the good points of the RMH, in my opinion. The next step is to define some goals. What would I want my ideal wood heater to do? In reaching those goals some compromises may need to be made, but if we never consider what we might want as a goal up front we do not have a hope of ever achieving that. So I thought I would start this thread and invite some comments. i.e. Have I left anything out? And which commercially available heaters do most of what I want? No sense in reinventing the wheel. Note that this is an "ideal", of course we will never achieve this but it's a target. So here is my list:
shared by the whole houses air handling equipment, I believe that you have a very complete list of what an I.W.S. should be/do !
So my comments should be 'mostly' judged as a prequel to your I.W.S. list !
I often speak about the rocket stove as having a 'built-in heat pump' effect. One of the things it does very well is to move heat energy from its internal
combustion chamber to the Thermal Bench! This can be located at some distance removed, with one likely report of Thermal Benches located on two
However, we need to consider using air handling/ heat exchanger equipment to carry much of the heating and cooling loads at multiple locations and/or
consider using (a minimum number of) additional Rocket Stoves the way multiple Masonry Stoves (with a single central chimney stack) heat individual
rooms in many Northern European Country Houses.
We also need to consider heat exchangers in their role in dealing with the need for 'make up air' created by air used-up by the fire burning in the Rocket
In the stuffy, over heated tropical bird houses we presently call homes, water vapor moves from the insides of the house through holes and breaks in the
vapor barriers where they find a dew point within the insulation in the exterior walls and condense, and freeze, removing the insulation value within
Two things/techniques can improve on this all to common insulation failure condition. A properly balanced air to air heat exchanger replaces air lost to com
bustion and replaces a certain percentage of the houses internal air, warming/conditioning it on the way from out to in ! Two, we can allow for a certain low
percentage of the houses make-up air to come from outside through these same all too common breaks in the vapor barriers removing the trapped water
vapors restoring most of the insulation value the home owner thinks he has, this to is called - 'lets not fool ourselves'!
When we consider the need for make-up air we must also remember that the heat energy units found in the living space air that goes 'up the chimney' does
not in fact go 'up the chimney' but is added to our heat energy stored in our thermal battery for latter use back in the living space. This and the energy saved
as noted in the paragraph above need not be counted in the heat load of the building as they are not in effect part of the 'heat load' !
Heat exchangers can also be coupled to an 'internal to the house' job, pre air drying the wood to be burned next/soon!
Stratification of the air near the ceiling must be handled with additional equipment though this could be as simple as a ceiling fan ! A layer of mere aluminum foil
with a proper air gap can reflect back over 85 % of radiated heat that otherwise would be lost through the ceilings, and into roof spaces !
For the good of the Craft ! Be safe, keep warm ! PYRO Logical Big AL - As always, your questions and comments are solicited and Welcome ! A. L.
Rion Mather wrote:I'm on board with hybrids. I'm obviously no expert but there are big differences between rocket stoves and Rocket Mass Heaters, including the vertical and horizontal feeders/burn chambers. As far as masonry stoves go...there are numerous styles to choose from. You should check out youtube. I have found it to be the best place to learn about stoves, in general.
I have done a lot of googling on the subject. I have looked a lot at what Peter Berg has done on donkey's proboard's, after first coming here. I've seen his prefabricated J tubes - the Dragon Burner. And the batch box ideas. I was motivated to learn Sketchup after looking at the work he has done. I've looked at masonry heaters. I've read a lot of what Erica and Ernie have written. I've also looked a lot on youtube. I like this heater in particular. I've built my own little rocket mass heater J section. Actually two of them. And I spent two whole weeks concentrating on understanding how the RMH and wood stoves in general operate well enough to start doing some spreadsheet simulation work. At that point, I realized that one thing was being glossed over, and that was the whole house heating capability of a RMH, which is only possible with extensive insulation. So much insulation that it is probably half way to being a Passivhaus, which is an excellent concept that really works, but obviously not something you can do unless you build your home from scratch.
Now, I am not going to say that the RMH doesn't serve a purpose and for those it works for, I'm sure it works very well. However, I've been thinking about the community that uses the CWS, why they use it and what do they want. One thing that motivates me is providing a solution for those people who will not accept less heat output than a CWS can provide, but who will only use it in a way that pollutes the air, gives me and my family increased emphysema and lung cancer risk, and cause/contribute to the asthma my children suffer from. I know that there are myriad CWS out there produced by different companies. Many are claimed to be advanced. I'm sure that even most of them aren't all that advanced, and if they were critically analysed against my matrix of desirable qualities, most would fall down somewhere but you would not know until you seriously trialled them. That's in part why I'm starting this thread - to see if anything is out there that is revolutionary and ticks all the boxes before I go wasting my time reinventing the wheel. If there was something that did the job as well as my Miele* vacuum cleaner cleans the floor including removing all allergens from the exhaust stream, I'd want to know about it. I wouldn't want to go into business competing with something near perfection.
Another thing I'd like to know is if something that ticked as many boxes as possible would sell well. Would people buy them or would the idea get lost among all the marketing BS that is out there from other companies?
*I'm a huge fan of Miele and their design principles. While the appliances they sell are not unattractive, they have a very intelligent approach to thinking up everything you really need in an appliance and making sure that it works properly. So it is not really surprising that this sort of thing is what I would want from a wood heater. The Passivhaus concept is hands down better than any wood heater because it obviates the need for space heating. However, a well designed wood heater would not go astray in the world.
One thing I forgot that you reminded me of was the pump effect that the riser and barrel have in an RMH, using the heat from the fire to drive the exhaust but not requiring heat to be exhausted in the process. i.e rather than the chimney drafting, the riser/barrel combo seem to create a pump.
I don't see why this sort of thing needs all the electronic monitoring to do 90% of the job that something similar could do passively if designed correctly, or why it would need to cost that much. Perhaps that's worth designing. Have the water storage, the firebox, the secondary burn and the heat exchanger all in the one unit. Use 2m or so of vertical space that is otherwise wasted above the footprint of the CWS. No need to route the heat around the house, the large surface area should radiate the heat and convect the heat effectively into the room (and surrounding rooms), much like a CWS. The "only" issue is reinforcing the floor to deal with 2 tonnes of water. This could be done in a basement though, for similar effect perhaps. The heat rises and warms the house.
The other idea is of course to design something similar to the CWS that will not need a thermal mass.