Mike Nott

The winter part of my greenhouse is totally double glazed I need to maintain a temp of 15-20c as for keeping it warm I also have a large solar set up not enough to heat the greenhouse but enough to use a 100w water heater in the container that would be insulated

You didn't ask my opinion on this but I feel that running a biodigestor to harvest brown's gas makes sense when you have more than three people eating communal meals and or animals. To create a source of feedstock just so you can run a biodigestor seems to me to be unnecessary work and investment: but I'm lazy like that.

It’s just an idea to save money on buying propane every year and I don’t mind working at it

I don’t have a cow unfortunately and was hoping to make the gas year round and possibly store it I worked out that a ibc wouldn’t be big enough to run it directly I have seen on some sites that they compress it into old propane bottles is this possible and practical?

Scrubbing the gas coming from the digester and thank you for the response

Hi all I have a 4215bn controller and currently 2x260w Canadian solar panels what is the absolute max panels the controller can take as I’m struggling to run a 300w water heater for my greenhouse don’t mind disconnecting the extra in summer if need be just need the boost in winter
thanks all

Hi all been looking for some time on ways to heat my greenhouse for free. I’ve looked at various ways from rocket mass heaters compost even hydrogen generators but these either don’t produce enough heat take to much power (only have a small solar set up) or require to much attention (work commitments).
So I’ve been looking at bio gas generators and hopefully the brilliant knowledge here will be able to help me. I’m looking at making one from a ibc to run my current propane heater so my questions are
1, can I run my propane heater on the gas produced.
2, will a ibc produce enough gas to run it
3, if no to no2 how much storage would be needed
4, would I need to scrub the gas if it’s only to be used in a greenhouse.

I’ve provided pictures of the heater and it’s specs and it’s only used for 3 months (feb-April) I’m based in the uk and if it helps last year I went through 2x19kg bottles of propane with the heater set at the temp and automatically fires up when needed
Thanks all and any advice and comments would be great

Hi all me again and I’m still trying to get my rmh right it’s only a small metal one at the moment but once I get it right I will build a more permanent one
So my question my air inlet is 100x100 mm2 and the rmh does get hot around 400c at the top my flue is currently a uninsulated 125mm flue liner and although it gets hot ish when I make it smoke it just seems to flow out as apposed to quickly coming out do you think the flue pipe is to large thanks all

While I’m here another question before I make some mods to it tomorrow what should the gap be between the riser and the top of the bottle please the riser is 100mm2
Many thanks

Glenn Herbert wrote:Since the water should never be in contact with the combustion core (so as not to steal heat from the fire and cool it and make it less efficient), the same setup I suggested before would work with an insulated firebrick core.

You didn't mention before that you plan to use exclusively woodchips as fuel. This makes your feed tube sensible, and also changes the parameters for how your firebox should be designed. Other people on Permies have experimented with woodchip feeders, and you might benefit from researching their efforts. An exposed metal feed which would tend to shed excess heat easily may be good, while a firebrick burn tunnel would let the heat build up for efficient combustion. I think you would want a smaller air supply opening. Reading about batch box primary and secondary air supply at batchrocket.eu should help you figure out a good system, even though it is geared to burning solid wood.

Many thanks for the link to batchrocket although very long the amount of detail and information is a eye opener and has given me ideas to try on my prototype especially with making the ventury as well as a secondary air intake
But the whole project still depends on heating water to run 4-5 radiators

Jeremy Baker wrote:I’ll second what Glenn mentions: try reducing the air intake. I made a similar stove. I placed a piece of sheet metal with a 2” hole in front of the air intake on mine and it helped.
Maybe insulate the exhaust flue??
How are the wood chips working.?

As long as they are dry they work very well just as good as pellets at the moment I’m drying them in the oven but obviously that’s not practical so I am currently looking at ways to dry them (solar dehydration, air dry in the summer with a black tarp on in the greenhouse) but hopefully going to try and use the rmh to dry them maybe forced air or as I’m hopefully going to be using a gravity fed hopper system to feed it the feed tube when full takes about 30mins to burn so I’m going to try and use a radiator in the hopper system to do the final drying as they get fed into the rmh