Ovens and indoor air quality
The PM2.5 air quality index (AQI) is a big deal where I live (China). The outdoor air is monitored in all major cities and activities are often planned around the current AQI. It's a lot easier to control indoor air quality than outdoor air quality. You can reduce indoor PM2.5 by 95% with a good HEPA-filter air purifier. For these reasons, I'm reluctant to introduce anything indoors that may compromise indoor AQI. Sometimes the AQI from people smoking indoors is worse than the AQI outdoors.
Is it possible to have completely clean air with a wood-fired oven indoors? I know it depends on the design of the flue and chimney, but even with the best design won't some particulate pollution enter the room?
I've also been looking at propane-fueled gas ovens. These also require ventilation. I've seen these in restaurants without a chimney. Instead, there is a wide PVC pipe that runs out the side of the building horizontally. Propane burns a lot cleaner than wood, but it will produce carbon monoxide and some soot.
Electric ovens are the cleanest option but they cost the most to operate. Propane is very cheap and may cost only 1/3 of what an equivalent electric oven costs to operate. Wood is likely the cheapest, although it will have to be hauled in from nearby villages.
and also take in oxygen in order to work efficiently. Electric ovens do not require intake but there does have to be some type of exhaust to relieve pressure build up. I don't think there will be such a thing as a completely clean combustion oven. We have a wood burning fireplace in our home with a lengthy chimney and efficient draw but one still gets the "fireplace odor" (which is slightly pleasant) when using it. Any oven having a door will see some back release into the room when the door is opened. The only way to minimize this is to have an open hearth oven but this would be less efficient in terms of fuel use. Wood burning results in particulate matter (which is why a chimney has to be cleaned periodically otherwise you risk a chimney fire at some point because of build up of volatile compounds).
If the propane is of high quality there should be very little soot produced and it is likely the best choice from a price/performance perspective. I don't know what types of wood you can source but hardwoods are always recommended for traditional fireplaces as they don't lead to as much build up in the chimney. New homes in our area of the US are regularly installing gas burning fireplaces with a horizontal vent pipe to the outside rather than a chimney. The building code in our area requires these be metal. I would be concerned about the temperature stability of PVC since ovens will likely produce much hotter exhaust than a fireplace. You also need to have adequate airflow in the kitchen so that combustion can suck in air and properly exhaust it. Last thing you want (and it will be the last thing!) is carbon monoxide buildup.
Hope this helps.
Why is that gas fires only need a horizontal vent pipe rather than a chimney? It will certainly be easier to install than a 4-story chimney for a wood-fired oven.
Another option we are considering is building a brick oven on the back of a three-wheel vehicle. Three-wheel carts with electric, gas, or pedal-power are common here. I'm not sure if they will bear the amount of weight or if they will still be movable with a brick oven on-board.
dictate the height of chimneys and the types of approved ventilation for furnaces and other things. I don't know what the situation is in China but in the US there are restrictions on the types of material and minimum heights.
There is not much enforcement of these types of regulations. Until recently we regularly saw street cleaners burning trash on the street in the early morning. I hope our kitchen can exceed requirements and use the most efficient energy sources. I suppose wood is the most efficient way to heat an oven. I was looking at rocket stove designs as a way to burn wood cleanly.