posted 6 years ago
I'm envisioning ways to generate negative pressure for off grid tiny house or small cabin passive cooling applications such as geothermal and evaporative cooling.
I believe I would need to generate pretty significant negative pressure in order to draw enough air through any passive cooling system regardless of the type.
I've thought of generating air flow using passive solar energy like simple thermal chimneys, utilising the heat that collects in the attic space above the insulated ceiling, and heating air by using a solar collector such as a modified solar cooker design, but I have my doubts that passive solar alone can provide enough air flow for effective cooling.
Years ago an old timer told me how long ago people would use their fireplace to cool their homes by creating negative pressure to draw cooler outside air into the house by heating and displacing air in the chimney.
So that started me thinking ... has anyone ever tried using a rocket stove specically as an air pump?
I know that rocket stoves draw a lot of air. It would be interesting to see what kind of negative pressure could be tolerated behind the air intake without losing too much combustive efficiency.
Undoubtedly the rocket stove would be best located outside the structure with air being drawn from the space being cooled by ductwork. With a significant amount of air resistance resulting from all the ductwork used in the cooling system I wonder if a closed system could sustain combustion at a rate sufficient to produce the pressure required to move air through the cooling system to result in effective cooling.
The rocket stove wouldn't even necessarily need to be used continually. It could be used in conjunction with passive solar heating to rapidly get air circulating during system startup, and also on days when the temperature is still very warm but there isn't enough consistent sunshine to maximize passive solar energy.
What do you think?
Porch sitting is my favorite thing