[redmower3]

A most interesting article and an excuse to drink beer

This would be an good project to provide some passive solar heat for a building (have a google of 'trombe wall') but for a greenhouse?

This device works in exactly the same way as a greenhouse, so will only provide heat when the greenhouse gets heat anyway. I would hazard a guess that without any controls as soon as the sun went down the thing would work in reverse ie removing heat from the greenhouse.

A further problem would be siting. In front of the greenhouse would be self defeating (unless your greenhouse was built on a dwarf wall) and above it could not work on convection alone.

A partial solution might be to adapt the heater to hold objects with a high thermal mass, such as bricks. (painted black of course!)  These would heat up during the day and 'release' their heat to the greenhouse as the sun goes down. (A bit like household night-storage radiators.

Just a thought

Mick