Step 1: Burner
Step 2: Convector
Step 3: The Radiator
Cautions this is a combustion heater using un sreened naked flames normal precautions to ventilation explosive atmospheres location etc should be observed, both pots get too hot to touch so you will need an oven glove when changing the tea lights. Also because of this place it away from flammable materials on a non flammable surface as the roasting tray got pretty hot too
Step 4: Field Trial
My parents have an old touring caravan they used as a storage shed which is nominaly frost free and convieniently my father keeps a max/min thermometers both inside and outside of it.
I started my experiment just before 7pm (3 hours after sun set) by lighting a tea light in a holder in the house so I could observe how much fuel was left.
I then went out to the caravan and set up the heater on a steel tool box roughly in the middle of the van zeroed the recorder floats in the termometer the temperature was +6c lit the tea lights and closed up the van. I checked and zeroed the out side thermometer it was reading +5c.
2 hours later the tea light in the house was still burning and whilst all the wax was molten there was still about 3mm depth left note this light was the first lit and is from the same batch as the ones being used in the heater. I went to check on the heater the outside temperature was still +5c. Inside the van the temperature had risen to +9c its maximum according to the recorder floats. How ever one of the tea lights powering the heater had already gone out the other three were also closer to going out than the one in the house molten wax only just covering the wick support.
This trial supports my earlier observation that this heater whilst not fantastic could well be capable of keeping a green house frost free over night or the plumbing in an ouside toilet from freezing.
I clearly need to repeat this test with just 4 tea lights spread around the van to see if the convector radiator arangment of flower pots is a more effficient means of transmiting the energy from the flames to the air than just burning the tea lights alone.
The internal dimensions of the van are 4.3m,1.9m,1.9m, that is 15.52 cubic metres.
As yet un written up experiments on the energy out put of these tea lights suggests over 90% of the released energy from this heater has been lost