Hi
I'm in the process of building a fridge / freezer using the reverse cycle Stirling engine from a Coleman Stirling Cooler. According to the manufacturer, this unit can deep freeze a well insulated box up to 200 litres. We have six inches of insulation in a much smaller compartment.
Unlike the Coleman Cooler which uses termosyphon CO2, heat transfer will be via large heatsinks inside the box bolted to the cold side of the Stirling engine. Since this will be a deep freeze with a thermostat controlled fan bringing cold air into the fridge compartment, there will be a build up of frost on the heat sinks.
I need one or two 12V strip heaters to heat the heatsinks to melt away the frost. I'm thinking two strip heaters around 20 - 30 W should do it. They must be flat strip heaters without fins which can be bolted direct to the heat sinks. The object is to heat the heat sinks quickly while heating the freezer compartment as little as possible. Once average run time etc. has been figured out, the strip heaters will be run on a timer which will switch the strip heaters on once per night while switching the fridge off, then turn the fridge back on once the frost has been removed.
Any ideas on a source for the 12V strip heaters would be most welcome. The ones I have found online are all 120 or 240V.
Owen, Donna and Sparky
Yacht Magic
St Maarten
Netherlands Antilles