Re: DetroiTug's Tug is going together
Posted: Sun Oct 25, 2020 12:42 am
I've been the route with various portable fridge systems. The best two are absorption cycle heated by propane and the compressor system that Bart suggests.
I used an ordinary RV propane fridge in Baja for several years and it just ran with zero issues. Two cubic feet and used a 20lb. bottle maybe every three weeks.
My present 25' I.C. powered boat has a 12v compressor. You have to get your head down next to it to tell if it is running. Pulls around 4 amps.
To my knowledge no one has heated an absorption cycle with another source of energy other than a flame or an electric heater with one exception. I saw a small RV propane fridge at a goat ranch in the Baja mountains that had a solar collector (Old satellite TV dish with aluminum foil!) that was arranged to focus on the hot end of the absorption tower. The whole fridge was on an old lazy susan turntable and was moved to follow the sun by hand. A couple of gallon jugs of water frozen to hold the cold overnight.
Using steam to heat one end and cold water on the other would probably work until you shut down the boiler for the night. Generating electricity to run either system would be deranged. Incredibly low thermal efficiency.
You could drive an automotive freon compressor from your main engine and have a holding plate in the fridge for overnight storage. Takes a fair bit of power though. If the box is well insulated you could run the compressor for two hours a day and get by overnight. Mostly a freezer operation.
Propane RV fridge powered by solar cells would be O.K. except for needing a battery at night. A compressor unit needs a battery too. No easy answer except getting by with warm beer. An English thing I'm told (grin).
I used an ordinary RV propane fridge in Baja for several years and it just ran with zero issues. Two cubic feet and used a 20lb. bottle maybe every three weeks.
My present 25' I.C. powered boat has a 12v compressor. You have to get your head down next to it to tell if it is running. Pulls around 4 amps.
To my knowledge no one has heated an absorption cycle with another source of energy other than a flame or an electric heater with one exception. I saw a small RV propane fridge at a goat ranch in the Baja mountains that had a solar collector (Old satellite TV dish with aluminum foil!) that was arranged to focus on the hot end of the absorption tower. The whole fridge was on an old lazy susan turntable and was moved to follow the sun by hand. A couple of gallon jugs of water frozen to hold the cold overnight.
Using steam to heat one end and cold water on the other would probably work until you shut down the boiler for the night. Generating electricity to run either system would be deranged. Incredibly low thermal efficiency.
You could drive an automotive freon compressor from your main engine and have a holding plate in the fridge for overnight storage. Takes a fair bit of power though. If the box is well insulated you could run the compressor for two hours a day and get by overnight. Mostly a freezer operation.
Propane RV fridge powered by solar cells would be O.K. except for needing a battery at night. A compressor unit needs a battery too. No easy answer except getting by with warm beer. An English thing I'm told (grin).