RE: Peltier or Compressor
I don’t know if I would convert an existing boat ice box to a Peltier 12 volt cooler or not, it would depend on my use of the boat and the energy needed to operate it. Before making a decision between a compressor driven and thermoelectric refrigeration it is best to consider the advantages and disadvantages of the Peltier units. Advantages of Peltier units: In a normal ice box conversion a thermoelectric unit has only one moving part the exterior fan. They do not use unfriendly refrigerants. They are maintenance free except for the fan. They can operate in any orientation and do no make noise or vibrate. They have the ability to heat and cool. Disadvantages of Peltier units Thermoelectric units can only reduce the temperature by 40 degrees F. below ambient. They appear to consume three times the energy to produce the same cooling effect of a compressor driven system. I did a web search to see if there was any actual data on thermoelectric units in boats. There are several write ups on home made systems but no actual performance information. This is an opinion taken from a web search of, Peltier 12 Volt Refrigeration. For a 5 cubic feet Ice box the Peltier (36 watts) shall run 24 hours /days. The inside temperature will be -40 deg. F from outside (ideal conditions) So under strong sun when the inside of the boat reach 90 f you will get not less than 50 f inside (based on a continuous duty) When the engine is running same temperature and even higher will be reach close to ice box. But the real killer is when you get the box to a suitable temperature. On a refrigeration system, you simply shut off the compressor and let the insulation keep the box cold for a while. With a Peltier cooler, you have a big heat sink on the inside connected to a big heat sink on the outside with only a fraction of an inch of silicon in between. When it is not making cold, the Peltier junction allows a lot of heat to pass through!
I don’t know if I would convert an existing boat ice box to a Peltier 12 volt cooler or not, it would depend on my use of the boat and the energy needed to operate it. Before making a decision between a compressor driven and thermoelectric refrigeration it is best to consider the advantages and disadvantages of the Peltier units. Advantages of Peltier units: In a normal ice box conversion a thermoelectric unit has only one moving part the exterior fan. They do not use unfriendly refrigerants. They are maintenance free except for the fan. They can operate in any orientation and do no make noise or vibrate. They have the ability to heat and cool. Disadvantages of Peltier units Thermoelectric units can only reduce the temperature by 40 degrees F. below ambient. They appear to consume three times the energy to produce the same cooling effect of a compressor driven system. I did a web search to see if there was any actual data on thermoelectric units in boats. There are several write ups on home made systems but no actual performance information. This is an opinion taken from a web search of, Peltier 12 Volt Refrigeration. For a 5 cubic feet Ice box the Peltier (36 watts) shall run 24 hours /days. The inside temperature will be -40 deg. F from outside (ideal conditions) So under strong sun when the inside of the boat reach 90 f you will get not less than 50 f inside (based on a continuous duty) When the engine is running same temperature and even higher will be reach close to ice box. But the real killer is when you get the box to a suitable temperature. On a refrigeration system, you simply shut off the compressor and let the insulation keep the box cold for a while. With a Peltier cooler, you have a big heat sink on the inside connected to a big heat sink on the outside with only a fraction of an inch of silicon in between. When it is not making cold, the Peltier junction allows a lot of heat to pass through!