Refrigerators Help
Refrigerators that are sold in department stores are generally not efficient enough to be powered by solar electricity. Improvements have been made in the last few years but they still use a lot of power. A refrigerator usually runs about half to three quarters of the time depending on the temperature of the room that it's in. 16 hours a day is a good guess. Super efficient refrigerators run much less due to higher insulation, more efficient motors and greater care in manufacturing. They will almost always pay for themselves in PV powered homes even though they cost $1600 to $3000. Propane refrigerators are also an option, and in fact may be a good choice if you have other appliances running on propane. At a dollar a gallon for propane it takes about ten years for a super efficient refrigerator and the panels and batteries to run it to equal the cost of a propane refrigerator and the propane to run it. This time of payback, of course, goes down as propane goes up. Try the cost of a system to run a regular AC refrigerator in the Virtual Solar Engineer and you will find that if you use 350 watts 16 hours a day in a good location with 5 days of storage the cost of the PV system will be over $10,000. Now try it with an efficient DC refrigerator using 65 watts of power for the same amount of time and same location and days of storage - you will find that it only costs about $2400 to run this refrigerator.
An efficient refrigerator pays for itself immediately when you consider the cost of the PV system that powers it. Always plan on buying an efficient refrigerator for use with PV systems or plan on using propane models.