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Home Forums General Discussion Home built fridges and freezers

This topic contains 0 replies, has 1 voice, and was last updated by  elnav 6 years ago.

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    elnav
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    Going off-grid always poses problems for getting enough electric power.

    There are several ways to achieve refrigeration without using electricity.

    Most of us are familiar with the ubiquitous RV fridge so common in trailers etc. Unfortunately they are more often than not too small for a decent quantity of food that must remain cold or frozen.

    If you hunt and bag a deer or bigger game none of the RV size are even close to being adequate.

    If you do not have enough solar panels, plus a battery and inverter to drive a regular home freezer how do you manage to keep things frozen?

    If your off grid homestead relies on a deep well pump you may already need to run a genset once a day to pump water. Boats have for many decades used engine driven holding plate freezers that remain cold 24 hours in between charging.

    If you are close to any major urban or industrial center you might be able to purchase ‘dry ice’ from an industrial gasses supplier such as Praxair

    A 5 pound chunk of dry ice will keep your fridge/freezer cold for many days. You can build an insulated box with plywood and Styrofoam insulation that will retain the cold for almost a week even in summer heat. For best results the box should be top loading and a smaller top opening than full box size works better.

    A more sophisticated method using carbon dioxide (dry ice) is a metered release of CO2 via a valve into the freezer box. Any supplier to a restaurant dispensing carbonated drinks can provide the required tanks of CO2. One bottle would last a month.

    The attraction of the CO2 approach being it does not require a motor genset and is silent.

    If your operation does require a motor or you have access to a water wheel you could resort to a mechanically driven compressor chilling holding pltes.

    Direct mechanical drives are more energy efficient thn first generating electrical power to power electrical compressors

    Almost any refrigeration shop can provide you with systems that use a. separate electrical motor. Substituting another source of rotary energy is not a big challenge.

    Home made designs

    When you get into building your own fridge /freezer box all sorts of innovative choices are available.

    For a combination unit you can make a partition that does not reach the top. The section holding the cold plates or is coldest from the CO2 is the freezer part. Because the partition is only part way up slightly warmer air spills over this partition into the other part. This is the fridge portion where milk and butter and drinks are stored without freezing solid.

    You may have to experiment to find the right place for the partition to suit your personal use. Maybe you want a large freezer or maybe the fridge part should be the largest.

    As long as you use quality plywood, good insulation foam boards and seal every seam this kind of design will stand up for years.

    Companies like Glacier Bay can provide special insulated panels with extremely high R factor insulation if you really need lots of insulation in thin panels. CO2 can flash freeze large quantities of game if that is required.

    The thing to remember is that chilling food is not restricted to factory made appliances.

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