Living Off Grid Part 5
Refrigeration is a necessity for most people who wish to live off grid. Unfortunately, refrigerators often use more energy than any other appliance since they run 24 hours a day, 7 days a week.
The energy source of the refrigerator is key, if a refrigerator is powered by only by electricity then, it will always be a drain on the power system, whether it be solar or gas generator.
Compressor based refrigeration needs a motor to drive the compressor, often this motor is powered by electricity or an internal combustion engine. Though it may be possible to drive the compressor using a clutch system connected to a steam turbine from a concentrated solar steam system. It may also be possible to drive the compressor using an electric motor, also on a clutch.
I was reading about absorption refrigeration:
https://en.wikipedia.org/wiki/Absorption_refrigerator
It is interesting to note that even Albert Einstein helped design an absorption refrigerator:
https://en.wikipedia.org/wiki/Einstein_refrigerator
Apparently there is an absorption refrigerator design that does not require any form of pumping or cool water (Baltzar von Platen and Carl Munters):
https://en.wikipedia.org/wiki/Absorption_refrigerator#History
This is the main design used in absorption refrigerators to this very day.
Absorption refrigeration is used extensively in modern day Recreational Vehicle applications:
https://en.wikipedia.org/wiki/RV_Fridge
If we look at the design of a more modern RV refrigerator:
https://en.wikipedia.org/wiki/Absorption_refrigerator#Single_pressure_absorption_refrigeration
We can see that only one electric heat source is needed.
https://en.wikipedia.org/wiki/Absorption_refrigerator#/media/File:Absorption_fridge.jpg
(Look at the device indicated by the number 7)
If instead of using electricity to heat the refrigerant we place the refrigerant container at the focus of a parabolic mirror or Fresnel lens, then we can provide refrigeration without using electricity. Depending on the required temperature, it may not be necessary to use a parabolic mirror or Fresnel lens, a well insulated solar oven may suffice.
It may still be a good idea to keep an electric heating element in the refrigerant so that refrigerator could keep cold at night.
It may also be possible to build a larger absorption refrigeration system to function as air conditioning without using electricity. In fact the wikipedia absorption refrigeration article mentioned a very useful application of Steam Power.
1. Steam could be used to drive a turbine to produce electricity.
2. Afterwards the steam/water mixture could be used to heat water.
3. Finally the steam/water mixture could be used in an absorption refrigerator.
This 3 stage use of steam/water would be perfect for Concentrated Solar Steam Power applications.
The substances used in absorption refrigeration are much simpler from a chemical standpoint when compared to compression type refrigeration. The only constituents are ammonia, hydrogen gas, and water. These are relatively easy to produce and/or obtain, especially in an off grid situation. Compression based refrigerators use Chlorofluorocarbons or Hydrofluorocarbons as a refrigerant.
Absorption refrigeration, in essence, allows people to keep foods cold and/or lower the ambient temperature of a room without having to use electricity. This may mean not having to pay money! (At least during the day, though with enough stored heat, you won't need electric power at night either)
The energy source of the refrigerator is key, if a refrigerator is powered by only by electricity then, it will always be a drain on the power system, whether it be solar or gas generator.
Compressor based refrigeration needs a motor to drive the compressor, often this motor is powered by electricity or an internal combustion engine. Though it may be possible to drive the compressor using a clutch system connected to a steam turbine from a concentrated solar steam system. It may also be possible to drive the compressor using an electric motor, also on a clutch.
I was reading about absorption refrigeration:
https://en.wikipedia.org/wiki/Absorption_refrigerator
It is interesting to note that even Albert Einstein helped design an absorption refrigerator:
https://en.wikipedia.org/wiki/Einstein_refrigerator
Apparently there is an absorption refrigerator design that does not require any form of pumping or cool water (Baltzar von Platen and Carl Munters):
https://en.wikipedia.org/wiki/Absorption_refrigerator#History
This is the main design used in absorption refrigerators to this very day.
Absorption refrigeration is used extensively in modern day Recreational Vehicle applications:
https://en.wikipedia.org/wiki/RV_Fridge
If we look at the design of a more modern RV refrigerator:
https://en.wikipedia.org/wiki/Absorption_refrigerator#Single_pressure_absorption_refrigeration
We can see that only one electric heat source is needed.
https://en.wikipedia.org/wiki/Absorption_refrigerator#/media/File:Absorption_fridge.jpg
(Look at the device indicated by the number 7)
If instead of using electricity to heat the refrigerant we place the refrigerant container at the focus of a parabolic mirror or Fresnel lens, then we can provide refrigeration without using electricity. Depending on the required temperature, it may not be necessary to use a parabolic mirror or Fresnel lens, a well insulated solar oven may suffice.
It may still be a good idea to keep an electric heating element in the refrigerant so that refrigerator could keep cold at night.
It may also be possible to build a larger absorption refrigeration system to function as air conditioning without using electricity. In fact the wikipedia absorption refrigeration article mentioned a very useful application of Steam Power.
1. Steam could be used to drive a turbine to produce electricity.
2. Afterwards the steam/water mixture could be used to heat water.
3. Finally the steam/water mixture could be used in an absorption refrigerator.
This 3 stage use of steam/water would be perfect for Concentrated Solar Steam Power applications.
The substances used in absorption refrigeration are much simpler from a chemical standpoint when compared to compression type refrigeration. The only constituents are ammonia, hydrogen gas, and water. These are relatively easy to produce and/or obtain, especially in an off grid situation. Compression based refrigerators use Chlorofluorocarbons or Hydrofluorocarbons as a refrigerant.
Absorption refrigeration, in essence, allows people to keep foods cold and/or lower the ambient temperature of a room without having to use electricity. This may mean not having to pay money! (At least during the day, though with enough stored heat, you won't need electric power at night either)
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