Wayback Machine: Solar Powered Refrigerator (in 1935!)
by Lloyd Alter, Toronto on 07.23.07
We keep looking for the perfect solar powered appliances, and keep finding them in Modern Mechanix. The Crosley Icyball was close; In 1935 California engineer Otto Mohr proposed combining an ammonia absorption cycle refrigeration unit (like the Icyball) with a spherical lens.
"Larger solar power units requiring up to four hours exposure can be used for heating or cooling entire homes, according to the inventor. A spherical lens catches the sun’s rays at all hours of the day. This lens gathers the rays, and changes the light into heat which is transferred to the refrigerating liquid, usually ammonia. The cooling operation is similar to that of ordinary gas refrigerators."
::Modern Mechanix
When I was growing up there was nothing to do but go to the small town library which had all kinds of books with ideas like these and many of the ideas were also perpetual motion machines so it goes to show that even if something gets published doesn't mean it would work.
The main issue I see with this design is the lense looks way to small. Maybe if it were 10 times that size it would capture enough sunlight to heat the outside coil.
I've seen solar powered icemakers for sale on the web. Here is at least one of them.
http://www.energy-concepts.com/isaac.html
If you can make ice then you can keep food cool or frozen.
I always wondered if this would work, especially for air conditioning...
I read about an ice-maker being used in a third-world country, using the ammonia adsorption process (what this fridge is using). The machinery was a little more complex and uses a larger solar collector than what this article shows, but the bottom line is it works. This was in Home Power magazine, and the ice is used to keep medicines cool.
I've seen designs for solar powered air conditioners for sale on the net. But there not exactly something everyone could easily put together.
A propane powered refrigerator for a Recreational Vehicle uses the same process, it heats the ammonia with a propane flame. thus running the cooling cycle. It would be possible to modify an RV refrigerator to run via solar power by relocating the heater location so that a solar lens could heat it. Though when the sun goes down.... the food heats up.
With sufficiently good insulation, you can get away with only cooling during the day. provided you don't open the fridge door more than necessary, The food stays cool. I have seen this on outback stations in australia which have diesel generators which only run for a few hours each night. Both refrigerators and freezers stay cool even when it's 40 degrees C or more, provided they are out of direct sunlight. Note that these are just normal refrigerators designed to run constantly!
Add some thermal mass to your fridge (put some rocks in it!) and you can open the door all you like, it will keep it's cool....
Yes, keeping the fridge door closed helps....Aerogel can also help to avoid heat transfer.
I was knowing that in olden days fridge used to run on candle 0r a small kerosene Lamp.
When I equired with my friends in Mechanical Engineering they said the sytem has been dicontinued due to very low efficiency. They were reluctant to consider the possiblity of using this "outdated technology " with solar heat instead of Lamp.
This concept may be suitable for the transportation industry!
Try this.. run two pipes from the low and high side. Put a check valve on one pipe allowing only one way flow and a throttle on the other.
Place a pneumatic motor driving the wheels on the low side before the throttle.
I may have the sides reversed on which side the pressure is on when the heat from the sun warms the device, but it would seem that the pressure from the sun's energy could be stored for driving the pneumatic motor easily in this manner. Improvements and refinements to the idea could be made, of course.