The absorption refrigerator was invented in 1859 and has been improved upon greatly since, with Einstein himself deigning to participate in a patent in the 1920’s, long after his fame was assured. In Kenya in 1969 we had no running water, no electricity, and no indoor Johnny. But we did have a pressure lamp for light and an absorption refrigerator, both powered by kerosene. The wick driving the full size refrigerator was about 1¼” in diameter and it burned continuously 24 hours a day. We could make ice cubes and keep our food cold. With a Primus camping stove to heat our bath water, we were all set.
Now I am using a frost free refrigerator that is powered by electricity generated far away at about 35% fuel efficiency, with another efficiency drop over power lines, and another drop in my compressor. I am guessing the same fossil fuel could drive three refrigerators if burned locally using a zero maintenance absorption refrigerator. Don’t even get me started on how much energy it takes to get fossil fuel from deep in the ground to point of use.
So why did Einstein take time out from his search for a unified theory of everything to work on a patent for a refrigerator? Well for one thing, food preservation is pretty important. When power went out for 4 days in our house, we were able to survive with candles, and residual water pressure, and cistern water. But we were in a panic about our freezer thawing out in July heat. (I will return to this theme soon in a post about cold storage for potatoes in Bangladesh using tri-generation, but for now let’s stay on track with our absorption refrigerator.) So we installed a propane generator to see us through such power outages.
But what happens if the propane runs out in an extended outage? Well unbeknownst to me, there is an even simpler intermittent absorption design that can use wood or solar heat in a relatively short burn to drive a refrigerator or freezer. In this design the cooling starts when the heat is removed. So after a one hour wood burn or a 4 hour solar run, the work of making ice begins. So in a world without grid power, I can have a refrigerator that is run by burning twigs once a day in a small firebox on my back porch. Want to make ice for more than one appliance or to sell? Fire it up two or three times a day. That is if I go to the trouble of designing and building a finished product.
I think I will call this effort SunWood Ice. And maybe it can exist as a Fusion Enterprise without any inc. or LLC after it. Just an enterprise to make something locally that doesn’t need fossil fuel to run.
Somehow I think Einstein would approve.