I think gas cycle refridgeration has the potential to be efficient. For one thing, the gas should be cooled as it’s being compressed to a high pressure, not after it’s been compressed to a high pressure. This could be done by running the gas through a cooling radiator after each stage of a multistage compressor. This minimizes the energy needed to compress the gas. Also it’s critical that the gas be decompressed with a turbine that recovers a lot of the energy needed to compress it, not simply bled to a low pressure with an expansion valve.
But if you cool the gas as you compress it, you no longer have a reverse Brayton cycle, you have a reverse Carnot cycle, and the Carnot cycle is theoretically the upper limit in heat engine efficiency.
Ever heard of a kerosene refrigerator? Flame underneath, cold above
The Servel by Dometic RK400 kerosene powered refrigerator requires no electricity to operate! Heat makes cold through the natural cooling power of evaporation and condensation. A small wick-type kerosene burner heats an ammonia mixture which is permanently sealed inside the service-free cooling coils. The thermostatically controlled flame never shuts off, providing constant cooling unlike electrical compressor refrigerators which cycle off and on. Kerosene refrigerators are exceptionally durable because the constant cycle of evaporation and condensation is performed without any moving parts, which means no mechanical wear and tear. No compressor motor also means no noise and vibration, just peace and quiet. Non-electric appliances such as a gas refrigerator are must-have items for “off-the-grid” sustainable living. When you’re generating your own electricity, it’s not cost effective to operate large “energy hog” conventional electric kitchen appliances. In order to keep your photovoltaic array and battery collection at a reasonable size, you’ll need to buy an all-gas range, a gas hot water heater, and a non-electric refrigerator. Inverters and generators simply can’t be run non-stop and expected to last for any length of time. Gas powered absorption cooling systems are very quiet and much more dependable than an electric refrigerator with no compressor or other moving parts to ever wear out. A tiny pilot light is all that’s needed to keep your food cold without electricity!
My grandparents had a refrigerator similar to this, but using natural gas instead of kerosene, so less odorous.
These were and still are popular in the Outback and South African Veld. Propane is plentiful in North America, but not in a lot of other places.
A South African geologist I worked with was surprised we did not have them in the bush here. Apparently they work fine and are based on the Platen Munters system cycle. Servel makes them as well, in propane or natural gas models.
The AC in my car is powered by fire, the fire is inside the engine and the engine drives the compressor. In fact, nearly everything in my car is powered by fire, the radio, windshield wipers, the head lights. However, the windows are powered by hamburgers, fries, TV dinners and beer
As to gas phase refrigeration cycles, I’m beginning to suspect that BIG FREON is using its muscle to suppress both gas phase and hydrocarbon based refrigeration cycles. I can’t confirm this but neither can I deny it. Unnamed sources have leaked memos and the fact that there is absolutely no evidence of this conspiracy only proves the extent of the coverup. 