How does a propane refrigerator work?Propane fueled refrigerators are the way to go for off-grid refrigeration and for very good reasons.
They’re dependable, reliable, and work efficiently in environments where electricity supply is not reliable.
Propane fridges can also be an amazing asset when you’re out touring your dream vacation spots, when camping at iconic campgrounds, and essentially, when spending time at any other place where electricity is not available.
But how does a propane refrigerator work and how good is its cooling efficiency?
Let’s take an in-depth look:
How does a propane refrigerator work?
In a nutshell, propane coolers produce a cooling effect by running a succession of chemical processes.
In fact, to drive the entire cooling process, it all boils down to hydrogen, ammonia, and water reacting.
In summary, here’s how it all works:
- The cooling cycle begins with a propane flame heating the chamber containing a solution of ammonia and water. Heating continues until the mixture boils.
- Next, because of the heat, the mixture of ammonia and water vaporizes into steam. The ammonia gas actually escapes to the condenser chamber through a pipe. Here it will cool back into liquid form.
- Action now shifts to the evaporation chamber – the ammonia (recall it’s now a liquid) flows into the evaporator. It will mix with the hydrogen gas here.
- The two substances – ammonia and hydrogen- react on contact. This chemical reaction will effectively absorb heat. In essence, the encounter will cause ammonia to evaporate, taking heat away from the ammonia-hydrogen mixture. This is what lowers the temperature inside the refrigerator enabling it to cool what you have preserved inside.
- The process is continuous and ammonia will turn into gas once more.
- Then, ammonia – together with hydrogen gas- will mix with water one more time.
- Now the ammonia dissolves in water forming a solution while the hydrogen gas starts to return to the evaporator.
- The cooling action is restarted and the propane refrigerator will shortly be cold enough to prevent your food from spoiling.
Quick Tip: Because propane refrigerators chill by ‘absorbing’ heat from propane fuel, they’re sometimes called absorption refrigerators.
Are propane refrigerators efficient?
In general, a 12 cu. ft. propane-powered refrigerator can run for up to 13 days on a regular 20lb. propane bottle- it supplies 430,000 BTUs of energy (when full).
Keep in mind that such a 12 cu. ft propane cooler consumes about 1.5 lbs. of propane/day, which comes to 1,400 BTUs of energy/hour (or 32,225 BTUs/day).
And so if you had two such bottles, you’d comfortably run the refrigerator for 26 days.
As you would expect, the actual consumption varies from one unit to the next- there are smaller units using less than 1 lb. of propane/day and bigger models that can consume nearly 2 lbs./day.
Turning to cost, while propane is priced differently across the country, the average price range per gallon is from $1.50 and $3.00 in many locations.
In truth, you can run the fridge throughout the year for approximately $150 to $300, even assuming higher propane prices where you live.
This is not terribly expensive compared to what it costs to run regular electric refrigerators and may be cheaper than some solar refrigerators, when you add the amounts spent annually in general repairs and parts replacement.
How long will a propane refrigerator run on a tank?
Well, if you’re wondering if your propane fridge can run on a tank the whole time, the short answer is: it depends.
And the determining factors can be quite a number: the BTUs/hr your specific cooler burns, your tank’s capacity (the 20lbs. propane tank is often the most common), whether there are other appliances connected to the tank (and their energy consumption), and more.
But to give you an idea, recall that modern-day 10 -12 cubic feet propane refrigerators use around 1.5 lbs. of propane/day (1,400 BTUs/hour).
And since a 20 lbs. propane tank usually holds 4 and ½ gallons of propane (Value in BTUs= 4.5 × 95500 = 430000 roughly, when full), then it will run for 430000/ (1400×24) = 13 days or 307 hours under normal conditions.
A 30 lbs tank (649,980 BTU capacity) will run constantly for 649,980/ (1400×24) = 19 days or 464 hours.
Of course, your tank should operate it for a longer period if you own a smaller refrigerator while you’d run out of propane sooner for larger units.
These are just estimates and it’s important to understand that the efficiency of the fridge (based on the settings and how well optimized it is) will also have a significant impact on run time.
How does a propane refrigerator work- related questions
Are propane refrigerators safe?
While propane refrigerators are not manifestly dangerous, there are a couple of safety concerns that arise because of the use of the gas.
One of the preventative precautions worth looking into is whether to vent the refrigerator or not- depending on the size of the room where you want to install it.
On the whole, venting propane refrigerators is especially important in motorhomes and tiny homes- this usually requires an intake vent and outlet exhaust.
On the other hand, venting may not be necessary if your refrigerator is to be mounted in a large room or an open space.
Still on safety, also remember to observe other propane safety best practices.
For example, check your propane tanks for leaks before use and ensure you don’t run out of propane (If a gas line/valve is open when supply runs out, propane could leak out on refilling).
Bleeding overfilled propane tank
Can you travel with propane refrigerator on?
Yes! There is nothing that bars you from traveling with the propane refrigerator on if the situation demands- you may, for instance, want to keep warm by running your RV’s heating system while traveling.
However, you need to be careful because doing so can be risky.
Imagine, for example, an accident happening- chances of propane leaking are pretty high and you will be risking a fire or an explosion.
You also have to live with the inconvenience of having to keep stopping to turn propane off before entering gas stations (and stopping again to turn it on after leaving a station) as required by the law in some territories.
Propane refrigerators can be perfect for off-grid homes, campers, recreational vehicles (RVs), and caravans since they can conveniently be powered with propane, rather than electricity.
These fridges can also come to the rescue of your food in areas where natural calamities have struck, cutting off electricity for a long time.
You now know how it works and hopefully, this will help you make a good decision for your needs.