Creating an autonomous cooling system is not just a technical experiment, but often a vital necessity for owners of summer houses, motorhomes and remote from the electricity of the sites. Gas refrigerator on an absorption basis, it operates silently, does not require electricity and is able to function for weeks from one propane cylinder. The principle of its operation is radically different from its compressor counterparts, which makes it a unique tool in the arsenal of any master.
Unlike conventional household models, it uses a thermodynamic cycle, where the refrigerant circulates due to heating, and not mechanical compression. Absorption system requires precise compliance with proportions and tightness, since high pressure is created inside the circuit. If you are thinking about how to make a gas refrigerator with your own hands, you will have to study the basics of chemistry and physics in order to assemble a really working unit.
A homemade device is often assembled from available materials, but the key element is always the factory or restored absorption module. It is almost impossible to independently make a sealed circuit from scratch at home without specialized equipment for welding pipes in an inert gas environment. Therefore the basis of the assembly will be a ready-made block from a decommissioned refrigeratorwhich we will integrate into a homemade housing and gas supply system.
The principle of operation of the absorption system
To successfully assemble the device, you need to clearly understand what is happening inside its tubes. It is based on the absorption process, where ammonia acts as a refrigerant, and water absorbs its vapors. A gas-powered heating element brings the mixture to a boil, separating the components and starting circulation without moving parts.
The process begins in the heater, where the ammonia concentrate releases gas, which then condenses into a liquid. Liquid ammonia evaporates in the evaporator, taking heat from the chamber, after which it is again absorbed by water. Circulation possible due to the difference in density of the hot and cold mixture, which eliminates the need for a compressor.
It is critical to ensure stable heating, since it is the temperature that determines the efficiency of everything cycle. If the heating is insufficient, gas separation will not occur and no cold will be generated. With excess pressure, the system can become dangerous, therefore temperature regulator valves play the role of fuses.
- 🔥 The heating element creates thermal energy to separate the mixture.
- ❄️ The evaporator absorbs heat from the inner chamber refrigerator.
- 💧 The absorber re-saturates the water with ammonia vapor to repeat the cycle.
It is worth noting that the efficiency of such a system is lower than that of a compressor system, but reliability compensates for this disadvantage. The lack of vibration and noise makes these units ideal for camper bedrooms. Understanding these processes will help you correctly set up the gas supply and avoid common installation mistakes.
⚠️ Attention: Ammonia is toxic and explosive when mixed with air. Any work on the absorption module must be carried out in a well-ventilated area. If you detect a smell, immediately turn off the gas and eliminate the leak.
Necessary materials and tools
Assembling an autonomous refrigerator requires preparing a specific set of tools. You will need not only standard plumbing supplies, but also equipment for working with gas lines. Tightness is the main requirement, so the quality of connections is given paramount attention.
The basis of the design will be a housing, which can be made from sandwich panels, polystyrene foam, or use an old housing from a household refrigerator. Thermal insulation should be as effective as possible, since absorption systems are sensitive to external heat. Wall thickness should not be less than 50 mm to maintain cold in the summer.
For the gas part you will need a reducer, hoses with appropriate markings and a burner with piezo ignition. Absorption unit (usually from Morozko type models or imported analogues) must be checked for integrity before installation. You will also need thermometers to control the temperature in different zones of the chamber.
☑️ Checklist of materials
Don't forget about personal protective equipment. Working with gas and potentially hazardous substances requires caution. Gloves and safety glasses will protect against burns and chemical exposure in case of accidental depressurization of the system.
| Material/Tool | Purpose | Importance |
|---|---|---|
| Absorption module | Cold generation | Critical |
| Gas burner | Heating the mixture | Critical |
| Thermal insulation | Temperature retention | High |
| Pressure reducer | Gas supply stabilization | High |
Preparation of the housing and thermal insulation
The quality of thermal insulation directly affects the performance of the gas refrigerator. Heat loss Through the walls they force the system to work harder, consuming more gas. Therefore, the choice of material and sealing of seams are key stages of assembly.
It is best to use extruded polystyrene foam high density. It does not absorb moisture and has excellent insulating properties. When assembling the body from panels, all joints must be carefully foamed and glued with aluminum tape to create a vapor barrier layer.
If you are using an old refrigerator, check the integrity of the internal plastic and door seals. Often in used models the seal dries out, which negates all efforts to create cold. Replace the elastic with a new one, selected in size, to ensure a tight fit.
The internal space should be divided into zones. The evaporator of an absorption system is usually located at the top, since cold air is heavier than warm air and sinks down. The placement of shelves should allow free circulation of air around the evaporator.
⚠️ Attention: Do not use toxic materials for internal lining that can release harmful substances when heated or in contact with products. Food grade plastic or painted plywood is the best choice.
Installation of the gas system and burner
The most critical stage is the installation of the gas part. Not only the performance, but also the safety of the entire device depends on this. Burner must be secured strictly under the heating pipe of the absorption module. Any displacement will lead to uneven heating and a decrease in efficiency.
Connection to the cylinder is made through a reducer, which reduces the pressure to the operating value (usually 0.03-0.05 bar for household burners). The hoses must be secured with clamps, and their length should be the minimum necessary to eliminate the risk of damage. Piezo ignition greatly simplifies operation, eliminating the need to hold an open flame for ignition.
It is important to ensure the correct flow of combustion air and removal of combustion products. The housing must have ventilation openings at the bottom and top, connected to the external environment by pipes. This will create the natural draft necessary for the burner to operate.
Procedure for checking tightness:1. Open the valve on the cylinder.
2. Apply soap solution to all connections.
3. Watch for the appearance of bubbles for 2-3 minutes.
4. If a leak is detected, turn off the gas and repack the connection.
Do not forget that the gas system requires regular maintenance. Nozzles burners can become clogged with dust or soot, which will change the flame characteristics. Periodic cleaning and purging will ensure stable operation for many years.
What to do if the flame comes off the burner?
If the flame comes off and goes out, this may indicate too high gas pressure or excessive air flow. Try reducing the pressure on the reducer a little or closing the air supply damper. Also check that the chimney is not clogged with combustion products.
Assembling and starting the refrigerator
The final assembly combines all components into a single system. The absorption module is installed in a prepared slot in the rear wall, the heat exchanger (radiator) must protrude outward for effective cooling. Condenser Often equipped with a fan (if electricity is available) or left for natural cooling.
The first start-up is carried out with caution. The flame should be moderate and cover the heater evenly. The process of entering the mode can take from 2 to 6 hours. At this time, you should not open the door often to allow the system to gain temperature.
Control the temperature using a thermometer placed in the center of the chamber. The normal operating temperature for absorption refrigerators is considered to be from +2 to +8 degrees Celsius. If the indicators are worse, check the draft in the chimney and gas pressure.
- 🔧 Check the reliability of fastening of all components before turning on.
- 🌡️ Let the system warm up for at least 2 hours before loading products.
- 👂 Listen to the work: only a quiet noise should be heard flowing liquid.
Successful launch marks the end of the main part of the work. However, operation requires compliance with certain rules, which will be discussed below. Correct setting will allow you to get stable cold even in hot weather.
Operation and safety measures
Using homemade gas equipment requires increased discipline. Safety should be priority number one. Regularly check the connections for smell and the condition of the hoses, which may crack over time.
This refrigerator can only be installed in a horizontal position. An inclination of more than 15-20 degrees can disrupt the circulation of the mixture inside the tubes, which will lead to the process stopping or, in the worst case, to water hammer. When transporting in a motorhome, secure the device tightly.
In the room where the gas refrigerator operates, supply and exhaust ventilation is required. Gas combustion products (carbon dioxide and water vapor) should not accumulate in the room. Carbon monoxide sensor will be an excellent addition to your security system.
⚠️ Attention: Never leave a running gas refrigerator unattended for a long time if you Not sure if the automatic shutdown is working properly. If the flame goes out, the gas should be shut off automatically.
Maintenance includes cleaning the burner from dust and checking the draft in the chimney. Once a season, it is recommended to carry out a complete preventive maintenance of gas fittings. This will extend the life of the device and protect you from unforeseen situations.
Frequently asked questions (FAQ)
Is it possible to use ordinary household gas from a cylinder?
Yes, standard propane-butane from a cylinder (for example, 50 liters) is an ideal fuel. However, be sure to use a reducer to reduce the pressure to the burner operating level (usually 30-50 mbar). Direct connection to a full cylinder will rupture the hoses or damage the burner.
Why does the refrigerator not freeze, although the burner is on?
There may be several reasons: a violation of the tightness of the absorption unit (ammonia/hydrogen leakage), clogging of the system with corrosion products or insufficient heating. If the tubes heat up, but there is no cold, most likely the circuit has depressurized and the unit must be replaced.
How much gas does such a refrigerator consume?
The consumption depends on the burner model and the ambient temperature. On average, a homemade refrigerator consumes about 200-300 grams of gas per day during continuous operation. One standard 50-liter cylinder can be enough for 2-3 months of autonomous operation.
Is it possible to convert a compressor refrigerator to a gas one?
No, this is impossible. Compressor refrigerators run on freon and require electricity to compress the gas. Gas ones use absorption technology. You can only replace the energy source (for example, power the compressor from an inverter and batteries), but the principle of operation itself cannot be changed.
Is it necessary to level the refrigerator strictly according to level?
Yes, absorption systems are extremely sensitive to tilts. For proper circulation of the mixture, the device must be positioned strictly vertically. Only a minimal tilt back (1-2 degrees) is allowed for the convenience of opening the door, but left-right distortions are unacceptable.