Conversion of used turning your refrigerator into a full-fledged incubator is not just a way to recycle old household appliances, but also an excellent opportunity to acquire a mini-farm in your own backyard. The old building is ideal for this purpose due to its thermal insulation properties tightness, which allows maintaining a stable microclimate necessary for the development of embryos. Unlike purchased analogues, a homemade design can be adapted to any volume of eggs and specific types of poultry, be it chicken, duck or quail.
The conversion process requires not so much metalworking skills as an understanding of the basic principles of thermodynamics and electrical engineering. You have to replace the freezing circuit with a heating and ventilation system, while maintaining the “skeleton” of the unit. Properly assembled incubator will ensure hatchability of chicks no worse than factory models, if temperature and humidity conditions are strictly observed at all stages of incubation. The main advantage here is the durability of the metal case and the possibility of year-round use in unheated rooms.
Before starting work, it is necessary to prepare all the tools and components, since the process will require time for assembly and, most importantly, careful equipment setup. Mistakes at the design stage can cost you a whole masonry, so the approach must be engineering and balanced. Let's consider in detail each stage of transformation in order to eliminate risks and get a working device the first time.
Selection and preparation of the refrigerator body
The ideal candidate for conversion is an old Soviet refrigerator, for example, brand ZIL or Saratov. Their main advantage lies in thick walls and high-quality door seals, which do not lose elasticity for years. Modern units are also suitable, but their thin plastic and complex shelf geometry may require additional modifications. It is important that the internal space is free from protruding elements that would interfere with the installation of trays.
The first step is always a complete removing the compressorcondenser and evaporator. These parts are no longer needed, and it is better to carefully desolder or cut off the copper tubes so as not to damage the inner lining. The holes from the tubes must be carefully foamed with mounting foam or sealed with sealant to prevent heat leakage. Internal plastic shelves and drawers can be left if they are durable, but most often they are replaced with metal grilles for better air circulation.
⚠️ Attention: When removing the back panel, be extremely careful with the heat exchanger (black grill) if you plan to use it. If you throw away old freon and oil, make sure that you do it in accordance with environmental standards, without pouring technical fluids into the soil.
The appearance of the housing is also important, especially if the incubator will be located in a residential area. Metal surfaces are easy to clean and disinfect, which is critical to preventing infections. If there is rust on the body, it must be cleaned and coated with heat-resistant paint. The tightness of the door is key success factor, so check the fit of the seal around the entire perimeter and, if necessary, replace it or restore the magnetic tape.
Calculation of the heating and ventilation system
The basis of the life of an embryo is stable warmth. To create a uniform temperature field inside the chamber, incandescent lamps with a power of 40–60 W or a nichrome spiral are most often used. Lamps are easier to install and replace, but they dry the air and therefore require humidity control. The spiral located in the lower part of the body creates more natural convection, but is more difficult to regulate without a high-quality thermostat.
Ventilation is the second pillar of successful incubation. Without air movement, “pockets” with different temperatures form in the corners of the refrigerator, which will lead to the death of part of the masonry. For circulation, computer coolers (120 mm) are used, which operate silently and consume little energy. The optimal layout includes one fan from below for air intake and one from above for its distribution, or side blowing.
- 🌡️ Thermoregulator - a device that automatically turns heating on and off, maintaining the set temperature with an accuracy of 0.1 degrees.
- 💨 Fan - ensures mixing of air masses, excluding gradients temperatures in different zones of the chamber.
- 💡 Heating element —a heat source, the power of which is calculated based on the chamber volume (approximately 10 W per 10 liters of volume).
The heater power is calculated empirically, but there is a rule: for good for an insulated refrigerator with a volume of 200 liters, 150–200 W is sufficient. Excessive power will lead to frequent switching on of the thermostat and overheating, while insufficient power will not allow you to reach the operating mode of 37.8°C. It is better to use several lamps of lower power, distributed along the height, than one powerful one.
Installation of electrical equipment and automation
Assembling an electrical circuit requires care and compliance with safety rules, since you are working with a 220V mains voltage. All connections must be securely insulated, and the wires must be protected from damage by the metal edges of the shelves. The central element of the control system becomes thermostat, which reads data from the temperature sensor and controls the load relay.
Modern digital controllers, such as XH-M131 or W1209, allow you not only to set the temperature, but also to adjust hysteresis (difference between on and off temperatures). The temperature sensor should be placed at the level of the egg trays, but without touching them or the heating elements. This will provide correct readings of the real environment in which the embryos develop.
Connection diagram (simplified):220V network → Thermoregulator (Input)
Thermostat (relay output) → Heater + Fan
Temperature sensor → Thermostat input
For ease of operation, it is worth displaying all indicators and controls on the external panel. This will allow you to control the process without opening the door and without disturbing the microclimate. It is also recommended to install a separate switch for the egg turning system and lighting, if provided. High-quality switching equipment service life and will prevent fire hazards.
Organization of a humidification system and turn
Maintaining humidity at 50–70% is a critical task, especially in the second half of incubation. In a homemade refrigerator incubator, the easiest way is to install wide baths of water in the lower part of the body. The area of evaporation directly affects the rate of moisture gain, so you can adjust this parameter by changing the size of the container or adding sponges to the water.
Automatic egg rotation is a function that significantly increases hatchability, imitating the behavior of a hen. The mechanism can be implemented using an electric motor (for example, from a car windshield wiper or gearbox) and a lever system that tilts the trays 45 degrees in each direction. The cyclicity of turns is set by a timer, usually every 2–4 hours.
| Parameter | 1–7 days | 8–14 days | 15–21 days |
|---|---|---|---|
| Temperature, °C | 37.8 – 38.0 | 37.8 | 37.5 |
| Humidity, % | 55 – 60 | 45 – 50 | 65 – 70 |
| Turning eggs | Every 2 hours | Every 2 hours | Not required |
| Ventilation | No | 5 min/day | 10-15 min/day |
If automating the rotation seems too complicated, you can make the trays removable and rotate them manually. However, in refrigerator conditions, where the volume can be large, a mechanical drive is preferable. The main thing is that the design of the trays is rigid and the eggs do not roll or hit each other when moving.
☑️ Checking the humidification system
Testing and calibrating the incubator
Starting empty incubator - a mandatory step before laying the first eggs. The chamber must be warmed up for 24 hours to ensure that the temperature is stable and all components are working. At this time, the uniformity of heating is checked: the thermometer sensor is moved to different angles, and the difference in readings should not exceed 0.2–0.3 degrees.
Calibration of sensors is a fine-tuning on which the result depends. Cheap Chinese sensors often have an error that can be corrected in the controller settings or software. Compare the readings from your incubator with the readings of a proven medical or laboratory thermometer placed directly in place of the future eggs.
⚠️ Attention: Do not place eggs in an unstable incubator. Even short-term overheating in the first days of development (more than 39°C) can lead to irreversible pathologies or death of the embryo. Make sure that the emergency shutdown system works correctly.
The testing process also evaluates the operation of the fans. The noise should not be annoying and the air flow should not be too strong so as not to cause the egg shells to dry out. If you notice strong drafts in the masonry area, install additional dividers or change the flow direction.
What to do if the temperature fluctuates?
If the amplitude of the fluctuations exceeds 0.5 degrees, check the power of the heater. Perhaps it is too large for the volume of the chamber, and heat accumulates faster than it can dissipate. In this case, installing a dimmer or reducing the power of the heating element will help. Also check the tightness of the door - drafts from the outside can disrupt the thermostat settings.
Disinfection and first start-up
Before the first installation, the inner surface of the refrigerator must be thoroughly washed and disinfected. Remnants of the old smell or microorganisms can destroy the future brood. Use a weak solution of potassium permanganate, chlorhexidine or special means for disinfecting incubators, avoiding aggressive chemicals with a strong odor.
The first launch with biological material is best done with a small batch of eggs in order to track the behavior of the system in real conditions. Record all parameters in the log: time when heating was turned on, duration of cycles, changes in humidity. This will help you quickly diagnose possible problems in the future.
Caring for the incubator after hatching is also important. After each cycle, remove remaining shells and fluff, wash the trays and wipe the inner walls. Regular maintenance will extend the life of your homemade device and ensure high hatchability for many years.
Frequently asked questions (FAQ)
Is it possible to use a refrigerator with a No Frost system?
Yes, you can, but you will have to dismantle the cooling system and close the extra holes. The advantage of such models is good insulation, but they often have complex internal geometry, which makes it difficult to install standard trays.
What humidity should be in the first days of incubation?
In the first weeks (days 1–7), the optimal humidity is 55–60%. If the humidity is lower, the embryos may dry to the shell; if it is higher, gas exchange through the shell will be difficult.
Is it necessary to ventilate the incubator?
Yes, ventilation is necessary, especially in the second half of incubation, when the embryos begin to actively consume oxygen and generate heat. Usually the door is opened for 10-15 minutes a day, starting from the 15th day.
How often should the eggs be turned?
The eggs should be turned at least 3-4 times a day, and ideally every 2 hours. This prevents the embryo from sticking to the shell and ensures uniform heating.