Converting a separate room or part of a warehouse into a full-fledged refrigeration chamber is a complex technical process that requires deep knowledge in thermodynamics and electrical engineering. Unlike installing a conventional household appliance, here you create a closed circuit from scratch, where the walls become a heat insulator, and the climate control equipment becomes a source of cold.
The main difficulty is that standard household refrigerators are not designed to cool large volumes of air or operate at subzero ambient temperatures. You will need to design a system that can compensate for heat inflows through walls, floors, ceilings, as well as heat generated by products and people.
Before purchasing materials, it is necessary to carry out an accurate thermal calculation. An error at the design stage will result in the compressor working non-stop, consuming a huge amount of electricity and quickly failing.
⚠️ Attention: Self-assembly of industrial refrigeration units requires skills in working with high voltage electricity and refrigerants. Incorrect installation can lead to freon leakage, electrical wiring fire or food damage.
Calculation of heat inflows and power selection
The first step is to determine the required cooling capacity of the unit. Heat inflows consists of several factors: thermal conductivity of the enclosing structures, air infiltration when opening doors, heat from products and operation of equipment inside the chamber.
To calculate, you need to know the volume of the room and the desired temperature. If you plan to store vegetables at +2°C, the requirements will be the same, but for freezing meat at -18°C, the requirements will be completely different. The thermal conductivity coefficient of walls directly depends on the thickness and type of insulation used.
It is important to take into account the air exchange rate. Every time you open the door, warm, humid air gets inside, which needs to be cooled and dried.
- 🌡️ Ambient temperature: the hotter it is outside the wall, the more powerful the compressor is needed.
- 📦 Loaded food volume: warm foods emit a lot of heat when cooling.
- 🚪 Operating mode: frequency of door opening and time of their open state.
For accurate selection of equipment, use a formula that takes into account the volume of the chamber in cubic meters, multiplied by a coefficient depending on the temperature regime.
Thermal insulation of the room: materials and technology
The most critical stage is the creation Thermos. Sandwich panels are the gold standard for industrial chambers, but for retrofitting an existing room, spray polyurethane foam (PPU) or extruded polystyrene foam boards are often used. Conventional foam plastic is not suitable here due to low mechanical strength and high hygroscopicity.
The thickness of the insulation must be calculated individually. For medium-temperature chambers (about 0°C) 100 mm of insulation is usually sufficient; for low-temperature chambers (below -18°C) the thickness increases to 150-200 mm. The key point is the absence of cold bridges.
The joints between the plates must be carefully sealed with polyurethane foam and glued with aluminum tape. Moisture is the main enemy of thermal insulation; penetrating inside, it freezes, destroys the structure of the material and sharply reduces its effectiveness.
Why can’t you use mineral wool?
Mineral wool is hygroscopic and, when wet, loses up to 80% of its thermal insulation properties. In the conditions of the refrigeration chamber, it will quickly turn into an ice porridge, which will lead to mold growth and heat loss.
⚠️ Attention: When using sprayed polyurethane foam, make sure that the room is well ventilated during work, since the components of the mixture are toxic before polymerization.
The floor also requires special attention. If the chamber will operate at sub-zero temperatures, it is necessary to lay a heating cable under the floor insulation or use passive ventilation of the foundation to prevent soil freezing and swelling of the floor.
Choice of refrigeration equipment: monoblock or split system
Two main types of equipment are used to cool the room: monoblocks i split systems. The monoblock is a single housing where the compressor, condenser and evaporator are assembled together. It is installed in a through hole in the wall.
Split systems consist of two blocks: a compressor-condenser unit (placed outside) and an air cooler (inside the chamber). This allows you to reduce the noise level inside the room and save useful volume.
When choosing a compressor, pay attention to the refrigerant. Modern systems most often run on R404A or R507, which are a replacement for the outdated R22. The compressor power should have a reserve of about 15-20% of the design load.
System installation and sealing
The installation process begins with preparing the opening. If you are using a monoblock, a hole of the appropriate size is cut in the wall. The edges of the hole are carefully insulated and sealed. A split system requires the laying of copper pipelines, which also require high-quality thermal insulation.
The most important element is fridge compartment door. It should have a magnetic seal around the entire perimeter and a self-closing mechanism. For low-temperature chambers, doors are often equipped with electrically heated perimeter to prevent the panel from freezing to the frame.
All pipe and cable penetrations through the wall must be sealed with a sealant that is resistant to low temperatures. Any gap will lead to a constant influx of warm air and the formation of ice.
☑️ Checklist before starting
After installation, the system is evacuated to remove moisture and air, after which freon is charged. The pressure in the system must strictly comply with the recommendations of the equipment manufacturer for a specific type of refrigerant.
Organization of ventilation and microclimate
The refrigerator compartment is not just a cold place, it is an environment with controlled humidity. If the evaporator is not operating properly, humidity can drop too low, causing food to dry out, or rise, causing mold to form.
Air cooler fans must ensure uniform air circulation so that the temperature at all points in the chamber is the same. Stagnant zones are a risk of product spoilage.
Vegetable and fruit storage rooms often require a supply and exhaust ventilation system with heat recovery to remove ethylene and carbon dioxide emitted by the products, while maintaining cold.
| Chamber type | Temperature range | Humidity | Equipment type |
|---|---|---|---|
| Vegetable storage | +1...+10°C | 85-95% | Split system with humidification |
| Meat shop | -2...+4°C | 80-90% | Medium monoblock power |
| Freezer | -18...-24°C | 85-90% | Low temperature monoblock |
| Blast freezing | -35...-45°C | - | Specialized unit |
Automation and control of parameters
A modern refrigerator cannot exist without controller. This electronic device controls the activation of the compressor, fans, defrost of the evaporator and signals about accidents.
Temperature sensors must be placed in the air return area to the evaporator in order to read the average temperature in the chamber. It is important to periodically calibrate sensors, as they can become inaccurate over time.
For commercial use, it is recommended to install a remote monitoring system (GSM modem or Wi-Fi module) that will send SMS notifications about a rise in temperature or a power outage.
Setting up parameters defrosting is a delicate process. Too frequent defrosting wastes energy and heats the chamber; too infrequent defrosting leads to ice fouling and cooling stops. The mode is selected experimentally depending on the humidity of the products and the frequency of opening the doors.
Frequently asked questions (FAQ)
Is it possible to use a regular household refrigerator by building it into the wall?
Absolutely not. Household refrigerators do not have sufficient power reserves to cool a large volume of air; their thermal insulation is designed for the internal volume, and not to work as a wall. In addition, their compressors are not designed for round-the-clock operation in this mode.
How thick should the insulation layer for a freezer be?
For temperatures down to -18°C, the minimum thickness of extruded polystyrene foam boards or PIR panels should be 150 mm. For lower temperatures (-25°C and below), it is recommended to increase the layer to 200 mm.
Do you need separate electrical wiring for the refrigeration unit?
Yes, industrial refrigeration units consume significant current, especially when the compressor starts. It is necessary to lay a separate cable with a cross-section corresponding to the power of the equipment, and install a circuit breaker with the correct characteristics.
How often do you need to defrost in such a chamber?
In a properly designed chamber with an automatic defrosting system, manual defrosting is not required. The system itself turns on the heating elements or switches the cycle to hot gas to remove ice from the evaporator using a timer or sensor.