The cooling temperature difference of commercial small refrigerators is manifested as not meeting the standard. The customer requires a temperature of 2~8℃, but the actual temperature is 13~16℃. The general solution is to ask the manufacturer to change the air cooling from a single air duct to a dual air duct, but the manufacturer has no such cases. Another option is to replace the compressor with a higher-power one, which will increase the price, and the customer may not be able to afford it. Under the dual constraints of technical limitations and cost sensitivity, it is necessary to start from tapping the potential performance of existing equipment and optimizing operation to find a solution that can both meet the cooling demand and fit the budget.
1.Optimization of air duct diversion
The single air duct design has a single path, resulting in an obvious temperature gradient inside the cabinet. If there is no experience in dual air duct design, a similar effect can be achieved through non-structural adjustments. Specifically, first, add a detachable diversion component inside the air duct without changing the physical structure of the original air duct.
Secondly, install a Y-shaped splitter at the air outlet of the evaporator to split the single air flow into two upper and lower streams: one keeps the original path directly to the middle layer, and the other is guided to the top space through a 30° inclined deflector. The fork angle of the splitter has been tested by fluid dynamics simulation to ensure that the flow ratio of the two air streams is 6:4, which not only ensures the cooling intensity in the core area of the middle layer but also fills the 5cm high-temperature blind area at the top. At the same time, install an arc-shaped reflection plate at the bottom of the cabinet. Taking advantage of the characteristics of cold air sinking, the cold air naturally accumulated at the bottom is reflected to the upper corners to form a secondary circulation.
Finally, install the splitter, test the effect, and observe whether the temperature reaches 2~8℃. If it can be achieved, it will be the optimal solution with very low cost.
2.Refrigerant replacement
If the temperature does not drop, re-inject the refrigerant (keeping the original model unchanged) to lower the evaporation temperature to -8℃. This adjustment increases the temperature difference between the evaporator and the air in the cabinet by 3℃, improving the heat exchange efficiency by 22%. Replace the matching capillary tube (increase the inner diameter from 0.6mm to 0.7mm) to ensure that the refrigerant flow is adapted to the new evaporation temperature and avoid the risk of compressor liquid hammer.
It should be noted that temperature adjustment needs to be combined with precise optimization of temperature control logic. Replace the original mechanical thermostat with an electronic temperature control module and set a dual trigger mechanism: when the central temperature in the cabinet exceeds 8℃, the compressor is forced to start; this not only ensures the cooling effect but also maintains the cooling efficiency at the best state.
3.Reducing external heat source interference
Excessive temperature in the cabinet is often the result of an imbalance between environmental load and cooling capacity. When the cooling power cannot be increased, reducing the environmental load of the equipment can indirectly narrow the gap between the actual temperature and the target value. For the complex environment of commercial places, adaptation and transformation need to be carried out from three dimensions.
First is the strengthening of cabinet heat insulation. Install a 2mm thick vacuum insulation panel (VIP panel) on the inner side of the cabinet door. Its thermal conductivity is only 1/5 of that of traditional polyurethane, reducing the heat loss of the door body by 40%. At the same time, paste aluminum foil composite insulation cotton (5mm thick) on the back and sides of the cabinet, focusing on covering the areas where the condenser is in contact with the outside world to reduce the impact of high ambient temperature on the refrigeration system. Secondly, for environmental temperature control linkage, install a temperature sensor within 2 meters around the refrigerator. When the ambient temperature exceeds 28℃, automatically trigger the nearby local exhaust device to divert hot air to areas far away from the refrigerator to avoid forming a heat envelope.
4.Optimization of operation strategy: dynamically adapt to usage scenarios
By establishing a dynamic operation strategy matching the usage scenarios, the cooling stability can be improved without increasing hardware costs. Set temperature control thresholds in different periods: maintain the upper limit of the target temperature at 8℃ during business hours (8:00-22:00), and lower it to 5℃ during non-business hours (22:00-8:00). Use the low ambient temperature at night to pre-cool the cabinet to reserve cold capacity for the next day’s business. At the same time, adjust the shutdown temperature difference according to the frequency of food turnover: set a 2℃ shutdown temperature difference (shutdown at 8℃, start at 10℃) during periods of frequent food replenishment (such as the noon peak) to reduce the number of compressor starts and stops; set a 4℃ temperature difference during periods of slow turnover to reduce energy consumption.
5.Negotiating to replace the compressor
If the root cause of the problem is that the compressor power is too small to reach 2~8℃, it is necessary to negotiate with the customer to replace the compressor, and the ultimate goal is to solve the temperature difference problem.
To solve the cooling temperature difference problem of commercial small refrigerators, the core is to find out the specific reasons, whether it is the small compressor power or the defect in the air duct design, and find the optimal solution. This also tells us the importance of temperature testing.
Post time: Sep-01-2025 Views: