Energy saving refrigerated supermarket
The classic refrigerated shelves in the supermarket, for example for dairy products (Mopro), offers some, sometimes very large possibilities for energy saving. The biggest focus here should be on the "open" front of this refrigerator. After all, an open refrigeration unit requires considerably more cooling capacity than a "glazed" refrigerated cabinet.
As "glazed" refers to those refrigerated cabinets, which are equipped with rotating or sliding doors. The glazing causes the heat input to the evaporator is reduced. Consequently, the power requirement on the refrigeration system also decreases.
Comparison of the required cooling capacities for Mopro refrigerated shelves
It can be seen very well here that glazed refrigerated cabinets reduce the power requirement of the refrigeration system by up to 66%.
Another positive effect is that the evaporation temperature of the system can be raised.
An increasing evaporation temperature means at the same time a larger volumetric cooling capacity of the refrigerant and thus a larger mass flow through the compressor.
As a result, the compressor cooling capacity and the COP increases.
What should not be ignored at this point is that the power consumption of the compressor also increases. Due to the increased cooling capacity, the systems reduce running time and energy is saved. Since at least two refrigerant compressors are installed in a supermarket, the downtimes of individual compressors are extended.
Based on an inventory refrigeration system with subsequently glazed refrigerated cabinets.
Cooling capacity of a compressor from the company Bitzer 4EES-6Y-40S with the refrigerant R134a
COP (Coefficient of Performance) is to be understood in principle as efficiency of the compressor.
The refrigeration capacity is compared with the power consumption.
COP = Qo / Pel
The evaporator fan ensures air circulation in a refrigerated rack.
In order to promote the heat introduced from the environment to the evaporator, a constant exchange of air must take place in the refrigerator. If you turn off the evaporator fan, the goods are no longer sufficiently cooled and it comes to goods damage. The same happens if a fan is defective.
As the goods are constantly left in the refrigerated cabinet (day and night), the fans must therefore also be in operation 24 hours / day. If you now assume that conventional fan motors have a power consumption of about 30W / fan, this means a power consumption of 262.8 KW / h per year (mind you 1 fan). In a refrigerated shelf with a length of 2.50m normally 2 fans are installed. In addition, heat losses of these shaded pole motors must be additionally dissipated by the refrigeration system.
It is therefore recommended to convert to energy-saving EC fans. These fans have an electrical power consumption of approx. 10W / fan with the same air output. The energy consumption is thus reduced by 2/3 compared to conventional shaded-pole motors. The efficiency of these fans is around 65% and thus also reduces the heat input to the refrigeration system.
For optimal presentation of the goods, the right lighting must be installed.
In refrigeration units, fluorescent tubes with different color temperatures were used in the past. The choice of color temperature depends on which product is to be presented. In addition, there are conventional ballasts with heat dissipation. It is therefore recommended to upgrade to LED technology.
The heat losses are well below the conventional fluorescent lighting and are variable in the color temperature.