The study from Southbank London University refers to the benefits that arise when cold room and warehouse doors are protected by transparent PVC strip curtains.
When the door opens for the distribution of products within and outside of the cold room then the warm air enters from the top of the entrance and the cold air exits from the bottom side.
The warm air which enters in the cold room, sometimes contains more moisture than the cold air that is exiting. This moisture can be spread across the cold room and mainly above the door which is the worst. In addition the moisture can be spread on the evaporator (cooling element) and the floor under the door.
If the cold room operates at a temperature below 0°C, this moisture will turn into ice. This heat must be removed, so that the refrigeration system condenses and freezes the moisture. This process increases the energy consumption and operational costs of the refrigeration unit.
If the machinery installation fails to extract this heat directly as a common result the ice will limit the surface of the evaporator.
A typical example of this is that control was performed in a plant for preparing fresh pie UK .The test chamber used to store fresh pies at 3-5 0C, while pies stored for 2-18 hours before the baking as the products traded within and outside the cold door was opened and closed several times. The cold room had two cold rooms’ doors and two did not bring protection (pvc strip curtains doors).
During the week when the plant was operating, the temperature of the pies into the cold room increased daily temperatures often reached their 12 0C (see graph). On the weekend, when the doors of cold rooms were closed, the temperature of the pies was kept below 30C.
This test demonstrated that the doors for cold rooms responsible for the penetration of heat to the chamber so finding methods to reduce this infiltration would be beneficial.
The thermal loads calculated for the cold room showed that the penetration of heat was responsible for 68 % of the heat load in the refrigeration chamber. Potentially this could be halved placed curtains of transparent PVC strips on the open door.
During the control was tested the generated energy from the refrigeration plant and the number of the door openings. The doors heat penetration caused a high thermal load is therefore placed PVC curtains doors of refrigerators and then the cold room tested again to give us comparative data with and without strip doors .
The investigation carried out without protection of the door with curtains, the cold room consumed 5,3KW while the doors were opened for 1.9 hours every 24 hours of the recording time.
If fitted in PVC transparent curtains strips, the average consumption was 4,3KW (19% decrease), while the doors were open every day for the same time.
Furthermore, the temperature of the stored products (fresh pies) significantly decreased to 5 0C. We conclude that if they use PVC transparent curtain strips increase storage product while limiting the penetration of moisture reduces the engine operating time, the cooling coils remain "clean" and therefore fully effective.
Moreover, the PVC transparent curtain strips are widely used as partitions sanitary food processing industries, protecting from dust, insects, odors, noise, since the overlap forming one curtain. Finally, the curtains have a low cost against major advantages they offer.
At the picture below we can see the pies' temperature at a cold room
At the picture below we can see the pies' tempearture at a cold room