Energy Efficient HVACR Solutions for cold rooms

A cold room is an insulated or cold-air room that keeps a specified temperature range. Cold rooms are for storing various kinds of goods across different sectors. Typical product types are food and beverages, biologics, textiles, and pharmaceuticals.

A cold room allows precise control of temperatures in commercial spaces where constant and efficient refrigeration or freezing is needed. Food or chemical storage means extended temperature control for perishable or unstable materials, lowering degraded rates, and the assurance the items will remain in optimal condition. The FDA recommends that pharmaceutical products should be kept in a suitable temperature, humidity, and light environment and be labeled as identifying and retaining their purity.

The way a cold room works is like a domestic refrigerator. You have an insulated box and a refrigeration system that extracts unwanted heat from the inside and expels it to the outside. It is controlled by a thermostat that turns on when the temperature inside the insulated box is too high and turns off when it is the correct temperature.

The main components are the insulated panels that make up the room complete with a door. The refrigeration system is normally made up of a condensing unit which houses the compressor, condenser, receiver, and associated electrics that is located outside the cold room and then the evaporator, which is placed inside the cold room along with the expansion device to remove the heat from within the cold room. The whole system is then controlled by a thermostat to start and stop the refrigeration system, so the correct temperature is maintained within the cold room.

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There are many different applications which range from farm to fork in the whole food chain such as removing field heat from produce in agricultural areas, food factories, food distribution, supermarkets, convenience stores, commercial kitchens, fast food. Other notable areas include pharmaceutical, floristry, mortuary, and production process.

There is no one specific answer due to the many varied requirements and different product types that require cooling.

Generally:

a. High Temperature Cold Room – an example could be to remove field heat from food produce such as tomatoes with a room temperature at approximately 12 °C

b. Walk-in Cold Room – an example could be a cold room in the back room of a commercial kitchen to store fresh food stuff with a room temperature of approximately 2 to 5 °C

c. Walk-In Freezer Room – an example could be a freezer room in the back room of a supermarket to store frozen food stuff with a room temperature at approximately -18 °C, or for longer term storage the temperature can be as low as -28 °C.

It is important to ensure the cold room structure and the refrigeration equipment has periodic maintenance, because when they are being used regularly, there are many different things that can go wrong or deteriorate over time.

For instance, the fabric of the cold room structure gets a lot of use, opening and closing of the door etc.

The refrigeration system components such as the condenser can get blocked with debris, the fins of the evaporator can get blocked with ice, the mechanical components such as fan motors, defrost heaters or compressor can fail, or the performance can deteriorate. The initial symptom of a failure would be that the cold room is not maintaining the correct storage temperature.

There are many ways to ensure the cold room is running as energy efficiently as possible, these include:

• The cold room structure is airtight, and the door closes properly
• Minimize the periods the door is open
• Use an air-curtain over the door opening to stop heat exchange and warm air / moisture entering the cold room
• Optimize the control settings to ensure the refrigeration system is operating correctly
• Keep the condenser clean / free from debris to ensure good airflow
• Ensure the evaporator airflow is not obstructed with products in the cold room
• Correct thermostat set point for the products stored

Yes, the floor should be insulated and have a heater mat or other systems to ensure the negative temperature in a freezer cold room does not freeze the natural moisture present in the sub floor foundations. Otherwise, the floor of the cold room could crack and become unstable. The effects of this are known as frost heave and can be severe.