What Is a Cold Room Refrigeration System?

A cold room is essentially a building component designed to cold constant freezing temperatures that align with the requirements of the things that they will hold. For instance, an industrial-grade commercial level cold room for restaurants will be set at a different temperature than the one designed for pharmaceuticals. Many experts agree that the cold room refrigeration system is perhaps the most essential part of the cold room envelope. However, to install a top-quality refrigeration system, one must first become acquainted with its different facets and components.

Essential Components of a Cold Room Refrigeration System

  • Compressor

    A compressor is essentially responsible for compressing the refrigerant gas. It is the heart of the whole operation. Therefore, it is important to opt for a compressor unit that matches the size of the cold room and the intended temperature it will be required to uphold.

  • Condenser

    The condenser is responsible for converting the refrigerant gas into liquid by cooling it down. It is important to liquefy the gas for concurrent functions.

  • Expansion Valve

    The expansion valve controls the flow of the liquified gas within the refrigeration system and determines when the liquified gas must expand and become vaporized.

  • Evaporator Coils

    When the liquified gas reaches the evaporator coils, it expands and then boils. This process requires a lot of energy to keep the coils cool throughout the process.

  • Circulation Fans

    Depending on the cold room refrigeration system, there can be either one or multiple circulations fans installed. These are responsible for passing air over the cool evaporator coils and into the cold room to maintain its cooling. Additionally, they may also pass air over pipes that contain antifreeze matter which has previously been cooled down via the evaporator. Finally, the fans are also responsible for evenly distributing cool air with the cold room thereby ensuring constant temperature within the room.

Different Types of Refrigerants

The type of refrigerant gas used in the cold room refrigeration system is determined by the type of system being installed. Here are some of the commonly used refrigerant gasses that will eventually be liquified via the compressor before being used:

  1. Ammonia

    Ammonia is perhaps the oldest and most common form of refrigerant gas used in refrigerant systems around the globe. Ammonia is generally used in centralized refrigeration systems that utilize a special machine room specifically installed for industrial or large-scale refrigeration systems that employ over 10,000 tonnes of cold storage.

  2. Freon

    Freon is most commonly used in small and medium-sized cold room refrigeration systems. Although it is widely used in cold storage rooms, experts recommend limiting its use in large cold room systems because of environmental concerns. The freon system can also be used in large cold room refrigeration systems with some ammonia.

  3. CO2

    The unique characteristics of CO2 only allow it to be used in ultra-efficient refrigeration systems such as the cascade or loading system. In these systems, the heat discharge temperatures are usually lower than the critical temperatures. For instance, if used in a cascade system, one of the stages; lower or higher will hold another refrigerant. Essentially, a lower temperature field is most suitable for a cascading system while a higher temperature field is best for a loading system. Due to the highly specialized functioning of the cascade system, it is considerably more expensive to install than the traditional ammonia and Freon systems.

Different Types of Compressor Units

Choosing the right compressor unit for your refrigeration system depends on the size of the cold room and the intended temperature it will be working on. One of the best features of the compressor unit is that it can be used with multiple other compressors. This helps ensure the reliable functioning of the refrigeration system. Additionally, multiple compressors are more economical especially when the refrigeration system runs on multiple different loads.

Here are the three common kinds of compressor units used in refrigeration systems:

  1. Reciprocating Compressors

    Semi-hermetic reciprocating compressors are best suitable for cold rooms with a comparably smaller capacity.

  2. Screw Compressor

    On the other hand, cold rooms with considerably larger capacities work well with open screw compressors. For instance, ammonia refrigeration systems usually employ open-type compressors, that mainly use open screw compressors.

  3. Scroll Compressors

    Scroll compressors compress the refrigerant gas by increasing its pressure and temperature. By moving in a singular circular motion, these are less noisy and much smoother than reciprocating compressors. Additionally, they are also considered more reliable and energy-efficient because of their fewer parts.

Different Types of the Liquid Supply

The liquid supply system is responsible for moving the refrigerant from the condenser to a pressure-reducing device. There are four different types of liquid supply systems available, direct expansion supply, gravity supply, liquid supply, and air pump supply. However, direct expansion and barrel pump forced liquid supply systems are the most commonly used ones in refrigeration systems.

The direct system uses the refrigerant directly instead of using a secondary coolant loop. It is one of the most common types of liquid supply systems used in small refrigeration systems.

In a gravity supply system, the liquid is moved from the feed accumulator to the evaporator with the help of gravity.

Barrel pump forced liquid supply systems are mostly used in large-scale refrigeration systems. Although the evaporator has a high exchange rate and a well-balanced cooling effect, the increased machine area also means a higher initial investment. Additionally, while the operating system of this liquid supply system is user-friendly and extremely reliable, the system oil return can be complicated. On the other hand, it is also well suited for long-distance liquid supply and known to increase the overall operational efficacy of the compressor.


In a nutshell, refrigeration systems are designed to compress