Industrial Refrigeration Equipment
Refrigeration is the process of mechanically cooling or reducing the temperature of a space, a product or a process. There are two primary applications of industrial refrigeration equipment:
- Cooling, freezing and temperature maintenance during storage, transportation and distribution of food products
- Air conditioning systems
Other applications of industrial refrigeration can be found in chemical plants, in manufacturing and construction, in ice and snow sports and in environmental test chambers. In some industries, most notably food and drink and chemicals, refrigeration accounts for a significant proportion of overall site energy costs.
There are eight sub-technologies within the industrial refrigeration technology category included in the ETL:
- Absorption & Other Heat Driven Cooling & Heating Equipment
- Air-cooled condensing units
- Automatic permanent refrigerant leak detection
- Refrigeration system controls
- Evaporative condensers
- Packaged chillers
- Refrigeration compressors
- Air blast coolers
Absorption and Other Heat Driven Cooling & Heating Equipment
This category only covers products installed as part of a Combined Heat and Power (CHP) scheme that has awarded a certificate from the CHP Quality Assurance (CHPQA) programme. The absorption chiller’s useful chilling effect must be driven by heat derived from the CHP plant. The absorption plant is assessed with the CHP plant under the CHPQA programme*.
Absorption coolers (chillers) are heat-driven (as opposed to electrically driven) machines used in industrial refrigeration to cool a process or product.
Air-Cooled Condensing Units
An air-cooled condensing unit consists of a compressor and an air-cooled condenser combined with various ancillary components, such as a liquid receiver, shut off valves, filter dryer, sight glass and controls.
The unit is factory assembled and wired as a complete unit. It provides a convenient method for ‘powering’ a cold room or other cooling equipment. Refrigerant vapour from the evaporator is compressed and condensed to a high pressure liquid for return to the evaporator via the expansion valve.
Medium and low temperature condensing units are widely used for frozen and chilled food storage. Evaporating temperatures are typically -35°C for frozen products and -10°C for chilled products. While high temperature units are used in air conditioning applications.
Automatic Permanent Refrigerant Leak Detection
Automatic permanent refrigerant leak detection systems are products designed to continuously monitor the atmosphere in the vicinity of refrigeration equipment and, in the event of detection of refrigerant, raise an alarm. This improves the energy efficiency of the refrigeration system and reduces carbon emissions and other greenhouse gases. The majority of industrial refrigeration systems currently use either an HCFC or HFC refrigerant. Some systems use ammonia; however, ammonia detection devices are currently outside the scope of the ETL.
Refrigeration System Controls
Refrigeration system controllers vary enormously in function and complexity. The simplest control is a thermostat which controls the temperature of the cooled space. More complex refrigeration systems, such as those with multiple compressors, require more sophisticated control. When used in the right way, these controls can significantly reduce the amount of energy a refrigeration system uses. The ETL currently includes:
- System management units or packages consisting of one or more control units or modules that are designed to optimise an entire refrigeration system.
- ‘Add-on’ controllers that are designed to be used in conjunction with a specific system management unit or package, and enable the operation of additional refrigeration compressors, evaporators and condensers to be optimised.
The potential annual savings achieved as a result of selecting ETL listed refrigeration system controls, at an industrial site running 8 evaporators and one cold room are calculated as:
- 26,200 kWh
- 9.2 tonnes CO2
Condensers are used in a refrigeration system to liquefy the refrigerant gas discharged by the compressor. In an evaporative condenser, the gas to be condensed flows through a coil which is continually wetted on the outside by recirculated water. Air is drawn over the coil, evaporating some of the water.
An evaporative condenser has two advantages over an air-cooled type:
- The evaporation of water is more effective at removing heat than dry air.
- The heat is rejected against the wet bulb ambient temperature rather than the dry bulb. The wet bulb temperature is up to 8°C lower than the dry bulb in hot weather.
Packaged chillers are factory assembled refrigeration units that are designed to cool liquid using a self-contained, electrically-driven mechanical vapour compression system. A packaged chiller includes the refrigeration compressor(s), controls and the evaporator in the packaged unit. The condenser may be built-in or remote.
The ETL covers four categories of products:
- Air-cooled packaged chillers that provide cooling only.
- Air-cooled, reverse cycle, packaged chillers that provide both heating and cooling.
- Water-cooled packaged chillers that provide cooling only.
- Water-cooled, reverse cycle, packaged chillers that provide both heating and cooling.
By selecting an ETL listed 400kW air cooled packaged chiller, rather than a non-compliant unit, the potential annual savings are calculated as:
- 41,800 kWh
- 14.7 tonnes CO2
The compressor in a refrigeration system compresses the refrigerant gas from the low pressure of the evaporator to a higher pressure so that it can condense in the condenser, thus rejecting heat to ambient air or water.
Commercial & Retail Refrigeration
Refrigeration is the process of mechanically cooling or reducing the temperature of a space, a product or a process.
There are two primary applications of commercial refrigeration equipment:
- Cooling, freezing and temperature maintenance during storage of food and drink products.
- Air conditioning systems.
There are six sub-technologies within the commercial refrigeration technology category of the Energy Technology List:
- Cellar cooling equipment
- Professional refrigerated storage cabinets
- Refrigerated display cabinets
- Curtains, blinds, doors and covers for refrigerated display cabinets
- Refrigeration compressors
- Refrigeration system controls
Cellar Cooling Systems
Cellar cooling systems maintain an indoor (cellar) environment at 10-12°C – suitable for the storage of chilled beverages and are used in pubs, restaurants and hotels.
There are three types of cellar cooling system eligible for the ETL:
- Split systems with the evaporator in the cellar and the condensing unit external (usually outside) are the most common type.
- Dual split systems, comprising two evaporators and one condensing unit.
- Free cooling units. These provide “free cooling” by using a fan to draw in outdoor air when the ambient temperature is sufficiently low.
Example: By installing an ETL listed 7.3kW cellar cooling system in place of a non-listed system of the same size the potential annual savings are calculated as:
- 4,900 kWh
- 1.7 tonnes CO2
Professional Refrigerated Storage Cabinets
Professional refrigerated storage cabinets (PRSCs) are appliances which have one or two solid doors and are typically used for the storage of food and beverages in commercial kitchens. They hold chilled food at between -1°C and 5°C and frozen food at between -18°C and -15°C.
Cabinets with single and double doors, larder and chest type, counter and under counter models for the storage of chilled and frozen food are listed on the ETL. PRSCs are fitted with solid faced lids, doors or drawers and are not used for displaying food (see instead refrigerated display cabinets section).
Refrigerated Display Cabinets
Refrigerated display cabinets are used by food retailers to exhibit food and beverages. The cabinet involves one or more evaporator/expansion device which uses a liquid refrigerant supplied by an integral condensing unit or a remote system.
All the common types of cabinet are listed on the ETL, including multi decks, chest freezers, upright freezers with glass doors and serve-over cabinets. They cover a wide range of storage temperatures from frozen food at -18°C, to chilled food at 5°C and at 10°C.
Example: By installing an ETL listed 2.5m open-fronted chilled food cabinet in place of a non-listed system of the same size the potential annual savings are calculated as:
- 2,000 kWh
- 0.7 tonnes CO2
Curtains, Blinds, Doors and Covers for Refrigerated Display Cases
Many refrigerated display cases are open-fronted, which significantly increases the heat load on the refrigeration system. There are various components available that can be added to reduce the heat load. These include:
Strip curtains – overlapping, transparent plastic strips that fit permanent to the open front of display cases.
- Doors – sliding or hinged transparent doors that fit permanently to the open front of display cases.
- Covers (bubble lids) – rigid plastic covers that fit permanently to the top of open freezers.
- Blinds – roller-type blinds fitted to the front of cabinets and may incorporate a motorised control system.
- Enhanced air flow management devices – these guide cold air more efficiently down the front of the open fridge cabinet.
To be effective in reducing the heat load, and therefore improving energy efficiency, care should be taken to ensure they are fitted correctly.
The compressor is part of a refrigeration system and works by compressing the refrigerant gas from a lower pressure to a higher pressure. The gas subsequently condenses, thus rejecting heat to ambient air or water in the condenser. The ETL covers the following types of refrigeration compressors:
- High temperature with HFC or HC refrigerant.
- Medium temperature with HFC or HC refrigerant.
- Low temperature with HFC or HC refrigerant.
- Medium temperature transcritical/subcritical with R744 refrigerant.
- Low temperature transcritical/subcritical with R744 refrigerant.
- Low temperature subcritical cascade with R744 refrigerant.
By installing an ETL listed compressor instead of a market average unit, the potential annual savings are calculated as:
- 2,970 kWh
- 1,040 kg CO2
Refrigeration System Controls
Refrigeration system controllers vary enormously in function and complexity. The simplest control is a thermostat which simply controls the temperature of the cooled space. More complex refrigeration systems, such as those with multiple compressors, ideally require more sophisticated control. When used in the right way, these controls can significantly reduce the amount of energy a refrigeration system uses.
The ETL currently includes:
- System management units that are designed to optimise an entire refrigeration system, including the operation of a refrigeration compressor(s), evaporator(s) and condenser(s).
- ‘Add-on’ controllers that are designed to be used in conjunction with a specific system management unit, and enable the operation of additional refrigeration compressors, evaporators and condensers to be optimised.