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Department for Business, Energy and Industrial Strategy

Evaporative Condensers

1.1    Scope

Evaporative condensers allow refrigeration systems to operate with lower head pressures and higher efficiencies than can be achieved using air-cooled condensers or water-cooled condensers. They use evaporative cooling to remove heat from the refrigerant vapour.

Evaporative condensers are generally used in larger refrigeration systems and the Energy Technology List (ETL) Scheme aims to encourage their purchase as an alternative to lower efficiency solutions.

To be eligible for inclusion on the ETL, products shall meet the requirements as set out below.

1.2    Definitions

Evaporative Condensers are specifically designed to cool and condense high-pressure refrigerant vapour by means of a heat exchanger that has a wetted external surface across which air is blown by a fan. 

1.3    Requirements 

1.3.1    Eligibility requirements  

To be eligible, products shall:

  • Incorporate:

     a)    A heat exchanger that is designed to cool and condense refrigerant vapour.

     b)    An axial or radial/plug fan that blows air over/through the heat exchanger.

     c)    A blow down facility for the water storage tank to enable total dissolved solids content of the water in the storage tank to be controlled.

     d)    And either: 
        –    A mechanism that wets the external surface of the heat exchanger that includes a water pump and a water storage tank; or
        –    A hybrid mechanism that wets the external surface of the heat exchanger at high ambient temperatures (evaporative cooling) and switches to dry operation when a user defined dry switch-point is reached at lower temperatures (dry cooling). The hybrid mechanism will also include a water pump and a water storage tank.

  • Conform with the requirements of The Pressure Equipment (Safety) Regulations 2016 in respect of its design, manufacture and testing procedures, or have an appropriate Conformity Assessment mark.
  • In addition, where products incorporate an automatic blow down control system, they shall also incorporate a means of measuring total dissolved solids content of the water in the storage tank. 

1.3.2    Information requirements 

Suppliers shall report the following parameters for each model, which will be published on the ETL Product Search:

  • The compatibility of the Evaporative Condenser with a variable frequency drive (VFD). 
  • The heat rejection capacity of the Evaporative Condenser at UK operating conditions, specifically: 32ᵒC condensing and 21ᵒC wet bulb temperatures.
  • If applicable, the average capacity rating (kW) of the compressor used in the Evaporative Condenser. 

1.4    Verification for ETL Listing 

There are no testing requirements, however manufacturers shall provide sales and technical brochures to evidence the conformity of their products against the requirements from section 1.3.  

1.5    Conformity testing

Products listed on the ETL may be subject to the scheme’s conformity testing programme in order to ensure listed models continue to meet the ETL requirements. 

1.6    Review 

1.6.1    Indicative review date 

This specification is scheduled to be reviewed during the 2025/26 review cycle.

1.6.2    Illustrative future direction of the requirements  

The next technical review will consider: 

  • Evaporative Condensers that incorporate VFD or EC motors as an eligibility requirement
  • Any progress Eurovent has made in establishing a testing standard for Evaporative Condensers
  • Adiabatic Condensers and evaluate the effectiveness of Evaporative Condensers compared to Adiabatic Condensers