BREEAM Free Cooling

[edit] Aim and benefits

Free cooling is promoted via BREEAM as it can reduce the need for mechanical cooling systems providing an energy and carbon saving. It can result in simpler building operation and easier maintenance. It can also contribute to reducing overheating for adaptation to climate change.

This issue offers the following potential benefits to end users and clients:

• Reduced energy consumption due to less cooling being required
• Increased thermal comfort for building occupants

[edit] When to consider

Concept Design Stage RIBA Stage 1 and 2

[edit] Step by step guidance

Free cooling is assessed as part of BREEAM Credit Ene 4 Low Carbon Design.

In order to achieve this element of the credit the Passive Design Analysis credit must first be achieved. The passive design analysis must include an analysis of free cooling and identify opportunities for the implementation of free cooling solutions.

The building must then use any of the following free cooling strategies to award the free cooling credit:

• Night time cooling
• Ground coupled air cooling
• Displacement ventilation (not linked to any active cooling system)
• Ground water cooling
• Surface water cooling
• Evaporative cooling, direct or indirect
• Desiccant dehumidification and evaporative cooling, using waste heat
• Absorption cooling, using waste heat
• The building does not require any significant form of active cooling or mechanical ventilation (i.e.. naturally ventilated).

The free cooling measure proposed must be verified and the energy reduction shown when compared to a mechanical system.

This is generally carried out via dynamic simulation modelling with the free cooling energy demand compared with a mechanical system and the associated energy savings reported. This will require the engineer to run two models - one the proposed design and the other a baseline to measure savings. The details of both should be included within the model report.

Free cooling is an enhanced passive design method that requires engineering design and modelling to demonstrate its effectiveness.

[edit] Questions to ask while seeking compliance

What free cooling strategy is proposed?

Will this strategy be implemented across the whole building? The credit cannot be award if free cooling is only utilised in part with mechanical cooling systems included elsewhere.

Who will carry out the analysis and what are qualifications do they have? Should be the building services engineer or an accredited energy assessor.

What tool is being used to model the free cooling demand reduction?

[edit] Tools and resources

BREEAM Manual

[edit] Tips and best practice

The free cooling should apply to all occupied spaces in the building. Small IT rooms and lift motor rooms are excluded.

Mechanical ventilation may only be used for small areas, e.g.. for kitchenettes and toilets.

Free cooling appraisal can typically be assessed using dynamic simulation modelling such as IES or TAS. This type of analysis is generally over and above what is carried out as part of the simulation duties on a project so needs to be included and assigned to the appropriate design team member.

[edit] Typical evidence

[edit] Design Stage

Confirmation the Passive design credit has been awarded and copy of the report detailing free cooling strategies.

Copy of the dynamic simulation modelling results showing feasibility of the free cooling strategy.

Drawings or specifications confirming the free cooling strategy will be implemented.

Confirmation the free cooling modelling and strategy has been prepared by a suitably qualified engineer/assessor.

[edit] Post Construction Stage

As Design Stage

[edit] Applicable Schemes

The guidelines collated in this ISD aim to support sustainable best practice in the topic described. This issue may apply in multiple BREEAM schemes covering different stages in the life of a building, different building types and different year versions. Some content may be generic but scheme nuances should also be taken into account. Refer to the comments below and related articles to this one to understand these nuances. See this document for further guidelines.

• UK New Construction 2014

BRE Global does not endorse any of the content posted and use of the content will not guarantee the meeting of certification criteria.

--Sarah Peterson 15:24, 20 Feb 2018 (BST)

--Tom Blois-Brooke 16:34, 01 Jul 2019 (BST)