Pol 01 Impact of refrigerants

Aim

To reduce the level of greenhouse gas emissions arising from the leakage of refrigerants from building systems.

Assessment criteria

This issue is split into two parts:

• Buildings that use no refrigerants (3 credits)

OR for buildings that use refrigerants

• Pre-requisite
• Impact of refrigerant (1 to 2 credits)
• Leak detection (1 credit).

The following is required to demonstrate compliance:

Three credits - No refrigerant use

1. Where the building does not require the use of refrigerants within its installed plant/systems.

OR alternatively, where the building does require the use of refrigerants, the three credits can be awarded as follows:

Pre-requisite

2. All systems (with electric compressors) must comply with the requirements of BS EN 378:20081BS EN 378 Refrigerating systems and heat pumps - Safety and environmental requirements, BSI, 2008 (parts 2 and 3) and where refrigeration systems containing ammonia are installed, the Institute of Refrigeration Ammonia Refrigeration Systems Code of Practice2Ammonia Refrigeration Systems Code of Practice, Institute of Refrigeration, 2009.

Two credits - Impact of refrigerant

3. Where the systems using refrigerants have Direct Effect Life Cycle CO₂ equivalent emissions (DELC CO_2e) of ≤ 100 kgCO_2e/kW cooling/heating capacity. To calculate the DELC CO_2e please refer to the Relevant definitions in the Additional information section and the Methodology section.

   OR

4. Where air-conditioning or refrigeration systems are installed the refrigerants used have a Global Warming Potential (GWP) ≤ 10.

OR

One credit - Impact of refrigerant

5. Where the systems using refrigerants have Direct Effect Life Cycle CO₂ equivalent emissions (DELC CO_2e) of ≤ 1000 kgCO_2e/kW cooling/heating capacity.

One credit - Leak detection

6. Where systems using refrigerants have a permanent automated refrigerant leak detection system installed; OR where an inbuilt automated diagnostic procedure for detecting leakage is installed. In all instances a robust and tested refrigerant leak detection system must be installed and must be capable of continuously monitoring for leaks.
7. The system must be capable of automatically isolating and containing the remaining refrigerant(s) charge in response to a leak detection incident (see Pol 01 Impact of refrigerants).

Checklists and tables

None.

Compliance notes

Methodology

The number of Pol 01 BREEAM credits achieved is determined by the assessor using the BREEAM Pol 01 calculator.

The Direct Effect Life Cycle CO_2e emissions (DELC) per kW of cooling/heating capacity are calculated using the following equation:

Where:

Refrigerant loss operational: (Ref_charge x Sys _op-life x (L1 + L2 + S1 + S2))/100

Refrigerant loss system retirement = Ref_charge x (1 - (Ref _RecEff/100))

Where:

1. Ref_charge: Refrigerant charge (kg)
2. Sys_op-life: System operational lifetime (years)
3. Ref_RecEff: Refrigerant Recovery Efficiency factor (%)
4. L1: Annual Leakage Rate (units: % Refrigerant charge)
5. L2: Annual Purge Release factor (% Refrigerant charge)
6. S1: Annual Service Release (% Refrigerant charge)
7. S2: Probability factor for catastrophic failure (% refrigerant charge loss/year)
8. GWP: Global Warming Potential of refrigerant
9. Cooling/heating capacity (kW).

The following default values must be used, where system specific data is not available:

Sys_op-life: System operational design life (years): see Table 59

Ref_RecEff: Refrigerant recovery efficiency factor (%): 95

L1: Annual leakage rates (% refrigerant charge): see Table 60 .

L2: Annual purge release factor (% refrigerant charge): 0.5 (if the system does not require an annual purge, zero should be used).

S1: Annual service release (% refrigerant charge): 0.25 (this applies where the system requires opening up to carry out the annual service. For systems which do not require opening up, there will be no associated annual release of refrigerant, therefore a default of zero should be used).

S2: Probability factor for catastrophic failure (% refrigerant charge loss/year): 1 (based on a failure rate of 1 in 100 systems).

The following information must be sourced from the design team's mechanical and electrical engineer and/or system manufacturer:

• System type
• Ref_charge: Refrigerant charge (kg)
• GWP: Global Warming Potential of refrigerant(s)
• Cooling/heating capacity (kW).

Table 59 Default system operational design life values

Table 60 Average annual leakage rates for the UK

Evidence

Additional information

Relevant definitions

Direct effect life cycle (DELC) carbon dioxide equivalent

A measure of the effect on global warming arising from emissions of refrigerant (in the case of this BREEAM assessment issue) from the equipment to the atmosphere over its lifetime (units: kgCO₂eq.). The calculation involves estimating the total refrigerant release over the period of operation and subsequent conversion to an equivalent mass of carbon dioxide. Should the system use several different refrigerants, e.g. a primary refrigerant and a secondary coolant, or a cascade system, individual calculations are made for all refrigerants which contribute to the direct effect (see Pol 01 Impact of refrigerants section for a description of how DELC is calculated).

Moderately airtight enclosure

This can be defined as an enclosure that does not produce a draught or significant fresh air ingress that would dilute any leaked refrigerant gas (dilution may prevent detection).

Refrigerant leak detection

An automated permanently installed multi-point sensing system, designed to continuously monitor the atmosphere in the vicinity of refrigeration equipment and, in the event of detection, raise an alarm. The system may be aspirated or have multiple sensor heads linked to a central alarm unit or BMS. Various sensor types are available including infra-red, semi-conductor or electro-chemical.

Refrigerant recovery

The process of removing refrigerant from a system and storing it in an airtight container.

Refrigerant pump down

The specification of automatic refrigerant pump down can further limit potential losses and damage to the environment and have subsequent economic benefits to the building owner. Under the United Kingdom Environmental Protection Act 1990 unwanted refrigerant and refrigerating system oil are classified as either controlled or hazardous waste. Not only is it an offence to discharge them to the environment, but there are procedures regarding transport, storage, transfer of ownership and ultimate disposal. Article 16 of EC Regulation 2037/2000 specifies that used CFCs and HCFCs must be recovered for destruction or recycling/reclamation.

Robust and tested refrigerant leak detection system

This is normally defined as that included on the Enhanced Capital Allowance (ECA) Energy Technology Product List4www.etl.decc.gov.uk. (or an equivalent list). Where the system does not fall within the scope of the ECA energy technology product list or an equivalent list, the design team must demonstrate to the assessor that the system specified meets the principles of the scheme as far as is applicable.

Small-scale white goods

These should be defined as domestic scale white goods and would also include small individual display cabinets, for example drinks cabinets in small retail shops.

Systems using refrigerants

The criteria of this issue apply to air-conditioning and refrigeration systems installed in the building for the following uses, regardless of the systems refrigerant charge (kg), including:

• Comfort cooling and/or space heating (including assessment of refrigerants in heat pumps)
• Cold storage, including commercial food/drink display cabinets but excluding small scale white goods (see definition above)
• Process-based cooling loads e.g. servers/IT equipment.

Global Warming Potential (GWP)

GWP is defined as the potential for global warming that a chemical has relative to 1 unit of carbon dioxide, the primary greenhouse gas. In determining the GWP of the refrigerant, the Intergovernmental Panel on Climate Change (IPCC) methodology using a 100-year Integrated Time Horizon (or ITH) should be applied.

Refrigerant

There are three main make-ups of refrigerants:

1. Hydrogenated Fluorocarbon Refrigerants (HFCs) are made up of hydrogen, fluorine, and carbon. Because they do not use a chlorine atom (which is used in most refrigerants) they are known to be one of the least damaging to the earth's ozone layer.
2. Hydrogenated Chlorofluorocarbon Refrigerants (HCFCs) are made up of hydrogen, chlorine, fluorine, and carbon. These refrigerants contain minimal amounts of chlorine; they are not as detrimental to the environment as some other refrigerants.
3. Chlorofluorocarbon Refrigerants (CFCs) contain chlorine, fluorine and carbon. These refrigerants carry high amounts of chlorine so they are known to be the most hazardous to the ozone layer.

The use of CFCs and HCFCs as refrigerants has been addressed under the Montreal protocol. Phase-out programmes have been agreed resulting in these substances no longer being used as refrigerants in all new installations and most existing situations. The industry's favoured replacements are currently HFCs which are often potent global warming contributors. Hydrocarbons and ammonia-based refrigerants have low or zero GWP and are therefore preferred long term options. These are now widely available and are valid alternatives to HFCs in all buildings, provided health and safety issues are fully addressed.
The United Nations Environment Programme (UNEP) hosts a HCFC Help Centre which contains information about the management and phase out of HCFCs and alternatives to HCFCs in the refrigeration and air-conditioning sector http://www.uneptie.org/ozonaction/topics/hcfc.asp.

Other information

Automatic isolation and containment of refrigerant

An example of a system which would meet criterion 7 could be one which initiates an automated shut down and pump down of the refrigerant into a separate storage tank.

Common refrigerants

Table 61 List of some common refrigerant types with low GWP

The formula used to calculate the Direct Effect Life Cycle CO_2e emissions in BREEAM is based on the Total Equivalent Warming Impact (TEWI) calculation method for new stationary refrigeration and air-conditioning systems. TEWI is a measure of the global warming impact of equipment that takes into account both direct emissions (as assessed in this BREEAM issue) and indirect emissions produced through the energy consumed in operating the equipment (which is assessed in the BREEAM energy section).

Refer to BS EN 378-15BS EN 378-1 Refrigerating systems and heat pumps - Safety and environmental requirements Part 1: Basic requirements, definitions, classification and selection criteria. BSI, 2008 and the British Refrigeration Association's (BRA) Guideline Methods of Calculating TEWI for further details. The BRA publication also includes sectorial release factors for new systems designed to best practice standards.

REAL Zero

The refrigeration and air-conditioning sector supported by the Carbon Trust is working across all sectors of business and industry, to help achieve significant reductions in carbon emissions due to refrigerant leakage from installed systems. The Institute of Refrigeration led initiative, Real Zero, is building a clearer understanding of where and why leakage occurs as well as how to prevent it.

For further information including guidance notes, calculators/tools and case study information visit: http://www.ior.org.uk/real zero.

BREEAM UK New Construction non-domestic buildings technical manual 2014
Reference: SD5076 – Issue: 5.0
Date: 23/08/2016
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