.. Level 3 Air Conditioning Inspections for Buildings 13. Refrigerants (Day 1) PRESENTED BY Anthony Balaam aircon@stroma.com

Refrigerants What is a Refrigerant? 1. “The refrigerant is the working fluid of the refrigeration cycle, which is circulated by the ‘compressor’.” 2. It is a ‘compound’ used in a ‘heat cycle’ that undergoes a ‘phase change’ from a ‘gas’ to a ‘liquid’ and ‘back' again. 3. All substances that exist in ‘liquid’ and ‘vapour’ state ‘absorbs heat’ during ‘evaporation’ and therefore can be used as a ‘refrigerant’.

Refrigerants Air Conditioning Refrigerants:- 1. Should ‘evaporate’ at the ‘required cooling temperature’ at a ‘reasonable pressure'. 2. Be able to be ‘condensed’ by a readily available ‘cooling medium’ (usually ‘ambient air’) at a ‘practical pressure’. 3. Common refrigerants are usually one of :- 1. CFCs – Chlorofluorocarbons 2. HCFCs – Hydro chlorofluorocarbons 3. HFCs – Hydro fluorocarbons 4. HCs – Hydrocarbons 5. NH3 – Ammonia 6. CO2 - Carbon Dioxide

Hazards Refrigerants & Refrigerant/ Oil/ Water Mixtures etc. Hazards:- 1. Fire 2. Explosion 3. Toxicity 4. Caustic effects 5. Freezing of skin 6. Asphyxiation 7. Panic Other risks include bursting or explosion due to over pressure of the refrigeration system, leading on from poor system design. Can lead to significant property damage and danger to people.

Health & Safety Regulations Air Conditioning Energy Assessors are expect to have awareness of additional regulations associated with refrigeration and heat rejection equipment covering:- Health and Safety 1. Health and Safety at Work etc. Act 1974 2. Management of Health and Safety at Work Regulations 1999:- Employers to assess risks to health and safety of employees. Appropriate measures to be undertaken for the prevention and control of risks. 3. Pressure Systems Safety Regulations 2000 :- All refrigeration systems with an input power greater than >25kW to be maintained properly and subject to a written scheme for regular safety inspections.

H&S Regulations 4. Pressure Equipment Regulations 1999 (pressure Equipment Directive) 1. Concerns design, manufacture and supply of equipment. 2. Covers all pressure equipment including: compressors, pipework, heat exchangers and safety devices. 3. Equipment to be manufactured and installed to meet certain requirements. 4. Subject to conformity assessment procedures. 5. Control of Substances Hazardous to Health Regulations:- 1. Employers to ensure that employees are not exposure to substances hazardous to health is prevented or adequately controlled. 2. it also covers exposure to refrigerants in plant rooms and control of legionella bacteria in water systems, including cooling towers and evaporative condensers.

H&S Regulations Other Guidance:- 6. Construction (Design and Management) (CDM) Regulations 1994:- 1. Requires designers to prepare a ‘Health and Safety File’ for the client. 2. For safety risk management when plant is maintained, repaired, renovated or decomissioned. 7. The Notification of Cooling Towers and Evaporative Condensers Regulations 1992 (SI 1992/225):- Requires that local authority is notified af all cooling towers and evaporative condensers. Other Guidance:- 1. BS EN 378: Refrigeration systems and heat pumps. Safety and environmental requirements 2. CIBSE GN1: CFCs, HCFCs, HFCs and halons 3. Institute of Refrigeration Safety Codes 4. HSC Approved Code of Practice and Guidance L8: Legionnaires’ disease: The control of legionella bacteria in water systems

Refrigerant key Elements As designers we have to consider the following key designation elements when choosing either the refrigerant, plant type and the type of work space and density being considered:- Safety Group the refrigerant applies to Flammability of the refrigerant Normal Boiling Point of the refrigerant Ozone Depletion Potential (ODP) Global Warming Potential (GWP) Occupancy category, whether ‘A’,’B’ and ‘C’ The next set of slides covers these elements from industry schedules and tables.

Refrigerants Refrigerant Designations Key elements

Refrigerants Refrigerant Designations Key elements

Refrigerants Refrigerant Designations Key elements

Safety Group Classification System Refrigerants Safety Group Classification System

Refrigerants New Refrigerants New refrigerants are blends of different substances, falling into two main categories:- Category 1 1. Low Ozone Depleting Potential (ODP) Used as transitional substances. And is based on HCFC R22 (E.g. R409A or R411B) Category 2 2. Zero ‘Ozone Depleting Potential’ (ODP) Have a longer term future. is based on HFCs (e.g. R404A or R407C) Or based on HCs (e.g. Care 30 or Care 50)

Transitional Substances:- Refrigerants Transitional Substances:- 1. Primarily used to convert existing systems. 2. Should not be specified for new equipment. 3. Include HCFC - R22 hence:- 1. Can operate with existing (mineral) oil in the system. 2. Conversion procedure is fairly simple – ‘drop in’ type procedure.

Refrigerants Blends are Based on HCFCs or HCs 1. Used to replace HCFC or CFC refrigerants. 2. No oil change necessary. Other Blends are Based on HFCs 1. Usually only used in new systems. 2. Otherwise oil change is needed.

Zeotropic Blend Issues:- Refrigerants Zeotropic Blend Issues:- 1. Blends behave differently in a system to a single substance like ‘R22’ or ‘R134a’. 2. At constant pressure a pure refrigerant has a single evaporating/condensing ‘temperature’. 3. Some blends evaporate and condense across a ‘small temperature’ range. 4. These are said to have a ‘temperature glide’ – hence zeotropic blends. When a refrigerant is a saturated liquid (e.g. about to start evaporating) it is at the ‘bubble temperature’ When the refrigerant is a saturated vapour (e.g. about to start condensing) it is at the ‘dew temperature’. 5. The difference between ‘bubble temperature’ and ‘dew temperature’ is the ‘temperature glide’ (usually between 1K to 8K difference).

Refrigerants Temperature Glide:- The temperature glide through evaporation and condensation can be a problem for the refrigerant control in water chilling. Makes component selection critical. Condenser Evaporator

Phase Out and Replacements Refrigerants Phase Out and Replacements ‘R134a’ has been the replacement for ‘R12’ and ‘R22’. Domestic, commercial refrigeration, including centrifugal compressors and water chillers. ‘R407C’ has been developed to replace ‘R22’. R407C is a blend of R32/R125/R134a, with a high ‘temperature glide’. R22 is only found in existing plant and is to be phased out by 2015. ‘R410A’ is a blend of ‘R32’ and ‘R125’. Has a minimal ‘temperature glide’, but as a higher working pressure. Commonly used in direct expansion (DX)systems, variable refrigerant flow (VRF) systems and water chilling applications.

Refrigerants Performance Comparison For Common Refrigerants Characteristic R407C R134a R410A Glide 6K 0K <0.5K Global Warming Potential 1610 1300 1890 Pressure @ 50˚C 19.6 bar 13.2 bar 30.8 bar Compressor COP* 95-101% 101% 92-100% Heat transfer* Same Slightly less Higher Tubing size* Larger Smaller System performance* 95-100% 98-106% System cost* Slightly higher Slightly lower Extent of re-design required* Minor Significant *Compared to R22 Evaporative and dessicant cooling are often used in conjunction with vapour compression or absorption, as they can only produce cooling temperatures down to about 15 °C. Absorption cooling using free thermal energy such as solar power will have almost infinite efficiency and zero carbon footprint, but if absorption systems are gas or hot water driven, their efficiency will be low and their carbon footprint high. (See section 6 for more information on absorption cooling.) Carbon dioxide is being increasingly used in computer systems with the cooling built into the computer hardware. Air cycle cooling is still at the development stage for building services applications. There are other methods of cooling such as thermoelectric, magnetic, vortex, Stirling cycle etc, which have very limited application at present.

Common Refrigerants:- R134a, R407C and R410A are HFC fluids. Have a high ‘Global Warming Potential’ (GWP). Regarded as transitional fluids; to be eventually replaced by zero-GWP fluids. Zero-GWP fluids include Ammnonia, Propane and Butane Issues regarding these are toxicity and flamability are in question. BS EN 378 and Institute of Refrigeration’s “Safety Codes” will apply. Ammonia is currently offered in packaged water chillers. Propane and Butane are offered in small DX and water chilling applications. Carbon Dioxide is increasingly used for computer hardware cooling.

R22 P-h Chart

R134a P-h Chart

R-290 P-h Chart

R404A P-h Chart

R407 P-h Chart

R410A P-h Chart

R600a P-h Chart

R717 P-h Chart

Refrigerants Identification Identification of Refrigerant Pipework BS 1710:1984

Refrigerants Identification Identification of Refrigerant Pipework Colour names may vary, however colour code with respect to BS 4800 remains the same. BS 1710:1984 (18 E 51) (16 C 37) (06 D 45) (02 C 37) (14 E 51) (08 C 35) (08 C 35)

Refrigerants Identification

Reference Material “Heating, Ventilation, Air Conditioning and Refrigeration”, CIBSE Guide B, Chartered Institute of Building Services Engineers, 2005 “CIBSE KS13: Refrigeration”, CIBSE Knowledge Series, Chartered Institute of Building Services Engineers, 2008 “ASHRAE Handbook: Fundamentals”, American Society of Heating, Refrigeration and Air Conditioning Engineers, 2001 “BS EN 378: Specification for Refrigeration Systems and Heat Pumps; Part 1: 2000: Basic Requirements, Definitions, Classification and Selection Criteria; Part 2: 2000: Design, Construction, Testing, Marking, and Documentation; Part 3: 2000: Installation Site and Personal Protection; Part 4: 2000: Operation, Maintenance, Repair and Recovery”, London: British Standard Institution, 2000 “The Pressure Systems Safety Regulations 2000”, Statutory Instrument No.128, Office of Public Sector Information “Health and Safety at Work etc. Act 1974”, Office of Public Sector Information “Control of Substances Hazardous to Health Regulations”, Office of Public Sector Information

LEVEL 3 Air Conditioning ENERGY ASSESSORS TRAINING ANY QUESTIONS OR FEEDBACK ON ANY SLIDE Any questions or clarity needed over this topic and slides 33

Contacts:- STROMA Certification Ltd – Contacts Web Links www.stroma.com/certification Contacts:- STROMA Certification Ltd. 4 Pioneer Way, Castleford, WF10 5QU 0845 621 11 11 training@stroma.com

Day One - End Test 3. - NOS Units 1 and 2 – 26 Questions