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

2. 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’.

3. 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

4. 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.

5. 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.

6. 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.

7. 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

8. 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.

9. Refrigerants
Refrigerant Designations
Key elements

10. Refrigerants
Refrigerant Designations
Key elements

11. Refrigerants
Refrigerant Designations
Key elements

12. Safety Group Classification System
Refrigerants
Safety Group Classification System

13. 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)

14. 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.

15. 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.

16. 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).

17. 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

18. 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.

19. Refrigerants Performance Comparison For Common Refrigerants
Characteristic
R407C
R134a
R410A
Glide 6K 0K
<0.5K
Global Warming Potential
1610
1300
1890
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.

20. 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.

21. R22 P-h Chart

22. R134a P-h Chart

23. R-290 P-h Chart

24. R404A P-h Chart

25. R407 P-h Chart

26. R410A P-h Chart

27. R600a P-h Chart

28. R717 P-h Chart

29. Refrigerants Identification
Identification of Refrigerant Pipework
BS 1710:1984

30. 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)

31. Refrigerants Identification

32. 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

33. 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

34. Contacts:- STROMA Certification Ltd – Contacts Web Links
Contacts:-
STROMA Certification Ltd.
4 Pioneer Way, Castleford, WF10 5QU

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