The document discusses refrigerants and their responsible use according to ASHRAE's position. It provides an overview of refrigerants and alternative technologies like CO2, hydrocarbons, and ammonia. It addresses issues for consideration like high ambient temperatures challenges, remaining open questions, and recommendations for future research on balancing safety, efficiency, cost and environmental impacts of refrigerants.

1. Refrigerants and their Responsible Use
ASHRAE Position Document
THE LATEST TECHNOLOGY IN AIR CONDITIONING AND REFRIGERATION INDUSTRY
ENERGY ISSUES AND CLIMATE CHANGE
NEW REFRIGERANTS, NEW EUROPEAN REGULATIONS AND CERTIFICATIONS,
MOBILE AIR CONDITIONING AND REFRIGERATED TRUCKS
Politecnico of Milan 7th- 8th June 2013
Walid Chakroun
ASHRAE

2. Contents
What is ASHRAE Position Document
Refrigerants Overview
Alternative Technologies
Issues for Considerations

3. ASHRAE Position Document
ASHRAE position documents are
approved by the Board of Directors and
express the views of the Society.

4. Pressure - Enthalpy Diagram

5. Definition
“Refrigerants are the working fluids in
refrigeration, air-conditioning, and heat-pumping
systems. They absorb heat from one area, such as
an air-conditioned space, and reject it into
another, such as outdoors, usually through
evaporation and condensation, respectively.”

7. Map of Refrigerant Change

8. Domestic
Refrigerators
& Freezers
Automotive
Air Cond’g
Room Air
Conditioners
Unitary Air
Conditioners
& Heat Pumps
Commercial
Air Cond’g &
Refrigeration
Large Air
Conditioning
Cooling Capacity
Fractional 200 kW (50 tons)
Reciprocating
Fractional 10 kW (3 tons)
Rotary
5 kW (1.5 tons) 70 kW (20 tons)
Scroll
150 kW (40 tons) 1500 kW (400 tons)
Screw
350 kW (100 tons) and up
Centrifugal

9. 9
100101.1
0
2
4
6
8
10
12
14
16
18
WATER COOLED CHILLER DUTY
CFM/TON
DELTAH,(Btu/lb)
POSITIVEDISPLACEMENT,
ROTARY,SCROLL,RECIP,SCREW
CENTRIFUGAL
113
123
11
114
124
134
152a
134a
12
500
22
502
125
507
143a
410A
32
Application Considerations
 The refrigerant and
application determine
 Flow
 Lift
 PD Compressors are
ideally suited for
higher lift
 Centrifugal
Compressors have
high volumetric flow

10. Where Are We Now
HFCs are greenhouse gases and the value of GWP quantifies this
effect on global warming-- In some applications, the “indirect” effect
of producing energy is much greater than the GWP effect of the
refrigerant itself.
Total equivalent warming impact (TEWI)--include both direct and
indirect impacts of refrigeration systems--Life cycle climate
Performance LCCP
Under the Kyoto Protocol, no specific mandates for reductions or
phase out of the HFCs -European Union enacting regulations on HFCs
--F-Gas Legislation-Some countries went even beyond by proposing
an amendment to the Montreal Protocol to start phasing down HFC.
These developments led to renewed and increased interest in natural
refrigerants and the development of new low-GWP options.

11. Present Facts
The process of switching to Low GWP is moving at different speeds
around the world—Challenges for High Ambient Temperature countries
Refrigerants selection and their operating systems still not based on a
holistic analysis of multiple criteria- energy efficiency, system
performance, potential impact on community safety, risk to personal
safety, cost, and minimization of direct and indirect environmental
impacts.
Some HFOs are available in limited quantities, Not yet fully tested in all
applications. Some HFOs and lower-GWP HFCs have mild flammability
and cost is high.
No ideal refrigerant yet. Natural refrigerants, the HFCs, the unsaturated
HFCs (also known as HFOs), and possibly blends will continued to be
used.

12. Challenges- High Ambient Temperature
(TEAP, 2012)
 High ambient temperatures lead to high condensing temperatures and
pressures.—Consequences COPs drops 20%- 25%.
 Constrains in high discharge temperature and pressure lead to the choice of
“medium pressure” refrigerant such as HFC-134a or HFC-1234yf for single
stage systems.
 Lack of low-GWP refrigerants with a large refrigeration capacity in order to
replace R-404A or HCFC-22 in single stage refrigeration systems.

13. Alternative Technologies
 Which refrigerant to use :
-The answer is very size and application dependent.
-Selection of the correct refrigerant requires: capital
cost, operating cost (including energy and
maintenance), equipment size and location, operating
temperatures/pressures, facility staff capability and
local, national, and international regulations.

14. CO2 Technology
Pressures in CO2 systems are approximately ten times
higher than those in ammonia—special equipment
designs-different manufacturing process-high cost
High pressure results in high gas density, allows far
greater refrigerating effect to be achieved from a given
compressor.
-cost effective for smaller products that requires high
pressure rating.
At low temperatures (-30 to -50 oC), CO2 produces very
small reductions in saturation temperature for a given
pressure drop allowing higher mass flux in evaporators
and suction pipes without efficiency penalties.--

15. Hydrocarbon Technology
Hydrocarbon refrigerants have excellent environmental,
thermodynamic, and thermo-physical properties, however
they are highly flammable.
Hydrocarbon refrigerants provide a range of boiling points
with applicability from cryogenics to air conditioning.
Mostly used in European and Asian countries, used with
commercial refrigeration systems including beverage and
ice-cream machines, Transport refrigeration systems for
trucks, Chillers in the range 0.3 – 40 tons of refrigeration

16. Ammonia Technology
Readily available inexpensive, operates at pressures
comparable with other refrigerants, absorb large amounts
of heat when it evaporates, zero ODP, Zero GWP, low
TEWI.
Ammonia has a low boiling point (-28°F @ 0 psig), high
latent heat of vaporization (nine times greater than R-12).
Ammonia is toxic effect at higher concentrations (i.e. =
above 300 ppm)-self -alarming odor, easy to repair leaks,
lighter than air.
Ammonia’s use in the HVAC&R industry should be
expanded as regulatory and code officials become
informed of its relative safety.

17. Ammonia Technology
Barriers to expanding its use must be addressed:
-Some real and perceived, generally relate to human
health and environmental safety, and system installation
-Continue research on topics such as handling,
application, operation, control of emissions and new
technology.
-Maintain and develop standards and guidelines for
practical and safe application of ammonia in refrigeration
systems.

18. Questions Remain open
 Issues with natural refrigerants include flammability, toxicity, high pressures, or, in some cases,
lower operating efficiencies
 Concern about the high GWP of some HFCs ---calling to reduce it. Research to extend lower-GWP
HFCs into new applications.
 The reduction has been proposed as a phase-down of HFC’s, however no country has formally
adopted a proposal nor is it currently included in either the Kyoto or the Montreal Protocols.
 At the present time, some hydrofluoroolefins (HFOs) are available in limited quantities, but they are
not yet fully tested in all applications. In addition, some HFOs and lower-GWP HFCs have mild
flammability.
 Research is also investigating blends across these refrigerant classes to identify combinations that
may optimize performance and minimize negative aspects.
 End-of-life disposal of refrigeration and air-conditioning systems is another important issue. At that
time, refrigerant should be recovered and recycled or disposed of safely to prevent loss of the charge
to the atmosphere.

19. Research Recommendations
 balancing the safety, energy efficiency, cost, and environmental impact for
refrigerants using a consistent and comprehensive methodology across all
refrigerants and system types using benchmarks like LCCP, life cycle
assessment (LCA) or TEWI
 advancing the design and development of refrigeration and air conditioning
equipment that facilitate reduced refrigerant emissions
 developing methodologies and practices to minimize or prevent refrigerant
loss during installation, operation, maintenance, and decommissioning of
refrigeration systems
 developing new refrigerants that minimize environmental impacts and safety
concerns