Transcript Slide 1

Introduction to Variable Refrigerant Flow Systems
Allen Anaya
Application Consultant
WM Carroll, LLC
Ph: 505-268-6776
Cell: 505-385-7338
Fax: 505-255-1329
E-Mail: [email protected]
11/16/2010
NM ASHRAE – Introduction to Variable
Refrigerant Systems
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Agenda
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Refrigerant Systems
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What is VRF?
V R F
Variable Refrigerant Flow
Also referred to as VRV ® – Variable Refrigerant Volume
VRV is a registered trademark
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VRF History
• 1973 – Global oil crises
• 1979 – New energy efficiency laws passes in
Japan
• 1980 – Chiller design engineers challenged
with making a higher efficiency chiller
• 1982 – The worlds first VRF System is
launched
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Refrigerant Systems
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VRF Global History
• VRF world first’s
World’s first CO 2
VRF system is
developed
First globally available
heat recovery VRF
VRF is launched globally
1982
World’s first VRF
system is
developed
1987
Industry changing
piping and defrost
technology
Worlds first R410A VRF
1990
1991
1998
2003
2007
2008
Worlds inverter driven
VRF
World’s first R407C
VRF system is
developed
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2005
NM ASHRAE – Introduction to Variable
Refrigerant Systems
First water cooled VRF
system is launch in the
USA
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Development of VRF Market Japan
Buildings under 70,000ft2
•
•
By 1996 VRF had established itself as a proven technology with 34% market share
With increased market acceptance as a replacement to traditional applied central
systems VRF achieved 47% market share by 2001
– 9% share was taken from the chiller/central plant market
– The 4% taken from the split and package section was through replacing VAV
projects and allowing customer to afford the “chiller” they originally wanted
Packaged/Splits
32%
VRF
34%
Packaged/Splits
28%
VRF
47%
1996
Chillers/Central
Plant
34%
Chillers/Central
Plant
25%
2001
6
Development of VRF Market Japan
Buildings over 70,000ft2
• Further evidence of acceptance can be seen by the increase
in VRF market share in the larger applications
– 12% share taken from the chiller/central plant market
• This trend was common in Europe, Australia and now North
America
VRF
15%
Packaged/Splits
40%
Chillers/Central
Plant
45%
1996
VRF
32%
Packaged/Splits
35%
Chillers/Central
Plant
33%
2001
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VRF Concept
Chiller
VRF
Simple system
Complicated
Outdoor
unit
Cooling
tower
Energy efficient
Space-conscious design
Pump
Water piping
Pump
AHU
FCU
Inefficient part
load operation
For
For
cooling
heating
2 heat sources
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Managed by
engineer
Refrigerant piping
FCU
indoor
unit
Remote
controller
NM ASHRAE – Introduction to Variable
Refrigerant Systems
Individual control
Simple Operation
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VRF Concept
Simple system
One Manufacturer
Top floor
Space-conscious design
Individual control
Building floors
One Point Of Contact For
Technical Support
Simple Installation
Simple Operation
Remote controllers
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Simple Maintenance
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VRF Concept
• Think of a VRF system as a chiller that circulates refrigerant to each zone
instead of water
• A heat pump system is equivalent to a 2 pipe chiller
– Major benefit is smaller heat/cool changeover zones due to the modular
build up
• A heat recovery system is equivalent to a 4 pipe chiller system
Heat Pump
Heat Recovery
6 Ton
12 Ton
6 Ton
Cooling
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Cooling
Heating
Heating
NM ASHRAE – Introduction to Variable
Refrigerant Systems
Cooling
Cooling
Heating
Heating
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VRF Concept
HEAT RECOVERY VRF
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VRF Concept
Advanced Zoning Capabilities
• Total comfort for occupants
–
–
–
–
–
–
Office buildings
Hospitals
Assisted living facilities
Schools
Hotels
Retail space
• Reduced operating costs
– Shut down zones that are not in use
• Variable capacity design enables maximization of diversity
– Each zone is individually controlled
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VRF Concept
Where does a VRF system position?
• VRF has the following attributes:– Energy Efficient
– Tight Temperature Control
– Quiet Operation
– The Ability To Have Many Zones
– Large Capacity (Modular Build Up)
– Centralized Plant (long piping)
– Advanced BAS Control
– Premium Specification & Priced Product
• Special Advantage of Modular Design: If you loose 1 condenser, you
only loose a small part of the building; NOT the entire building.
• Modular design only requires installation of a zone as required;
entire cooling and heating system does not have to be piped during
initial construction
VRF competes most naturally as a chiller.
(this doesn’t mean it can only compete with chillers)
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Agenda
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How does VRF Operate?
HEAT TRANSFER MEDIA
Air
0.46 Btuh/lb
Water
8.98 Btuh/lb
Refrigerant
88.2 Btuh/lb
VAV
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VWV
NM ASHRAE – Introduction to Variable
Refrigerant Systems
VRF
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How does VRF Operate?
Inverter Drive System
+V
T(sec)
-V
Frequency (Hz)
• The inverter control adjusts the
supply frequency
• Thus the rotational speed of the
compressor is controlled
• Exactly the right amount of
refrigerant gas is pumped to meet
the cooling requirements
Inverter Box
+V
T(sec)
-V
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Frequency (Hz)
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Refrigerant Systems
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How does VRF Operate?
Inverter = Energy Efficiency
 The start/stop cycle is repeated less frequently
– reducing energy loss at startup
 As room temperature nears set point capacity
is automatically “throttled down”
 Capacity is regulated
when outdoor
temperature changes
 Startup time is
reduced by 1/3
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How does VRF Operate?
Other Inverter Benefits
•
•
•
•
•
Very low startup amperage
No locked rotor amps
No stress on windings or compressor frame
No “light flicker”
Lubrication of bearings increases before
speed increases
• System pressures increase gradually
reducing noise and stress on piping
• Quiet compressor startup
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NM ASHRAE – Introduction to Variable
Refrigerant Systems
How does VRF Operate?
Other Inverter Benefits
• Longer Run Periods at Lower Capacities
– Better Dehumidification
– Fewer compressor starts mean less wear and tear on
the compressor = longer life!
– Lower compressor speeds = higher system efficiency
since the condenser coil surface remains large in
relation to reduced capacity
– Higher efficiency = Lower electric bills!
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How does VRF Operate?
Electronic Expansion Valve (EEV) Control
• EEV’s receive ‘PID’ control feedback to adjust
refrigerant volume
PID Control
Signal
– Up to 2000 steps of control
 Continual management of
flow rate controls super heat
and coil capacity for optimum
performance and energy
efficiency
Valve
Mechanism
Inlet
Outlet
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How does VRF Operate?
Proportional, Integral & Derivative (PID)
• Electronic expansion valve using PID
– Continuously adjusts the refrigerant volume in response to load
variations
– Comfortable room temperature is maintained without the wide
temperature swings of a conventional system
T2
CPU
(PID Control)
T4
LEGEND
T1: Refrigerant Liquid Line Temp.
T2: Refrigerant Suction Line Temp.
T3: Return Air / Remote Sensor Temp.
T4: Controller Temperature Sensor
TSET: Controller Set Point Temp.
Controller
(TSET)
T1
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How does VRF Operate?
T2
System Capacity Control
T3
EACH INDOOR CONTROLS ITS CAPACITY VIA PID
CONTROL AND AN E.E.V.
CPU
(PID Control)
T4
Controller
(TSET)
T1
1
2
3
4
CONDENSING UNIT ADJUST THE INVERTER
COMPRESSOR TO PROVIDE THE REQUIRED CAPACITY
(Large or Small)
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Refrigerant Systems
LEGEND
T1: Refrigerant Liquid Line Temp.
T2: Refrigerant Suction Line Temp.
T3: Return Air / Remote Sensor Temp.
T4: Controller Temperature Sensor
TSET: Controller Set Point Temp.
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How does VRF Operate?
DC Fan Motor Efficiency
AC Fan Motor
DC Fan Motor
Magnet
100
DC Motor
Motor Efficiency [%]
• Efficiency improved in all
areas compared to
conventional AC motors,
especially at low speeds
90
Approx.
20%
Approx.
increase
40%
80
increase
AC Motor
70
10
20
30
40
50
60
70
80
90
100
110
Revolutions [rps]
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Agenda
• What is VRF?
– History
– Concept
• How does VRF Operate?
– Refrigerant
– Compressor
– Fan Coil
• Important Standards
– ASHRAE Standard 15
– AHRI-1230-2010
• VRF Benefits
– Installation & Design Flexibility
– User Comfort
• The Future of VRF in North America
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Important Standards / Code Information
Overview of ASHRAE Std 15
•
•
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Specifies minimum safety requirements in the event of a refrigerant leak
into an occupied space.
Safety Issues:
1. Flammable refrigerants causing injury or death by fire.
2. Toxic refrigerants possibly causing injury or death by poisoning.
3. Non flammable and non toxic refrigerants causing injury or death by
asphyxiation from oxygen displacement.
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Important Standards / Code Information
Scope of Standard 15
•
•
•
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Scope
2.1 This standard establishes safeguards for life, limb, health, and
property and prescribes safety requirements.
2.2 This standard applies
a. To the design, construction, test, installation, operation, and
inspection of mechanical and absorption refrigeration systems,
including heat pump systems used in stationary applications,
b. To modifications including replacement of parts or components
if they are not identical in function and capacity, and
c. To substitutions of refrigerant having a different designation.
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Refrigerant Systems
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Important Standards / Code Information
Basic Steps
• Determine volume of smallest occupied space (cu.ft.)
• Determine refrigerant qty potential of the smallest
occupied space (lbs)
• Check that refrigerant qty potential doesn’t exceed the
allowable Refrigerant Concentration Limit (RCL) per
1000cuft.
• Check routing of piping (must be non obstructive) in
corridors, lobbies and versus the RCL requirements
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Important Standards / Code Information
Compliance Responsibilities
• Specifies application, not manufacturing requirements.
• Impossible for a unit to comply, only an application can comply.
• Design engineer is responsible for assessment and compliance.
– ASHRAE Std 15 has an easy to follow “Users Handbook” that
can be purchased by the Engineer / Contractor.
• All units should comply with mandatory U.S. manufacturing
standards.
• ASHRAE Std 15 equivalent standards exist in Europe and Asia and
are just as stringent. “Direct” systems such as VRF are the most
common solution in these regions and are applied successfully to
meet these standards
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Important Standards / Code Information
Current Situation
• All VRF Equipment is currently
sold under a waiver from the
DOE
– No available testing and rating
standard
• This means that only full load
EER and COP can be published
• Advantage can not be taken of
the true VRV system benefits:– Part load performance
– Low ambient heating
capabilities
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Important Standards / Code Information
AHRI 1230
• The industry has been working on
the VRF testing and rating
standard for the last 5 years
– Now, the hard work has paid off!
• We are proud to announce that
the VRF testing and rating
standard, AHRI 1230, will be
launched and the efficiency levels
will be in ASHRAE 90.1 by January
2011
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Important Standards / Code Information
AHRI-1230 Explanation of the Ratings
• All efficiency values will be based on the total system performance
including:– Outdoor unit power input
– Power input of indoor units
– Piping loss correction factors to reflect real life building performance
• With this; We can now promote efficiency levels for Ducted, Ductless and
Mixed combinations
Rating
System Full Load EER
System Full Load COP
System Low Ambient COP (17°F)
IEER (Part Load Operation)
SCH (Heat Recovery Mode)
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Daikin VRVIII
PB Series
Other VRF





?
?
?
?
?
NM ASHRAE – Introduction to Variable
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Agenda
• What is VRF?
– History
– Concept
• How does VRF Operate?
– Refrigerant
– Compressor
– Fan Coil
• Important Standards
– ASHRAE Standard 15
– AHRI-1230-2010
• VRF Benefits
– Installation & Design Flexibility
– User Comfort
• The Future of VRF in North America
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VRF/VRV Benefits
Outdoor Unit
Indoor Units
 Main features
 Energy Saving
 Individual control
 Long refrigerant Piping
 Wide range of units
 Low Noise Level
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VRF/VRV Benefits
Users Comfort Accurate Temperature Control
VRF system
Conventional A/C
Room Temperature
30
25
20
Cooling mode with VRF System:
Down to 1F
15
10
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30
40
50
NM ASHRAE – Introduction to Variable
Refrigerant Systems
60
70
Min..
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VRF/VRV Benefits
User Comfort Low Operating Sound
• Ductless operating sound levels as low as 28dB(A)
• Ducted operating sound Levels as low as 35dB(A)
Cassette Ductless
Sound Levels
Standard Ducted
Sound Levels
45
44
41
40
34
31
40.0
28
35.0
33
29
39
38
45.0
45.0
35
40.0
35.0
30.0
30.0
25.0
25.0
20.0
20.0
15.0
15.0
10.0
10.0
5.0
5.0
0.0
0.0
12 MBH 24 MBH
Lo w F an
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36MBH
12 MBH 24 MBH
Low Fan
Hig h F an
NM ASHRAE – Introduction to Variable
Refrigerant Systems
36MBH
Hig h Fan
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VRF/VRV Benefits
Lightweight, Small & Flexible
• Indoor units are lightweight and compact
– Fit into nearly any ceiling space
• Outdoor units don’t require special cranes or
lifting devices
– Can be hauled using a hand-lift and the
building elevator
Conventional
System
VRV
System
• Installation by floor
– If necessary, installation can be done by
floor
• No need to wait until the full system is
installed to test the system sections
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VRF/VRV Benefits
For 10 Tons capacity
Reduced Intallation Space
Refrigerant R-410A
Ø 1-1/8“
Water
Ø 1/2“
Ø 2“
Ø 2“
Air
24“
Always two
ducts needed
16“
24“
49“
or
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or
NM ASHRAE – Introduction to Variable
Refrigerant Systems
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VRF/VRV Benefits
Advanced Controls Solutions
~ Ethernet
(for use in Lon Works
networks)
BMS
Fire alarm Security
~
HRV
Power supply facility
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Agenda
• What is VRF?
– History
– Concept
• How does VRF Operate?
– Refrigerant
– Compressor
– Fan Coil
• Important Standards
– ASHRAE Standard 15
– AHRI-1230-2010
• VRF Benefits
– Installation & Design Flexibility
– User Comfort
• The Future of VRF in North America
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•
•
The Future of VRF in North America
Worlds
First
CO2
VRF
This year; the worlds first CO based VRF System was released
2
for sale in Europe
– One of the most environmentally friendly refrigerants
with a GWP of 1
New Technologies
– New optimized swing compressor to handle the higher
pressures and reduce leakage
– Dual stage intercooler to help control the refrigerant and
reduce pipe dimensions
– New 3 row heat exchanger and pass pattern for optimum
heat transfer
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The Future of VRF in North America
What’s Next: Domestic and Hot Water Heating
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Conclusion
• VRF provides and alternative, realistic choice to
traditional central systems.
• It captures many of the features of chilled water
systems, while incorporating the simplicity of DX
systems.
• Allows for the correct equipment selection with
both air cooled and water cooled equipment
• It brings some of the latest technology to the
market and provides a higher degree of reliability,
comfort and energy efficiency that is expected
from today's consumer.
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Introduction to Variable Refrigerant Flow Systems
Thank You!
Allen Anaya
Application Consultant
WM Carroll, LLC
Ph: 505-268-6776
Cell: 505-385-7338
Fax: 505-255-1329
E-Mail: [email protected]
11/16/2010
NM ASHRAE – Introduction to Variable
Refrigerant Systems
43