variable refrigerant volume tech ology

© 2005 Daikin AC

Variable Refrigerant FlowOverview

Thomasena Philen– Technical Trainer

Daikin AC ( Americas), Inc.

National Educators & Trainers Conference

Las Vegas 2011

© 2005 Daikin ACSlide 2Presentation Title : Presenter Name : Date

Hea

t

OUTDOOR Unit

Low Pressure Vapour

INDOOR Unit

Low Pressure Liquid

Wa

rm a

ir e

xtr

acte

d a

nd

co

ol a

ir in

tro

du

ce

dHeat

exchanger

DX Refrigeration Cycle – Cooling Mode


High Pressure Liquid

Hea

t

High Pressure Vapour

Coo

l a

ir e

xtr

acte

d a

nd

wa

rm a

ir in

tro

du

ce

d

INDOOR UnitOUTDOOR Unit

Heat

exchanger

DX Refrigeration Cycle – Heating Mode


Comfort Cooling & Heating

Developed as a measure for humidity control

Overlaps process cooling in many applications

Americans think “Inside the Box”

1930’s Efficiency not an issue

R-12 – 64.7 BTU/lb

R-22 – 100.5 BTU/lb

R-410A – 116.8 BTU/lb


Efficiency & Coil Size

Residential Market – Push for more efficiency

Green Building

R-22 & High Efficiency

Footprint & Technology


Variable Air Volume/Zoning

Commercial VAV

Residential Zoning

Efficiency & End-user comfort generally applied to

the airside


Compressor Multiple Step Control

Standard HVAC system

1 to 2 stages of capacity

Uses mechanical unloading techniques

VRV uses inverter technology

Electronic inverter varies compressor rotational speed in steps

50% 100% 52~230HzCompressor capacity Applied frequency

Load

Load

Unloader Principle Multi-Step Control Principle


Design Conditions

Block Load

Peak Load

Diversity


VRV-VRF

What is VRF, History & Concept

How it Operates

VRF Benefits

Efficiency & Capacity Performance

Installation & Design Flexibility

User Comfort

Latest Technology

The Future of VRF in North America


What is VRF?Variable Refrigerant Flow

Also referred to as VRV ® – Variable Refrigerant Volume

VRV is a registered trademark


Background of Development of VRF

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


VRF Global History

VRF world first’s

19901982

World’s first VRF

system is

developed

20071987

VRF is launched globally

2003

Worlds first R410A

VRF

20081991 1998

First globally

available heat

recovery VRF

World’s first

R407C VRF

system is

developed

Worlds inverter

driven VRF

2005

First water cooled

VRF system is

launch in the USA

World’s first CO 2

VRF system is

developed

Industry changing

piping and defrost

technology


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

VRF competes most naturally as a chiller.

(this doesn’t mean it can only compete with chillers)


VRF Concept

Multiple indoor units connected to one outdoor unit

Up to 62 on a single refrigerant piping network

Available in either air cooled or water cooled


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

6 Ton

6 Ton

Heat recovery

Cooling Cooling Heating Heating

12 Ton

Heat Pump


T(sec)

+V

-VFrequency (Hz)

T(sec)

+V

-VFrequency (Hz)

Inverter Technology


Start with smooth inverter voltage output current wave

Smooth waveRough wave

DC Inverter


ulse mplitude odulation

I(A)Vc

I(A)

VcSW

Standard rectifier circuit (without PAM) provides a smooth, steady voltage. However, under peak load conditions, efficiency is lost

due to modulation of the current wave.

Daikin rectifier circuit (with PAM) adds a coil and switching contact that cycles at 20 kHz. This creates an improved current wave resulting in

10% higher compressor efficiency than standard inverter systems.

Pulse Amplitude Modulation (PAM)


High Efficiency in Part-Load conditions

Very low startup amperage

No locked rotor amps

No stress on windings or compressor

frame

No “light flicker”

Lubrication of bearings increases

before speed increase

System pressures increase gradually

reducing noise and stress on piping

Quiet compressor startup

Better Dehumidification

Fewer start/stop cycles

As room temperature nears set point

capacity is automatically throttled down”

Very consistent comfort levels

Capacity is adjusted as the load changes Low

Ambient control - Standard

Inverter Benefits


0 1 2 3 4 5Time [Hour]

122

86

104

68

50

32

Te

mp

era

ture

F

150

90

120

60

30

0 Fre

qu

en

cy o

f co

mp

resso

r [H

z]

0 1 2 3 4 5Time [Hour]

122

86

104

68

50

32

Te

mp

era

ture

F

150

90

120

60

30

0 Fre

qu

en

cy o

f co

mp

resso

r [H

z]Inverter Unit

Non-Inverter Unit Outdoor temp: 32F Set Temp: 73F

Room Temp.

Outlet Temp.

Compressor Freq

Room Temp

Outlet Temp

Compressor Freq.

Operation Cycle – How it Looks


Electronic control of the compressor

High outdoor ambient temperature

Temperature sensors identify high temperature condition

Compressor speed is electronically reduced to limit high side pressure and energy usage

Reduces energy usage during peak conditions

Great heating performance

Compressor increases speed during cold outdoor ambient conditions

Generates higher head pressure, discharge gas temperatures and discharge air temperatures

Achieves the same heat output as competitive systems with electric booster heat without using the extra energy

Additional Inverter Benefits


Neodymium


CompressorsDigitally Commutated (DC) Motors in both Swing and Scroll

dc_rotor_coil.exe

optimised_dc_stator_coil.exe


Advanced VRF Controls

Individual Zone Controllers Multi-zone Controllers

Open Protocol Gateways Adapter PCB’s


Heat Transfer Media The commonly used methods of Heat Transfer in Air Conditioning Solutions each

exercise different operational characteristics regards adding or removing heat energy to a conditioned space as follows: -

This diagram represents the Energy Transfer possible per lb of media due to the performance characteristic of the fluid used.

Water

2.6 watts/lb

25 watts/lb

Refrigerant

Air

0.14 watts/lb

VAV VWV VRF

Why Refrigerant?


Comparable Chilled Water System

Cooling tower

EXP tankFCUAHU

Header

Chiller

Pump

Boiler

Valves

Top floor

Machine Room

Building floors

Water pipe

And also …

Complicated installation

Complicated maintenance

Multiple

Manufacturers

“Blame Game” When

System Does Not

Operate Correctly


VRF Concept

Top floor

Building floors

Space-conscious design

Simple system

Individual control

Simple Installation

Simple MaintenanceRemote controllers

One Point Of

Contact For

Technical Support

Simple Operation

One Manufacturer


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


AHRI 1230 is a testing and rating

standard specially designed for VRF

type equipment.

This will allow us to show VRV

efficiency levels for:

Full Load

Part Load

Heat Recovery

We have been working on the VRF

testing and rating standard for the

last 5 years

Now, the hard work has paid off

What is 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 the new VRVIII we can now promote efficiency levels

for Ducted, Ductless and Mixed combinations

Rating

Daikin VRVIII

PB Series Other VRF

System Full Load EER ?

System Full Load COP ?

System Low Ambient COP (17°F) ?

IEER (Part Load Operation) ?

SCH (Heat Recovery Mode) ?


AHRI 1230 vs. DOE Waiver

AHRI 1230 does not replace the DOE wavier

DOE has to officially recognize AHRI 1230 before the waiver

becomes obsolete.

This may happen as soon as January 2012

AHRI 1230 numbers can still be published because

they were cited in Daikin’s waiver application to the

DOE


Air Cooled & Water Cooled VRV

Systems from 65-300MBH can be

certified with an AHRI rating

Systems above 300MBH can be rated to

the standard but they are not part of the

certification program

Program was written before larger VRF

systems were available.

Will be updated in the future

Systems under 65MBH such as VRV-S or

Multi or single splits are currently covered

by AHRI 210/240.

Which products are covered?


The Biggest VRF Design Mistakes

Positioning VRF as a “big multi split”

This is a chiller that circulates refrigerant

instead of water

FCU in every room

Think of it as you would designing a

VAV system

Ductless focus

This leads to a FCU in every room

Over 55% of VRF FCU sold world wide are ducted

The whole application must be VRF


System Capacity Control

1 2 3 4

EACH INDOOR CONTROLS ITS CAPACITY

VIA PID CONTROL AND AN E.E.V.

CONDENSING UNIT ADJUST THE INVERTER

COMPRESSOR TO PROVIDE THE REQUIRED

CAPACITY (Large or Small)

INDEPENDENT

BRAIN

T3

T4

T2

T1

Controller

(TSET)

CPU(PID Control)

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.


8 & 10 Ton Outdoor UnitsThe Capacity Build-up


6,8,10,12*Ton 12,14,16,18,20, 30 Ton

6 8 10 12 14 16 18 20

460 v

208/230 v

VRF

H/P H/R

Air Cooled 3ph Outdoor Unit Range


6 & 7 Ton 12,14Ton

Water Cooled Outdoor Unit Range

6 7 12 14 18 21

208/230VVRF-W

18,21Ton

Geothermal Application With Limits


Air Cooled Single Phase Outdoor Unit Range

3 4

208/230VVRF


39

Indoor Type

Capacity Range

MBH 07 09 12 18 24 30 36 42 48

Tons 0.6 0.75 1 1.5 2 2.5 3 3.5 4

Vertical Air Handling

Ceiling Mounted Cassette Type

Ceiling Mounted Built-in Type

Concealed Ceiling Unit (Medium Static)

Slim Duct Concealed Ceiling Mounted FXDQ-M

Floor Standing Type

Floor Standing Type (uncased)

Ceiling Suspended Type

Wall Mounted Type

2x2

3x3


What About Efficiency?

Typical energy consumption in office building

How can VRF reduce energy costs?

Air Conditioning 47%

Other utilities

20%Lighting 33%


Partial Load Performance (VRV)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Load

EER75%

595

340

680

340

170

425

510

255

85

Operation Hours

of Main Machine75% of total operation

hours- less than 70% of full load

Partial Load System Performance VRF


Standard VRF Capacities at Low Ambient

76

80

84

86

88

91

93

97

102

106

108

108

108

108

108

108

108

5.5

9.5

13

15

17

19

22

26

30

35

39

44

47

51

54

57

60

AM

BIE

NT

TE

MP

(F

)

70% of Capacity at 5.5F


3.99

2.70

0.0

1.0

2.0

3.0

4.0

72 MBH Heat

Recovery @

47F

72 MBH Heat

Recovery @

5.5F

But What About Efficiency?

COP Comparing a 6 Ton VRF Heat

Recovery outdoor only unit at -

Full load in heating @ 47°F

COP of 3.99

Full load heating at @ 5.5°F

COP of 2.76

Efficiency increases at part load


Hotel 4 Pipe with Chiller vs. VRF

91,000 ft2 Hotel

4 Pipe System

80% Gas Boiler

200 ton Water Cooled Chiller – 0.65 kW/ton

Heat Recovery VRF

(5) 16 ton

(4) 20 ton

$0.10/kWh electricity cost

$1.30/therm natural gas cost

Annual Energy Cost Conventional VRV III Savings

New York $ 132,608 $ 93,014 $ 39,594 30%

Atlanta $ 124,297 $ 90,366 $ 33,931 27%

Phoenix $ 117,413 $ 89,270 $ 28,143 24%

St. Louis $ 134,985 $ 95,492 $ 39,493 29%


Office Rooftop VAV vs. VRF

11,000 ft2 Office

Rooftop Packaged VAV

30 ton - 9.5 EER w/economizer & hot water reheat terminal boxes

Heat Recovery VRF

(1) 12 ton

(2) 8 ton

$0.10/kWh electricity cost

$1.30/therm natural gas cost

Annual Energy Cost Conventional VRV III Savings

New York $ 9,796 $ 7,138 $ 2,658 27%

Atlanta $ 9,562 $ 7,274 $ 2,288 24%

Phoenix $ 10,216 $ 7,789 $ 2,427 24%

St. Louis $ 10,323 $ 7,528 $ 2,795 27%


Total Piping length

1,000 ft (3280ft)

165 ft

(295ft)

50 ft

Actual

piping length(liquid line)

492 ft (540ft)

Top

130 ft

(295ft)

No oil traps

Sight Glasses

Driers

VRF Piping Flexibility


Eldorado Business

Tower

High-rise office building

In a


Location : Sao Paul BZ.

Office building

Height : 33F + B3

Total Floor area : 728,178 ft2

Typical floor area: 17,222 ft2

Completion : 2007

Building Profile


Location of CDU

217 ft

167 ft

How to

overcome

higher level

difference

384 ft


CDU on Upper Roof

217 ft

167 ft

1454 Tons


CDU on Lower Roof

217 ft

167 ft

1259 Tons


Standard refrigerant balancing joint and header

HEADER

JOINT

Simple Pre-Engineered Piping Installation


Wide range of indoor capacity to fit to your room

Ducted and Ductless

0.6 Ton

8 TonRoom 1

Room 2

Design Flexibility


It is suitable for putting an outdoor unit on each floor or in mechanical rooms

Duct

Louver

Window

Exhaust

duct

Suction

Suction louver

Exhaust duct

Up to 0.32” W.G

Design Flexibility-Indoor Installation


Flexible Installation

Floor by floor installation

and commissioning

Ideal for new construction or

renovation projects

Time and cost saving


They fit in the elevator

SMALL FOOTPRINT

Easy Installation


Ideal for Random Occupancy

Individual Operation


30-Ton

Refrigerant

Pipework

6-Ton

Ductwork

“ VRF meets VAV”

Heat Transfer Media - Installation


Simple, Easy, Flexible Wiring Installation A simple 2 wire daisy chain communication system

16-18 gauge AWG Not polarity sensitive

Up to 6560ft of total system wiring

Longest length up to 3280ft

Auto Addressing

Cost savings at installation

Cost savings at commissioning


Low Operating Sound Levels

Ductless operating sound levels as low as 27dB(A)

Ducted operating sound levels as low as 29dB(A)


Users Comfort Easy Maintenance & Repair

Self-Diagnostics

Should an error occur, a fault code is displayed

Up to 66 Alphanumeric malfunction codes

Each code relates to an indoor, outdoor or system fault

Automatic storage of data for improved repair response

time

Operating

Automatic

operation

data storage

of the last 3

minutes just

before the

malfunction

Malfunction


Compressor Back Up Operation

OperationTrouble

Alarm

INV

Activated by remote

control or field setting

Operation

INV INV

INV

Trouble

INV


Oil Recovery

The Oil separator recovers up to

95% of the migrating oil

Logic checks the integrated

amount of oil leaving the

compressor

Automatic oil return starts after 2

hours working after cold start

Duration of up to 6 minutes.

Every 8 hours of accumulated

operation

Centrifugal oil separator


High/Low Pressure Gas Pipe

Liquid pipe

Suction gas type

BS unit

Heating HeatingHeating Heating

LL LL LL LL

Defrost Defrost

Defrost Operation

Each outdoor completes defrost operation individually, in doing so heating operation

continues at each indoor unit. (Manifolded system example)


ASHRAE HQ Renovation Success Story

28 tons of VRF heat recovery & 4

tons of single phase VRF were

installed into the first floor office

space and learning center

In addition to this 5 tons of

Inverter Driven Splits were

installed in the data room

The VRF systems helped

ASHRAE in achieving LEED

Platinum


Worlds First CO2 VRF This last year, the worlds first CO2 based VRF System

was released 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


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.


Thank You

Any Questions?

variable refrigerant volume tech ology

Documents