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IntroductionTo VRF:

SystemOverview,

Applications,

& Savings

Opportunities

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System System

Overview Overview

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What is VRF?

• Zoning System

• Two-Pipe / Three Pipe System

• Packaged DDC Control

• Operates as a Heat Pump

• Simultaneous Cooling & Heating

• Inverter Technology / Variable Speed

Compressor

• Multiple Indoor Units – Up to 50 Indoor

Units Per System

• Connected Diversity – Up to 150%

• Variable Capacity Indoor Units

• EMS / BMS Compatibility

• High Turn Down Ratios – Below 10% In

Many Cases

Variable

Refrigerant

Flow

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INVERTER Technology

Changes electrical frequency from 60 Hz (line Power) to a varyingrange (10 Hertz to 110 Hertz – depending on the system)

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INVERTER Technology

Time

R o o m T e m p e r a t u

r e

Automatically adjusts compressor speed to meet load

Sizing flexibility with variable capacity Strives to run long periods at lower speeds.

• Reduced / eliminated cyclic losses

Improved temperature control

• No more minimum cycle timers – no temperature

overshoot.

VRFVRF

V R F

SETPOINT

CONVENTIONALCONVENTIONAL

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AHRI Standard 1230 – VRF HAS ARRIVED !

3.27 VRF Multi-Split System . A split system air-conditioner or heat

pump incorporating a single refrigerant circuit, with one or

more outdoor units, at least one variable speed compressor or

an alternative compressor combination for varying the capacityof the system by three or more steps, multiple indoor fan coil

units, each of which is individually metered and individually

controlled by a proprietary control device and common

communications network. The system shall be capable ofoperating either as an air conditioner or a heat pump. Variable

refrigerant flow implies three or more steps of control on

common, inter-connecting piping.

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The Evolution VRF

Example (Mitsubishi City Multi):

Japan 20+ Years, Tried and Proven! Europe 15+ Years, depending on the country

Latin America 10+ Years, from Mitsubishi US

Bermuda 10+ Years

USA since 2002!

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Simultaneous Systems Components

OUTDOORUNIT

RemoteControllers+

BC / BranchCONTROLLER +

INDOORUNITS+

or

WATER-SOURCE UNIT

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Typical Simultaneous 2-Pipe VRF System Layout

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Changeover Systems Components

OUTDOORUNIT

CONTROLS+INDOORUNITS+

or

WATER-SOURCE UNIT

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Typical Changeover VRF Systems Layout

COOLING

HEATING

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Power Supply

Controls Example

Central Controllers

Power Supply

TG-2000LAN

Hub

TG-2000

PCControl

Remote Controllers

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Building Management System (BMS)

Hub

Ethernet

LonTalk

Central Controller

BACnet

Building Management Systems

May Be AHardwareInterface

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Applications Applications & System & System

Capabilities Capabilities

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Target Commercial Applications

Buildings wherezoning is required

Applications where sound is important

HistoricRenovations

Multi-Story Office Buildings

Hotels

Banks

Universities

Churches

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SEACOAST PROTECTION

Hospital Admin Areas /MOB – Non Procedure

RESIDENTIAL

BANKS

Additional Applications

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Building UseOccupant LoadSolar Load

Cooling Diversity – 3 Types

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VRF Excels at Heat Recovery Applications !

Typical Winter Loads

Heat

CHILLER,COOLINGTOWER, &PUMPS

H e a t BOILER& PUMPS

$

$

Why SpendMoney On

Both?

H e

a t

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BTU/$ - VRF Makes Good Sense !

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Diversity - Heating

Minimal Diversity Available !

Ambient Modification Charts• Available capacity decreases

• Both outdoor and indoor units de-rated• Defrost Operation

Evaluation of De-ratings Important!• Use tools available from VRF manufacturer to

accurately access de-ratings.

Auxiliary Heating Changeover Point• Try and maximize heat pump hours – depends on

climate.Columbus Ohio:

90% of heating hours above 25 Deg F based onHourly Average Weather Data.

Evaluation of De-ratings Important !• Use tools available from VRF manufacturer to

accurately access de-ratings.

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Typical Range Of Available VRF Systems

Air Cooled6 – 24 Ton (Simultaneous)

6 – 30 Ton (Change Over)

208/230, 460 Volt – 3 Phase

62 dB(A) Operating Sound Level

Water Cooled6 – 20 Ton (Simultaneous)

6 – 30 Ton (Change Over)

208/230, 460 Volt – 3 Phase

Single Phase3, 4 Ton (Change Over)

208/230, 1 - Phase

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Partial Backup capability with multiple / twinned units.

The remaining one or two units will perform backup operation

Twinned Units Typically Required above 12 Tons

Partial Back-up Operation

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Typical Outdoor Temperature Operating Range

Cooling – Can be extended with low ambient options (as low as -10 F)

-20

-4

-15

5

-10

14

-5

23

0

32

5

41

10

50

15

59

20

68

25

77

30

86

35

95

40

104

45

113

50

122

oCDB

oFDB

Heating

-24

-13

-13

-10

-20

-4

-15

5

-10

14

-5

23

0

32

5

41

10

50

15

59

20

68

25

77

30

86

35

95

40

104

oCWB

oFWB

Outdoor Temperature

Outdoor Temperature

115 F23 F Single Phase – Air Cooled

23 F Simultaneous & Changeover – Air Cooled 115 F

23 F 115 FExtended Heat Capacity – Air Cooled

Single Phase – Air Cooled0 F 60 F

Simultaneous & Changeover – Air Cooled-4 F 60 F

Extended Heat Capacity – Air Cooled 60 F-13 F

NOT your typical Heat Pump Technology !

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Extended Range Heat Pump Technology

70 o F

entering

air temp

Not Your Typical Heat Pump !

0

20

40

60

80

100

120

-13 -4 5 17 25 30 35 40 47

Outdoor Temperature o FWB

% H e a t i n g C a p a c i t y

Extended Rang VRF Standard VRF

100%

87%

75%

50%

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Water-source VRF Units - Changeover Systems

Heat Recovery In Water Loop Only Heat Recovery In Water Loop Only

Water Circuit

System System “ “ AA” ” in in

COOLING Mode COOLING Mode (refrigerant (refrigerant

absorbing heat) absorbing heat)

Heat is

recovered

between the

units within

the water loop

System System “ “ B B ” ” in in

HEATING Mode HEATING Mode

(refrigerant (refrigerant

discharging heat) discharging heat)

PQHY Unit “A”

PQHY

Unit “B”

Cooling

Cooling

Cooling

Cooling

Heating

Heating

Heating

Heating

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Water-source VRF Units – Simultaneous Systems

Heat Recovery In Two Locations

Indoor unitsIndoor units

Water circuit

Indoor unitsIndoor unitsHeat recovery

Heat recovery

Cooling

Cooling

Cooling

Cooling

Heating

Heating

Heating

Heating

PQRY

PQRY

Heat is recovered

between the units within

the water

loop

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Directly Coupled to a

Lake or Pond Open Loop

NO

NO

Directly Coupled to

Ground water Open Loop

Water-source VRF Units

Installations not allowed! NO

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Heat ExchangerIsolation

Coupled to a Lake or Pond

Closed Loop

HX

YES Heat ExchangerIsolation

Coupled to Ground Water

Closed Loop

HX

YES


Installations allowed YES

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Closed Piping

Loop

Coupled to Earth

Vertical Closed Loop

YES

Closed Piping Loop

Coupled to Earth

Horizontal Closed Loop

YES


Installations allowed YES

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Indoor Indoor Equipment Equipment

Flexibility Flexibility

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Indoor Unit Flexibility

Multiple styles ranging from 6,000 to 96,000 Btu/h

Typically single phase below 6 Nominal Tons

Linear Expansion Valve

Variable Capacity Operation

Mode: Fan,Fan, Cool,Cool, Dry,Dry, AutoAuto, HeatHeat

Built in or accessory condensate removal options from factory.

Typical Ventilation Air options – most models

Average operating sound levels around 35 dB(A) +/-

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Wall Mounted6 - 30 MBtu/h

Ceiling Suspended15 - 36 MBtu/h

Floor Standing6 – 24 MBtu/h

Product Review CITY MULTI VRF


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4 – Way Large Cassette

12 - 36 MBtu/h

4 - Way Small Cassette

8 – 15 Mbtu/h

One Way Cassette6 – 15 Mbtu/h



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Enhanced air distribution by

independent vane settings

Independent Vane Control

Vanes can be independently adjustedby a remote controller

Fixed

Horizontal

Air Vanes – 4 Way Cassettes

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Medium Static6 – 54 Mbth/h

High Static

15 – 96 Mbtu/h

Low Profile

15 – 24 Mbtu/h

Vertical Ducted12 – 54 Mbtu/h


Indoor Unit Flexibility – Ducted Units

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Recessed Unit – St. Xavier Cathedral

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Refrigerant Refrigerant

Piping & Piping & Refrigerant Refrigerant

Leakage Leakage

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Refrigerant Piping Flexibility – 2 Pipe Example

393 ft.984 ft.-

1640 ft.3,280 ft.1,804 ft.-2,460 ft.1,804 ft.-2,625 ft.Total Piping Length

PIPING LENGTH`

SimultaneousAir Cooled

2-Pipe

SimultaneousWater Cooled

2-Pipe

Changeover

Air Cooled

2-Pipe

Changeover

Water Cooled

2-Pipe

SinglePhase Air

Cooled

Farthest Indoor unit 541 ft. 541 ft. 541 ft. 541 ft. 262 ft.

PIPING HEIGHT

Simultaneous Air& Water Cooled

2-Pipe

Changeover Air &Water Cooled

2-Pipe

SinglePhase Air

cooled

Outdoor Unit HIGHER than Indoor Unit 164 ft.* 98 ft.

Outdoor Unit LOWER than Indoor Unit 131 ft. 65 ft.

Indoor Unit to Any BC Controller 49 ft. n/a n/a

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Two Pipe Example

• Soft Copper BC to IU

• Reducers possible at BC

• Soft Copper BC to IU

• Reducers possible at BC

12 indoor-unit system – Heat Recovery12 indoor-unit system – Heat Recovery

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Three Pipe Example

• Hard copper from OU toBS

• Reducer fittings

• Hard copper from OU toBS

• Reducer fittings

12 indoor-unit system – Heat Recovery12 indoor-unit system – Heat Recovery

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Refrigerant Leakage Concentration Levels

What is RCL?

Refrigerant Concentration Limit (RCL): “the refrigerant concentration limit, in air, determined in accordance with this

standard and intended to reduce the risks of acute toxicity asphyxiation and flammability hazards in normally occupied,enclosed spaces”

RCL typically expressed as lbs/1000 ft3

D t i ti f RCL

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Determination of RCL

Referenced Codes/Standards International Mechanical Code

• Previously set RCL for R-410A at 10 lbs/MCF• 2009 Revisions raises RCL to 25 lbs/MCF

ISO-5149

• ISO-5149 sets R-410A RCL as 18.7 lbs/MCF

ASHRAE 15-2007• ASHRAE 15-2007 establishes the R-410A RCL as 25lbs/MCF

through reference to ASHRAE 34.

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Critical Concentration Calculation

RCL (R410A) = 25 lb./McfRefrigerant Charge (Rc) of a P72 = 23 lbs 3 oz = 23.1875 lbs

MAV = Minimum Applied Volume (cubic feet)MAV = Rc/RCL

MAV = (23.1875 lbs)/(25 lbs/1000 cu ft)MAV = 927.5 cu ft

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Appropriate Solutions

Option 1-Locate Equipment within larger space

•Ducted communicating spaces w/ no closure devices that restrictairflow below 10% of peak airflow.

Option 2-Do not use equipment with refrigerant

Option 3-Increase room volume through the use of openings

•Door Undercuts, transfer ducts or grilles.

Option 1Option 2

Option 3

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• Inverter-driven compressors / part load

performance !

• Variable

capacity indoor units !

• Extended Heat Pump (Air to Air)

Capability !

• Simultaneous cooling and

heating !

The Efficiencies from “VRF System Effect”

S f R f i t M t

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Summary of Refrigerant Management

Refrigerant Concentration Limit is a tool to protectthe public

Informed and educated engineers can incorporatenecessary measures to meet the RCL.

R410A is of lowest toxicity and is NOT combustible.

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Energy Standards Energy Standards

& Savings & Savings

AHRI 1230 & IEER

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AHRI 1230 & IEER

AHRI Standard 1230 created a testing standard for VRF equipment above 65,000Btu/h (below 65,000 Btu/h continues to be rated in accordance with AHRI Standard210/240-2008)

On January 1st, 2010, IEER superseded IPLV as the testing standard for VRFequipment above 65,000 Btu/h

Unlike testing VRF for IPLV (according to AHRI Standard 210/240), testing for IEERinvolves actual testing at part load conditions and assigning weighted values to eachtest point

Testing VRF for IEER involves testing at four fixed conditions: 100%, 75%,50%, & 25% load. The equipment is still not allowed to vary compressor speedand indoor unit capacity to meet a varying load as it was designed to do

Simultaneous Heating and Cooling Efficiency (Not Yet Tested)

SCHE = (Heating Capacity (Btu/h) + Cooling Capacity (Btu/h)) / Total System PowerInput (Watts)

ASHRAE 90 1 2010 VRF B h k

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ASHRAE 90.1-2010 VRF Benchmarks

ASHRAE 90 1 2010 VRF B h k

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ASHRAE 90.1-2010 VRF Benchmarks

Energy Star Requirements

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Energy Star Requirements

Energy Modeling

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Energy Modeling

EnergyPro Version 5.0

Accepted by the USGBC forCompliance with Energy and

Atmosphere Credit 1

What Makes Energy Pro Different

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Sample Building in Part Load: OA Temp 50oF

Simultaneous Load:

Cooling: 27000 BTU

Heating: 21000 BTU

3000 BTU

6000 BTU

3000 BTU

3000 BTU

3000 BTU

Elect

Janitor

Break RoomLobby/

Waiting Room

Conference

Room

Office #1 Office #2

Cubicle Area

Open Work

Room

6000 BTU

12000 BTU

6000 BTU

3000 BTU

3000 BTU

WomenMen

PURY-P72



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Cooling Power Input PURY-P72

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

0 12000 24000 36000 48000 60000 72000 84000

System Load BTUH

P o w e r I n p

u t K W

72,000 BTUH6.48 KW

27,000 BTUH2.38 KW


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Outdoor Temperature Power Input Correction

(For a 68 Indoor WB Temperature)

1.5000

1.6000

1.7000

1.8000

1.9000

2.0000

2.1000

2.2000

2.3000

2.4000

0 10 20 30 40 50 60 70 80 90 100

OA Temperature FDB

P o w e r I n p u t K W

2.38 KW at 95oF

1.87 KW at 50oF

What does this mean

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What does this mean

Getting 27,000 BTUH of cooling and 21,000 BTUH ofheating, while providing only 1.87 KW to the outdoorunit.

This savings cannot be realized without the ability tomodel simultaneous heating and cooling.

For this scenario,Calculated Efficiency of 25.7 EER

School Energy Modeling Results

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School Energy Modeling Results

School--Percentage Energy Cost Savings V/S Comparable Systems

0% 4% 7% 11% 14% 18% 21% 25% 28% 32%

Atlanta

Miami

Boston

NYC

Chicago

Dallas

LA

Seattle

L o c a t i o n

Energy Savings

CM v/s VAV

CM v/s 4 Pipe

CM v/s WSHP

Office Building Energy Modeling Results

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Office Building Energy Modeling Results

Percentage Energy Savings V/S Comparable Systems

0% 4% 7% 11% 14% 18% 21% 25%

Atlanta

Miami

Boston

NYC

Chicago

Dallas

LA

Seattle

L o c a t i o n

Energy Savings

CM v/s 4 Pipe

CM v/s VAVCM v/s WSHP

Questions & Answers

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Questions & Answers

Thank You For Having UsToday!

We Are Here To Help Make Your VRFProjects Successful !

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