Introduction To VRF - Dayton...

Introduction

To VRF:

System

Overview,

Applications,

& Savings

Opportunities

System System

OverviewOverview

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

INVERTER Technology

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

INVERTER Technology

Time

Room Temperature

� 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

VR

FSETPOINT

CONVENTIONALCONVENTIONAL

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 capacity of 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 of operating either as an air conditioner or a heat pump. Variable refrigerant flow implies three or more steps of control on common, inter-connecting piping.

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!

Simultaneous Systems Components

OUTDOORUNIT Remote

Controllers+BC / BranchCONTROLLER + INDOOR

UNITS+

or

WATER-SOURCE UNIT

Typical Simultaneous 2-Pipe VRF System Layout

Changeover Systems Components

OUTDOORUNIT

CONTROLS+INDOORUNITS+

or

WATER-SOURCE UNIT

Typical Changeover VRF Systems Layout

COOLING

HEATING

Power Supply

Controls Example

Central Controllers

Power Supply

TG-2000 LAN

Hub

TG-2000

PC Control

Remote Controllers

Building Management System (BMS)

HubEthernet

LonTalk

Central Controller

BACnet

Building Management Systems

May Be A HardwareInterface

ApplicationsApplications

& System & System

CapabilitiesCapabilities

Target Commercial Applications

Buildings where zoning is required

Applications where sound is important

HistoricRenovations

Multi-Story Office Buildings

Hotels

Banks

Universities

Churches

SEACOAST PROTECTION

Hospital Admin Areas / MOB – Non Procedure

RESIDENTIAL

BANKS

Additional Applications

Building UseOccupant LoadSolar Load

Cooling Diversity – 3 Types

VRF Excels at Heat Recovery Applications !

Typical Winter Loads

Heat

CHILLER, COOLINGTOWER, &PUMPS

Heat BOILER& PUMPS

$

$

Why Spend Money On

Both?

Heat

BTU/$ - VRF Makes Good Sense !

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 on Hourly Average Weather Data.

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

accurately access de-ratings.

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

Partial Backup capability with multiple / twinned u nits.

The remaining one or two units will perform backup operation

Twinned Units Typically Required above 12 Tons

Partial Back-up Operation

Typical Outdoor Temperature Operating Range

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

-20-4

-155

-1014

-523

032

541

1050

1559

2068

2577

3086

3595

40104

45113

50122

oCDBoFDB

Heating

-24-13

-13-10

-20-4

-155

-1014

-523

032

541

1050

1559

2068

2577

3086

3595

40104

oCWBoFWB

Outdoor Temperature

Outdoor Temperature

115 F 23 F Single Phase – Air Cooled

23 F Simultaneous & Changeover – Air Cooled 115 F

23 F 115 F Extended 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 !

Extended Range Heat Pump Technology

70oF 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 oFWB

% H

eatin

g C

apac

ity

Extended Rang VRF Standard VRF

100%

87%

75%

50%

Water-source VRF Units - Changeover Systems

Heat Recovery In Water Loop OnlyHeat Recovery In Water Loop Only

Water Circuit

System System ““ AA”” in in COOLING ModeCOOLING Mode

(refrigerant (refrigerant absorbing heat)absorbing heat)

Heat is recovered

between the units within

the water loop

System System ““ BB”” in in HEATING ModeHEATING Mode

(refrigerant (refrigerant discharging heat)discharging heat)

PQHY Unit “A”

PQHY Unit “B”

Cooling

Cooling

Cooling

Cooling

Heating

Heating

Heating

Heating

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

Directly Coupled to a Lake or PondOpen Loop

NO

NO

Directly Coupled to Ground water

Open Loop

Water-source VRF Units

Installations not allowed! NO

Heat Exchanger Isolation

Coupled to a Lake or PondClosed Loop

HX YESHeat ExchangerIsolation

Coupled to Ground WaterClosed Loop

HX

YES

Water-source VRF Units

Installations allowed YES

Closed PipingLoop

Coupled to EarthVertical Closed Loop

YES

Closed Piping Loop

Coupled to EarthHorizontal Closed Loop

YES

Water-source VRF Units

Installations allowed YES

IndoorIndoor

Equipment Equipment

FlexibilityFlexibility

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) +/-

Wall Mounted6 - 30 MBtu/h

Ceiling Suspended15 - 36 MBtu/h

Floor Standing6 – 24 MBtu/h

Product Review CITY MULTI VRF

Indoor Unit Flexibility

4 – Way Large Cassette12 - 36 MBtu/h

4 - Way Small Cassette8 – 15 Mbtu/h

One Way Cassette6 – 15 Mbtu/h

Product Review CITY MULTI VRF

Indoor Unit Flexibility

Enhanced air distribution by independent vane settings

Independent Vane Control

Vanes can be independently adjusted by a remote controller

Fixed

Horizontal

Air Vanes – 4 Way Cassettes

Medium Static6 – 54 Mbth/h

High Static15 – 96 Mbtu/h

Low Profile15 – 24 Mbtu/h

Vertical Ducted12 – 54 Mbtu/h

Product Review CITY MULTI VRF

Indoor Unit Flexibility – Ducted Units

Recessed Unit – St. Xavier Cathedral

Refrigerant Refrigerant

Piping & Piping &

Refrigerant Refrigerant

LeakageLeakage

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`Simultaneous

Air Cooled

2-Pipe

Simultaneous Water Cooled

2-Pipe

Changeover

Air Cooled

2-Pipe

Changeover

Water Cooled

2-Pipe

Single Phase Air

Cooled

Farthest Indoor unit 541 ft. 541 ft. 541 ft. 541 ft. 26 2 ft.

PIPING HEIGHTSimultaneous Air & Water Cooled

2-Pipe

Changeover Air & Water Cooled

2-Pipe

Single Phase 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

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

Three Pipe Example

• Hard copper from OU to BS

• Reducer fittings

• Hard copper from OU to BS

• Reducer fittings

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

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

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.

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

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 1 Option 2

Option 3

• 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”

Summary of Refrigerant Management

� Refrigerant Concentration Limit is a tool to protec t the public

� Informed and educated engineers can incorporate necessary measures to meet the RCL.

� R410A is of lowest toxicity and is NOT combustible.

Energy Standards Energy Standards

& Savings & Savings

AHRI 1230 & IEER

� AHRI Standard 1230 created a testing standard for VRF equipment above 65,000 Btu/h (below 65,000 Btu/h continues to be rated in accordance with AHRI Standard 210/240-2008)

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

� Unlike testing VRF for IPLV (according to AHRI Standard 210/240), testing for IEER involves actual testing at part load conditions and assigning weighted values to each test point

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

� Simultaneous Heating and Cooling Efficiency (Not Ye t Tested)

� SCHE = (Heating Capacity (Btu/h) + Cooling Capacity (Btu/h)) / Total System Power Input (Watts)

ASHRAE 90.1-2010 VRF Benchmarks

ASHRAE 90.1-2010 VRF Benchmarks

Energy Star Requirements

Energy Modeling

EnergyProVersion 5.0

Accepted by the USGBC for Compliance with Energy and

Atmosphere Credit 1

Sample Building in Part Load: OA Temp 50oF

Simultaneous Load:

Cooling: 27000 BTUHeating: 21000 BTU

3000 BTU

6000 BTU

3000 BTU

3000 BTU

3000 BTU

Elect

Janitor

Break RoomLobby/Waiting Room

ConferenceRoom

Office #1 Office #2

Cubicle Area

Open WorkRoom

6000 BTU12000 BTU

6000 BTU

3000 BTU

3000 BTU

WomenMen

PURY-P72

What Makes Energy Pro Different

What Makes Energy Pro Different

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

Pow

er

Inpu

t KW

72,000 BTUH6.48 KW

27,000 BTUH2.38 KW

What Makes Energy Pro Different

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

Pow

er In

put K

W

2.38 KW at 95oF

1.87 KW at 50oF

What does this mean

� Getting 27,000 BTUH of cooling and 21,000 BTUH of heating, while providing only 1.87 KW to the outdoor unit.

� This savings cannot be realized without the ability to model simultaneous heating and cooling.

For this scenario,Calculated Efficiency of 25.7 EER

School Energy Modeling Results

School--Percentage Energy Cost Savings V/S Comparab le Systems

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

Atlanta

Miami

Boston

NYC

Chicago

Dallas

LA

Seattle

Loca

tion

Energy Savings

CM v/s VAV

CM v/s 4 Pipe

CM v/s WSHP

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

Loca

tion

Energy Savings

CM v/s 4 Pipe

CM v/s VAV

CM v/s WSHP

Questions & Answers

Thank You For Having Us Today!

We Are Here To Help Make Your VRF Projects Successful !