Introduction To VRF: System Overview, Applications, & Savings Opportunities

Introduction To VRF: System Overview, Applications, & Savings Opportunities

System Overview

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 Variable Refrigerant Flow High Turn Down Ratios Below 10% In Many Cases

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 Room Temperature SETPOINT VRF VRF CONVENTIONAL VRF 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. Time

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 OUTDOOR UNIT + BC / Branch CONTROLLER + INDOOR UNITS + Remote Controllers or WATER-SOURCE UNIT

Typical Simultaneous 2-Pipe VRF System Layout

Changeover Systems Components OUTDOOR UNIT + INDOOR UNITS + CONTROLS or WATER-SOURCE UNIT

Typical Changeover VRF Systems Layout HEATING COOLING

Controls Example PC Control TG-2000 TG-2000 LAN Hub Central Controllers Power Supply Power Supply Remote Controllers

Building Management Systems Building Management System (BMS) BACnet LonTalk May Be A Hardware Interface Hub Ethernet Central Controller

Applications & System Capabilities

Target Commercial Applications Universities Banks Multi-Story Office Buildings Hotels Churches Buildings where zoning is required Applications where sound is important Historic Renovations

Additional Applications BANKS Hospital Admin Areas / MOB Non Procedure RESIDENTIAL SEACOAST PROTECTION

Cooling Diversity 3 Types Solar Load Occupant Load Building Use

VRF Excels at Heat Recovery Applications! Typical Winter Loads Heat CHILLER, COOLING TOWER, & PUMPS $ Heat Why Spend Money On Both? Heat BOILER & PUMPS $

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 Cooled 6 24 Ton (Simultaneous) 6 30 Ton (Change Over) 208/230, 460 Volt 3 Phase 62 db(a) Operating Sound Level Water Cooled 6 20 Ton (Simultaneous) 6 30 Ton (Change Over) 208/230, 460 Volt 3 Phase Single Phase 3, 4 Ton (Change Over) 208/230, 1 - Phase

Partial Back-up Operation Partial Backup capability with multiple / twinned units. The remaining one or two units will perform backup operation Twinned Units Typically Required above 12 Tons

Typical Outdoor Temperature Operating Range NOT your typical Heat Pump Technology! Cooling Can be extended with low ambient options (as low as -10 F) 23 F Single Phase Air Cooled 115 F 23 F Simultaneous & Changeover Air Cooled 115 F 23 F Extended Heat Capacity Air Cooled 115 F -20-4 Heating -15 5-10 14-5 23 0 32 5 41 10 50 15 59 20 68 Outdoor Temperature 25 77 30 86 35 95 40 104 45 113 50 o CDB 122 o FDB 0 F Single Phase Air Cooled 60 F -4 F Simultaneous & Changeover Air Cooled 60 F -13 F Extended Heat Capacity Air Cooled 60 F -24-13 -13-10 -20-4 -15 5-10 14-5 23 0 32 5 41 10 50 Outdoor Temperature 15 59 20 68 25 77 30 86 35 95 40 o CWB 104 o FWB

Extended Range Heat Pump Technology Not Your Typical Heat Pump! 120 % Heating Capacity 100 80 60 40 20 75% 87% 50% 100% 70 o F entering air temp 0-13 -4 5 17 25 30 35 40 47 Outdoor Temperature o FWB Extended Rang VRF Standard VRF

Water-source VRF Units - Changeover Systems Heat Recovery In Water Loop Only Cooling Heat is recovered between the units within the water loop PQHY Unit A Cooling Cooling Cooling System A in COOLING Mode (refrigerant absorbing heat) Heating PQHY Unit B Heating Water Circuit Heating Heating System B in HEATING Mode (refrigerant discharging heat)

Water-source VRF Units Simultaneous Systems Heat Recovery In Two Locations Heat is recovered between the units within the water loop PQRY Heat recovery Heat recovery Cooling Cooling Cooling Heating Indoor units Heating PQRY Heating Heating Indoor units Water circuit Cooling

Water-source VRF Units Installations not allowed! Directly Coupled to a Lake or Pond Open Loop NO Directly Coupled to Ground water Open Loop NO NO

Water-source VRF Units Installations allowed YES Coupled to a Lake or Pond Closed Loop Coupled to Ground Water Closed Loop HX YES HX YES Heat Exchanger Isolation Heat Exchanger Isolation

Water-source VRF Units Installations allowed Coupled to Earth Vertical Closed Loop YES YES Coupled to Earth Horizontal Closed Loop YES Closed Piping Loop Closed Piping Loop

Indoor Equipment Flexibility

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, Cool, Dry, Auto, Heat Built in or accessory condensate removal options from factory. Typical Ventilation Air options most models Average operating sound levels around 35 db(a) +/-

Indoor Unit Flexibility Wall Mounted 6-30 MBtu/h Ceiling Suspended 15-36 MBtu/h Floor Standing 6 24 MBtu/h Product Review CITY MULTI VRF

Indoor Unit Flexibility 4 Way Large Cassette 12-36 MBtu/h 4 - Way Small Cassette 8 15 Mbtu/h One Way Cassette 6 15 Mbtu/h Product Review CITY MULTI VRF

Air Vanes 4 Way Cassettes Independent Vane Control Horizontal Enhanced air distribution by independent vane settings Fixed Vanes can be independently adjusted by a remote controller

Indoor Unit Flexibility Ducted Units Medium Static 6 54 Mbth/h High Static 15 96 Mbtu/h Low Profile 15 24 Mbtu/h Vertical Ducted 12 54 Mbtu/h Product Review CITY MULTI VRF

Recessed Unit St. Xavier Cathedral

Refrigerant Piping & Refrigerant Leakage

Refrigerant Piping Flexibility 2 Pipe Example 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 Total Piping Length 1,804 ft.-2,625 ft. 1,804 ft.-2,460 ft. 3,280 ft. 984 ft.- 1640 ft. 393 ft. 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 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 12 indoor-unit system Heat Recovery Soft Copper BC to IU Reducers possible at BC

Three Pipe Example 12 indoor-unit system Heat Recovery Hard copper from OU to BS Reducer fittings

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 ft 3

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./mcf Refrigerant 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 3 Option 1 Option 2 Option 1-Locate Equipment within larger space Ducted communicating spaces w/ no closure devices that restrict airflow 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.

The Efficiencies from VRF System Effect Inverter-driven compressors / part load performance! Variable capacity indoor units! Extended Heat Pump (Air to Air) Capability! Simultaneous cooling and heating!

Summary of Refrigerant Management Refrigerant Concentration Limit is a tool to protect 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 & 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 allowed 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 Yet 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 EnergyPro Version 5.0 Accepted by the USGBC for Compliance with Energy and Atmosphere Credit 1

What Makes Energy Pro Different Sample Building in Part Load: OA Temp 50 o F Cubicle Area 3000 BTU Lobby/ Waiting Room Conference Room 12000 BTU 6000 BTU Break Room 3000 BTU Elect 3000 BTU Janitor 6000 BTU Open Work Room 6000 BTU 3000 BTU Office #1 Office #2 3000 BTU 3000 BTU Men Women PURY-P72 Simultaneous Load: Cooling: 27000 BTU Heating: 21000 BTU

What Makes Energy Pro Different Cooling Power Input PURY-P72 7.00 6.00 72,000 BTUH 6.48 KW 5.00 Power Input KW 4.00 3.00 2.00 27,000 BTUH 2.38 KW 1.00 0.00 0 12000 24000 36000 48000 60000 72000 84000 System Load BTUH

What Makes Energy Pro Different 2.4000 Outdoor Temperature Power Input Correction (For a 68 Indoor WB Temperature) 2.3000 2.38 KW at 95 o F 2.2000 2.1000 Powe r Input K W 2.0000 1.9000 1.87 KW at 50 o F 1.8000 1.7000 1.6000 1.5000 0 10 20 30 40 50 60 70 80 90 100 OA Temperature FDB

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 Comparable Systems Seattle LA Dallas CM v/s VAV CM v/s 4 Pipe CM v/s WSHP Location Chicago NYC Boston Miami Atlanta 0% 4% 7% 11% 14% 18% 21% 25% 28% 32% Energy Savings

Office Building Energy Modeling Results Percentage Energy Savings V/S Comparable Systems Seattle LA Dallas Location Chicago NYC CM v/s 4 Pipe CM v/s VAV CM v/s WSHP Boston Miami Atlanta 0% 4% 7% 11% 14% 18% 21% 25% Energy Savings

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