VARIABLE REFRIGERATE FLOW

1. BUILDING SERVICES
SEMESTER – VII
VARIABLE
REFRIDGERANT
FLOW (VRV) SYSTEM
SUBMITTED BY:-
RIDDHESH RAJENDRA VARIK
15SA31 4TH YEAR B.ARCH
ST.WILFRED’S INSTITUTE OF
ARCHITECTURE
SUBMITTED TO:-
AR.SIDDHARTH SHARMA SIR

2. SR.NO TOPIC PAGE.NO
1 INTRODUCTION 1
2 MULTIPLE SPLIT SYSTEMS 2
3 SPLITAIR CONDITIONERS 3
4 VARIABLE REFRIDGERATE FLOW
SYSTEMS
4
5 VRF HEAT PUMP SYSTEMS 5
6 HEAT RECOVERYVRF SYSTEM 6
7 APPLICATIONS 7
8 ADVANTAGESAND LIMITATIONS 8
9 CONCLUSION 9
INDEX

3. INTRODUCTION
• CONTROLLED REFRIGERANT IS SUPPLIED IN THE EVAPORATOR UNIT AS
PER LOAD REQUIREMENT.
• NO INTERMEDIATE MEDIUM FOR THE HEAT EXCHANGE WHICH MAKES
IT EFFICIENT.
• IN A VRF SYSTEM, MULTIPLE INDOOR FAN COIL UNITS MAY BE
CONNECTED TO ONE OUTDOOR UNIT.
HISTORY:
• VARIABLE REFRIGERANT FLOW (VRF), ALSO KNOWN AS VARIABLE
REFRIGERANT VOLUME (VRV), IS INVENTED IN JAPAN BY DAIKIN
COMPANY IN 1982.
• DAIKIN HAD REGISTERED THE VRV TERM AS AN OFFICIAL TRADEMARK.
ALL OTHER COMPANIES USE VRF FOR THEIR SIMILAR HVAC SYSTEMS.
• EVENTUALLY, VRF IS THE MORE COMMON TERM FOR THESE TYPES OF
SYSTEMS, AND THIS IS THE TERM THAT WILL BE USED FOR THE REST OF
THE ARTICLE.
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4. MULTI SPLIT SYSTEMS
• THERE ARE MULTIPLE EVAPORATOR UNITS CONNECTED TO ONE EXTERNAL CONDENSING UNIT. THESE
TYPE OF SYSTEMS WERE DESIGNED MAINLY FOR SMALL TO MEDIUM COMMERCIAL APPLICATIONS.
• EACH INDOOR UNIT HAS ITS OWN SET OF REFRIGERANT PIPE WORK CONNECTING IT TO THE OUTDOOR
UNIT.
ADVANTAGES OF MULTI-SPLITS:
• NO NEED OF DUCT WORK INSTALLATION.
• SYSTEM EFFICIENCY IMPROVES THEN INDIVIDUAL SPLIT UNIT.
• MULTI-SPLITS ARE SUITABLE FOR SINGLE THERMAL ZONE APPLICATIONS I.E. EITHER FOR COOLING
MODE OR HEAT MODE.
DRAWBACKS:
• MAIN DRAWBACK IS THAT INDIVIDUAL SYSTEM CONTROL NOT POSSIBLE.
• IN THIS SYSTEMS WHOLE SYSTEM WILL TURN OFF OR ON COMPLETELY IN RESPONSE TO A SINGLE
THERMOSTAT. THESE SYSTEMS ARE THEREFORE NOT SUITABLE FOR AREAS/ROOMS WITH VARIABLE
HEAT GAIN/LOSS CHARACTERISTICS
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5. SPLIT AIR CONDITIONING
• IT CONSISTS OF ONE INDOOR UNIT ALONG WITH AN
OUTDOOR UNIT CONSTITUTE A SINGLE SPLIT AC.
SOURCE-CARRIER
ADVANTAGES :
• THESE AC’S HAVE LOW INITIAL COST
• EASE OF INSTALLATION
• NO DUCTING REQUIRED
• EACH SYSTEM HAVE OWN CONTROL.
DISADVANTAGES :
• DISTANCE BETWEEN INDOOR AND OUTDOOR UNIT
SHOULD NOT BE GREATER THAN 100- 150 FT
OTHERWISE THE PERFORMANCE WILL SUFFER.
• LIMITED AIR THROW 3

6. VARIABLE REFRIGERANT FLOW
SYSTEM
• ADJUST COOLING AND HEATING BY ADJUSTING REFRIGERANT FLOW
AND VARIABLE SPEED COMPRESSOR . INDOOR UNITS CAN BE IN
DIFFERENT MODES .
• VRF SYSTEMS ARE EQUIPPED WITH ENHANCED FEATURES LIKE
INVERTER DRIVES, PULSE MODULATING ELECTRONIC EXPANSION
VALVES AND DISTRIBUTED CONTROLS.
TYPES OF VRF SYSTEMS :
• COOLING ONLY SYSTEMS :
THOSE SYSTEMS CAN ONLY COOL. HEATING IS NOT AVAILABLE. FAN AND
DRY MODES ARE AVAILABLE FOR EACH INDOOR UNIT INDEPENDENTLY.
• HEAT PUMP SYSTEMS :
ALL THE INDOOR UNITS CAN EITHER HEAT OR COOL . FAN AND DRY
MODES ARE AVAILABLE FOR EACH INDOOR UNIT INDEPENDENTLY.
• HEAT RECOVERY SYSTEMS :
THESE SYSTEMS ARE THE MOST SOPHISTICATED ONES, WHERE COOLING
AND HEATING MAY BE AVAILABLE BY EACH INDOOR UNIT,
INDEPENDENTLY, AT THE SAME TIME.
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7. VRF HEAT PUMP SYSTEMS
• VRF HEAT PUMP SYSTEMS PERMIT HEATING OR COOLING IN ALL OF THE
INDOOR UNITS BUT NOT SIMULTANEOUS HEATING AND COOLING.
• WHEN THE INDOOR UNITS ARE IN THE COOLING MODE, THEYACT AS
EVAPORATORS; WHEN THEYARE IN THE HEATING MODE, THEYACT AS
CONDENSERS.
• THESE ARE ALSO KNOWN AS TWO-PIPE SYSTEMS.
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8. HEAT RECOVERY VRF SYSTEM
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9. APPLICATIONS
• VRF SYSTEMS MAY BE A PARTICULARLY GOOD
OPTION FOR BUILDINGS WITH MULTIPLE ZONES
OR WIDE VARIANCE HEATING/COOLING LOADS
ACROSS MANY DIFFERENT INTERNAL ZONES.
• THESE SYSTEMS PROVIDE INDIVIDUAL CONTROL
AND ARE THE MOST VERSATILE OF THE MULTI-
SPLIT SYSTEMS. HOTELS, SCHOOLS AND OFFICE
BUILDINGS ARE GOOD EXAMPLES.
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10. ADVANTAGES :
• ENERGY SAVING CLAIMED UP TO 40 %.
• SPACE SAVING
• LESSER NOISE
• PRECISE TEMPERATURE CONTROL
• SIMULTANEOUS HEATING AND COOLING (THREE-PIPE VRF HEAT RECOVERY
SYSTEM ONLY)
• HEAT RECOVERY
• ZONED COMFORT
LIMITATIONS :
• INITIAL COST IS HIGH ,SINCE ADDITIONAL BACKUP UNIT IS NEEDED
• SEPARATE VENTILATION SYSTEM
• REFRIGERANT PIPING
• ENVIRONMENTAL CONCERNS
• FOR HIGH RISE BUILDING THE SYSTEM CANNOT BE USED
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11. CONCLUSION
• THE VARIABLE REFRIGERANT FLOW SYSTEM IS
CONSIDERED TO BE ONE OF THE MOST
PROMISING ENERGY SAVING TECHNOLOGIES
GAINING ITS MOMENTUM IN RECENT YEARS.
• A VIABLE ENERGY EFFICIENT TECHNOLOGY IS
NEEDED TO CONSERVE ENERGY AS WELL AS TO
ACHIEVE BETTER HUMAN COMFORT.
• SO THIS IS BEEN RELATIVELY NEW AND
EFFICIENT WAY TO DESIGN HVAC SYSTEM WITH
VRF TECHNOLOGY.
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