Variable Refrigent Flow

7/29/2019 Variable Refrigent Flow

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Presented by : Rohit kumar sahu (12541011)

Ashvini kumar mishra (12541002)

MIED,IIT ROORKEE


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1.What is Variable Refrigerant Flow?2. How does VRF work?3. Benefits of VRF Capacity Control4. Different VRF Systems5. Design Around Diversity6. Comparing VRF to Conventional Systems7. Various companies using VRF Technology8. Advantages of VRF technology9.Different aspects of various company


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VRF technology was invented in Japan in the 1990s

The VRF technology/system was developed and designed by Daikin

Industries, Japan who named and protected the term variable

refrigerant volume (VRV) system so other manufacturers use theterm VRF "variable refrigerant flow".

VRF is an air-condition system configuration where there is one

outdoor condensing unit and multiple indoor units.

VRF - controls the amount of refrigerant flowing to the multiple

evaporators, enabling the use of many evaporators of differing

capacities and configurations connected to a single condensing unit.


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The arrangement provides an individualized comfort control at

different zones.

According to ASHRAE Journal April 2007

The term Variable Refrigerant Flow refers to the capability

of a HVAC system to control the amount of refrigerantflowing to each of the indoor units/evaporators,

enabling the use of multiple evaporators of differingcapacities and configurations , individualized comfort

control, simultaneous heating and cooling in different zoneswith heat recovery from one zone to another


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Outdoor UnitMultiple indoorUnits


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2 Pipe System cooling only

2 Pipe System heat pump cooling or heating

3 Pipe System simultaneous cooling and

heating


heatingair cooled


heatingwater and geothermal application


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Building Characteristics Building Load Profile

Sustainability

Simultaneous Heating and Cooling First Costs


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The refrigerant pipe-work (liquid and suction lines) is very long,running in several hundred of feet in length for large multi-story

buildings

It introduce pressure losses in the suction line and, unless the correctdiameter of pipe is selected.

The maximum allowable vertical distance between an outdoor unitand its farthest indoor unit is 164 ft;

The maximum permissible vertical distance between two individualindoor units is 49 feet,

The maximum overall refrigerant piping lengths between outdoorand the farthest indoor unit is up to 541 ft.


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Determination of

1.The cooling load and load profiles including location, hours of

operation, number/type of occupants, equipment being used,

etc

2.The required system configuration in terms of the number of

indoor units and the outdoor condensing unit capacity by

taking into account the total capacity and operationalrequirements, reliability and maintenance considerations


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Higher efficiency compared to conventional units.

Cooling power in a VRF system is regulated by means ofadjusting the rotation speed of the compressor which can

generate an energy saving around 30%.

Use of non-ozone depleting environment-friendly refrigerantssuch as R-410a.

Opting for heat pump instead of electrical resistance heatingin areas demanding both cooling and heating. Heat pumpsoffer higher energy efficiency


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The installed cost of a VRF system is highly variable, projectdependent, and difficult to pin down.

Studies indicate that the total installed cost of a VRF system

is estimated to be 5% to 20% higher than air or water cooledchilled water system, water source heat pump, or rooftop DX

system providing equivalent capacity.

This is mainly due to long refrigerant piping and multipleindoor evaporator exchanges with associated controls.


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VRF-HR systems are equipped with enhanced features like

inverter drives, pulse modulating electronic expansion valves

and distributed controls that allow system to operate in net

heating or net cooling mode, as demanded by the space.

Each indoor unit is branched off from the 3 pipes using

solenoid valves. An indoor unit requiring cooling will open its

liquid line and suction line valves and act as an evaporator. An

indoor unit requiring heating will open its hot gas and liquidline valves and will act as a condenser .

Extra heat exchangers in distribution boxes are used to transfer

some reject heat from the superheated refrigerant exiting the

zone being cooled to the refrigerant that is going to the zone tobe heated .


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1. Occupancy

2. Time of Day

3. Heating & Cooling


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Comfort

Design Flexibility

Flexible Installation

Energy Efficiency

Reduced Noise Levels

Reliability

Maintenance and Commissioning

Aesthetics


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The main advantage of a variable refrigerant flow system is its

ability to respond individually to fluctuations in space load

conditions.

The user can set the ambient temperature of each room as perhis/her requirements and the system will automatically adjust

the refrigerant flow to suit the requirement.


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A single condensing unit can be connected to wide range

of indoor units of varying capacity (e.g., 0.5 to 4 tons

ducted or ductless configurations such as ceiling recessed,

wall-mounted and floor console). Current products enableup to 48 indoor units to be supplied by a singlecondensing unit;

A VRF system can start functioning even while the

building/house is still being constructed; unlike large duct orchiller systems which cannot function until the construction

project is completed


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VRF systems enable floor by floor installation andcommissioning .

VRF systems are lightweight, require less outdoor plant space

and offer space-saving features.

It is less disruptive to fit in existing buildings and its modularformat lends itself to phased installations.

It is modular and self contained. A multiple of these units can

be installed to achieve cooling capacities of hundreds of tons.


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VRF technology yields exceptional part-load efficiency. Since most HVAC

systems spend most of their operating hours between 30-70% of theirmaximum capacity, where the coefficient of performance (COP) of theVRF is very high, the seasonal energy efficiency of these systems isexcellent.

Field testing has indicated that this technology can reduce the energyconsumption by as much as 30 to 40% a year compared to traditionalrotary or reciprocating type compressors.

Inverter compressor technology is highly responsive and efficient. The modulararrangement permits staged operation, i.e. Indoor units can easily be turned offin locations requiring no cooling, while the system retains highly efficientoperation.


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VRF systems with their standardized configurations and

sophisticated electronic controls are aiming toward near plug-

and-play commissioning.

Normal maintenance for a VRF system is similar to that of anyDX system.

No water pumps to maintain or air ducts to be cleaned, less

maintenance is required compared to other technologies.


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Total System is stopped during night time If one person is working overtime, the complete

system must operate

Unevenly Air Conditioned space

Possibility of Water Pipe Corrosion

Maintain Water Quality

Lots of Piping & Wiring

Lots of Space Required for Machines

Time Consuming Design


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For Property Owners1.Can be adapted to meet various applications in buildings due

to multiple style and capacity indoor units

2. Creates Added Value to the building due to:

Comfort Levels (Space temperature controlled individuallyOperation only required in zones used

Power consumption can be reduced by up to 30%

3.Provides advanced space efficiency at a good price


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For Consultants / Contractors / Installer

Easy to design

No Zoning considerations with heat recovery

Short design period compared

Easy to install

No need for expensive controls

Easy to maintain

All system components supplied by one vendor


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For Users

Can be operated to suit individual needs

Exact temperature control for each office/ zone

Comfortable working space improves productivity.


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Voltas- Digital VRF systemInverter VRF system

Blue star- Inverter VRF system

] Digital VRF system

LG

Daikin

Carrier

Trane

Mitsubishi industries with Mingledorffs

ETA General


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Right solution for multi-zoned space Advantages-

Modular capacity that can be built up using 3.5 HP to 64

discrete units

A choice of designer cooling units is available Its is a R410A based eco friendly system

Simple installation and maintaince

High energy saving and simplified computer control operation

Use frequency modulated inverter compressor technology forprecise temp. and control


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The versatile cooling solution for Indian extreme condition ADVANTAGE

Same as inverter expect in 12 HP 63 discrete units are

required.

Compatibility with AHUs Advanced computer control

DIGITAL SCROLL COMPRESSOR IS USED


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Corporate offices Educational institute

Buildings

Hotels and commercial apartments

Health care

Commercial complexes and showrooms


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They have latest generation MDV-III ADVANTAGE

High efficiency

Range of capacity-system operating b/n

10 % to 100 % of capacity


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Stepless adjustment of compressor capacity


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The latest generation MDV-4

ADVANTAGE

Worlds largest capacity outdoor unit

Higher indoor-outdoor unit connectivity

High efficiency

Corrosion resistance

Minimum installation space


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Inverter of VRF technology Patent name VRV

WORKING

Inverter heat pump

Inverter heat recoveryScroll compressor

Advantages

Optimized use of R410A

Lightweight, compacted

Energy efficient

Eco friendly


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Documents

Variable Refrigent Flow