Commercial Kitchen Exhaust (PCU / Ecology

Unit)

OBJECTIVES - Commercial kitchen exhaust

• Few facts & figures.

• Day to day challenges / complains.

• Possible solutions:

– Design - kitchen exhaust / makeup air.

– How to control kitchen effluent (grease & odour)?

– Codes & standards.

– Appropriate products available.

– Recommendation.

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DO WE KNOW ?????

Source : E source data from U.S. Energy International Administration

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Day to day challenges / practical scenarios

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LEAKING GREASE DUCTS

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GREASE EMISSIONS

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ACCUMULATION OF GREASE IN PLENUM

Source : ASHRAE , Commercial kitchen ventilation presentation

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POOR CAPTURE PERFORMANCE IN FIELD

Source : ASHRAE , Commercial kitchen ventilation presentation8

KITCHEN FAN INLET AREA

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WHAT WE SHOULD OPT ?

Temporary Arrangement Responsible Solution

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1. Focus towards

exhaust / makeup air

design.

POSSIBLE SOLUTIONS

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KICTHEN EXHAUST SYSTEM

Effective Exhaust System means - get rid of :

Heat

Particulate Matter

Grease Laden Steam

Cooking Vapor

Increases Efficiency

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EHAUST AIR HOW MUCH????

Required Exhaust Air for Canopy Hoods

A = Horizontal Area in Sqft.

D = Distance (ft.) between lower lip of hood to cooking surface.

P = Perimeter (ft.).

Q = Exhaust Air CFM.

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UNIFORM MECHANICAL CODE METHOD

Base Exhaust Flow = 50 x Hood (L) x Hood (W) Ft

Additional Air Requirement

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EXAMPLE

Base Air Flow : 10 x 4.5 x 50 = 2,250 CFM

Additional Flow

Griddle : 37 x 4 = 148 CFM

Oven : 0

Charbroiler : 8 x 95 = 760 CFM

Total Additional : 908 CFM

Required Exhaust : 908 + 2,250 = 3,158 CFM

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NFPA - 96 METHOD

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CALCULATION OF EXHAUST

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INPUTS

1 . Wall Mounted Hood (13.6” x 4.6”)

2 . Clearance 6” (0.5’) both side

3 . Gas Convection Oven : 175 CFM/ft.

4 . Gas Deep Fryer : 265 CFM/ft.

5 . Spacer : 100 CFM/ft.

6 . Electric Griddle : 255 CFM/ft.

7 . Gas Stove : 275 CFM/ft.

8 . Spacer (Clearance) : 100 CFM/ft.

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CALCULATION

Left Clearance : 0.5 x 100 CFM/ft. = 50 CFM

Gas Convection Oven : 3.5 x 175 CFM/ft. = 613 CFM

Gas Deep Fryer : 1.5 x 265 CFM/ft. = 398 CFM

Spacer : 1.5 x 100 CFM/ft. = 150 CFM

Electric Griddle : 3 x 255 CFM/ft. = 765 CFM

Gas Stove : 3 x 275 CFM/ft. = 825 CFM

Right Clearance : 0.5 x 100 CFM/ft. = 50 CFM

Total : 2851 CFM

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MAKE - UP, WHY??

Outdoor Air + Replacement Air = MUA

To provide better IAQ ASHRAE 90.1-2010.

To avoid excessive de-pressurization.

To comply code requirement.

To increase efficiency of Hood.

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MAKE – UP AIR

RULE OF THUMB

Supply dedicated MA @ 80~85% of Exhaust.

15~20% from adjacent space.

Designer keep ratio of 60/40%.

Use ERVs for Make-up air with energy recovery.

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ENERGY MANAGEMENT

Manual Control System with VFD motor (simple system)

No complex automation, but compatible with BMS.

Can be adjusted by 3 speed of Exhaust and FA blower.

100% working on high speed.

Operated by individual with selector switch.

Auto Control System with VFD motor & Temp Sensor (complex system)

Temp sensor in Duct Collar.

EA & FA varies with temp requirement.

Interlocked with Fire Alarm (Common with manual).

During fire SA off (Common with manual).

Auto operation Expensive.

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IMPORTANT CONSIDERATION

High Speed Duct Velocity should be 7.6 ~ 9.0m/s.

ASHRAE research suggest if velocity goes lowered up to 2.5 m/s

grease deposition doesn’t increase.

The above is useful for VFD driven EA & Multi-hood connection.

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2.Control odour /grease

POSSIBLE SOLUTIONS

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WHY GREASE & ODOUR CONTROL

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ESP to break high chain carbon compound

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ESP – MICRON RANGE

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ESP PARTS

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ESP CELL

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Filter Cell (stainless Steel)

ESP - MAINTENANCE

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1

3

2

4

1. Take out the filter cell and distribution plate

2. Jet cleaning of filter cell

3. Soak cleaning of distribution plate

4. Soak cleaning of filter cell

ESP- INSULATOR CLEANING

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OPTIONS – ODOUR CONTROL

The available options are as follows :

• Caron filter bank: Different combination with carbon module based on duty cycle.

• Spray System - Produces a compressed air stream and when used in conjunction with odour neutralizer, produces a very fine mist that is sprayed into the extract ductwork or stack. The mist interacts with the odour particles and neutralizes them.

• Ozone generator – Ozone is used to disrupt odour by breaking down combined substances into their base components.

• UVC Filtration - The cleansing mechanism of UV is a photochemical process. The contaminants that pollute the indoor environment are almost entirely based upon organic or carbon-based compounds. These compounds break down when exposed to high-intensity UV at 240 to 280 nm.

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ELECTRICAL CONTROLS

Motor starter panel

Filter status panel

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SOLUTIONS

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3. Codes & standards.

RELATED CODES & STANDARDS

• 2003 ASHRAE Handbook Chapter 31

• ASHRAE Standard 154-2003

• UL 710

• 2001 NFPA 96

• Australian Standard AS 1668.2-2012

• Uniform Mechanical Code

• International Mechanical Code

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KEY TEST PARAMETERS

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TEMPERATURE TEST

1. An appliance is set below the hood/duct and

adjusted to the desired surface temperature

(varies depending on appliance).

2. The appliance is brought to equilibrium (fairly

quickly).

3. The hood/duct components cannot rise by

more than a maximum of 480°F for

galvanized steel and 1310°F for 430 stainless

steel.

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COOKING SMOKE AND FLARE- UP

TEST

1. No evidence of smoke or flame escaping from the

unit is allowed.

2. The air exhaust rate is set to the minimum amount.

3. The appliance is brought to equilibrium and food

product containing fat is cooked.

4. This is commonly known as a Capture and

Containment Test.

5. It is used for determining acceptable minimum

exhaust rates.

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ABNORMAL FLARE-UP TEST

1. The desired exhaust rate is to be established.

2. One pint of vegetable oil is brought to ignition on top

of an appliance and below the test hood.

3. The vegetable oil is left to burn out completely.

4. The exhaust airstream cannot exceed 375°F and

flames cannot enter the hood exhaust collar.

5. Hood parts shall not be damaged such that they

present an electrical or fire risk.

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FAN FAILURE TEST

1. This test is similar to Abnormal Flare Up Test.

2. One pint of vegetable oil is brought to ignition on

top of an appliance and below the test hood.

3. The vegetable oil is left to burn out completely.

4. The exhaust airstream cannot exceed 375°F and

flames cannot enter the hood exhaust collar.

5. Hood parts shall not be damaged such that they

present an electrical or fire risk.

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FIRE TEST

o During the test , flame shall not enter the test

collar connected to the exhaust hood.

o Parts of the exhaust hood, including bodies,

shelving, framing, and dampers,

o Shall not warp or otherwise be damaged to

an extent that results in the product

developing a risk of fire or electric shock in

continued use.

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OVERVOLTAGE AND UNDERVOLTAGE

OPERATION TEST

The operating parts and electronic circuits of a

control unit shall be able to withstand 110

percent of its rated voltage continuously

without damage during the normal operating

condition,

And the control unit shall operate successfully

during the normal operating condition at the

increased voltage.

It shall also operate successfully at 85 percent

of its rated voltage.

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DIELECTRIC VOLTAGE WITH

STAND TEST

o A unit shall withstand, without breakdown for a

period of 1 minute,

o The application of a 60 hertz potential as

follows:

1000 volts plus twice rated voltage is applied

between high-voltage live parts and dead metal

parts.

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SOLUTIONS

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4. Appropriate product

Ecology Unit Commercial

Kitchen Ventilation System

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ADVANTAGES WITH ECOLOGY UNIT

Compact design with DIDW fan.

High Efficiency Filtration, More than 55⁰ C.

Permanent Ionizer/Collector Elements: No Filter Replacement Cost; Just Wash, Dry and Reinstall.

Low Pressure Drop: Lower Energy Cost to Operate Compared to Media and Cartridge Units.

Hinged Filter Access: No Tools Required for Quick and Easy Service.

Designed in Modules.

Factory fitted Motor starter & filter status panel.

Computerized selection software .

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SOLUTIONS

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5. Recomendation

RECOMMENDATION

Calculate correct exhaust flow rate.

Correct Selection of hood.

Adequate overhanging.

Minimizing cross draft.

Supply/Extract has to be VFD controlled.

Timely maintenance as per manufacturer recommendation.

Odour control solution.

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MANDATORY REQUIREMENT

• UL / ETL Listing under UL 710 / (complete ecology & hood).

• Filters Should be UL Listed or complying fire property as per NFPA.

• Fan Should be VFD driven to handle different duty cycle to same energy.

• Fire Damper should be placed at correct location.

• Fan has to be AMCA certified for Air, Sound & FEG.

• Motor has to be high efficiency ( ≥ IE2).

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Saurabh Bhatia(Asst. Technical Manager)

QUESTIONS?

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