pressure fryers for food service … products pressure fryers for food service applications – bki...

Emerging Products

PRESSURE FRYERS FOR FOOD SERVICE

APPLICATIONS – BKI FKM-FC

ET10SCE1320 Report

`

Prepared by:

Emerging Products

Customer Service Business Unit

Southern California Edison

March 2012

Revised March 2014

Pressure Fryers for Food Service Applications ET10SCE1320

Southern California Edison Page ii Emerging Products March 2012 (rev April 2014)

Acknowledgements

Southern California Edison’s Emerging Products (EP) group is responsible for this project. It

was developed as part of Southern California Edison's Emerging Technologies Program

under internal project number ET10SCE1320. EP project managers Brian James and Carlos

Haiad conducted this technology evaluation with overall guidance and management from

Paul Delaney. For more information on this project, contact [email protected].

Disclaimer

This report was prepared by Southern California Edison (SCE) and funded by California

utility customers under the auspices of the California Public Utilities Commission.

Reproduction or distribution of the whole or any part of the contents of this document

without the express written permission of SCE is prohibited. This work was performed with

reasonable care and in accordance with professional standards. However, neither SCE nor

any entity performing the work pursuant to SCE's authority make any warranty or

representation, expressed, or implied, with regard to this report, the merchantability or

fitness for a particular purpose of the results of the work, or any analyses, or conclusions

contained in this report. The results reflected in the work are generally representative of

operating conditions; however, the results in any other situation may vary depending upon

particular operating conditions.


Southern California Edison Page iii Emerging Products March 2012 (rev April 2014)

ABBREVIATIONS AND ACRONYMS

ASTM American Society for Testing and Materials

Btu British Thermal Unit

CFM Cubic Feet Per Minute

Cp Specific Heat

CT Current Transducer

DAS Data Acquisition System

F Fahrenheit

ft Feet

FTC Foodservice Technology Center

Hv Heat of Vaporization

Hz Hertz

hr Hour

in Inches

kW Kilowatts

kWh Kilowatt-hours

lb Pound

Min Minutes

SCE Southern California Edison

V Volt

VAR Volt-Ampere Reactive


Southern California Edison Page iv

Emerging Products March 2012 (rev April 2014)

CONTENTS

EXECUTIVE SUMMARY _______________________________________________ 1

INTRODUCTION ____________________________________________________ 2

BACKGROUND ____________________________________________________ 3

GOALS OF THE STUDY _______________________________________________ 4

APPLIANCE EVALUATED _____________________________________________ 5

TEST METHODOLOGY _______________________________________________ 6

RESULTS AND DATA ANALYSIS ________________________________________ 10

CONCLUSION ____________________________________________________ 13

APPENDIX A – BKI-FKM SPECIFICATIONS ______________________________ 14

REFERENCES _____________________________________________________ 16


Southern California Edison Page v


FIGURES

Figure 1. BKI Model FKM-FC Pressure fryer ...................................... 5

Figure 2. DAS Interface With National Instruments LabVIEW ............. 6

Figure 3. BKI FKM-FC Pressure Fryer Preheat Curve ....................... 10

TABLES

Table 1. Cooking Energy Efficiency Results .................................... 11

Table 2. Cooking Efficiency and Uncertainty Results ........................ 11

Table 3. Cooking Energy Rate Results ........................................... 12

Table 4. Production Capacity Test Results ...................................... 12

EQUATIONS

Equation 1. Cooking Energy Efficiency............................................. 9

Equation 2. Cooking Energy Rate ................................................... 9

Equation 3. Production Capacity ..................................................... 9


Southern California Edison Page 1


EXECUTIVE SUMMARY The pressure fryer is similar to an open-kettle (open vat) fryer, but with the addition of a

heavy, gasketed lid with a pressure valve. Pressure fryers come in three sizes: four, six,

and eight heads of chicken capacity; one head of chicken constitutes approximately eight

pieces of chicken.

This project assesses the energy efficiency level of the BKI Model FKM-FC electric pressure

fryer and seeks to determine an appliance baseline and a minimum energy efficiency level

necessary to qualify for the food service qualifying product list. The food service qualifying

product list identifies the most efficient commercial kitchen appliances within a specific

appliance category; the qualifying appliances are eligible to receive incentives for their use.

The BKI Model FKM-FC pressure fryer, a six head chicken capacity electric pressure fryer,

was examined for various performance metrics. A test procedure was conducted in order to

characterize the pressure fryer’s energy input rate, preheat energy consumption, cooking

energy efficiency, and production capacity, according to the American Society for Testing

and Materials (ASTM) F 1964-11 Standard Test Methods for Performance of Pressure Fryers.

Southern California Edison’s Foodservice Technology Center (FTC) in Irwindale, CA

performed the testing. Cook time, pressure fryer temperature, pressure fryer power input,

and the weight and temperature of the test food were carefully measured. The test food

used in this study was chicken breasts.

From the extensive measurements collected, pressure fryer efficiency and numerous heat

rate and uniformity factors were calculated. The test data provides key information to help

determine the operational costs and the percentage of total kitchen productivity a single

appliance can deliver.

The following parameters of the BKI FKM-FC pressure fryer were determined during the test

procedures:

Energy Input Rate: The maximum energy input rate recorded during the test was

16.7 kilowatts (kW).

Preheat Energy Consumption: The pressure fryer took 11.3 minutes to reach a

temperature of 325° Fahrenheit (F), yielding a preheat energy consumption of 2.68

kilowatt-hours (kWh).

Idle Energy Rate: The amount of energy needed to maintain a 325°F setpoint was

0.67 kW.

Cooking Energy Efficiency: The average cooking energy efficiency as determined

by three heavy-load tests was 77%.

Production Capacity: The average measured production capacity was 64 pounds

(lbs)/hour (hr).




INTRODUCTION The pressure fryer is similar to an open-kettle (open vat) fryer, but with the addition of a

heavy, gasketed lid with a pressure valve. As steam escapes from the food and builds up

above the frying medium, typically oil or fat, the pressure inside the kettle rises. Moisture in

the food reaches higher temperatures before escaping into the kettle, and the cook time is

somewhat decreased compared to an open-kettle fryer. Pressure fryers come in three sizes,

four, six, and eight heads of chicken capacity; one head of chicken constitutes

approximately eight pieces of chicken.

The BKI Model FKM-FC pressure fryer, a six-head chicken capacity electric pressure fryer,

was examined for various performance metrics. A test procedure was conducted in order to

characterize the pressure fryer’s energy input rate, preheat energy consumption, cooking

energy efficiency, and production capacity, according to the American Society for Testing

and Materials (ASTM) F 1964-11 Standard Test Methods for Performance of Pressure

Fryers.1

Cook time, pressure fryer temperature, pressure fryer power input, and the weight and

temperature of the test food were carefully measured. Frozen, 5 ounce, whole meat,

boneless, skinless chicken breasts were used as the test food. Pressure fryer efficiency and

numerous heat rate and uniformity factors were calculated based on the collected

measurements.




BACKGROUND Southern California Edison (SCE) is committed to the advancement of the food service

industry and is part of a statewide team offering a food service qualifying product list that

identifies the most efficient commercial kitchen appliances within a specific appliance

category. The qualifying appliances are eligible to receive incentives for their use. Currently,

pressure fryers are not listed as one of the appliance categories on the food service

qualifying list. Testing is in progress to create different categories and add manufacturers to

the qualified equipment list.




GOALS OF THE STUDY This project evaluates the operation and performance of the BKI Model FKM-FC pressure

fryer using ASTM standard F 1964-11 test methods. The testing seeks to determine the

efficiency level of the appliance. Once a large enough sampling of pressure fryers from

various manufacturers is tested, an appliance baseline and a minimum efficiency level for

inclusion into the food service qualifying product list can be determined. The testing

examines the:

Energy Input Rate: The peak rate at which a pressure fryer consumes energy, in

kilowatts (kW).

Preheat Energy Consumption: The amount of energy consumed, in kilowatt-hours

(kWh), by the pressure fryer while preheating its cook zone from the ambient

temperature until the primary heating elements cycle off.

Idle Energy Rate: The convection pressure fryers required rate of energy

consumption (kW), when only the cooking medium is present, which is necessary to

maintain its cook zone temperature at a specified thermostat setpoint.

Cooking Energy Efficiency: The quantity of energy imparted to a specific food

product; this is expressed as a percentage of energy consumed by the pressure fryer

during the cooking event.

Cooking Energy Rate: The average rate of energy consumption (kW) during the

heavy load-cooking test.

Production Capacity: The rate, pounds (lbs)/hour (hr), at which a pressure fryer

brings the specified food product to a specified cooked condition. This does not

necessarily refer to the maximum rate, and the production rate varies based on the

amount of food cooked.




APPLIANCE EVALUATED The BKI Model FKM-FC Pressure Fryer, shown in Figure 1, is a six-head chicken capacity

electric pressure fryer. It uses controlled low pressure, a pressure regulated lid interlock

system, and made of a stainless steel outer construction. The filtration system improves

operations through proper alignment and the built-in cold zone collects breading “fall-off” to

extend the life of the frying medium. The pressure fryer is rated at 17 kW. Appliance

specifications and the manufacturer’s literature are included in Appendix A.

The biggest market barriers of electric pressure fryers are the lack of:

customer education on efficient pressure fryers and incentives;

efficient pressure fryers listed on the food service qualifying product list; and

incentives from the utilities.

FIGURE 1. BKI MODEL FKM-FC PRESSURE FRYER




TEST METHODOLOGY Laboratory testing of this pressure fryer was performed according to the ASTM F 1964-11

test method for pressure fryers. Testing methods are applicable to floor model natural gas

and electric pressure fryers. The testing provides information to determine:

Energy Input Rate

Preheat Energy Consumption

Idle Energy Rate

Cooking Energy Efficiency

Cooking Energy Rate

Production Capacity

LABORATORY AND INSTRUMENTATION DESCRIPTION Testing was performed at the SCE Foodservice Technology Center (FTC), a 2,000

square-foot demonstration and equipment test center. The center is part of the

Energy Education Center, located in Irwindale, CA and is a certified ASTM testing

laboratory. The FTC is capable of maintaining voltage regulations to ± 1 volt (V) on

120V, 208V, and 240V single- and three-phase. Receptacle configurations range

from 20 amperes (A)/120V single-phase to 100 A/208V/240V single- and three-

phase. The FTC is also equipped with a Data Acquisition System (DAS), a National

Instruments LabVIEW-based software (Figure 2), used to monitor power (kW),

amperage, voltage, power factor, frequency, and volt-ampere reactive (VAR) from all

receptacles, and displays the results in a real-time graph during testing. The

electrical consumption of the pressure fryers is logged in intervals of 1 second, and

the data from up to 36 thermocouples and 8 resistant temperature detection sensors

is recorded. The interface also allows the user to configure the monitoring

parameters and select specific monitoring hardware.

FIGURE 2. DAS INTERFACE WITH NATIONAL INSTRUMENTS LABVIEW




The DAS system is equipped with multi-functional digital transducers, integrated

serial current transducers (CTs), and voltage leads. The multi-functional digital

transducers create power readings from the CT and voltage inputs, and have an

accuracy of ± 0.5% over the full-scale readings. The CTs used in this project are

accurate to 10% full scale or better and have a frequency response ranging from 44

Hertz (Hz) to 3,000 kilohertz (kHz). The DAS system was calibrated in November

2009 and uses K type thermocouples and connectors. The K type thermocouples can

read a temperature range of 50°F to 400°F with accuracy of ± 1°F.2 A Teflon™

insulated 24-gauge thermocouple was used to determine the cook zone temperature

as well as the temperature of the chicken breasts. When determining the weight of

the chicken, a model A&D FG-60KAL digital scale that has a resolution of 0.01 (lb)

and an uncertainty of 0.01 lb. was used.

TEST SITE SETUP The test site setup refers to the installation of the pressure fryers, condition of the

environment, and the setup of temperature measurements for the chicken. At the

test site, the pressure fryer was installed according to the manufacturer's

instructions and placed under a deep canopy exhaust hood that was mounted against

the wall. The lower edge of the hood was positioned 6 feet (ft.), 6 inches (in.) from

the floor, with the front edge of the pressure fryer door inset 6 in. from the vertical

plane of the front edge of the hood. Both sides of the pressure fryer were 3 ft. away

from any nearby walls. The exhaust ventilation rate was set to 300 cubic feet per

minute (cfm) per linear foot of hood length. The ambient conditions were kept at a

temperature of 75 ± 5°F during operation of the exhaust ventilation system. The

pressure fryer was connected to a calibrated energy test meter, and supply voltage

was maintained within 2.5% of the manufacturer's nameplate voltage.

The bead of a bare junction thermocouple measured the temperature of the test

chicken breasts both before they were cooked and immediately after testing,

measured from the center of each monitored test chicken. The initial temperatures

for the chicken breasts were 75 ± 5°F.

ENERGY INPUT RATE AND PREHEAT ENERGY CONSUMPTION

Both the energy input and preheat energy consumption are used to confirm proper

operation of the pressure fryer. The preheat test records the required amount of

time and energy needed to raise the pressure fryer cook zone temperature from an

ambient of 75°F to 325°F. Preheat is judged complete when the temperature at the

monitored location reaches 325°F.

The energy input rate is the peak energy consumption of the pressure fryer while

preheating the pressure fryer from ambient temperature until the primary heating

element cycles off. The peak energy consumption, measured by an electrical meter,

must be operating within 5% of the nameplate energy input rate.




IDLE ENERGY RATE

After stabilization, the idle energy rate was taken by monitoring the consumption of

the pressure fryer for a 2-hour period. The fryer remains uncovered throughout the

idle test. The idle energy rate is the pressure fryer’s required rate of energy

consumption (kW), when only the cooking medium is present, needed to maintain its

cook zone temperature at a specified thermostat setpoint. For this test, the cook

zone temperature was maintained at 325°F.

COOK TIME DETERMINATION

The cook time for the pressure fryer is determined as the time required to cook the

six heads of chicken such that the internal temperature of the coldest piece is

greater than 165°F and the recorded weight of the cooked load has a weight loss of

27 ± 2% relative to the pre-cooked load.

COOKING ENERGY EFFICIENCY AND PRODUCTION CAPACITY

The cooking energy efficiency is the quantity of energy imparted to the specific food

product, and is expressed as a percentage of energy consumed by the pressure fryer

during the test. For pressure fryers, chicken breasts were used for the cooking

efficiency test, which was run under a heavy-loading scenario. The heavy load

testing required six heads of chicken. The test assumes eight chicken breasts make

up one head of chicken. The heavy-load testing was run at least three times.

The chicken breast tests consisted of eight chicken breasts per batch with each batch

weighing 2.4 ± 0.1 lb. Each test consists of 48 ± 3 chicken breasts, for a total pan

weight of 15.0 ± 0.5 lbs. Five test loads were run to constitute one heavy-load test.

The first load was a stabilization load with the subsequent four loads as test loads.

The chicken was removed from the refrigerator and immersed briefly in a dipping

solution consisting of 45°F to 50°F ice water. Then, the chicken was transferred to a

breading pin consisting of flour and weighed on the scale.

The average chicken breast temperature began at 50°F ± 5°F. The chicken was

methodically loaded into the fryer and cooked for the pre-determined cook time.

When the cook time elapsed, the pressure fryer was immediately shut off. The

weight of the cooked chicken breasts was measured and compared to the pre-cooked

weight.

Cooking energy efficiency is a precise indicator of pressure fryer energy performance

when cooking a typical food product. Equation 1 calculates the cooking energy

efficiency.




EQUATION 1. COOKING ENERGY EFFICIENCY

100

][)]()([100

,,12,

fryer

vfchickenichickenchickenichicken

fryer

food

cookE

HWWTTFCpW

E

E

Where:

ηcook = Cooking energy efficiency (%)

Efood = Amount of energy into the food (British thermal unit

(Btu))

Wchicken,i = Total weight of test food before cooking (lbs)

Wchicken,f = Total weight of test food after cooking (lbs)

Cpchicken(F) = The specific heat of the chicken breasts (0.84 Btu/lb °F)

Hv = Heat of vaporization at 212°F (970 Btu/lb)

T2 = Average final temperature of the food (°F)

T1 = Average initial temperature of the food (°F)

Efryer = Amount of energy into the appliance (Btu)

The cooking energy rate is the average rate of energy consumption (kW) during the

heavy load test. The cook energy rate is calculated using Equation 2.

EQUATION 2. COOKING ENERGY RATE

t

EE

fryer

cookrate

60

Where:

Ecookrate = Cooking energy rate (kW)

Efryer = Amount of energy consumed by an appliance during cook

testing (kWh)

t = Cook test time (min.)

Production capacity is the production capability of a pressure fryer as it is used to

cook a typical food product. This information can be used to determine the proper

size and the quantity needed to fit any user's needs. Equation 3 is used to calculate

the production capacity.

EQUATION 3. PRODUCTION CAPACITY

t

WPC

food 60

Where:

PC = Production capacity of the pressure fryer (lb/hr)

Wfood = Weight of food required for a heavy load

t = Cook test time (min.)

For cooking energy efficiency and production capacity results, the percentage of

uncertainty in each result is specified to be no greater than ±10% based on at least

three test runs.




RESULTS AND DATA ANALYSIS

ENERGY INPUT RATE AND PREHEAT ENERGY CONSUMPTION The energy input rate and preheat energy consumption are used to confirm proper

operation of the pressure fryer.

During the test, the BKI Model FKM-FC pressure fryer took 11.3 minutes to preheat

the pressure fryer cook zone from 79°F to 325°F, yielding a preheat energy

consumption of 2.68 kWh. Figure 3 shows a graph of the pressure fryer chamber

temperature versus time.

FIGURE 3. BKI FKM-FC PRESSURE FRYER PREHEAT CURVE

The energy input rate is the peak energy consumption of the pressure fryer while

preheating the pressure fryer from ambient temperature until the primary heating

element cycles off. The maximum energy input rate recorded during the test was

16.4 kW.




IDLE ENERGY RATE The idle energy rate is the pressure fryer’s required rate of energy consumption (kW) (when empty) needed to maintain its

cook zone temperature at a specified pressure or thermostat setpoint. During this test, the idle energy rate was taken after

stabilization by monitoring the consumption of the pressure fryer for a 2-hour period at 325°F. The idle energy rate was

calculated to be 0.67 kW.

COOKING ENERGY EFFICIENCY, ENERGY RATE AND PRODUCTION CAPACITY The cooking energy efficiency is the quantity of energy imparted to the specific food product, and is expressed as a

percentage of energy consumed by the pressure fryer during the test. Cooking energy efficiency is a precise indicator of

pressure fryer energy performance when cooking a typical food product. Results of three heavy load cooking energy

efficiency tests, presented as the average of the four test loads in each heavy load, are shown in Table 1.

TABLE 1. COOKING ENERGY EFFICIENCY RESULTS

TEST RUN W

CHICKEN, INITIAL [LBS]

M RAW

MOISTURE

CONTENT [%]

CP CHICKEN

BREAST

[BTU/ LB-°F]

T1 [°F]

T2 [°F]

E

SENSIBLE

[BTU]

HV

CHICKEN

BREAST

[BTU/LB]

W

CHICKEN, FINAL

[LBS]

W WATER, LOSS [LBS]

E EVAP

[BTU]

E

FRYER [BTU]

E

FOOD

[BTU]

N COOK

EFFICIENCY

[%]

Heavy load 1 15.34 0.73 0.79 45.00 182.06 1,661 970.00 11.18 4.93 4,864 8,116 6,446 79.70

Heavy load 2 15.30 0.73 0.79 45.02 195.41 1,818 970.00 11.03 5.11 4,954 8,317 6,772 81.51

Heavy load 3 14.96 0.73 0.79 43.48 181.29 1,629 970.00 10.97 4.34 4,210 8,233 5,839 70.99

Heavy load 4 14.99 0.73 0.79 45.50 185.17 1,653 970.00 10.74 4.82 4,673 8,395 6,326 75.40

The average efficiency and uncertainty results are shown in Table 2.

TABLE 2. COOKING EFFICIENCY AND UNCERTAINTY RESULTS

N, EFFICIENCY AVERAGE STANDARD DEVIATION ABSOLUTE UNCERTAINTY UNCERTAINTY PERCENT

76.90% 0.047 0.075 9.72%

The cooking energy rate is the average rate of energy consumption (kW) during the heavy load test. The results of the

Cooking Energy Rate Test are shown in Table 3.




TABLE 3. COOKING ENERGY RATE RESULTS

TEST RUN E PRESSURE FRYER [KWH] T [MINUTES] E COOKRATE [KW]

Heavy load 1 2.38 14.11 10.1

Heavy load 2 2.44 14.11 10.4

Heavy load 3 2.41 14.19 10.2

Heavy load 4 2.46 14.24 10.4

Production capacity information is the production capability of a pressure fryer as it

is used to cook a typical food product. This information can be used to determine the

proper size and the quantity needed to fit any user's needs. The results of the

Production Capacity Test are shown in Table 4.

TABLE 4. PRODUCTION CAPACITY TEST RESULTS

TEST RUN

W

CHICKEN

, INITIAL

[LBS] T [MIN] PC

[LB/HR]

PC, AVG

PROD. CAPACITY

[LB/HR] STANDARD

DEVIATION ABSOLUTE

UNCERTAINTY UNCERTAINTY

PERCENT

Heavy load 1 15.34 14.11 65.22

64.17 1.12 1.78 2.78% Heavy load 2 15.30 14.11 65.06

Heavy load 3 14.96 14.19 63.27

Heavy load 4 14.99 14.24 63.13




CONCLUSION The following parameters of the BKI Model FKM-FC pressure fryer were determined during

the testing procedure:

Energy Input Rate: The maximum energy input rate recorded during the test was

16.4 kW.

Preheat energy consumption: The pressure fryer took 11.3 minutes to reach a

temperature of 325°F, yielding a preheat energy consumption of 2.68 kWh.

Idle Energy Rate: The idle energy rate, the amount of energy to maintain a 325°F

setpoint, was recorded as 0.67 kW.

Cooking Energy Efficiency: The average cooking energy efficiency as determined

by three heavy-load tests was 77%.

Production Capacity: The average measured production capacity was 64 lbs/hr.




APPENDIX A – BKI-FKM SPECIFICATIONS




REFERENCES

1 American Society for Testing and Materials, 2011. Standard Test Method for Performance

of Pressure Fryers. ASTM Designation F1964-11. In Annual Book of ASTM Standards, West

Conshohocken, PA

2 http://www.omega.com/temperature/z/pdf/z204-206.pdf

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