XLT Ovens, Eyebrow Hood and Model 3255-TS3 Gas … · XLT Ovens, Eyebrow Hood and Model 3255-TS3 Gas Conveyor Pizza Oven Capture and Containment Performance Tests Application of …

XLT Ovens, Eyebrow Hood and Model 3255-TS3 Gas Conveyor Pizza Oven

Capture and Containment Performance Tests

Application of ASTM Standard Test Method F 1704-05

FSTC Report 5011.09.05

Food Service Technology Center July 2009

Prepared by: Rich Swierczyna

Paul Sobiski Architectural Energy Corporation

Prepared for: Pacific Gas & Electric Company

Customer Energy Efficiency Programs P.O. Box 770000

San Francisco, California 94177

2009 by Fisher-Nickel Inc. All rights reserved.

The information in this report is based on data generated at the PG&E Food Service Technology Center

its affiliated Commercial Kitchen Ventilation Laboratory (CKVL)

Acknowledgments

California consumers are not obligated to purchase any full service or

other service not funded by this program. This program is funded by

California utility ratepayers under the auspices of the California Public

Utilities Commission.

Los consumidores en California no estan obligados a comprar servicios completos o adi-

cionales que no esten cubiertos bajo este programa. Este programa esta financiado por los

usuarios de servicios públicos en California bajo la jurisdiccion de la Comision de Servicios

Públicos de California.

A National Advisory Group provides guidance to the Food Service

Technology Center Project. Members include:

Applebee’s International Group

California Energy Commission (CEC)

Denny’s Corporation

East Bay Municipal Utility District

Enbridge Gas Distribution Inc.

EPA Energy Star

Gas Technology Institute (GTI)

In-N-Out Burger

National Restaurant Association

Safeway, Inc.

Southern California Edison

Underwriters Laboratories (UL)

University of California at Berkeley

University of California at Riverside

US Department of Energy, FEMP

Specific appreciation is extended to XLT Ovens for supplying the gas conveyor pizza oven for controlled testing at the CKV Laboratory.

Policy on the Use of Food Service Technology Center Test Results and Other Related Information

• Fisher-Nickel, inc. and the Food Service Technology Center

(FSTC) do not endorse particular products or services from any

specific manufacturer or service provider.

• The FSTC is strongly committed to testing food service equipment

using the best available scientific techniques and instrumentation.

• The FSTC is neutral as to fuel and energy source. It does not, in

any way, encourage or promote the use of any fuel or energy

source nor does it endorse any of the equipment tested at the

FSTC.

• FSTC test results are made available to the general public through

technical research reports and publications and are protected under

U.S. and international copyright laws.

• In the event that FSTC data are to be reported, quoted, or referred

to in any way in publications, papers, brochures, advertising, or any

other publicly available documents, the rules of copyright must be

strictly followed, including written permission from Fisher-Nickel,

inc. in advance and proper attribution to Fisher-Nickel, inc. and the

Food Service Technology Center. In any such publication, sufficient

text must be excerpted or quoted so as to give full and fair repre-

sentation of findings as reported in the original documentation from

FSTC.

Legal Notice

This report was prepared as a result of work sponsored by the California Public Utilities Commission (Commission). It does not necessarily repre-sent the views of the Commission, its employees, or the State of Califor-nia. The Commission, the State of California, its employees, contractors, and subcontractors make no warranty, express or implied, and assume no legal liability for the information in this report; nor does any party rep-resent that the use of this information will not infringe upon privately owned rights. This report has not been approved or disapproved by the Commission nor has the Commission passed upon the accuracy or ade-quacy of the information in this report.

Disclaimer

Neither Fisher-Nickel, inc. nor the Food Service Technology Center nor any of its employees makes any warranty, expressed or implied, or as-sumes any legal liability of responsibility for the accuracy, completeness, or usefulness of any data, information, method, product or process dis-closes in this document, or represents that its use will not infringe any privately-owned rights, including but not limited to, patents, trademarks, or copyrights. Reference to specific products or manufacturers is not an endorsement of that product or manufacturer by Fisher-Nickel, inc., the Food Service Technology Center or Pacific Gas & Electric Company (PG&E). Retention of this consulting firm by PG&E to develop this report does not constitute endorsement by PG&E for any work performed other than that specified in the scope of this project.

Contents

DRAFT 5011.09.05 i

Food Service Technology Center

Page

1-1 XLT Ovens 3255-TS3 ........................................................... 1-3

1-2 XLT Ovens Close-Coupled Eyebrow Hood ........................... 1-4

1-3 Baffle Filter for Exhaust Hood ............................................... 1-4

2-1 Laboratory Layout .................................................................. 2-1

2-2 Equipment Layout .................................................................. 2-4

2-3 Schlieren Visualization Image at Spill Condition .................... 2-5

2-4 Schlieren Visualization Image at C&C Condition.................... 2-5

Page

1-1 Appliance Specifications ....................................................... 1-3

1-2 Hood Specifications ............................................................... 1-4

3-1 Summary of Capture and Containment Performance ............ 3-2

Page

1 Introduction ................................................................................. 1-1

Background ............................................................................ 1-1

Objectives ............................................................................... 1-2

Appliance Description ............................................................. 1-3

Hood Description .................................................................... 1-4

2 Methods ....................................................................................... 2-1

Airflow Visualization ............................................................... 2-1

Capture and Containment Testing ......................................... 2-2

Setup and Instrumentation ..................................................... 2-3

3 Results ......................................................................................... 3-1

Capture and Containment Testing ......................................... 3-1

4 Conclusions ................................................................................. 4-1

5 References ................................................................................... 5-1

Appendix A: Appliance Specifications

Appendix B: Hood Specifications

Figures

Tables

1 Introduction

5011.09.05 1-1


Conveyor pizza ovens allow for the rapid cooking of food products with

consistency and ease of operator use. They generally have a large kitchen

footprint, a high-input gas burner or electric elements, and a high volume

capacity to cook the food at a very high rate. The importance of considering

the required ventilation rate as well as the energy input and efficiency for

such a powerful appliance cannot be understated.

Dedicated to the advancement of the food service industry, the Food Service

Technology Center (FSTC) has focused on the development of standard test

methods for commercial food service equipment since 1987. The primary

component of the FSTC is a 10,000 square-foot appliance laboratory

equipped with energy monitoring and data acquisition hardware, 60 linear

feet of canopy exhaust hoods integrated with utility distribution systems,

appliance setup and storage areas, and a state-of-the-art demonstration and

training facility.

Likewise, the Commercial Kitchen Ventilation Laboratory (CKV Lab) has

been dedicated to the improvement of kitchen ventilation since the early

1980’s. The test cell at the CKV Lab is a 900 square foot airtight room,

equipped with similar energy metrology. In addition, two schlieren and two

flow visualization systems are available to verify proper hood capture and

containment performance and provide evaluation of hood and appliance

modifications in real-time.

The hand-in-hand teamwork of the two facilities has provided the commer-

cial kitchen industry with information regarding the hood and appliance sys-

tems that has been the foundation for codes, standards, ASHRAE Hand-

books, and helped drive energy conservation with regards to commercial

kitchens.

Background

Introduction

5011.09.05 1-2


The test methods, approved and ratified by the American Society for Testing

and Materials (ASTM), allow benchmarking of equipment such that users

can make meaningful comparisons among available equipment choices. End-

use customers and commercial appliance manufacturers consider the FSTC

to be the national leader in commercial food service equipment testing and

standards, sparking alliances with several major chain customers to date.

The performance of a hood and appliance system is not only characterized

by preheat time, energy profile, and production capacity, but also by the ex-

haust airflow rate needed to capture and contain the thermal and cooking

plumes generated by the appliance during idle and cooking conditions.

The XLT Ovens 3255-TS3 conveyor pizza oven features a stackable design.

This design provides the end user with the option to purchase the appliance

in a one, two or three deck configuration and each deck operates independ-

ently. The oven was tested under an XLT Ovens designed close-coupled

eyebrow hood. The hood and appliance was tailored as a system by XLT

Ovens by careful integration of panels and food take-away shelves while

maintaining ease of use by personnel.

The objective of this report is to examine capture and containment perform-

ance of XLT Ovens 3255-TS3 conveyor pizza oven and close-coupled eye-

brow hood system under the controlled conditions of ASTM standard test

method F1704-05, Capture and Containment Performance of Commercial

Kitchen Exhaust Ventilation Systems. The scope of testing included:

1. Determining the exhaust rates required for one, two and three-

deck operation in a baseline configuration.

2. Determining the change in required exhaust rate for appliance

operation without the integrated panels.

3. Determining any capture and containment performance im-

provements to be had with minor alterations, such as adding

holes to the food take-away trays.

Objectives

Introduction

5011.09.05 1-3


XLT Ovens’ 3255-TS3 conveyor pizza oven is a stackable unit and was

tested in the triple deck configuration. The oven is equipped with an 88-inch

long by 32-inch wide variable speed conveyor, which passes through a 55-

inch long high-velocity impingement bake zone using a natural gas burner

rated at 150,000 Btu/h per deck and a 120 VAC electrical input rated at 6

amps per deck. The oven is of stainless steel construction and features a

solid-state control panel for temperature and conveyor speed adjustments.

Appliance specifications are listed in Table 1-1, an image of the appliance is

shown in Figure 1-1, and the manufacturer’s literature is in Appendix A.

Table 1-1. Appliance Specifications.

Manufacturer XLT Ovens

Model 3255-TS3

Generic Appliance Type Conveyor Pizza Oven

Rated Gas Input 150,000 Btu/h (per deck)

Rated Electrical Input 6 amps @ 120 VAC

Cooking Area 32″ x 55″

Controls Solid State

Construction Stainless Steel

Appliance Description

Figure 1-1.

XLT Ovens’ 3255-TS3.

Introduction

5011.09.05 1-4


The hood used for testing was an XLT Ovens close-coupled eyebrow hood,

which had overall dimensions of 111.5 inches long, 48.3 inches deep, and 20

inches tall. It had two 2.7 foot filter banks, each with a 15.5-inch high by

19.5-inch wide baffle filter located directly over the entrance and exit of the

oven. Each filter bank had a 16-inch wide by 8-inch tall duct which con-

nected to a 12-inch by 12-inch exhaust collar. A summary of the hood speci-

fications is presented in Table 1-2, an image of the hood is shown in Figure

1-2, and an image of the filter used in the hood is shown in Figure 1-3.

Table 1-2. Hood Specifications.


Model Prototype

Generic Hood Type Eyebrow Hood

Length 111.5 inches

Depth 48.3 inches

Height 20.0 inches

Filtration Two Baffle Filters, 15.5 inches x 19.5 inches each

Exhaust Collar 12.0 inches x 12.0 inches

Hood Description

Figure 1-2.

XLT Ovens’

Close-Coupled

Eyebrow Hood

Figure 1-3.

Baffle Filter

2 Methods

5011.09.05 2-1


The primary tools used for airflow visualization were schlieren and shadow-

graph systems, which visualize the refraction of light due to air density

changes. Since the hot air and effluent generated by the cooking process

change the air density around the equipment, the sensitive flow visualization

systems provide a graphic image of the thermal activity along the perimeter

of the hood. The left and right lower edges of the hood were monitored by

schlieren systems located at a height that was between the typical 36-inch

appliance height and the 78-inch hood height. The front lower edge of the

hood was monitored using a shadowgraph system, located at the same height

as the hood edge or adjusted to be in line with the oven deck being evalu-

ated. Other flow visualization tools used to seed the thermal plume included

small smoke sticks. Figure 2-1 shows a plan view of the laboratory with the

relative position of the hood and flow visualization tools.

6'-9"

11'-6"

19'-10"

9.3 ft x 4.0 ft x 1.7 ft

Eyebrow HoodOptics Box

Schlieren

5'-5 1/2"

PiezometerRing

Supply Diffuser Wall

Shadow

gra

ph

Shadow

gra

ph

Optics Box

Schlieren

Hood Collar

Supply Diffuser Wall

Airflow Visualization

Figure 2-1.

Laboratory Layout.

Methods

5011.09.05 2-2


"Hood capture and containment" is defined in ASTM F1704-05 [Ref 1],

Capture and containment performance of commercial kitchen exhaust venti-

lation systems, as "the ability of the hood to capture and contain grease laden

cooking vapors, convective heat and other products of cooking processes”.

Hood capture refers to the products getting into the hood reservoir, while

containment refers to these products staying in the hood reservoir and not

spilling out into the space. "Minimum capture and containment" is defined

as "the conditions of hood operation at which the exhaust flow rate is just

sufficient to capture and contain the products generated by the appliance in

idle and heavy load cooking conditions, or at any intermediate prescribed

load condition."

For each capture and containment (C&C) evaluation, the exhaust rate was

reduced until spillage of the plume was observed along the perimeter of the

hood using airflow visualization techniques described in the previous sec-

tion. The exhaust rate was then increased in fine increments until capture

and containment was achieved. For most cases, single-test determinations

were used to establish the airflow rate for threshold capture and contain-

ment. The airflow measurements in the laboratory comply with the AMCA

210/ASHRAE 51 Standard [Ref 2]. The error on the airflow rate measure-

ment is less than 2%. The repeatability of capture and containment determi-

nations is typically within 5%.

Capture and Containment Testing

Methods

5011.09.05 2-3


The XLT Ovens 3255-TS3 was installed under the XLT Ovens close-

coupled eyebrow hood. The appliance operation was varied to evaluate ven-

tilation rates for one, two, and three deck operation. Operation was usually at

idle conditions, with some cooking conditions included to evaluate sensitiv-

ity. The configuration of the system was modified to evaluate the effective-

ness of the panels and the food take-away trays. During the performance

evaluation, schlieren flow visualization systems were used to ensure proper

effluent capture and containment and were augmented by shadowgraph and

smoke visualization. A photograph of the typical test setup of the triple deck

oven, eyebrow hood, and integrated panels is shown in Figure 2-2, and a

photograph illustrating schlieren visualization is shown in Figure 2-3.

The oven was calibrated and operated during the hood performance testing

according to ASTM F1817 Standard Test Method for the Performance of

Conveyor Ovens [Ref 3], except where noted. The standard required a cali-

brated oven cavity temperature of 475°F, which was achieved using a 465°F

setpoint. If cooking, capture and containment performance was determined

while baking plain 12-inch cheese pizzas under heavy-load conditions, which

maximizes the coverage of the conveyor with pizza.

Exhaust static pressure was measured using four pitot-static pressure sensors

connected to a piezometer ring located in a 16.75 inches by 16.50 inches rec-

tangular section of the exhaust duct. The peizometer ring was located 15

inches downstream from the boot used to transition between the rectangular

duct and 12 inch round ductwork connected to the hood collar.

Setup and Instrumentation

Methods

5011.09.05 2-4


Figure 2-2.

Equipment configuration.

Methods

5011.09.05 2-5


Figure 2-3.

Schlieren visualization during spill condition at 400 cfm with three decks in operation.

Figure 2-4.

Schlieren visualization during C&C condition at 1200 cfm with three decks in operation.

3 Results

5011.09.05 3-1


At idle conditions, 200, 700, and 1100 cfm was documented for the best cas-

es of one, two, and three deck operation, respectively. By switching off

decks as demand allowed, a reduction of up to 82% was possible if the top

deck was in operation rather than all three decks.

The panels significantly reduced the required exhaust rate for proper capture

and containment. Two-deck operation required 700 cfm at idle conditions.

For comparison, operation without the integrated panels required 2400 cfm

during two-deck operation. Therefore, the panels provided a reduction of

1700 cfm, or 71%, for two-deck operation.

For two testing scenarios, modification or removal of the take-away trays

was evaluated and shown to be beneficial. This modification provided up to

a 100 cfm reduction, or 13%. The capture and containment test results are

summarized in Table 3-1.

Capture and Containment Testing

Results

5011.09.05 3-2


Table 3-1. Summary of Capture and Containment Performance During Idle Conditions at

465°F Setpoint (unless otherwise noted).

Number of

Decks

C&C

Rate

[cfm]

Exhaust Static

Pressure

[in. of water]

Panel

Configuration

Tray

Configuration

1 Deck 200 0.01 End load,

end discharge Load w/o trays,

discharge with holes in trays

1 Deck a 400 0.04 End load,




end discharge Without trays


end discharge With solid trays

2 Deck b 800 0.16 Side load,


2 Deck 800 0.16 Side load,


2 Deck 2400 2.70 Without panels Without trays


end discharge With holes in trays








discharge with solid trays


end discharge Without trays a 465°F setpoint, cooking conditions.

b 540°F setpoint, idle conditions.

4 Conclusions

5011.09.05 4-1


XLT Ovens’ 3255-TS3 conveyor pizza oven and hood system performed

well under the rigorous conditions of the ASTM F1704-05 Standard Test

Method for the Capture and Containment Performance of Commercial

Kitchen Exhaust Ventilation Systems. When optimized with integrated panels

and improved food take-away trays, the required ventilation rate was as low

as 200 cfm for the top deck operation. With all three decks in operation, the

required exhaust rate was 1100 cfm.

The optimization of the hood and appliance as a system significantly reduced

the required exhaust rate. Without the optimization of integral panels, 2400

cfm was needed for proper ventilation of two deck operation. With the pan-

els installed and the food take-away trays removed, the exhaust rate was re-

duced to 700 cfm, which is a reduction of 1700 cfm, or 71%. The combina-

tion of an excellent conveyor pizza oven, close-coupled eyebrow hood, and

carefully engineered integration of the two devices has resulted in an effi-

cient system that can deliver a high quantity of pizza while operating with a

very low quantity of exhaust.

5 References

5011.09.05 5-1


1. ASTM 2005. ASTM Designation F1704-05, Capture and Containment Performance of Commercial

Kitchen Exhaust Ventilation Systems. West Conshohocken, PA.

2. Air Movement and Control Association, Inc. and American Society of Heating, Refrigeration, and Air

Conditioning Engineers, Inc. Laboratory methods of testing fans for rating. AMCA Standard

210/ASHRAE Standard 51, Arlington Heights, IL and Atlanta, GA.

3. American Society for Testing and Materials. 2007. Standard Test Method for the Performance of Con-

veyor Ovens. ASTM Designation F 1817-03, in Annual Book of ASTM Standards, West Conshohocken,

PA.

A Appliance Specifications

5011.09.05 A-1


Appendix A includes the product literature for the XLT Ovens 3255-TS3

conveyor pizza oven.

Table A-1. Appliance Specifications.


Model 3255-TS3

Generic Appliance Type Conveyor Pizza Oven

Rated Gas Input 150,000 Btu/h

Rated Electrical Input 6 amps @ 120 VAC

Cooking Area 32″ x 55″

Controls Solid State

Construction Stainless Steel


5011.09.05 A-2



5011.09.05 A-3



5011.09.05 A-4



5011.09.05 A-5


B Hood Specifications

5011.09.05 B-1


Documents

XLT Ovens, Eyebrow Hood and Model 3255-TS3 Gas … · XLT Ovens, Eyebrow Hood and Model 3255-TS3 Gas Conveyor Pizza Oven Capture and Containment Performance Tests Application of …