AccuTemp Steam n Hold, Model 208-D8-300 and 400 Electric Steamers In-Kitchen Appliance Performance Report FSTC Report 5011.01.90 Food Service Technology Center Manager Final Report, December 2001 Prepared by: Shawn Knapp Judy Nickel Todd Bell Fisher-Nickel, Inc. Prepared for: Peter Turnbull, Senior Program Manager Pacific Gas and Electric Company Customer Energy Management 123 Mission Street, P.O. Box 770000, Mail Code N6G San Francisco, California 94177 2001 by Pacific Gas and Electric Company. All rights reserved. The information in this report is based on data generated at Pacific Gas and Electric Company s Food Service Technology Center.
Acknowledgments This program is funded by California utility customers and administered by Pacific Gas and Electric Company under the auspices of the California Public Utilities Commission. A National Advisory Group provides guidance to the Food Service Technology Center Project. Members include: California Energy Commission (CEC) California Restaurant Association (CRA) Carl Karcher Enterprises, Inc. Darden Restaurants, Inc. DJ Horton & Associates Electric Power Research Institute (EPRI) Enbridge\Consumers Gas Gas Technology Institute (GTI) International Facility Management Association (IFMA) McDonald s Corporation M.I.G.A. Restaurant Construction Management National Restaurant Association Safeway, Inc. Underwriters Laboratories (UL) University of California, Berkeley (UC Berkeley) University of California, Riverside (CE-CERT) Policy on the Use of Food Service Technology Center Test Results and Other Related Information The Food Service Technology Center (FSTC) is strongly committed to testing food service equipment using the most appropriate 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 Pacific Gas and Electric Company 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 Pacific Gas and Electric Company in advance and proper attribution to Pacific Gas and Electric Company and the Food Service Technology Center. In any such publication, sufficient text must be excerpted or quoted so as to give full and fair representation of findings as reported in the original documentation from FSTC. Specific appreciation is extended to AccuTemp for supplying the Food Service Technology Center with model Steam n Hold, 208-D8-300 and 208-D8-400 electric steamers for controlled testing in the appliance laboratory and subsequent installation and monitoring in the production-test kitchen. Legal Notice This report was prepared by Pacific Gas and Electric Company for exclusive use by its employees and agents. Neither Pacific Gas and Electric Company nor any of its employees: (1) makes any written or oral warranty, expressed or implied, including, but not limited to those concerning merchantability or fitness for a particular purpose; (2) assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, process, method, or policy contained herein; or (3) represents that its use would not infringe any privately owned rights, including, but not limited to, patents, trademarks, or copyrights. 5011.01.90
Contents Page Executive Summary... iii 1 Introduction... 1-1 Background... 1-1 Objective... 1-2 The Production Test Kitchen... 1-2 Appliance Description and Operation... 1-2 2 Controlled Energy Tests... 2-1 Purpose... 2-1 Methods and Results... 2-1 3 Production Monitoring... 3-1 Energy Performance... 3-1 Estimated Annual Energy Cost... 3-3 Food Production... 3-5 Items Cooked... 3-5 In-Kitchen Observations... 3-7 4 Conclusions and Recommendations... 4-1 Production... 4-1 Energy Consumption and Conservation Potential... 4-2 5 References... 5-1 Appendix A: Glossary Appendix B: Manufacturer s Product Specifications Appendix C: Energy Monitoring System Appendix D: Frequency Distribution of Dataset Appendix E: PG&E Energy Rates Appendix F: Summary of ASTM Test Results 5011.01.90 i
Contents Figures Page 1-1 Two STEAM n HOLD in stacked configuration... 1-4 1-2 Pacific Gas and Electric Company Learning Center, Production-test kitchen and typical appliance layout... 1-5 2-1 STEAM n HOLD instrumented for testing under controlled laboratory conditions... 2-3 2-2 Preheat and idle characteristics... 2-3 3-1 Typical daily energy consumption profile of upper steamer... 3-3 3-2 Typical daily energy consumption profile of lower steamer... 3-4 3-3 Typical daily energy consumption profile of combined steamers... 3-4 3-4 AccuTemp electric steamers in the production-test kitchen... 3-6 Tables Page ES-1 Summary of AccuTemp Model 208-D8-300 and 400 Electric Steamer Performance... iv 1-1 Appliance Specifications... 1-4 2-1 Summary of Controlled Energy Tests of AccuTemp Steam n Hold Electric Steamer... 2-2 3-1 Average Daily Energy Performance... 3-2 3-2 Estimated Annual Energy Cost... 3-5 5011.01.90 ii
Executive Summary This Food Service Technology Center (FSTC) research report presents the results of monitoring two AccuTemp electric steamers, model 208-D8-300 and model 208-D8-400 as they were used for routine menu production in Pacific Gas and Electric Company s production-test kitchen and during tests under controlled laboratory conditions 1. The manufacturer supplied a cabinet frame to place the steamers in a double-stacked configuration. Each steamer could be operated independent of the other. AccuTemp steamer s unique vacuum cooking process allows the generation of steam at a lower temperature than conventional atmospheric steamers. The boiler-less design eliminates the water feed and condensate drain, leaving a user-friendly and low maintenance machine. The thermostatic controls maintain food at a desired temperature until ready to serve. The steamer was monitored in the production-test kitchen over a 6-month test period. The production energy consumption and appliance operational hours were recorded. To supplement monitoring information acquired during actual production conditions, controlled energy tests were also conducted. 1 The measured peak energy input rate for a single steamer was 8.34 kw, which was 4.25% higher than its 8.00 kw nameplate input. A single steamer consumed 1.71kWh of energy over the 12.3-minute preheat period. The rate of idle energy use averaged 1.2 kw. A summary of the test results is presented in Table ES-1. 1 Food Service Technology Center. AccuTemp STEAM n HOLD, Model 208-D8-300. Application of ASTM Standard Test Method Designation F1484-99. Report 5011.99.75. Customer Energy Management Department, San Francisco. California: Pacific Gas and Electric Company, 1999. 5011.01.90 iii
Executive Summary Table ES-1. Summary of AccuTemp Model 208-D8-300 and Model 400 Electric Steamer Performance Rated Energy Input (kw) a 8.00 Measured Energy Input Rate (kw) a 8.34 Preheat Time (min) 12.3 Preheat Energy (kwh) 1.71 Idle Energy Rate (kw) 1.2 Idle Duty Cycle (%) 14.4 Model 208-D8-300 (upper steamer) Daily Production Energy Use (kwh/day) b 17.8 Appliance On-Time (h/d) 9.5 Production Energy Consumption Rate (kw) c 1.8 Production Duty Cycle (%) 22.6 Model 208-D8-400 (lower steamer) Daily Production Energy Use (kwh/day) b 12.1 Appliance On-Time (h/d) 6.8 Production Energy Consumption Rate (kw) c 1.9 Production Duty Cycle (%) 22.8 Both Steamers Combined Daily Production Energy Use (kwh) b 29.9 Average Appliance On-Time (h/d) 8.2 Production Energy Consumption Rate (kw) c 3.7 Production Duty Cycle (%) 22.7 a Per individual steamer. b Includes preheat and idle energy over the hours of operation when steamer was in use. c Note that the average production energy consumption rate was based on aggregate preheat, idle and cooking energy for the hours of appliance operation. 5011.01.90 iv
Executive Summary Energy use data for the six-month test period were reduced to include only days that reflected typical steamer usage in the production-test kitchen (i.e., days when the steamer was used for three-meal periods). The steamers were on for an average of 8.2 hours, consuming 29.9 kwh per day. This includes the aggregate preheat, idle, and cooking energy for the entire day of appliance operation. The average rate of production energy use for both steamers combined was 3.79 kw, resulting in a production duty cycle of 22.7%. Based on a 5-day per week, 52-week-per-year food service operation, the steamer would consume 7774 kwh per year. The total yearly cost to operate the steamer would be $689: consumption accounts for $644, while demand accounts for $45. This calculation is based on Pacific Gas and Electric Company s A-10 schedule for commercial electric rates ($0.0824/kWh and $3.91/kW per month) dated April 2000. The steamer was one of the most frequently used appliances in the production-test kitchen; it was used heavily to prepare a wide variety of items for lunch and dinner, including fresh and frozen vegetables, rice, beans, pasta, potatoes, sauces, and fish. Over a typical day, the operators cooked about 200 pounds of food. Although the daily quantity of food was considered light compared to high volume full-service restaurants, it was considered representative of many corporate/commercial cafeteria operations offering a diverse menu mix to a broad customer base. 5011.01.90 v
1 Introduction Background Steaming provides a fast-cook option for preparing large quantities of food while retaining vital nutrients in the cooked product. Beyond the capital cost, steamers should be evaluated with regard to long-term performance and operational costs characterized by cooking energy efficiency, production capacity and water consumption. AccuTemp s new steamer places the cabinet under a vacuum to speed the creation of steam. The Pacific Gas and Electric Company s Food Service Technology Center (FSTC) developed a standard testing procedure to evaluate the performance of gas and electric steam cookers. This test procedure was submitted to the American Society for Testing and Materials (ASTM) and accepted as a standard test method in December 1993 1. In keeping with ASTM s policy that a standard be periodically reviewed, the FSTC revised the steamer test method in February 1999 under the Designation F 1484-99 2 (originally published as F 1484-93). Modifications to the test method included replacing the ice-load test with frozen green peas to capture real-world application and reducing the three loading scenarios to two. Pacific Gas & Electric Company s Development and Validation of a Uniform Testing Procedure for Steam Cooker 3 documents the developmental procedures and test results of several gas and electric steamers. The Food Service Technology Center monitored the AccuTemp electric steamers, model 208-D8-300 and model 208-D8-300 under both laboratory and in-kitchen conditions. They were used for routine menu production in Pacific Gas and Electric Company s production-test kitchen over a 6-month period: June through December 2000. Two other electric steamers have similarly been monitored at the production-test kitchen facility. 4,5 5011.01.90 1-1
Introduction To supplement production energy monitoring data, controlled energy test data were also documented. The glossary in Appendix A is provided so that the reader has a quick reference for the terms used in this report. Objective The objective of this appliance performance report was to document the energy consumption characteristics of the AccuTemp electric steamers during the six months they were in operation at the production-test kitchen. The report documents steamer usage in relationship to its energy consumption and cost while in production. Therefore, the reader should bear in mind that this information is specific to Pacific Gas and Electric Company s production-test kitchen, a corporate, cafeteria-style operation. The Production Test Kitchen The 1,500-square-foot kitchen is an integral component of the campus-style dining facility at Pacific Gas and Electric Company s Learning Center in San Ramon, California. Typically 10 or more cooking appliances are centrally located on two sides of a utility distribution system (UDS). The UDS functions as a central spine that contains all plumbing, wiring, and natural gas distribution lines. A 16-foot, double-sided canopy exhaust hood ventilates the equipment island at a design air flow of 9,600 cfm. Grilles along the front face of the hood direct conditioned makeup air into the kitchen. The UDS was designed to accommodate quick connection and disconnection of the appliances as they are rolled in or out of the line, with the flexibility to accommodate either a gas or an electric model in each appliance slot. Gas and electric meters interface with a remote data acquisition and processing system. Appliance monitoring and performance evaluations are conducted by the FSTC research team, independent of the food service operation. 5011.01.90 1-2
Introduction Appliance Description and Operation AccuTemp Products, Inc supplied the Food Service Technology Center with two steamers. The model 208-D8-300 steamer came equipped with a 90- minute timer and the model 208-D8-400 steamer was equipped with a 180- minute timer. The manufacturer also supplied a stand to house the two steamers in a double-stacked configuration (Figure 1-1). The model 208-D8-300 steamer was placed above model 208-D8-400 steamer in the stand. Each steamer could be operated independently; the energy consumption of each steamer was monitored separately. The STEAM n HOLD is a stainless-steel, natural-convection steamer powered by an 8-kW electric heating element. Steam is generated within the food compartment without a separate boiler. Water is manually added to the compartment. Elements beneath the compartment bottom heat the water to produce steam. Water is drained manually using a valve at the front of the steamer, eliminating the need for water feed and drain hookups. The cooking chamber can accommodate six 12" x 20" x 2½" pans, four 12" x 20" x 4" pans, or three 12" x 20" x 6" pans. The unique timer/hold feature allows food to be cooked to the desired temperature and held until it is ready to be served. Table 1-1 presents the specifications for the AccuTemp steamers and the manufacturer s product literature appears in Appendix B. Figure 1-2 is a floor plan of the production-test kitchen and appliance lineup. 5011.01.90 1-3
Introduction Table 1-1. Appliance Specifications. Manufacturer AccuTemp Products, Inc. Model 208-D8-300 and 208-D8-400 STEAM n HOLD Generic Appliance Type 1-compartment, natural-convection, electric, vacuum steamer. Rated Input Technology 8 kw for each compartment. Boiler-less steamer with natural-convection, vacuum-sealed chamber. Construction Double-wall, stainless-steel. Interior 14 Ga. Exterior 22 Ga. Controls Main ON-OFF buttons. Model 208-D8-300 is equipped with a 90-minute mechanical timer with continuous steam and hold setting. Model 208-D8-400 is equipped with a 180-minute mechanical timer with continuous steam and hold setting. Thermostat dial with temperature ranging from 140 F to 212 F. Compartment Capacity 6 (12" x 20" x 2½" ) pans 4 (12" x 20" x 4" ) pans 3 (12" x 20" x 6" ) pans Dimensions 23" x 23 1 /4" x 30" Figure 1-1. Two STEAM n HOLDs in stacked configuration. 5011.01.90 1-4
Introduction Figure 1-2. PG&E Learning Center, Production-test kitchen and typical appliance layout. 5011.01.90 1-5
2 Controlled Energy Tests Purpose The objective of this section of the report is to examine the operation and performance of the AccuTemp electric steamer, model 208-D8-300, under the controlled conditions of the ASTM standard test method. The AccuTemp electric steamer, model 208-D8-300 is equipped with a 90-minute timer. The AccuTemp electric steamer, model 208-D8-400 steamer, equipped with a 180-minute timer was also monitored in the production-test kitchen, but not tested under controlled conditions. The model 208-D8-300 and 208-D8-400 steamers differ only by specifications of the timer. The scope of this testing was as follows: 1. Verify that the appliance is operating at the manufacturer s rated energy input. 2. Determine the preheat duration and energy consumption of the steamer. 3. Determine the steamer s idle energy rate. 4. Document the cooking energy consumption and efficiency under four different scenarios: full-load frozen green peas (six pans), light-load frozen green peas (one pan), full-load red potatoes (six pans), and light-load red potatoes (one pan). 5. Determine the production capacity and the water consumption rate for each loading scenario. Methods and Results FSTC researchers operated the AccuTemp STEAM n Hold electric steamer under controlled laboratory conditions and in accordance with the ASTM Standard Test Method for the Performance of Steam Cookers (Designation F1484-99) 2. For a detailed discussion of the development of the procedures and test results, refer to Pacific Gas and Electric Company s Development 5011.01.90 2-1
Controlled Energy Tests and Application of a Uniform Testing Procedure for Steam Cookers (Report 1022.95.19). 3 A complete application of the standard test method was applied to the AccuTemp s electric steamer and is discussed in FSTC performance report. 6 See appendix F for a complete summary of results from the application of the standard test method. The energy input rate was determined as part of the preheat test. For the idle test, the steamer boiler was allowed to stabilize and then the steamer energy consumption was monitored for a minimum of two hours. Results of the controlled testing are summarized in Table 2-1. Table 2-1. Summary of Controlled Energy Tests for the AccuTemp STEAM n HOLD Electric Steamer Rated Energy Input Rate (kw) 8.00 Measured Energy Input Rate (kw) 8.34 Preheat Time (min) 12.3 Preheat Energy Consumption (kwh) 1.71 Idle Energy Rate (kw) 1.2 Idle Duty Cycle (%) 14.4 5011.01.90 2-2
Controlled Energy Tests Figure 2-1. STEAM n HOLD steamer instrumented for testing under controlled laboratory conditions. 250 25 225 Temperature ( F) 200 175 150 125 100 75 50 Water Temperature Cavity Temperature Vacuum in Cavity 20 15 10 5 Vacuum (inches of Hg) Figure 2-2. Preheat and idle characteristics 25 0 0 20 40 60 80 100 120 Time (min) 0 5011.01.90 2-3
3 Production Monitoring Energy Performance Two steamers were installed in the production-test kitchen, a model 208-D8-300 and a model 208-D8-400. The steamers were mounted on a stand, with the model 208-D8-300 on top, model 208-D8-400 on the bottom. Both steamers were identical except for the cook timers. The model 208-D8-300 came with a 90-minute timer and model 208-D8-400 came with a 180-minute timer. The energy consumption of each steamer was monitored separately and the performance results reported for both the individual steamer and the combined steamers as one unit. The dataset from which the typical day characteristics were quantified covers a six-month period, from June through December 2000. All Fridays, Saturdays, Sundays, and holidays were eliminated from the dataset because they were not considered typical of steamer usage in this operation. The combined production duty cycle was derived by dividing the total average production energy consumption by the combined appliance s peak energy input rate. The average daily energy performance for the AccuTemp STEAM n HOLD steamer is summarized in Table 3-1. The energy monitoring system used to collect the data is described in Appendix C. The energy consumption of the upper steamer (model 208-D8-300) varied from 2.5 kwh to 28.3 kwh per day, and appliance on-time varied from 3.8 hours to 15.3 hours per day. The energy consumption of the lower steamer (model 208-D8-400) varied from 0.7 kwh to 23.6 kwh per day, and appliance on-time from 0.5 hours to 14.8 hours per day. The upper steamer was more frequently used then the lower steamer because its higher position made it easier to load and unload food. The frequency distributions for daily 5011.01.90 3-1
Production Monitoring production energy use and hours of operation for the steamers are presented in Appendix D. Table 3-1. Average Daily Energy Performance Measured Peak Energy Input Rate (kw) a 8.34 Model 208-D8-300 (upper steamer) Daily Production Energy Use (kwh/day) b 17.8 Appliance On-Time (h/d) 9.5 Production Energy Consumption Rate (kw) c 1.8 Production Duty Cycle (%) 22.6 Model 208-D8-400 (lower steamer) Daily Production Energy Use (kwh/day) b 12.1 Appliance On-Time (h/d) 6.8 Production Energy Consumption Rate (kw) c 1.9 Production Duty Cycle (%) 22.8 Both Steamers Combined Daily Production Energy Use (kwh) b 29.9 Average Appliance On-Time (h/d) 8.2 Production Energy Consumption Rate (kw) c 3.79 Production Duty Cycle (%) 22.7 a Measured peak energy input per compartment. Two compartments were monitored. b Includes preheat and idle energy over the hours of operation when the steamer was in use. c Note that the average production energy consumption rate was based on aggregate preheat, idle and cooking energy for the hours of operation. The energy consumption profiles plotted in Figure 3-1 through 3-3 characterize the typical daily energy use for the steamer in the production-test kitchen. Figure 3-1 is a plot of the energy usage for the upper steamer. Figure 3-2 is a plot of the energy usage for the lower steamer. Figure 3-3 plots the energy usage for both the lower and upper steamers combined. The energy consumption data is presented on a 1-minute basis (dotted line plot) and a 15- minute sliding window average (solid line plot). The energy consumption plots illustrate that the steamers were used throughout the day for a total ap- 5011.01.90 3-2
Production Monitoring pliance on time of 10 hours. The higher energy consumption peaks at the beginning of each operation reflect the energy required to preheat the steamer to a set operating temperature. Following each preheat period, the intermittent spikes above the idle or base rate of energy use reflect the incremental energy required to cook the food product loaded into the steamer. Estimated Annual Energy Cost Based on the average daily energy consumption and assuming a 5-day per week, 52-week-per-year food service operation, the steamers would consume an estimated 7774 kwh per year. This estimated average contribution to demand assumes that the appliance is operating when the maximum building demand occurs. At a cost of $0.08238 per kwh and 3.91/kW/month, the total cost to operate the steamer would be $689 per year: production accounts for $644, and demand accounts for $45. 10 Preheat 1-Minute Data 15-Minute Average Cooking Energy Consumption Rate (kw) 8 6 4 Idle 2 Figure 3-1. Typical daily energy consumption profile of upper steamer. 0 4 5 6 7 8 9 10 11 12 1 2 3 4 5 AM PM Time of Day 5011.01.90 3-3
Production Monitoring 10 Preheat 1-Minute Data 15-Minute Average 8 Cooking Energy Consumption Rate (kw) 6 4 Idle Figure 3-2. Typical daily energy consumption profile of lower steamer. 2 0 4 5 6 7 8 9 10 11 12 1 2 3 4 5 AM Time of Day PM Note: The energy consumption profile for the typical day is plotted on a 15-minute average. The 1-minute plot reflects the instantaneous input of energy into the appliance during preheat and subsequent element cycling during idle, while the 15-minute plot better characterizes the average rate of energy use (see Appendix C). Energy Consumption Rate (kw) 20 18 16 14 12 10 Figure 3-3. Typical daily energy 4 consumption profile of 2 steamers combined. 0 8 6 Preheat Cooking 1-Minute Data 15-Minute Average Idle: Two Compartments Idle: One Compartment 4 5 6 7 8 9 10 11 12 1 2 3 4 5 AM Time of Day PM 5011.01.90 3-4
Production Monitoring These costs of operation, as shown in Table 3-2, were calculated using a seasonally weighted average of Pacific Gas and Electric Company s electric rates (Schedule A-10) for small commercial customers, which would be applicable if the production test kitchen were billed separately (Appendix E). Table 3-2. Estimated Annual Energy Cost Total Annual Production Energy Consumption (29.9 kwh/days x 5 days/week x 52 weeks/year) 7774 kwh/yr Energy Consumption Charge (7774 kwh x $0.08238 per kw) a $644 Probable Demand Charge (3.79 kw x $3.91 per kw per month x 12 months/year) b $45 Annual Energy Cost b Total Annual Energy Cost for Both Steamers c $689 a Note: Estimates are based on Pacific Gas and Electric Company s A-10 rate schedule in effect on April 2000 (see Appendix E). b The probable demand charge was based on the assumption that the steamer was operating at it average production energy rate during the peak period of time that the billing demand was likely to be set. The actual contribution to billing demand may vary significantly at other food service operations, depending on the steamer usage pattern (operating schedule, appliance on-time, etc.) in relation to the electric equipment at the facility. c Does not include customer charges. Food Production The AccuTemp electric steamers were frequently used for preparation of many lunch and dinner items in the production-test kitchen. An FSTC researcher observed the electric steamer during several periods of normal operation and interviewed the cooks. The cooks daily worksheets were also reviewed to obtain a list of the food items prepared and to determine how the steamer was being used. Figure 3-4 depicts the AccuTemp steamer in operation. Items Cooked The steamer was used daily to prepare similar items for both the lunch and the dinner meal period: fresh and frozen vegetables, rice, beans, pasta, potatoes, sauces and fish. 5011.01.90 3-5
Production Monitoring Figure 3-4. AccuTemp electric steamers in the production-test kitchen. 5011.01.90 3-6
Production Monitoring In-Kitchen Observations In-kitchen observations provided information about actual kitchen operation of the steamers over a typical day by the kitchen staff. The steamers were used daily. They were operated for around 6 hours over two distinct periods, augmenting more than 500 meals per day. They consumed about 29.9 kwh of energy per day. The steamers were usually turned on at 5:00 A.M. and turned off anywhere between 3:00 P.M. and 8:00 P.M. It was good to note that the chefs would cook food using the steamer s timer function instead of the continuous steam function. In the timer mode, after the cook cycle time expires the steamer goes into a hold mode, which reduces the energy consumption of the unit. The chefs also would turn the unit off during the day when not needed, resulting in a significant reduction in on time as compared to the operating hours for other steamers tested in the production test kitchen. During cooking periods, it was used to cook approximately 200 pounds of food. The period of heaviest cooking occurred between 7:00 A.M. and 11:00 P.M. Interviews with the chefs furnished researchers with non-energy performance information about the steamers. The AccuTemp steamer received high praise for ease of use and convenience of its controls. Equipped with a timer, the AccuTemp steamer was a food saver, resulting in very little over cooked product. Chefs noted that the steamers cooked slightly slower than the previous steamers in the production-test kitchen that had higher energy input and production energy usages. Chefs compensated for the slightly slower cook times by adjusting the production schedule. 5011.01.90 3-7
4 Conclusions and Recommendations Production The energy performance of the AccuTemp STEAM n HOLD electric steamer was successfully monitored and documented as it was operated in the production-test kitchen. In-kitchen observations were beneficial to understanding how the food service staff used the appliance. Steamer usage was typical of many food service operations in that the staff cooked a variety of foods including, fresh and frozen vegetables, rice and sauces. Although the quantity of food cooked (an average of 200 pounds per day) could be considered light compared to high-volume, full-service restaurants, it was considered representative of many corporate/commercial cafeteria operations offering a diverse menu mix to a broad customer base. The steamers were operated an average of 8.2 hours per day, with the upper and lower steamers operating an average of 9.5 and 6.8 hours per day, respectively. The steamers were routinely turned off between meal periods and at the end of the day resulting in a lower daily on-time as compared to other steamers previously tested in the production-test kitchen. The AccuTemp electric steamer is a workhorse appliance and, as supported by interviews with the kitchen staff, performed favorably. Both the laboratory and in-kitchen performance indices reflect that this steamer is an energy efficient appliance. The staff noticed that the steamer had slightly slower cook times relative to other steamers tested in the production-test kitchen. The Chefs compensated for this by adjusting the production schedule. The steamers were a good match for the production needs in this facility. 5011.01.90 4-1
Conclusions and Recommendations Energy Consumption and Conservation Potential Laboratory testing at the FSTC found the AccuTemp electric steamer to have high cooking energy efficiencies compared to other electric steamers tested 6. In the production-test kitchen, the production energy consumption rate was significantly lower for this steamer, reflective of the increased energy efficiency. The chefs generally turned the steamers on at 5 A.M. and left them on until 3-8 P.M. An 8% reduction in energy use is possible if one steamer could be turned off for 2 hours each day. Even under such medium-use patterns, as seen in the production-test kitchen, a 2-hour non-production period is feasible between the lunch period and the beginning of dinner preparation (see Figure 3-1). It was estimated that the steamer would consume 7774 kwh per year for this 5-day per week food service operation. This corresponds to an annual energy cost of $777.40 based on Pacific Gas and Electric Company s applicable electric rates (A-10) for small, commercial core customers. 5011.01.90 4-2
5 References 1. American Society of Testing and Materials. Standard Test Methods for the Performance of Steam Cookers. Designation F1484-93. In Annual Book of ASTM Standards. Philadelphia: American Society for Testing and Materials. 2. American Society of Testing and Materials. Standard Test Methods for the Performance of Steam Cookers. Designation F1484-99. In Annual Book of ASTM Standards. Philadelphia: American Society for Testing and Materials. 3. Food Service Technology Center. 1995. Development and Validation of a Uniform Testing Procedure for Steam Cookers. Report 1022.95.19. Products and Services Department. San Francisco, California: Pacific Gas and Electric Company. 4. Food Service Technology Center. 1997. Groen Model HY-6E HyPerSteam Electric Pressureless Steamer In-Kitchen Performance Report. Report 5011.95.23. Department of Research and Development. San Ramon, California: Pacific Gas and Electric Company. 5. Food Service Technology Center. 1991. PG&E Production Test Kitchen Appliance Performance Report: Cleveland Electric Pressureless Steamer. Report 008.1-90.30. Department of Research and Development. San Ramon, California: Pacific Gas and Electric Company. 6. Food Service Technology Center. 1999. AccuTemp Model STEAM n HOLD, Model 208-D8-300 Electric Steamer Performance Test. Report 5011.99.75. Products and Services Department. San Francisco, California: Pacific Gas and Electric Company. 5011.01.90 5-1
A Glossary Appliance On-Time (minute, hour) Hours of Operation Operating Period Operating Time The total period of time that an appliance is operated (from the perspective of food service staff) from the time it is turned on to the time it is turned off. Appliance on-time excludes any off periods between the first and last appliance operation. Average Daily Production Energy Consumption Rate (kw or kbtu/h) The average rate of production energy consumption based on the daily production energy consumption and the appliance operating or on time. Average Daily Production Energy Rate = Daily Production Energy Consumption Appliance On - Time Note: By basing the total daily production energy consumption on a 24-hour period, the total quantity of pilot energy (if applicable) is considered within the average production energy consumption rate and is based on the actual period of appliance usage. Average Production Energy Consumption Rate (kw or kbtu/h) Average Production Energy Rate Average Production Energy Use Rate The average rate of production energy consumption based on the production energy consumption and the appliance operating or on time for a specified period of appliance operation. Average Production Energy Consumption Rate = Production Energy Consumption Operating Time Baseload Energy Consumption (Btu or kbtu) Baseload Energy The total amount of energy that would be consumed over the operating period of an appliance if it had never been used to cook food. Baseload Energy Consumption Rate (kw or kbtu/h) Base Rate Baseload Energy Rate Baseload Rate The lowest rate of energy consumption reflected by the energy consumption profile (based on a 15-minute sliding window average) recorded during appliance operation. Generally, this definition is not extended to include the rate of pilot energy consumption. It is typically equal to the lowest value of idle energy consumption rate. Cooking Energy Consumption (kwh or kbtu) The total energy consumed by an appliance during the cooking period. Cooking Energy Consumption Rate (kw or kbtu/h) The average rate of energy consumption during the cooking period. 5011.01.90 A-1
Glossary Cooking Energy Efficiency The quantity of energy input to the food products; expressed as a percentage of the quantity of energy input to the appliance during the heavy-, medium-, and light-load test. Cooking Period (minute, hour) The period of time (derived from in-kitchen monitoring or by interpreting the energy consumption profile) that an appliance is actually used for cooking. Daily Energy Consumption (kwh or kbtu) Daily Energy Use Daily Production Energy Consumption Daily Production Energy Use The total amount of energy consumed by an appliance as it is used within the Production-Test Kitchen over a 24-hour period. Note: By basing the total daily production energy consumption on a 24-hour period, the total quantity of pilot energy (if applicable) is considered within the average production energy consumption rate. Energy Consumption Profile Energy Use Profile A plot of appliance energy consumption showing energy consumption rate on the Y-axis and time on the X-axis. Note: The area under the curve (plot) represents the total energy consumption for the period of integration. For uniformity in production reports, use the following terms and units for the coordinate labels: y-axis: x-axis: (Min) Energy Rate (kw or kbtu/h) Time (AM & PM): (Hour) Energy Consumption Rate (kw or kbtu/h) Energy Input Rate Energy Rate The rate of appliance energy consumption over a specified period of operation (see Energy Consumption Profile). Energy Use Data Set A set of daily energy consumption data compiled in accordance with typical day criteria. Idle Energy Consumption (kwh or kbtu) Idle Energy Use The amount of energy consumed by an appliance operating under an idle condition over the duration of an idle period. Idle Energy Consumption Rate (kw or kbtu/h) Idle Energy Input Rate Idle Energy Rate Idle Rate The rate of appliance energy consumption while it is idling or holding at a stabilized operating condition or temperature. Idle Duty Cycle (%) Idle Energy Factor Idle Load Factor The idle energy consumption rate expressed as a percentage of the measured energy input rate. Idle Energy Factor = Idle Energy Consumption Rate Measured Energy Input Rate 100 Idle Temperature ( F, Setting) The temperature of the cooking cavity/surface (selected by the appliance operator or specified for a controlled test) that is maintained by the appliance under an idle condition. Idle Time (minutes, hour) Idle Period A period of time that an appliance is consuming energy at its idle energy consumption rate while maintaining a specified stable operating condition or temperature. Note: Idle time may include both necessary or unnecessary appliance idling. This is simply differentiated by applying the appropriate adjective to the idle energy period term (e.g., needless idle time, necessary idle period.) 5011.01.90 A-2
Glossary Heating Value (Btu/ft 3 ) Heating Content The quantity of heat (energy) generated by the combustion of fuel. For natural gas, this quantity varies depending on the constituents of the gas. Measured Energy Input Rate (kw, W or kbtu/h, Btu/h) Measured Input Measured Peak Energy Input Rate Peak Rate of Energy Input The maximum or peak rate at which an appliance consumes energy, measured during appliance preheat or while conducting a water-boil test (i.e., the period of operation when all burners or elements are on ) Pilot Energy Consumption (kbtu) Pilot Energy Use Standing or Constant Pilot Energy Consumption Standing or Constant Pilot Energy Use The amount of energy consumed by the standing pilot of an appliance over a specified period of time. Pilot Energy Rate (kbtu/h) Average Pilot Energy Rate Average Pilot Energy Use Rate Pilot Energy Consumption Rate The rate of energy consumption by the standing or constant pilot while the appliance is not being operated (i.e., when the thermostats or control knobs have been turned off by the food service operator). Preheat Energy Consumption (kwh or kbtu) Preheat Energy The total amount of energy consumed by an appliance during the preheat period. Note: The reporting of preheat energy must be supported by the specified temperature/operating condition. Preheat Energy Rate The rate of appliance energy consumption while it is preheating to a predetermined temperature. Preheat Time (minute, hour) Preheat Period The time required for an appliance to preheat from the ambient room temperature (75 ± 5 F) to a specified (and calibrated) operating temperature or thermostat set point. Production Day Production Period The time period when an appliance is used by the kitchen staff, typically between the hours of 5 A.M. and 8 P.M. Production Duty Cycle (%) Load Factor Production Energy Factor Production Factor The average production energy consumption rate (based on a specified operating period for the appliance) expressed as a percentage of the measured energy input rate. Production Duty Cycle = Average Production Energy Consumption Rate 100 Measured Energy Input Rate Production Energy Consumption (kwh or kbtu) Production Energy Use The total amount of energy consumed by an appliance as it is used within the Production-Test Kitchen over a specified time period (e.g., 10 A.M. to 1 P.M., dinner period). Production energy consumption is numerically equal to daily energy consumption if the production period is not specified. Note: This integrated energy use includes preheat energy, idle energy, and pilot energy associated with the specified time period. Rated Energy Input Rate (kw, W or kbtu/h, Btu/h) Input Rating (ANSI definition) Nameplate Energy Input Rate Rated Input The maximum or peak rate at which an appliance consumes energy as rated by the manufacturer and specified on the nameplate. 5011.01.90 A-3
Glossary Typical Day A selected day of energy usage based on predetermined criteria that will generate a production energy consumption profile reflecting typical production usage for a specific appliance. The typical day criteria may comprise: Typical day energy consumption should approximate average daily energy consumption for energy use data set. A specified number of appliance operations and/or cooking periods (e.g., lunch and dinner only). A specified range in operating hours. A specified mode of operation (or combination of modes) may be associated with a typical day s operation. Test Method A definitive procedure for the identification, measurement, and evaluation of one or more qualities, characteristics, or properties of a material, product, system, or service that produces a test result. 5011.01.90 A-4
B Manufacturer s Product Specifications 5011.01.90 B-1
C Energy Monitoring System Energy data are collected once each minute, which means that the highest resolution measurement of energy rate is a 1-minute average. This 1-minute average, shown as the dotted line on the graph of the typical day profile, differs from actual instantaneous power explained in the following paragraphs. Short periods of full input are not reflected as full input. Heating elements and burners are usually either full on or off. A plot of 1-minute data may show some less-than-full-on 1-minute values because the elements or burners operate on full for only part of the minute. Long periods of constant input rate are usually reflected as a saw tooth pattern. Electric pulses are generated by the meter, which measures the flow of electricity to the appliance. Each pulse corresponds to a specific quantity of electric energy consumed. The system stores the number of pulses for each minute, but it only stores an integer value for the number of pulses even though the actual energy consumed during the period corresponds to a noninteger value. For example, if the actual consumption during a 1-minute period corresponds to 6.6 pulses, only the integer 6 will be stored for that minute. The 0.6 will be carried forward and added to pulses generated during the next minute. If the energy consumed during the next minute is also 6.6 pulses, then the pulse value stored will be the integer portion of 7.2 (6.6 + 0.6) and the 0.2 will be carried to the next time interval. 5011.01.90 C-1
D Frequency Distribution of Dataset 5011.01.90 D-1
18 16 14 Number of Days 12 10 8 6 4 Figure D-1. Frequency of electric steamer daily production energy consumption (top unit). 2 0 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 Production-Energy Consumption (kwh) 35 30 Number of Days 25 20 15 10 5 Figure D-2. Frequency of electric steamer daily on-time (top unit). 0 0 2 4 6 8 10 12 14 16 18 On-Time (h/day) 5011.01.90 D-2
16 14 Number of Days 12 10 8 6 4 Figure D-3. Frequency of electric steamer daily production energy consumption (bottom unit). 2 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Production-Energy Consumption (kwh) 35 30 Number of Days 25 20 15 10 5 Figure D-4. Frequency of electric steamer daily on-time (bottom unit). 0 0 2 4 6 8 10 12 14 16 18 On-Time (h/day) 5011.01.90 D-3
16 14 Number of Days 12 10 8 6 4 Figure D-5. Frequency of electric steamer daily production energy consumption (combined units). 2 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Production-Energy Consumption (kwh) 35 30 Number of Days 25 20 15 10 5 Figure D-6. Frequency of electric steamer daily on-time (combined units). 0 0 2 4 6 8 10 12 14 16 18 On-Time (h/day) 5011.01.90 D-4
E PG&E Electric Rates 5011.01.90 E-1
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F Summary of ASTM Test Results 5011.01.90 F-1
Table F-1. Summary of AccuTemp Model 208-D8-300 and 400 Electric Steamer ASTM Performance Rated Energy Input (kw) a 8.00 Measured Energy Input Rate (kw) a 8.34 Preheat Time (min) 12.3 Preheat Energy (kwh) 1.71 Idle Energy Rate (kw) 1.2 Idle Duty Cycle (%) 14.4 Full-Load Frozen Green Peas Cooking Energy Efficiency (%) 88.5 Full-Load Frozen Green Peas Production Capacity (lb/h) b 94.0 Light-Load Frozen Green Peas Cooking Energy Efficiency (%) 65.9 Full-Load Red Potatoes Cooking Energy Efficiency (%) 67.2 Full-Load Red Potatoes Production Capacity (lb/h) c 101.1 Light-Load Red Potatoes Cooking Energy Efficiency (%) 32.0 Model 208-D8-300 (upper steamer) Daily Production Energy Use (kwh/day) d 17.8 Appliance On-Time (h/d) 9.5 Production Energy Consumption Rate (kw) e 1.8 Production Duty Cycle (%) 22.6 Model 208-D8-400 (lower steamer) Daily Production Energy Use (kwh/day) d 12.1 Appliance On-Time (h/d) 6.8 Production Energy Consumption Rate (kw) e 1.9 Production Duty Cycle (%) 22.8 Both Steamers Combined Daily Production Energy Use (kwh) d 29.9 Average Appliance On-Time (h/d) 8.2 Production Energy Consumption Rate (kw) e 3.7 Production Duty Cycle (%) 22.7 a Per individual steamer. b Based on the full-load cooking test with a 180 F endpoint. c Based on the full-load cooking test with a 195 F endpoint. d Includes preheat and idle energy over the hours of operation when steamer was in use. e Note that the average production energy consumption rate was based on aggregate preheat, idle and cooking energy for the hours of appliance operation. 5011.01.90 F-2
Table F-2. Summary of Controlled Energy Cooking Tests for the AccuTemp STEAM n HOLD Electric Steamer Full-Load Frozen Peas a Cooking Energy Efficiency (%) 88.5 Production Rate (lb/h) 94.0 Cook Time (min) 30.7 Average Cooking Energy Rate (kw) 8.3 Light-Load Frozen Peas a Cooking Energy Efficiency (%) 65.9 Production Rate (lb/h) 43.6 Cook Time (min) 11.0 Average Cooking Energy Rate (kw) 5.1 Full-Load Red Potatoes b Cooking Energy Efficiency (%) 67.2 Production Rate (lb/h) 101.1 Cook Time (min) 28.6 Average Cooking Energy Rate (kw) 5.0 Light-Load Red Potatoes b Cooking Energy Efficiency (%) 32.0 Production Rate (lb/h) 18.5 Cook Time (min) 26.1 Average Cooking Energy Rate (kw) 1.9 Water Consumption During Cooking Efficiency Tests (gal/h) <0.2 a Based on the full-load cooking test with a 180 F endpoint temperature. b Based on the full-load cooking test with a 195 F endpoint temperature. 5011.01.90 F-3
100 90 80 Peas 88.5% Energy Efficiency (%) 70 60 50 40 30 20 Potatoes 67.2% Peas 65.9% Potatoes 32.0% 10 0 Full Load (6 pans) Light Load (1 pan) 1 2 Figure F-1. Steamer cooking energy efficiency under full- and light-load scenarios. 120 110 Production Capacity (lb/h) 100 90 80 70 94.0 lb/h 101.1 lb/h 60 50 Peas 1 2 Potatoes Figure F-2. Steamer production capacity. 5011.01.90 F-4