INTEGRATION OF DEMAND RESPONSE INTO TITLE 20 FOR COMMERCIAL ICE MACHINES

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1 Design & Engineering Services INTEGRATION OF DEMAND RESPONSE INTO TITLE 20 FOR COMMERCIAL ICE MACHINES Phase1: Demand Response Potential DR Report Prepared by: Design & Engineering Services Customer Service Business Unit Southern California Edison November 30, 2009 What s Inside Executive Summary... Introduction... Market Size/Barriers... DR Strategies and Potential... Results... Recommendations... References

2 Acknowledgements Southern California Edison s Design & Engineering Services (DES) group is responsible for this project in collaboration with the Tariff Programs & Services (TP&S) group. It was developed as part of Southern California Edison s Demand Response, Emerging Markets and Technology program under internal project number DR DES project manager Devin Rauss conducted this technology evaluation with overall guidance and management from Carlos Haiad of DES, and Jeremy Laundergan of TP&S. For more information on this project, contact devin.rauss@sce.com. 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

3 ABBREVIATIONS AND ACRONYMS ARI CEC DR PG&E SCE SDG&E Title 20 Air Conditioning and Refrigeration Institute California Energy Commission Demand Response Pacific Gas and Electric Southern California Edison San Diego Gas and Electric California s Appliance Efficiency Regulations Southern California Edison Page i

4 EXECUTIVE SUMMARY This project assesses the demand response (DR) potential associated with commercial ice machines and the potential to include DR capable commercial ice machines in California s Appliance Efficiency Regulations (Title 20). This project may follow up with demonstrations of the DR strategies identified, and could ultimately lead to the development of code language in phases 2 and 3, respectively. Ice machines are capable of responding to a DR event by stopping ice production and relying on pre-made ice. Previous work indicates that this is a viable DR strategy. This study looks at the entire population of commercial ice machines, uses market acceptance factors, and determines technical potential to calculate the overall DR potential for commercial ice machines. This study found that on average a commercial ice machine has the potential to drop load by 2 kw in response to a DR event. This response is possible through implementation of a sensor noting the ice level, the appropriate communication equipment, and the proper control algorithm. Overall, based on this information, and a high market acceptance rate, 180 MW can be reduced within Southern California Edison (SCE) service territory by introducing commercial ice machine DR strategies. Statewide this figure was determined to be 450 MW of DR potential. This study also shows that the technology currently exists that enables the necessary communication. Although manufacturers do not currently include this equipment in their products, this indicates that, if required, they can. The cost effectiveness was not investigated, but from a purely technological standpoint, this is a viable option for inclusion in Title 20. This DR strategy works, yet many questions remain. These questions center on what the critical ice level is in different applications (how little can they live with), how different classifications of ice machine dictate the critical level, and how agreeable manufacturers are to incorporate this equipment in the factory. Further studies on the critical ice levels, by end use and ice type, and engagement of manufacturers is recommended. Southern California Edison Page 1

5 INTRODUCTION This project seeks to validate and establish demand response (DR) potential for commercial ice machines. It is part of a multi-phase, multi-year effort to evaluate the potential for DR to be incorporated into the California Appliance Efficiency Regulations (Title 20) for a series of 13 commercial and residential appliance categories from refrigerated display cases to ice machines. This project aligns well with the objective of Southern California Edison s (SCE) SmartConnect TM by fostering and accelerating the availability of DR-ready appliances in the market place. Furthermore, this project supports the California Public Utilities Commission goal of zero net energy for residential new construction by 2020 and commercial new construction by Phase 1, of this potential three-phase effort, addresses the DR potential for commercial ice machines; if Phase 1 yields encouraging results, Phase 2 will demonstrate DR capabilities and strategies for ice machines; and if the demonstration is successful, Phase 3 will develop a Title 20 Codes and Standards Enhancement initiative to incorporate DR requirements for commercial ice machines. This report reviews the findings from Phase 1 and estimates the DR potential for ice machines. This phase entails assessing the demand reduction associated with ice machines, the population statewide and within SCE service territory, and the market/consumer acceptability of DR strategies associated with ice machines. TECHNOLOGY DESCRIPTION An automatic commercial ice machine is a factory-made assembly (not necessarily shipped in one package) consisting of a refrigeration system, an ice-making mechanism, a water supply system, insulation and a case, as shown in Figure 1. Such a system operates as an integrated unit, used to make and harvest ice. It may also include means for storing and/or dispensing ice. There are three types of ice machines: 1 Ice-making head units: Standard ice machines with the ice-making mechanism and the condensing unit in a single package, but with a separate ice storage bin. Self-contained units: Models in which the ice-making mechanism and the storage compartment are in an integral cabinet. Remote condensing units: Split-system models in which the ice-making mechanism, the condensing unit, and the ice storage bins are in separate sections. Southern California Edison Page 2

6 FIGURE 1. COMMERCIAL ICE MACHINE (ICE MAKING HEAD UNIT TYPE) Most of the applications use ice-making heads and self-contained units. All Air- Conditioning and Refrigeration Institute (ARI)-certified ice machines use vapor compression refrigeration. About 80% of them have air-cooled integrated condensers, while the rest have either integrated water-cooled condensers or remote air-cooled condensers. Ice machines can also be classified by the type of ice made: Cube: clear, regularly shaped ice of a certain weight. Flake: ice formed into flakes that contain high liquid water contents. Nugget/Chip: ice made by extruding flake ice into small pieces that are soft for chewing and usually hard enough for dispensing Crushed: ice that consists of small, irregular pieces made by crushing larger chunks of ice. These four types of ice are defined based on the ice making process, rather than the ice shape, as their names suggest. The cube type can be cube shaped, or in half cube, cylinder, octagon, or crescent shapes. What they have in common is that they are all made in a process with alternating freezing and harvesting cycles. As a result, cube type ice machines are commonly referred to as batch ice machines. Cube ice typically has a quality in the range of %, meaning % of the water is frozen. Crushed ice is usually made from cube ice; therefore, it has similar ice quality. For both crushed and cube ice, this means that they have a relatively large amount of thermal mass. Flake type ice and nugget/chip type ice are made continuously with the freezing and harvesting processes occurring at the same time. These ice machines can often be referred to as continuous ice machines. In these machines, the evaporator coil loops around the cylindrical space where liquid water is fed into from the bottom tube. As water freezes into ice, the rotating auger removes the ice from the interior wall and transfers it to the output port at the top. In a flake type machine, this is where the process stops. For a nugget/chip type, the flake ice is pushed through an extruder, compacting the ice into larger pieces; nuggets/chips. The continuous process leads to lower quality ice, as it does not have as much time to freeze. Typically, flake ice has a quality around 60%-70%. Whereas nugget/cube type will be slightly better due to the compression, and typically ranges from 80%- 90%. These types of ice have a relatively small thermal mass, and as a result will degrade quicker. Southern California Edison Page 3

7 CURRENT ENERGY CODE REQUIREMENTS As of January 1, 2008, commercial ice machines are regulated by the California Energy Commission (CEC) under Title 20. Table 1 shows the minimum performance levels required by the CEC. Additionally, under the direction of the Energy Policy Act of 2005 the Federal government regulates the performance of ice machines, effective January 1, It is important to note that the Federal regulations will explicitly apply only to cube type ice machines, whereas the state regulations do not distinguish which types of ice machines are covered. A Codes and Standards Enhancement (CASE) initiative was created to examine the performance of nugget type ice machines, and has been completed. Given the CEC s priorities for the current rulemaking, this project is not being pursued further at this point. TABLE 1. CALIFORNIA ENERGY PERFORMANCE STANDARDS FOR ICE MAKERS 2 EQUIPMENT TYPE Ice-Making Head Ice-Making Head Remote Condensing (but not remote compressor) Remote Condensing and Remote Compressor Self-Contained Self-Contained TYPE OF COOLING Water Air Air Air Water Air MAXIMUM DAILY HARVEST RATE [H] (LBS ICE/24 HR) MAXIMUM DAILY ENERGY USE (KWH/100 LBS ICE) CONDENSER WATER USE (GAL/100 LBS ICE) < H H 500 and < H H H < H N/A H N/A < H N/A N/A < H N/A N/A < H H H < H N/A N/A Similarly, the Environmental Protection Agency (EPA) has ENERGY STAR labels available for continuous ice machines, but not for batch (nugget and flake type) ice machines. The ENERGY STAR performance criterion also became effective January 1, 2008, and is shown in Table 2. Southern California Edison Page 4

8 TABLE 2. ENERGY STAR PERFORMANCE CRITERIA 3 EQUIPMENT TYPE Ice Making Head Remote Condensing Unit (without remote condenser) Remote Condensing Unit (with remote condenser) Self Contained Unit HARVEST RATE [H] (LBS ICE/DAY) ENERGY USE LIMIT (KWH/100 LBS ICE) POTABLE WATER USE LIMIT (GAL/100 LBS ICE) < H H 25 < H < H < H DEMAND PROFILE AND ENERGY CONSUMPTION As the components of the various classifications of ice machines are fairly consistent, the load drawn by the units is also fairly consistent. On average a 500-lb ice machine draws over 2 kw of power, 4 regardless of type. Despite the similarities in demand, the various types of ice machines consume noticeably different amounts of energy. This is a result of the aforementioned differences in the ice production process. Since cube type ice machines operate on batch production, they have a reduced run time, resulting in reduced energy consumption. Based on an extrapolation of data presented in the Arthur D. Little report, and conservative ice machine population growth (2% annually), the total consumption for ice makers in California is estimated at 1.07 billion kwh/year. Of this 20% is estimated to be from non-cube type ice machines - with an estimated population of 16,201 machines, this equates to approximately 13,210 kwh/yr per machine. For cube type machines, similar calculations, using a population of 144,757, the average consumption is estimated to be 5,910 kwh/yr per machine. MARKET SIZE Based on information from the CASE study that established the current Title 20 requirements for commercial ice machines, there are approximately 225,000 ice machines in California. 5 Estimates are made that roughly 40% of these ice machines are found in SCE service territory, or 90,000 units. MARKET BARRIERS A foreseen barrier of acceptance for this DR strategy is ensuring an adequate amount of ice to meet the demand. Any DR strategy for an ice machine can not reduce the production of ice so much that the ice in the storage bin falls below a certain level, which depends on application. Outside of this need to maintain functionality, there are no major food or safety concerns associated with DR strategies for ice machines. Southern California Edison Page 5

9 DEMAND RESPONSE STRATEGIES AND POTENTIAL For the purpose of this evaluation, the demand response potential is defined in Equation 1. EQUATION 1. DEMAND RESPONSE POTENTIAL DR potential = (kw reduction /unit) x (Market Size) x (Market Acceptance) STRATEGY 1 ICE MACHINE SHUT OFF STRATEGY DESCRIPTION This strategy relies on a signal sent to an ice machine that, depending on current ice storage levels, allows the machine to shut off until the critical storage level is reached. A previous study performed by SCE demonstrated the viability of this strategy for commercial ice machines, with a particular focus on customer acceptance. 4 TECHNICAL DEMAND REDUCTION As this strategy results in no operation of the ice machine, the entire electrical demand, 2 kw/ice machine, can be saved. The amount of time that the ice machines can be shut off is dependent on the end-use and ice production quality (ice storage time). MARKET ACCEPTANCE As previously noted the major acceptance barrier is the preservation of functionality. For functionality to be maintained the ice machine must be able to store enough ice to last throughout the DR event, which again depends on the end-use and type of ice. A cube type ice machine is able to be shut off longer as the ice produced can be stored longer without negatively impacting the quality of the ice, when compared to a non-cube type ice machine. However, based on the ability of the machine to know the ice storage level, as demonstrated in a previous work, 4 it is assumed that acceptance issues can be mitigated resulting in a high market acceptance. DEMAND RESPONSE POTENTIAL Using Equation 1, the total demand response potential is calculated to be 180 MW within SCE s territory. Again, this is based on assumptions of 90,000 units, 100% market acceptance, and 2 kw saved per unit. Using the statewide market size of 225,000 machines, the statewide potential is determined to be 450 MW. RESULTS The strategy identified in this report, ice machine shut off, provides significant DR potential for SCE s service territory and statewide. Within SCE s service territory this strategy can reduce load by 180 MW. Statewide this number is 450 MW. Southern California Edison Page 6

10 RECOMMENDATIONS The DR strategy identified in this report is already proven to be technically feasible, and based on the savings potential it is recommended that it is further pursued. Recommended next steps include engaging customers to determine what the critical ice storage level is for the various end-uses and machine types. Specifically, a study of the DR capability of non-cube type ice machines would be beneficial. Additionally, engagement of manufacturers to incorporate DR-enabling technologies at the point of manufacture is recommended, both to drive cost down and to increase market adoption. Southern California Edison Page 7

11 Integration of Demand Response into Title 20 for Commercial Ice Machines DR YY06 REFERENCES 1 Little, Arthur D Energy Savings Potential for Commercial Refrigeration Equipment 2 California Appliance Energy Efficiency Standards. CEC REV Southern California Edison. March DR Demand Response Strategies Using Two-Way Connectivity for Commercial Ice Machines (DES Project document, available upon request.) 5 Fernstrom, Gary B. Pacific Gas and Electric. April Analysis of Standards Options for Commercial Packaged Refrigerators, Freezers, Refrigerator-Freezers and Ice Makers CASE_Pac kaged_refrigeration.pdf Southern California Edison Page 8