Automated Demand Response Using OpenADR

Transcription

1 Automated Demand Response Using OpenADR Application Guide Rev. 3, July, 2011

2 Rev. 3, July, 2011 NOTICE Document information is subject to change without notice and should not be construed as a commitment by Siemens Industry, Inc. Companies, names, and various data used in examples are fictitious unless otherwise noted. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express written permission of Siemens Industry, Inc. All software described in this document is furnished under a license and may be used or copied only in accordance with the terms of such license. For further information, contact your nearest Siemens Industry, Inc. representative. Copyright 2011 by Siemens Industry, Inc. Patent Pending CREDITS Product or company names mentioned herein may be the trademarks of their respective owners. TO THE READER Your feedback is important to us. If you have comments about this document, please send them to SBT_technical.editor.us.sbt@siemens.com Printed in the U.S.A.

3 Table of Contents About this Application Guide... 5 Application Guide Organization... 5 Suggested Reference Materials and Web Sites... 5 Getting Help... 6 Where to Send Comments... 6 Chapter 1 Introduction... 7 What is Demand Response?... 7 Active Markets... 7 Anticipated Market Growth... 8 What is OpenADR?... 8 Chapter 2 Working with the ADR Client Application What is the ADR Client Application? Guidelines for Setting up DRAS Communication Parameters Information Needed Proxy Server Examples DRAS Server Examples Chapter 3 Demand Response Strategies How to Design DR Control Strategies Requirements Important Considerations Key Terms and Concepts Factors Affecting DR Potential Methods of Executing DR Control Strategies Return to Normal Strategies Common DR Control Strategies Strategy 1: Adjusting the Zone Temperature Strategy 2: Decreasing the Duct Static Pressure Setpoint Strategy 3: Increasing the Supply Air Temperature Strategy 4: Limiting the Fan VFD Strategy 5: Increasing the Chilled Water Supply Temperature Setpoint Strategy 6: Limiting the Chilled Water Cooling Valve Position Strategy 7: Restricting Chiller Operation Strategy 8: Dimming the Lighting Level Strategy 9: Turning Off Lights Strategy 10: Pre-Cooling Buildings Chapter 4 Typical Workflow for Implementing Demand Response Strategies Steps for Implementing Strategies Step 1: Assess utility/iso DR programs and incentives Siemens Industry, Inc. 1

4 Automated Demand Response Using OpenADR Application Guide Step 2: Conduct DR-ready audits Step 3: Select DR programs in which to participate Step 4: Identify DR control strategies and sequences of operation Step 5: Test and deploy selected DR control strategies Step 6: Develop performance measurement and verification reports (Optional) Step 7: Develop standard operating procedures for DR participation Chapter 5 Deploying Demand Response Strategies with the ADR Client Application Installing the ADR Client Application on Different System Architectures SOAP Server and APOGEE System BACnet IP to BACnet Field Panels BACnet IP to Insight BACnet Server Calculating Baseline and Actual Demand Reduction Important Considerations Calculation Methods Achieving Desired DR Levels and Automatic DR Approaches for Achieving DR Levels Approaches for Achieving Automatic DR Understanding Differences in Commanding Control Points Command Priority Properties Selecting Command Priorities APOGEE Points BACnet Points Setting up the ADR Client Application on an APOGEE System Step 1: Identify control points for executing DR control strategies Step 2: Create control points for DR event information Step 3: Create additional control points for DR control actions Step 4: Create additional control points to allow exclusions from DR events Step 5: Decide how to implement DR control actions Step 6: Determine offset times for DR control actions Step 7: Configure notification points Step 8: Configure response points Step 9: Configure control points for DR control actions Step 10: Write PPCL for DR control actions Step 11: Test DR strategies and publish DR test reports Step 12: Create graphic screens for real-time monitoring (Optional) Appendix A Sample Building Data for Deploying Demand Response Strategies Building Data HVAC System Data Primary Cooling Primary Heating AHU/Terminal Systems Pumps and Cooling Tower Fans Siemens Industry, Inc.

5 Table of Contents Lighting System Data Area Lighting Plugged and Other Electrical Loads Utility/ISO Data Maximum Demand Minimum Demand Months Control System Architecture Recommended DR Control Strategies Selected DR Strategies DR Strategies Mapped to DR Mode Levels Deploying DR Control Strategies with the ADR Client Application Required Software Modules Appendix B Sample Templates for Demand Response Audits Building Data HVAC System Data Primary Cooling Primary Heating AHU/Terminal Systems Exhaust Systems Pumps Cooling Tower Fans Lighting System Data Area Lighting Plugged and Other Electrical Loads Utility/ISO Data Energy Types Indices Maximum Demand Minimum Demand Months Sub-Metering Glossary Siemens Industry, Inc. 3

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7 About this Application Guide About this Application Guide This guide is designed to help identify how you can plan and develop demand response (DR) strategies for an APOGEE Building Automation System (BAS), and describes DR deployment methods using the Automated Demand Response (ADR) Client application. Due to the lack of standardization in DR programs throughout the country, this guide does not provide information on all possible DR programs in the U.S. The majority of the information in this guide is based on programs in the state of California, and is the only market where the OpenADR standard protocol is supported at the time of this document s creation. This guide assumes that you understand the concepts of building automation and database management. It also assumes that you are familiar with APOGEE system concepts and understand its basic operations. However, most of the information and strategies presented in this guide also apply to non-apogee systems. Application Guide Organization This guide contains the following chapters: Chapter 1 Introduction describes DR and explains how OpenADR works. Chapter 2 Working with the ADR Client Application provides guidelines for setting up the ADR Client application to communicate with utilities and a sample configuration. Chapter 3 Demand Response Strategies provides an overview of how to determine DR control strategies, and describes common strategies. Chapter 4 Typical Workflow for Implementing Demand Response Strategies discusses the steps involved in planning, developing, and deploying DR control strategies. Chapter 5 Deploying Demand Response Strategies with the ADR Client Application describes DR deployment methods using the ADR Client application. Appendix A Sample Building Data for Deploying Demand Response Strategies describes a sample building and its data, operating schedules, HVAC and BAS systems, and DR strategies. Appendix B Sample Templates for Demand Response Audits includes sample templates that you can use to collect DR audit data. The Glossary describes terms and acronyms used in this guide. Suggested Reference Materials and Web Sites In addition to this guide, you may also want to become familiar with the following reference materials: APOGEE SOAP Server User Guide. Contains detailed information on the installation, configuration, and use of the APOGEE SOAP Server. To obtain a copy, contact the Custom Solutions department in Buffalo Grove. Automated Demand Response (ADR) Client User Guide ( ). Contains detailed information on the installation, configuration, and use of the ADR Client application. The guide is included with the ADR Client application. Siemens Industry, Inc. 5

8 Automated Demand Response Using OpenADR Application Guide ASHRAE Standard BACnet: A Data Communication Protocol for Building Automation and Control Networks (Standard ). Describes the BACnet communication services and protocols for computer equipment used for monitoring and controlling heating, ventilation, and air conditioning (HVAC) and other building systems. For more information, see: Green Building Solutions Application Guide ( ). This application guide describes how you can use existing technology to achieve or enhance green building design, construction, operation, and maintenance; how Siemens Industry, Inc. products and solutions can assist you in obtaining LEED credits for LEED certification of new and existing buildings; and how to execute green building projects. Leveraging APOGEE: A Tiered Approach to Submetering in Your Facility ( ). This application guide provides you a greater understanding of how your facility uses energy and how your building automation system can be leveraged to optimize energy consumption and save money. NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 1.0. Provides a high-level conceptual reference model for the Smart Grid, identifies existing standards, documents action plans, and describes the strategy to establish requirements and standards to help ensure Smart Grid cyber security. For more information, see Open Automated Demand Response Communications Specification (Version 1.0). California Energy Commission, PIER Program. CEC Describes an open standards-based communications data model designed to promote common information exchange between the utility or independent system operator and electric customers using demand response price and reliability signals. For more information, see PIER Demand Response Research Center Web site. Contains information on DR research in California, along with several DR publications from the Lawrence Berkeley National Laboratory (LBNL). Technical Glossary of Building Controls Terminology and Acronyms ( ). This glossary defines hundreds of words, terms, and acronyms that you will encounter when using Siemens Industry, Inc. documentation. External documents are available from their respective organizations. Information about other Siemens Industry, Inc. products, services, and technical training classes can be obtained from your local Siemens Industry, Inc. representative. Getting Help For more information about automated DR using the ADR Client application, contact Systems Applications in Buffalo Grove. Where to Send Comments Your feedback is important to us. If you have comments about this guide, please submit them to: SBT_technical.editor.us.sbt@siemens.com. 6 Siemens Industry, Inc.

9 Chapter 1 Introduction Chapter 1 Introduction This chapter describes DR and explains how OpenADR works. What is Demand Response? As defined by the U.S. Federal Energy Regulatory Commission, DR is an action taken to reduce electricity demand in response to price, monetary incentives, or utility directives so as to maintain reliable electric service or avoid high electricity prices 1. Participants of DR events agree under contracts with utilities to carry out various demand response control strategies to curb their electrical demand (kw) in order to gain financial benefits, which typically are received through incentives and reduction in electrical costs. Utilities have established DR programs to: motivate changes in electric consumption by customers in response to changes in the price of electricity over time. motivate lower electricity use at times of high market prices or when grid reliability is jeopardized by providing incentive payments. For more information on DR programs, see Step 1: Assess utility/iso DR programs and incentives in Chapter 4. Active Markets According to an internal study conducted in January 2010 by Siemens Industry, Inc., the most active DR markets are mainly in the state of California and in the Northeast region of the country. The following figure shows the current state of the DR market in the U.S. Map of DR in the U.S. 1 U.S. Federal Energy Regulatory Commission. Assessment of Demand Response and Advanced Metering Staff Report, Docket AD Siemens Industry, Inc. 7

10 Automated Demand Response Using OpenADR Application Guide Anticipated Market Growth It is anticipated that the DR market will grow to include different parts of the country and mature over the years. For more information on DR market potential, see Assessment of Demand Response & Advanced Metering. 2 The growing interest in DR is also evident in environmental protection efforts. The U.S. Green Building Council, which developed the LEED Green Building Rating Systems, created a pilot LEED credit for DR 3. As part of this pilot, a DR credit has been proposed in addition to the LEED s energy efficiency requirements to emphasize the value of peak load reduction. By incorporating DR strategies in the design and operation of building systems, a project could gain additional LEED points and realize benefits from the reduction in carbon emissions. To further support the growing market for DR in California, the California Energy Commission (CEC) funded the development of Open Automated Demand Response, also known as OpenADR. What is OpenADR? Developed by the Demand Response Research Center (DRRC), OpenADR is a communications data model designed to facilitate sending and receiving DR signals between a utility or independent system operator (ISO) and electric customers. The data model interacts with building control systems that are preprogrammed to take action based on a DR signal, enabling a DR event to be fully automated, with no manual intervention. 4 In September 2009, the Open Automated Demand Response Communications Specification (Version 1.0) gained national recognition when the National Institute of Standard Technology selected it as one of the recommended standards and specifications for achieving smart grid interoperability. 5 The specification addresses three different types of interface groups, which include: Utility and ISO operator interfaces Participant operator interfaces DR Automation Server (DRAS) client interfaces The following figure shows the context of these interface types. 2 U.S. Federal Energy Regulatory Commission. Assessment of Demand Response and Advanced Metering Staff Report. 3 U.S. Green Building Council. LEED Pilot Credit 8: Demand Response Mary Ann Piette, Girish Ghatikar, Sila Kiliccote, Ed Koch, Dan Hennage, Peter Palensky, and Charles McParland. Open Automated Demand Response Communications Specification (Version 1.0) California Energy Commission, PIER Program, CEC National Institute of Standards and Technology. NIST Framework and Roadmap for Smart Grid Interoperability Standards Release 1.0 (Draft) U.S. Department of Commerce. 8 Siemens Industry, Inc.

11 Chapter 1 Introduction DRAS Client Interface Types. 6 The ADR Client application described in this guide incorporates a DRAS client as defined in the Open Automated Demand Response Communications Specification (Version 1.0) and also enables you to configure and automatically execute DR control actions. See Chapter 2 Working with the ADR Client Application for an overview of the ADR Client application. For detailed information on OpenADR, it is strongly recommended that you become familiar with the CEC s Open Automated Demand Response Communications Specification (Version 1.0), available at The following sections are particularly helpful: Executive Summary Section 1.0: Introduction Section 4.0: Use of This Specification Section 6.1: Automated Demand Response Architecture Section 6.5.3: Demand Response Automation Server Client View of Demand Response Events Section D.2.1: Critical Peak Pricing (CPP) Use Cases Section D.2.7: Generic Real-Time Pricing Based Programs (RTP) Use Cases 6 See note 4. Siemens Industry, Inc. 9

12 Automated Demand Response Using OpenADR Application Guide Chapter 2 Working with the ADR Client Application This chapter provides guidelines for setting up the ADR Client application to communicate with utilities and a sample configuration. NOTE: For detailed information on using the ADR Client application, see the Automated Demand Response (ADR) Client User Guide ( ) that is provided with the application. What is the ADR Client Application? The ADR Client application is a DR application developed by Siemens Industry, Inc. that works with an OpenADR DRAS and APOGEE BAS. It receives DR events from an OpenADR DRAS, processes DR event information with pre-defined DR control actions, and commands DR control points to execute control actions such as turning off lights, raising thermostat settings, limiting fan speed, locking out chillers, etc. High-level Architecture of the ADR Client Application. The ADR Client application consists of the following components: Windows Service. The Siemens DR Client service runs in the background and continuously processes DR event information from a utility DRAS server. By default, the polling frequency is 1 minute, which you can change through the user interface. The Windows service supports the following: BACnet Adapter. Communicates with BACnet field panel controllers (APOGEE or third-party) and commands BACnet objects. It also communicates with the Insight BACnet Server and commands APOGEE control points that are exported as BACnet objects. 10 Siemens Industry, Inc.

13 Chapter 2 Working with the ADR Client Application SOAP Adapter. Communicates with the APOGEE SOAP Server and commands APOGEE control points using the APOGEE SOAP interface. User Interface. From the user interface, you can configure the DRAS server communication parameters, control points, and pre-defined DR control actions. Guidelines for Setting up DRAS Communication Parameters You must configure the communication parameters so that the DRAS client component can communicate with a utility DRAS server. Because communication is handled over the Internet, you will most likely need to use a proxy server for security purposes. A proxy server will be included in the examples throughout this section. Information Needed Gather the following data to set up your DRAS communication parameters. If needed, contact your IT department for proxy server information. Proxy Server Item Proxy Server URL Port User Name Domain Password* Notes Data * Keep the password in a safe place to prevent unauthorized use. DRAS Server Item DRAS Server URL User Name Password* Polling Interval** Communication Timeout Notes Data * Keep the password in a safe place to prevent unauthorized use. ** In seconds. Specifies how often the ADR Client application checks for DR events. In seconds. Specifies how long the ADR Client application waits before timing out and sending a warning message. Siemens Industry, Inc. 11

14 Automated Demand Response Using OpenADR Application Guide Proxy Server Examples As described by Wikipedia 7, a proxy server is a server (a computer system or an application) that acts as an intermediary for requests from clients seeking resources from other servers. Clients connect to the proxy server and request a service, such as a file, connection, Web page, or other resource. The proxy server evaluates the request according to its filtering rules. For example, it may filter traffic by IP address or protocol. If the filter validates the request, the proxy server provides the resource by connecting to the relevant server and requesting the service on behalf of the client. A proxy server may optionally alter the client s request or the server s response, and sometimes it may serve the request without contact the specified server. In this case, it caches responses from the remote server, and returns subsequent requests for the same content directly. Proxy servers are used for: protecting the anonymity of computers behind it for security. speeding up access to resources through caching. applying access policies to network services or content (for example, blocking sites). logging/auditing usage. bypassing security controls. scanning transmitted content for malware before delivery. scanning outbound content to protect against data leaks. circumventing regional restrictions. Sample Proxy Server Data Item Proxy Server URL Port 80 User Name Domain Data john.doe US111 Password ******* Notes Contact IT network admin, Jane, at x222 for questions and support. In the ADR Client application s Internet Settings dialog box, the data would be entered similar to the following example. 7 Wikipedia. Proxy Server Siemens Industry, Inc.

15 Chapter 2 Working with the ADR Client Application DRAS Server Examples Sample Proxy Server Settings in the ADR Client Application. The main purpose of a DRAS server, which is set up and managed by a utility, is to communicate DR event information to all DR participants. DR event information is formatted according to the Open Automated Demand Response Communications Specification (Version 1.0). Sample DRAS Server Data Item DRAS Server URL User Name Data Siemens1 Password ******** Polling Interval* 60 Communication Timeout* 60 Notes * In seconds. Contact utility DRAS admin at for questions and support. In the ADR Client application s Demand Response Automation Server Settings dialog box, the data would be entered similar to the following example. Sample DRAS Server Settings in the ADR Client Application. Siemens Industry, Inc. 13

16 Automated Demand Response Using OpenADR Application Guide Chapter 3 Demand Response Strategies This chapter provides an overview of how to determine DR control strategies, and describes common DR strategies for a typical commercial office building. How to Design DR Control Strategies Requirements You must design DR control strategies that: achieve and maintain the desired DR level; otherwise, there will be no benefits from participating. are based on good engineering design and operational practices. maintain occupant productivity and minimize discomfort, inconvenience, and loss of revenue of the participating facilities. have transitions that are fast enough to achieve the level of demand reduction before or at the start of the DR event, but slow enough to prevent the building occupants from noticing sudden changes. In addition, it is highly recommended that you send mass notifications to building occupants about the extent and effect of DR control actions, and the benefits that the company will gain by participating in the DR event. When fully informed, building occupants will more likely tolerate any resulting short-term discomfort and inconvenience. Important Considerations Ask the Following Questions. How do DR control strategies work? Are the strategies suitable for Day-Ahead or Day-Of DR event timing notification? How much electrical demand reduction can be achieved by executing a DR control strategy? How far in advance of the DR event start time must the DR control action be executed so that the reduction is realized (with high certainty) at the start time of the DR event? What will be the required sequence of operation to properly execute the DR control actions? Will the sequence require some types of interlocking and/or time delay to ensure the reliability of operation and to prevent physical damages to the mechanical devices? What will be the impact to the indoor environmental quality of the occupied space? What will be the impact to overall HVAC mechanical devices and systems operation? How will the reduction in electrical demand be measured and verified? What will be the sequence of operation to gracefully exit (return to normal) the DR control action? Test Your Strategies. Because DR control strategies vary, it s important to select ones that will fit with the overall building sequences of operation and HVAC systems. This can be difficult, since electrical loads are dynamic and sensitive to weather conditions, occupancy, and other factors. You should conduct field experiments to test various strategies to best 14 Siemens Industry, Inc.

17 Chapter 3 Demand Response Strategies determine the necessary control strategies and the level of achievable demand reduction. This is especially important for strategies such as raising zone temperature setpoints. Avoid Incurring Penalties. DR events with mandatory participation usually carry stiff penalties for non-compliance. Typically, participation in a capacity market option is mandatory as the load commitment from participants represent a firm resource level for the utility. DR events with voluntary options provide participants an incentive to reduce demand, but do not penalize for non-compliance. Participation in critical peak pricing programs and/or dynamic pricing programs is usually voluntary. Include the Ability to Opt-out/Override. When carrying out semi-automatic or automatic DR control actions, building operators must be able to opt-out or override DR control actions during the DR events if they deem that such control actions are undesirable, unacceptable, or can impact the safety of building occupants. Minimize the Rebound Effect. The rebound effect is the extra energy used to return building systems to normal operating conditions, or the degree of disruption to a graceful return to proper building environmental control, after a DR event. If possible, minimize the rebound effect by extending the DR period until the building is unoccupied. Otherwise, gradually return to normal building control strategies. Key Terms and Concepts DR Operation Mode Values Target electrical demand reduction is determined by the following DR operation mode values: NORMAL. Normal operation. MODERATE. Moderate level of demand reduction. HIGH. High level of demand reduction. SPECIAL. Specific levels of demand reduction as determined on a case-by-case basis between DR participants and utilities (typically at a level higher than HIGH). NOTE: Specific electrical demand (kw number) targets for different DR operation modes will vary among DR participants and will depend on facility, HVAC, and lighting types; the availability of distributed generation capacity; and the level of system control. See Factors Affecting DR Potential for more information. Day-Ahead and Day-Of: Timing of DR Event Notification Notification of DR events to participants can come a day before (Day-Ahead) and/or on the day of (Day-Of) the DR event. Day-Ahead. Customers are notified one day (24 hours) in advance of a DR event. This notification type allows participants to deploy load-shifting and load-shaping strategies to achieve the demand reduction. Day-Of. Customers are notified on the day of the DR event. The notification can arrive instantaneously of the event, 5 minutes, 15 minutes, 30 minutes, 1 hour, or 6 hours, in advance of the DR event start time. End-users who are equipped with enabling technologies that allow automatic DR actions will be able to effectively handle the Day-Of notification. Also, as notification time decreases, incentives increase. Absolute and Relative Setpoint Adjustments There are two common ways to adjust setpoints identified by DR control strategies: absolute and relative. Siemens Industry, Inc. 15

18 Automated Demand Response Using OpenADR Application Guide Absolute. Assigns a specific value (within acceptable high and low limit values) to the new setpoint. The advantage is that there is no need to check whether the new setpoint value will fall outside the acceptable range. The drawback occurs when the actual sensed value is already at or over the new setpoint the HVAC system can do nothing to adjust its operation, resulting in no further demand reduction. For example, a zone temperature setpoint is set to an absolute value of 75 F during the DR event. However, if the actual zone temperature is already at 75 F or above, there will be no further demand reduction. Relative. Relative setpoint adjustment increases or decreases the setpoint relative to the last sensed value before the start of the DR event. This guarantees that HVAC systems can adjust their operation to achieve the new setpoint. The drawback is that you must check the high and low limit values against the new setpoint to ensure that the new setpoint is within an acceptable range. For example, a relative setpoint adjustment action calls for increasing the zone temperature setpoint 3 F above the current actual zone temperature during the DR event. Further demand reduction will occur, since the system will not have to work as hard during the DR event to maintain the new setpoint. NOTE: Factors Affecting DR Potential The ADR Client application can only command control points with absolute values. If you want to perform relative adjustment to setpoints, calculation of the new control setpoint and execution of the control strategies must be programmed and executed at the field panel level controller. The following factors, with examples, affect the effectiveness of DR control strategies and should be considered when selecting and executing DR control strategies. Outside Weather Extreme outside weather conditions can directly impact the effectiveness of DR control strategies, especially when the strategies are related to changing zone temperature setpoints. For example, at midday during peak summer months when the outside temperature is high an HVAC system might have already been operating at full capacity and may be unable to maintain the proper cooling setpoint temperature. In addition, the zone s actual temperature could already be at or above the zone setpoint temperature determined by the DR control strategy. In such a scenario, the DR control strategy of raising the zone setpoint temperature will be ineffective, resulting in zero additional kw reduction. 16 Siemens Industry, Inc.

19 Chapter 3 Demand Response Strategies Mechanical System Size Item Undersized Oversized Comments Cannot achieve expected DR, since the system is already operating at full capacity. To supplement the system capacity, you need to use a precooling strategy for the environment. DR could be lower than expected, since the system is already operating at partial capacity. HVAC Systems Since the level of demand reduction (kw) depends on the controllability of the HVAC system, and the controllability of the HVAC system depends on the design and configuration of the mechanical system, the effectiveness of DR control strategies will depend heavily on various types and configurations of mechanical systems being controlled. Air Distribution Side Item All-air System: Constant Air Volume All-air System with Electric Reheat: Constant Air Volume All-air System: VAV All-air System with Electric Reheat: VAV Comments Cannot reduce airflow, so you cannot reduce motor power. Can disable electric reheat to reduce power demand. For the cooling season, electric reheat could be required for humidity control; therefore, disabling electric reheat for a long period of time could result in humidity-related problems. Can reduce airflow, so you can achieve predictable DR from fan motor power reduction. Fan motor power reduction for VAV AHU with VFD is higher than VAV AHU with variable inlet vane or variable discharge damper. Can decrease chilled water supply temperature through the chilled water cooling coil so you can reduce the amount of air flow through the cooling coil, thus reducing fan motor power. Can reduce airflow and temporarily disable electric reheat. Cooling Plant Distribution Side Item All-water System: Constant Primary and Secondary All-water System: Constant Primary, Variable Secondary Comments Cannot reduce water flow, so you cannot reduce pump motor power. Can reduce water flow in the secondary water circuit, so you can achieve predictable demand reduction from secondary pump motor power reduction. Siemens Industry, Inc. 17

20 Automated Demand Response Using OpenADR Application Guide Item All-water System: Variable Primary and Secondary All-refrigerant System: Variable Refrigerant Comments Can reduce water flow in primary and secondary water circuits, so you can achieve predictable demand reduction from primary and secondary pump motor power reduction. Can reduce refrigerant flow, so you can achieve predictable demand reduction from compressor motor power reduction. Plant Equipment Item Multi-stage Reciprocating Chiller Electric Centrifugal Chiller with Variable Speed Drive Multiple Chillers Absorption Chiller Comments Can reduce compressor stage, so you can achieve predictable demand reduction from compressor motor power reduction. Can reduce compressor speed, so you can achieve predictable demand reduction from compressor motor power reduction. Compressor motor power reduction of centrifugal chiller with VFD is higher than that of chiller with compressor inlet vane control. Can turn off one of multiple online chillers. Implement cooling plant optimization programs, such as CPOP. The absorption chiller is driven by a source of energy besides electricity, so turning on an absorption chiller can help reduce compressor power demand of the electrical centrifugal chiller while maintaining continuous plant cooling capacity. Cooling Plant Heat Rejection Side Item Comments Air-cooled: Multi-stage and Variable Speed Fans Water-cooled: Multi-stage and Variable Speed Fans The fan motor power reduction of an air-cooled condensing unit with a variable speed fan is higher than that of one with a single- or multi-stage fan. The fan motor power reduction of a water-cooled cooling tower with a variable speed fan is higher than that of one with a single- or multi-stage fan. Thermal and Electrical Storage Systems You can use chilled water or ice thermal storage systems to provide cooling during DR events. During the night when electricity is cheaper, you can produce chilled water and ice; then, on the day of the DR event, you can lock out the electrical chillers and discharge the storage system to provide the needed cooling capacity. Lighting Systems Lighting systems with dimming control are highly effective for DR purposes. Dimming the lighting level can result in an instantaneous power demand reduction while still maintaining the lighting level required for performing tasks and maintaining the safety and security of building occupants. 18 Siemens Industry, Inc.

21 Chapter 3 Demand Response Strategies Methods of Executing DR Control Strategies You can execute DR control strategies manually, semi-automatically, or automatically. Manual. Actions involve labor-intensive approaches to manually turning equipment off and on, and changing setpoints of control parameters. Semi-automatic. Actions involve preprogrammed control strategies that are carried out by building operators, typically through centralized building automation and control systems. Automatic. Actions do not need human intervention but are executed automatically by building automation and control systems upon receipt of DR event signals. When used with the ADR Client application, an APOGEE building automation and control system can automatically execute DR control strategies. Return to Normal Strategies At the end of a DR event, the systems under DR control strategies must be returned to their normal conditions, which should be clearly defined and accepted by the building operators. For example, if a DR strategy is zone temperature adjustment, at the end of the DR event, the zone temperature should be returned to the last zone setpoint value before the DR event started, not the default value. For an HVAC system, returning the building to normal operation could suddenly increase the cooling requirement, which would cause a sudden spike in electrical demand. To minimize this rebound effect, you should have strategies to gradually return the system to normal operation. This could be done by gradually and systematically returning different parts of buildings and systems to normal operation with some time delay in between. Rebounding control strategies can also incorporate a ramp-up period to gradually ramp-up the fan, pump, and compressor motors. If DR strategies involve shutting down major HVAC equipment, such as a chiller or a boiler, you must carry out proper start-up sequences to ensure that equipment is starting up in the right order with the appropriate time delay, and thoroughly check all safety parameters before starting up such major equipment. Sample Return to Normal Strategies Slow Recovery. This slowly recovers the target parameters that were controlled during the DR event. To bring setpoints back to normal operation, change the setpoints gradually over time or in small, step-by-step increments over a long time period. Sequential Equipment Recovery. If many pieces of equipment are controlled by DR strategies, you should restore the original control setpoints for each piece of equipment oneby-one at specified time intervals. Extended DR Control Period. To avoid a rebound peak, extend the DR control beyond the DR event end time, or until the end of building s occupancy schedule. Common DR Control Strategies The DR control strategies described here represent commonly-used DR control actions in typical commercial office buildings and are compiled from various research reports; in particular, those produced by the DDRC at LBNL. NOTE: This is not an exhaustive list of strategies. If needed, you should determine other DR strategies that could better suit your needs, the buildings, and the HVAC systems that you want to control. Siemens Industry, Inc. 19

22 Automated Demand Response Using OpenADR Application Guide NOTE: The order of the strategies listed here does not indicate any preference. Strategy 1: Adjusting the Zone Temperature This DR strategy is one of the best for gradually entering and exiting from DR events, as it ensures that HVAC and plant equipment will unload and reload in a smooth, continuous, and automatic fashion. For example, if zone cooling setpoint temperatures are increased globally throughout a facility when a DR event occurs, power demand will instantly be reduced because the zone s cooling requirement will instantly be reduced. This instant reduction in the source cooling load will immediately cause a reduction in the air handler fan, reducing the fan power demand, which in turn reduces the thermal load on the cooling coils, which then reduces the loading on the chiller(s), distribution chilled water pumps, and cooling tower pumps and fans. The result of these activities lets you automatically reduce the power demand for chilled water pumps, chiller compressors, and cooling tower fans in a smooth, continuous way. While this DR strategy is relatively easy to implement, it doesn t provide a high level of certainty in predicting the level of actual power demand (kw) reduction because the temperature used as the basis for estimating the reduction during a previous field test of the strategy could be different than the current actual temperature. For example, if the normal zone temperature setpoint is 72 F and a DR event occurs in the middle of the summer in hot outside air conditions, and the DR control strategy calls for an increase of 3 F during the DR event, increasing the zone temperature setpoint from 72 F to 75 F would result in a power demand (kw) reduction of fan motors, pump motors, chiller compressors, and cooling tower fan motors. However, the potential reduction would only be effective if the actual temperature in the zone before the adjustment is 72 F or lower. If the actual temperature is already at 75 F, then increasing the setpoint to 75 F will result in no additional power demand reduction. In this example, it would be better to use outside air temperature as a basis for estimating the electric demand reduction from adjusting space temperature setpoints, and to perform multiple field tests to measure the demand reduction at various outside air temperatures. Applying this control strategy to an undersized HVAC system also involves uncertainty because the system may already be running at full capacity and unable to maintain the designated setpoint, or the actual zone temperature may already be at the level determined by this strategy, which would result in no demand reduction. A similar but opposite logic applies to zones in an electric heating mode application. That is, a suitable DR strategy for reducing electrical demand when zones are in a heating mode would be to lower space temperature setpoints. Prerequisite The control system is capable of commanding global or individual zone temperature setpoints. DR Event Notification Timing Day-Of Estimation of Demand (kw) Reduction It may be difficult to calculate expected power demand reduction from this DR strategy without actual field experiments, or using building and energy simulation models to estimate the power demand reduction. To identify potential demand reduction, it may be helpful to refer to International Performance Measurement & Verification Protocol: Concepts and Options for Determining Energy and Water 20 Siemens Industry, Inc.

23 Chapter 3 Demand Response Strategies Savings Volume I, Option A: Retrofit Isolation with Key Parameter Measurement 8. This option is based on a combination of measured and estimated factors. Measurements are spot or shortterm and are taken at the whole building level. For example, take a spot measurement of power (kw) on a hot summer day when the majority of room temperature setpoints are at the same level, and the majority of actual room temperatures are at or close to the setpoint. Then, raise the room temperature setpoint by 3 F. Once the setpoint is reached, take another spot measurement. For the cooling season, you can use the reduction of power from setpoint changes for future DR estimation, which can be expressed as kw reduction per degree of increasing setpoint per square foot of occupied space (kw/f/sq.ft). Offset Time For a large HVAC system, it could take 15 to 30 minutes to achieve the expected power demand reduction from fan motors, pump motors, chiller compressors, and cooling tower fans due to the thermal flywheel effect. So, execute this strategy 15 to 30 minutes before the DR event start time. This will be referred to as offset time throughout this guide. Sequence of Operation Acceptable range for the zone temperature setpoint: Cooling season: 72 to 78 F Heating season: 62 to 72 F Absolute setpoint adjustment: Moderate DR operation mode (offset time: 15 minutes): Cooling season: Set the zone temperature setpoint to 75 F Heating season: Set the zone temperature setpoint to 69 F High DR operation mode: (offset time: 15 minutes) Cooling season: Set the zone temperature setpoint to 78 F Heating season: Set the zone temperature setpoint to 66 F Relative setpoint adjustment: Moderate DR operation mode (offset time: 15 minutes): Cooling season: Increase the zone temperature setpoint by 3 F Heating season: Decrease the zone temperature setpoint by 3 F High DR operation mode (offset time: 15 minutes): Cooling season: Increase the zone temperature setpoint by 6 F Heating season: Decrease the zone temperature setpoint by 6 F Indoor Environmental Quality Impact In a cooling mode application when this DR strategy is executed, occupants could feel some discomfort due to the rise in zone temperature; therefore, they must be notified about the cause and underlying reasons. If the zone temperature reaches an intolerable level, you may have to cancel the DR control actions and forfeit the financial benefit of opting-in to the DR event. You 8 International Performance Measurement & Verification Protocol Committee. International Performance Measurement & Verification Protocol: Concepts and Options for Determining Energy and Water Savings Volume I Efficiency Valuation Organization, DOE/GO Siemens Industry, Inc. 21

24 Automated Demand Response Using OpenADR Application Guide should establish and strictly follow standard operating procedures for canceling DR control actions after the event has already been opted-in. During the DR event, it s also possible that the building may be unable to comply with ASHRAE Standard 55 Paragraph , because the temperature drift rate would be shorter than what is required. Measurement and Verification Measure the demand (kw) at the building level to verify the demand reduction. Calculate the reduction based on the actual measurement and the baseline number, as defined in the DR contract. Return to Normal Strategy To prevent a sudden surge in cooling demand at the end of the DR event, if you can t postpone normal operation until the end of the occupied period, you should incrementally decrease the cooling temperature setpoint over time (for example, 30 minutes) to allow the HVAC system to properly ramp up. Strategy 2: Decreasing the Duct Static Pressure Setpoint CAUTION: Do not use this strategy if the air distribution system is improperly balanced. NOTE: This strategy can be accomplished simply by increasing (for zones in cooling mode) or lowering (for zones in heating mode) the space temperature setpoints. In a VAV air distribution system, a VAV AHU responds to changes in heating and cooling loads by reducing the amount of conditioned air flowing to the space. You can manipulate the amount of air by controlling the duct static pressure, which reduces the air volume, which in turn reduces the fan motor power. The amount of fan motor power demand reduction will be greater if the fan motor is equipped with a VFD controller. It is necessary to verify that all VAV boxes are functioning properly at the current static pressure setpoint. If the current static pressure setpoint is already at a higher level than necessary, decreasing the static pressure setpoint will reduce fan power demand without causing discomfort for occupants. If the current static pressure setpoint is already at the proper level, decreasing it will cause some zones to starve for airflow because the reduction will not be shared evenly between all VAV terminal boxes. The zones that require most amount of air will be the ones whose airflow will immediately decrease, creating hot spots that might be intolerable to building occupants. Prerequisites VAV air distribution system VAV AHU (most effective if equipped with a VFD controller) Duct static pressure sensor All VAV boxes are operating properly at the current static pressure setpoint under normal conditions. The control system is capable of commanding a static pressure setpoint. 9 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ASHRAE Standard : Thermal Environmental Conditions for Human Occupancy ISBN Siemens Industry, Inc.

25 Chapter 3 Demand Response Strategies DR Event Notification Timing Day-Of Estimation of Demand (kw) Reduction Use fan laws to estimate (approximate) the demand reduction. To approximate the percentage of kw reduction, use the following equation. NOTE: This equation is only an approximation, since the static pressures referred to in the calculation technically should be taken across the fan (fan discharge minus fan suction static pressure), and not 2/3 of the way down the duct, as is typically located for fan static pressure control. SP % kw Reduction = 1 SP1 where: 3/ SP2: New static pressure setpoint SP1: Current static pressure setpoint Then, calculate the demand (kw) reduction by multiplying the fan motor power rating (full load kw/bhp) by the results of the above equation. Offset Time A reduction in the duct static pressure setpoint for a VAV fan should show an almost immediate effect on the reduction of fan power, since there is very little thermal capacitance in a fan static pressure control loop. A VAV fan static pressure loop is a fast-acting loop. Sequence of Operation For each air-duct system, check the as-built drawings and sequence operations for the acceptable duct static pressure setpoint. Absolute setpoint adjustment: Moderate DR operation mode (offset time: 0 minute): Set the new static pressure setpoint 10% lower than the operating static pressure setpoint. High DR operation mode: (offset time: 0 minute): Set the new static pressure setpoint 20% lower than the operating static pressure setpoint. Relative setpoint adjustment: Moderate DR operation mode (offset time: 0 minute): Decrease the static pressure setpoint by 10% from the current static pressure setpoint. High DR operation mode: (offset time: 0 minute): Decrease the static pressure setpoint by 20% from the current static pressure setpoint. Indoor Environmental Quality Impact When you reduce the amount of cool air supplied to each zone, some zones may experience decreased air flow, which might be intolerable to building occupants. Ventilation rates in certain zones could drop below the required level. Siemens Industry, Inc. 23

26 Automated Demand Response Using OpenADR Application Guide Measurement and Verification Measure the demand (kw) at the fan motor to verify the demand reduction. Return to Normal Strategy To prevent a sudden surge in fan power at the end of the DR event, set back the duct static pressure setpoint one fan at a time, with a few minutes time delay between each. Strategy 3: Increasing the Supply Air Temperature NOTE: This strategy can be accomplished simply by increasing (for zones in cooling mode) or lowering (for zones in heating mode) the space temperature setpoints. Increasing the cooling supply air temperature setpoint will reduce the chilled water flow requirement through the cooling coil, resulting in a reduced electrical demand for secondary chilled water pumps and compressor motors. This strategy works best when combined with Strategy 1: Adjusting the Zone Temperature. CAUTION: In variable-speed CHW plants, it s best to lower the supply air temperature setpoint due to the interaction (coupling) of the power performance chiller with the CHW distribution pumps and air handler fans. If the zone temperature is not adjusted to a higher setpoint value, or if the fan speed is not locked in position before executing this strategy, this strategy may cause an increase in AHU fan motor power. This is caused by VAV boxes calling for increased air to maintain the current zone temperature setpoint in order to compensate for the higher temperature of supply air, and the VAV AHU will increase the fan motor speed to provide more air, resulting in an increase in fan motor power. For an air distribution system with electric reheat, increasing the zone supply air temperature will also reduce electrical demand of electric reheat coils. Prerequisite The control system is capable of commanding a global supply air temperature setpoint or individual supply air temperature setpoint. DR Event Notification Timing Day-Of Estimation of Demand (kw) Reduction Similar to Strategy 1: Adjusting the Zone Temperature, it could be difficult to calculate the expected power demand reduction from this DR strategy. You may need to experiment with different levels of supply air temperature increase to determine a proper level of increase and expected power demand reduction. Offset Time For large HVAC systems, it could take 15 to 30 minutes to achieve the expected power demand reduction from pump motors, chiller compressors, and cooling tower fans. So, execute this strategy 15 to 30 minutes before the DR event start time. Sequence of Operation Acceptable supply air temperature setpoint range: Cooling season: 45 to 60 F (55 F is a typical setpoint) Heating season: 100 to 125 F 24 Siemens Industry, Inc.