Three years ago an ASHRAE committee was formed to develop an open and interoperable standard for the description of the control logic used in building control systems. The committee started with the work done by the DOE funded "Open Building Control" project (see obc.lbl.gov) and reviewed existing commercial control sequence languages.
The draft standard contains definitions for a Control Description Language (CDL) which is defined in the modeling language "Modelica". It also has a version of CDL called the Controls eXchange Format (CXF) which is defined using JSON-LD. CDL and CXF share the definitions for over 130 "elementary functions" such as "Add", and "PID".
CDL and CXF will enable sharing control logic in a machine readable form from design to deployment and between control systems.
The public review period runs from 2/2/2024 - 3/18/24. The draft document and a link to enter comments can be found at https://osr.ashrae.org/ . The project committee is encouraging public review and comments.
Introducing ctrl-flow, an online tool for Design of High-Performance Control Sequences
There are many advantages to using high performance control sequences, but these are often hard to properly specify and deploy correctly. ASHRAE Guideline 36 provides a great starting point to develop an accurate sequence, but editing what is in the guideline is also a challenge. To help with this, Lawrence Berkeley National Laboratory (LBNL) has developed a new software tool called ctrl-flow with funding from the US Department of Energy. This tool is freely available for online use at https://ctrl-flow.lbl.gov.
The initial release of ctrl-flow allows designers to easily input project information, the desired systems, and their configurations. The tool will then provide an edited sequence based on ASHRAE Guideline 36-2021 that is specific to the selected options. This saves the time and effort needed to manually edit the guideline and reduces risks of editing errors.
Currently the tool supports the following:
· Options for SI or IP units
· Code compliance for ASHRAE 90.1 / 62.1 or California Title 24
· Selection of climate zones
· Airside systems including Multiple-Zone VAV Air Handlers and Cooling-only and Reheat VAV Terminals
Future releases of the tool will include:
· Support for a broad range of systems including all systems in Guideline 36
· The ability to provide additional project information and then download more detailed documentation including:
o Points lists
o Systems diagrams
o The control logic for the specified sequence in the Control Description Language (CDL) as well as in the Control Exchange Format (CXF)
o A Modelica model of the HVAC system selected that can be used with tools such as the Spawn of Energy Plus.
The tool is designed to help support the needs of HVAC system designers, control contractors, commissioning agents, and energy modelers in evaluating and deploying advanced control sequences. More information on the tool is available on the site or by contacting ctrl-flow@lbl.gov.
Control Description Language to Become an ASHRAE Standard
Properly designed and implemented sequences for building control can dramatically improve the energy efficiency, comfort and safety of commercial buildings. Unfortunately the process to develop, document, implement, and support these sequences is complicated and error prone and as a result many buildings operate sub-optimally. Building Intelligence Group helped to define and lead a program called “Open Building Control” that is working to resolve this issue. The program is centered at the Lawrence Berkeley National Laboratory, and is funded by the US Department of Energy and others. The project is focused on a digital process that will allow designers to select high performance sequences, measure how effective they can be through simulations, then provide documentation to the contractor in a digital format called the “Control Description Language” or CDL. The use of CDL enables the ability to easily model the efficiency of control sequences, check for errors in design, and to translate or compile the logic into code that can be used on commercial controllers.
The definition of CDL has been completed as an open source project and the results can be found at https://obc.lbl.gov/specification/cdl.html .
The next step is to work with industry to review what has been created for CDL and to develop what will become a US and eventually international standard. Moving this to a standard provides the potential to gain broad industry acceptance so that designers, suppliers, servicing contractors, and owners can benefit from a consistent method to define and document control system logic.
The American Society of Heating Refrigerating and Air Conditioning Engineers (ASHRAE) is an ANSI standards organization and they have agreed to start a committee to create a standard based on CDL. Paul Ehrlich from Building Intelligence Group has been asked to lead this project, which should start in the Summer of 2020.
Members are needed to participate in the standards project. More information about the project can be found in this presentation.
Commercial Building Controls and Grid Integration in India
In February 2020 Paul Ehrlich of Building Intelligence Group was invited to present a paper on “Optimized Building Controls and Grid Integration” at Energise 2020 an energy efficiency conference in Hyderabad India sponsored by ACEEE and their affiliate in India AEEE. See: https://www.energiseindia.in
The conference provided a good opportunity to gain a glimpse into the challenges faced by the second largest (and growing) country in the world. India has four times the number of people as the US, yet uses less than half as much electricity. Their usage of power varies greatly from the US. While we have fairly even usage between residential buildings, commercial buildings and industry, India has over 60% used by industry, 25% by commercial buildings, but only 8% in commercial buildings. The reason for the low usage is that they have relatively few larger, air-conditioned commercial buildings. But that is rapidly changing, and they are anticipating a 200% gain in the number of commercial buildings over the next ten years. They have an aggressive plan to address residential cooling efficiency, and a lot of focus on improving industrial efficiency. One key finding was that in commercial buildings they have challenges with controls, both with their getting omitted due to budget, as well as with operators being able to use them properly.
A key take away from the conference was that while much of our challenge in North America is in retrofitting our existing stock for improved efficiency and flexibility, while in India the opportunity is to build new buildings right for the future.
Open Building Controls - Translation Demonstration Update
The demonstration project for translating the open Controls Description Language (see post below) into a commercial controls language is now in its final stage. The prototype translator is completed and functional, and it has helped us learn the process and challenges involved in translation. A demonstration is planned for May 2020 - more details to follow!
Demonstration case with controllers and I/O
Artificial Intelligence in Building Automation
One of the most promising new technologies, is the use of big data analytics coupled with artificial intelligence. The concept is to use the power of computing to allow for decision making that could be as good (or ideally better) than the decisions made by a human operator. There are many places that this is being applied from robotics to autonamous vehicles.
There is also the potential to apply these concepts to enhance the operation and control of buildings and homes. One application for control is what is referred to as “Model Predictive Control” (MPC) which uses calculations that could include historical performance, algorithms, and other data to provide for better control. Today most of our control systems operate using a certain level of error or imprecision. The most accurate control (such as PID) try to minimize this inaccuracy. MPC has the potential to provide for more accurate control as well as optimized operation. For example one current research project is attempting to control a fans energy use at the limits of the fan curve and reduce the error that exists with the use of conventional “trim and responsible” control.
While these new concepts show great potential, they are also generally more complicated and computationally intensive than what they replace. As computing power get cheaper and programming tools get easier, it will likely be broadly adopted. We would anticipate that the first application may be embedded in equipment, since there is enough volume to justify the added costs to develop the strategy. In time it will be more broadly used across building control systems. In the meantime it is a good time to learn about the technology and what it can and can’t do.
For some added information take a look at a recent article on this topic in Engineered Systems magazine. https://www.esmagazine.com/articles/99449-es-roundtable-is-ai-a-tangible-asset-in-the-built-environment
Open Building Controls Demonstration Project
Building Intelligence Group is helping to support the Open Building Control project being led by Lawrence Berkeley National Laboratory (see http://obc.lbl.gov). Part of our participation on this project is to coordinate a demonstration to show how the “Controls Description Language” can be translated into a commercial building controls programming language.
Open Building Controls:
The Open Building Control (OBC) project is intended to provide a set of tools that can be used to simplify the design, specification and deployment of commercial building control sequences, resulting in reduced project cost, higher quality, and improved energy efficiency of building systems.
There are several elements and tools that are part of this project. These include:
Modeling Tools: Tools to allow for modeling of control sequences to allow for evaluating their potential performance. These tools are intended primarily for researchers and designers so that they can compare and select the most energy efficient sequences.
Sequence Selection Tool: This tool would simplify the task of selecting and specifying sequences. Ideally it will allow designers to easily select and specify their own sequences, or industry “best in class” sequence options such as those in ASHRAE Guideline 36. Controls
Description Language: CDL provides an open source definition for how to describe a control sequence in a machine-readable format. The CDL specification is available on the OBC project website (http://obc.lbl.gov/specification/index.html) and has been reviewed extensively by industry. The project team has developed translators that can represent a CDL file both in a JSON format as well as in HTML.
CDL Translators: The project team envisions these as a control system vendor provided tool that would take a CDL file, (or the file translated to JSON) interpret it, and use the content to generate code that could readily be compiled and downloaded into a control system.
Validation Tools: The final parts of the OBC tool-chain are tools that can be used to verify the correct operation of the control sequences. These tools would be used for commissioning and analysis of existing systems with an eye toward further optimization.
2019 - Fifteenth Year for Building Intelligence Group
2019 marks 15 years since Building Intelligence Group was formed. We started in the early days of the Intelligent Building and our focus was on assisting the industry with convergence of building systems with IT. Our firm remains focused on integrated building systems but has transitioned to assisting owners, and the industry with the benefits this provides for improved energy efficiency, operations, and coordinated operation of buildings with the energy grid.
Our team is experienced in all aspects of energy efficiency including planning, design, existing system analysis, energy modeling, and project management. We are focused both on assisting owners to improve their building performance, and also on how to assist the building systems industry in improving performance through education, tools, pilots, and other programs focused on transforming how efficiency is delivered.
In late 2016, Building Intelligence Group stopped accepting new projects when founder and president Paul Ehrlich, took a position as program manager and technical advisor at the Department of Energy’s Pacific Northwest National Laboratory. Paul relocated to Portland Oregon and worked on a series of projects including advanced building controls, facility operations and building to grid integration. This provided invaluable experience about the process and focus being pursued on the part of the US government to help with efficient and grid integrated buildings.
Paul recently returned to Building Intelligence Group, and our firm is now pursuing new project opportunities. Areas of expertise include:
Energy Efficiency: Assisting owners on how to effectively improve building energy efficiency while maintaining comfort and safety. Our services range from energy audits, modeling, and schematic design, through design, project management and finally commissioning and training.
Systems Integration: Support for master planning, project design, use of open protocols, cyber security, contractor / supplier qualification and commissioning.
Industry and Market Transformation: Develop programs that document current practices and development of plans for improved process, training, and solutions.
Research and Pilot Projects: Small and large scale approaches to testing new process and technology. This includes site selection, contractor and product selection, testing methodology, owner coordination, measurement and verification, and documentation through case study.
We are available for projects both locally in the Pacific Northwest, as well as across the US and internationally. We appreciate your time and support for our shared interest in sustainability through improved building performance and efficiency.
Building Automation System Innovation
In many ways it seems like products available for building automation have been largely static with little in terms of innovation. But in reality subtle changes and improvement are now allowing the design of systems that are all network based and have added capability to support semantic tagging and encrypted communications. See the November issue of Engineered Systems for an article by Building Intelligence Groups, Paul Ehrlich highlighting these changes and some of the resulting challenges.