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checkRetrocommission HVAC controls.

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Description

Perform retrocommissioning (RCx) of HVAC controls to fine-tune operating conditions and improve performance. RCx, also called existing building commissioning, is a three-stage process:

  • Developing an operations plan
  • Test systems to determine whether they are meeting the plan's requirements
  • Repair or replace under-performing systems
  • Project Talking Points

    • Provides a comprehensive picture of the facility’s HVAC systems and optimal operating conditions.
    • Identifies opportunities where repairing or replacing equipment would lead to substantial savings on utility bills.
    • Optimizes performance both of individual pieces of equipment and of the entire building HVAC system.
    • Extends the life and efficiency of HVAC equipment through preventive maintenance.
    • Locates and addresses leaks, moisture accumulation, and faulty sealants before they attract mold growth or pests.
    • Sets the foundation for development of a preventive maintenance plan.
  • Triple Bottom Line Benefits

    • Cost benefits: Energy savings result in cost savings. Retrocommissioning is an inexpensive way to adjust controls with immediate payback. (See case studies for specific examples.) Extending the life of equipment also saves on costs.
    • Environmental benefits: Reducing energy use always has an environmental benefit (see the Benefits Calculator page). Extending the life of equipment also has recognizable environmental benefits, although these are harder to quantify.
    • Social benefits: Depending on the improvements made to operations during retrocommissioning, improvements to the comfort and safety of patients, visitors, and staff may be significant. Track and report all benefits that result from retrocommissioning efforts.
  • Commissioning Connections

    The ASHE Health Facility Commissioning Guidelines and accompanying Health Facility Commissioning Handbook are good information sources for undertaking this performance improvement measure.

    • 4.3 Facilitate Implementation of HVAC Control System Trends – Trends make it easier to diagnose control problems and identify system operations that are wasting energy or affecting space conditions and/or critical pressure relationships.
    • 4.4 Prepare the Commissioning Report and Systems Manual – one of the most important uses of the system manual is as a condensed system-level troubleshooting guide for O&M personnel.
    • 4.8 Facilitate Development and Implementation of the Building Maintenance Program (BMP) – The BMP should utilize a computerized maintenance management system (SMMS) software program.
    • 5.5 Benchmarking Energy Performance – The benchmarking process is based on actual energy and water consumption and costs as compared to the EPA target.
    • Chapter 6: Retrocommissioning – Retrocommissioning health care facilities can significantly reduce annual energy costs.
    • 6.1.2 (11) – Conduct a detailed review of automatic temperature control systems, including water chillers, boilers, air terminals, air-handling units, exhaust fans, domestic water heating equipment, and fan coil units. Identify existing sequences of operation and set points.
  • How-To

    1. Determine who's on the team: health facility commissioning authority (HFCxA), building engineer, HVAC maintenance personnel, and building automation system (BAS) manager.
    2. Establish an ENERGY STAR Portfolio Manager account for the health care facility. See the Roadmap performance improvement measure Establish baseline for current energy consumption for details.
    3. Review the whole-building energy performance baseline data gathered under Roadmap performance improvement measure “Establish baseline for current energy consumption.” (See Section 6.1.2, Items of Work for Retrocommissioning Energy-Consuming Systems in the ASHE Health Facility Commissioning Guidelines and Health Facility Commissioning Handbook.)
    4. Document the retrocommissioning effort in a written report.
    5. Perform a walk-through of the facility to identify and record the status of all meters, sensors, and other building system controls. Examples of critical sensors to calibrate include (BetterBricks: Building Operations Tools & Technical Advice – Common Opportunities):
      • Outside air, supply air, mixed air, and return air temperature sensors
      • Chilled water and hot water temperature sensors
      • Carbon dioxide (CO2) sensor
      • Carbon monoxide (CO) sensor
    6. Develop a log of all controls and include the manufacturer’s recommended calibration interval, the baseline calibration, and the calibration history (if available) for each control. Consider the accuracy and reliability of the sensors, particularly humidity, CO2 and CO sensors.
    7. Access your systems to answer the following questions (Portland Energy Conservation, Inc. Energy Management Systems: A Practical Guide, 1997)
      • Were your sensors and actuators calibrated when originally installed?
      • Have your sensors or actuators been calibrated since installation?
      • Have temperature complaints come from areas that ought to be comfortable?
      • Are any systems performing erratically?
      • Do any areas or equipment repeatedly have comfort or operational problems?
      • Are any systems (area zones) simultaneously cooling and heating?
      • Is there a written sequence of operations describing the control logic for air handlers and zone temperature control?
      • How are your buildings currently being used and occupied? In particular, have former health care areas been converted to administrative uses? If so, this may present an opportunity to recommission systems accordingly.
    8. If the facility is equipped with a building automation system (BAS), verify that the controls included in the log are tracked by the BAS and that the BAS system has been programmed to issue an alarm if sensors or controls vary outside acceptable setpoints.
    9. Calibrate controls within the manufacturer’s recommended interval.
    10. Integrate regular recalibration into the facility’s preventive maintenance program, scheduling it every five years at minimum or in accordance with the manufacturer’s recommendation (whichever is shorter).
    11. Develop an HVAC systems manual with operating plan using the facility’s operations and maintenance manual (if available) or manufacturer’s recommendations. At minimum, include the following information:
      • Description of all HVAC systems and narrative sequence of operations under normal and emergency scenarios.
      • Description of all controls, the manufacturer’s recommended calibration interval, the baseline calibration, and the calibration history (if available)
      • Monitored conditions (e.g., air temperature, humidity, pressure relationship, filtration, ventilation, etc.)
      • Mode of operation (e.g., occupied/unoccupied)
      • Time-of-day schedule for every day of the week plus holidays (include seasonal variation, if applicable)Optimal operating setpoints (stratify information by occupancy type, if applicable)
    12. Use an electronic commissioning tool that interfaces with the automatic temperature control system to significantly expedite the retrocommissiong effort. Such tools use a standard communication protocol to query a massive database and quickly identify previously undetected problem areas. After the retrocommissioning effort is completed, O&M staff can use the tool to continuously monitor HVAC controls and dispatch maintenance personnel to handle problems. The retrocommissioning effort should lead toward implementation of a continuous commissioning effort that is appropriate for the specific facility. (See Section 6.1.3, Striving for Continuous Commissioning) in the ASHE commissioning books).
  • Tools

  • Case Studies

    Othello Community Hospital

    • Key Point
      • Retrocommissioning resulted in recalibration of several sensors and controls. For example: An improperly calibrated CO2 sensor was responsible for introducing 2,000 cfm of unnecessary outdoor air into the facility. An inappropriate control sequence for a short-cycle chiller resulted in continuous cycling at low loads.

    Peace Health, St Joseph Hospital

    • Key Points
      • Retrocommissioning allowed the hospital to develop an energy management plan for HVAC systems.
      • First year savings of $100,000 simply from modifying sequence of operations and scheduling.

    Saint Francis Care

    • Key Points
      • Occupant feedback (e.g., daily resetting temperature controls) led to an investigation of temperature setback controls.
      • Correcting the night setback controls contributed to $9,100 energy savings per year in a 30,000 sq. ft. area.

    St. Luke’s Regional Medical Center

    • Key Points
      • Focused the first phase of retrocommissioning on the ten largest air handlers, rather than retrocommissioning the entire HVAC system.
      • Retrocommissioning process identified potential for $250,000 annual savings (5% annual energy cost).

    Shriner’s Hospital

    • Key Points
      • Interviewing staff regarding which operational improvements would be most productive contributed to retrocommissioning success.
      • The data generated through retrocommissioning was used to justify requests for capital-intensive improvements.

    University of Pittsburgh Medical Center

    • Key Point
      • $2 million in annual gas savings from retuning boilers.
  • Regulations, Codes and Standards, Policies

  • Cross References: LEED

    • LEED for Existing Buildings: Operations + Maintenance
      • Energy & Atmosphere Prerequisite 1: Energy Efficiency Best Management Practices—Planning, Documentation, & Opportunity Assessment
      • Energy & Atmosphere Prerequisite 2: Minimum Energy Performance
      • Energy & Atmosphere Credit 1: Optimize Energy Efficiency Performance
      • Energy & Atmosphere Credit 2.1: Existing Building Commissioning—Investigation & Analysis
      • Energy & Atmosphere Credit 2.1: Existing Building Commissioning—Implementation
      • Energy & Atmosphere Credit 3.1: Performance Measurement—Building Automation System
      • Energy & Atmosphere Credit 5: Measurement & Verification
      • Indoor Environmental Quality Credit 1.2: Indoor Air Quality Best Management Practices—Outdoor Air Delivery Monitoring
      • Indoor Environmental Quality Credit 2.3: Occupant Comfort—Thermal Comfort Monitoring
    • LEED for Healthcare: New Construction and Major Renovations
      • Energy & Atmosphere Prerequisite 1: Fundamental Commissioning of Building Energy Systems
      • Energy & Atmosphere Prerequisite 2: Minimum Energy Efficiency Performance
      • Energy & Atmosphere Credit 1: Optimize Energy Efficiency Performance
      • Energy & Atmosphere Credit 3: Enhanced Commissioning
      • Energy & Atmosphere Credit 5: Measurement and Verification
      • Indoor Environmental Quality Credit 1: Outdoor Air Delivery Monitoring
      • Indoor Environmental Quality Credit 6.2: Controllability of Systems: Thermal Comfort
      • Indoor Environmental Quality Credit 7: Thermal Comfort: Design and Verification
  • Cross References: GGHC

    • Green Guide for Health Care Operations Section
      • Facilities Management Prerequisite 1: Energy Efficiency Best Management Practices—Planning, Documentation, & Opportunity Assessment
      • Facilities Management Prerequisite 2: Minimum Energy Efficiency Performance
      • Facilities Management Credit 1: Optimize Energy Efficiency Performance
      • Facilities Management Credit 3.1: Existing Building Commissioning—Investigation & Analysis
      • Facilities Management Credit 3.2: Existing Building Commissioning—Implementation
      • Facilities Management Credit 3.3: Existing Building Commissioning—Ongoing Commissioning
      • Facilities Management Credit 4.3: Building Operations & Maintenance: Building Systems Monitoring
  • PIM Synergies

  • Education Resources

    Energy UniversityEnergy University Courses

    The American Society for Healthcare Engineering (ASHE) has approved the courses below for continuing education credits. ASHE issues credits in quarter-hour increments, and a total of 10 contact hours equals 1 continuing education credit.

    Commissioning For Energy Efficiency – not called out but to be considered somewhere. 
    Studies of commissioning projects in existing buildings show median paybacks of 1.1 years and savings of up to 30%, sometimes more. Commissioning is a process to ensure building performance problems are understood and corrected. Deficiencies such as design flaws, construction defects, malfunctioning equipment, and deferred maintenance have a multitude of consequences, ranging from equipment failure, to poor indoor air quality and comfort, to unnecessarily high energy use or under-performance of energy efficiency strategies. Fortunately, an emerging form of quality assurance, known as building commissioning, can identify and cure most deficiencies. This course will explain the purpose of a commissioning process, and discuss the impact of the commissioning process on energy efficiency.
    ASHE has approved this course for .50 contact hour.

    Building Controls I: An Introduction to Building 

    ControlsHave you ever been in a meeting in a conference room where the room was just too hot? Or too cold? Did you find it uncomfortable and hard to concentrate? Have you ever considered how much money is wasted when things like that are not addressed? What's the solution? The control system within a building is very important to the energy efficiency of the building, and also to the comfort of the building's occupants. In this class, we will learn a simple definition of a control system, learn the components of a control system, and describe some fundamental types of control and control loops.
    ASHE has approved this course for .50 contact hour.

    Building Controls II: Control Sensors

    Building control systems are important facets in any building's energy management plan. They help avoid waste and save money. A vital component of a control system is the sensors that are incorporated into the system. We must measure what we wish to control. We need to have a way to make measurements accurately and repeatedly. Sensors measure the data that the controller uses to make decisions based on its set of programmed standards and set points. Sensors are the first step of control. This course provides an overview of the various sensors integrated in a building control system, and looks at the variety of designs and need for correct placement.
    ASHE has approved this course for 1 contact hour.

    Building Controls III: Introduction to Control Loops

    The purpose of this course is to provide you with an overview of basic building control technology used in buildings, so that you will understand how building controls can contribute to energy efficiency. We will examine the five controller loop responses and review the terms associated with controller loop responses.
    ASHE has approved this course for .50 contact hour.

    Building Controls IV: Two Position and Floating Responses

    The purpose of this course is to examine the two-position response and the floating response. We'll also spend some time working in an interactive example whereby you can simulate how changing a VAV box will affect static pressure and temperature in the environment.
    ASHE has approved this course for .50 contact hour.

    Building Controls V: Proportional and PID Responses

    The purpose of this course is to define proportional control responses along with investigating how integral and derivatives affect proportional control responses. We'll also spend some time explaining the appropriate use of each control response
    ASHE has approved this course for .50 contact hour.

    Building Controls VI: When to Use Each Response

    The purpose of this course is to define proportional control responses along with investigating how integral and derivatives affect proportional control responses. We'll also spend some time explaining the appropriate use of each control response.
    ASHE has approved this course for .50 contact hour.

    Building Controls VII: Interactive Illustration of PID Response

    The purpose of this course is to see how proportional control may oscillate and stabilize at a point above the setpoint and how an integral term helps a control loop to achieve a result closer to the setpoint. We'll also spend some time explaining how derivatives help to prevent overshoots.
    ASHE has approved this course for .75 contact hour.

    Building Controls VIII: Controllers and Controlled Devices

    If we can control an environmental system we can tell equipment when to turn on and off, how slow or fast to run, and how cool or hot the temperature of air or water needs to be. For an environmental control, or building automation system to work effectively, three things must take place: Measured data must be input into the system. That data must be compared with a set of standards or instructions. Lastly, an action to change or maintain current environmental conditions must be made. In the previous class in this series we looked at how controllers respond to the inputs they receive. We will now look at the different classifications of controllers. We'll also see how the control loop is completed by controlled devices, which take the actions that maintain or change current environmental conditions.
    ASHE has approved this course for .50 contact hour.

  • More Resources

  • PIM Descriptors

    Energy

    Level: Beginner

    Category List:

    PIM Attributes:

    • Optimize Operations
    • Repair or Optimize Existing Systems (fix what you have)

    Improvement Type:

    Department:

    • Engineering/Facilities Management
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