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4  FM quick reads on HVAC

1. Solid Maintenance Programs keep Chillers Operating Efficiently


As chillers age, their components wear, heat transfer surfaces become fouled with scale, and breakdowns become more frequent. Solid maintenance programs that address tracking performance, conducting regular inspections, and performing all scheduled maintenance activities can extend system life while maintaining the performance of the system, but they can not completely eliminate the impact that time has on the chiller. Eventually simple wear and tear will cause maintenance costs to increase and system reliability to suffer.

To evaluate system reliability, start with a review of the chiller's operating log. Operating logs track data related to the operation of the chiller, including drive motor current and voltage, condenser water supply and return temperatures, evaporator and condenser pressures, and oil temperature and pressure. Additional information, such as the need to add oil to the system and scheduled and unscheduled maintenance activities, should be recorded in the chiller log.

Reviewing this information on a regular basis can identify trends that may be negatively impacting system performance and reliability. Are the maintenance requirements and breakdowns increasing? Is the length of time that the chiller is out of service the result of a breakdown increasing?

Another reliability factor that must be taken into consideration is the availability of replacement components. While chiller manufacturers maintain an inventory of replacement components for practically all of their models regardless of their age, it does become more difficult to get replacement components for older models. Time delays in locating and shipping these components result in longer outages for managers and building occupants.


2.  HVAC: Utility Rebate Programs Can Help Fund Audits, Commissioning

While the audit/commissioning process is crucial for all buildings, its price tag will vary, depending on the size and age of the HVAC system components. In an effort to make these studies more accessible to the average building owner, local utility rebate programs can incentivize energy optimization in commercial buildings, both old and new. In many ways, utility rebate programs can help fund HVAC audits and commissioning.

The two types of utility incentives offered for commercial buildings include service incentives and cash incentives. With the service incentive, the utility company pays an engineering firm or other service provider directly for their technical services, such as retrocommissioning or energy assessment. The incentives range anywhere from 100 percent of services in cities like Chicago to 50 percent of services in others like New York.

In the case of the cash incentive, the utility provides the commercial building owner with a check based on the size or energy impact of the installation of energy efficient equipment.

Obtaining a utility incentive means working with the utility company or their corporate liaison hired to administer the program, or working directly with an industry professional, such as a consulting engineer, contractor or energy efficiency firm that is an approved provider with the sponsor utility.

Incentive programs, like the ComEd Smart Ideas retrocommissioning program in Chicago, have made a sizeable impact throughout its area in commercial office buildings, both those with prior sustainable certification and those without.

One example is the Hyatt Center in Chicago. Built in 2005, the 49-story Hyatt Center is one of Chicago's newest landmarks. Energy Star labeled since 2008, the building received LEED-EBOM Platinum certification in 2010. As a new building, the Hyatt has new equipment throughout, including a robust, fully digital DDC control system. Rewriting programming logic in the system and making technical adjustments to the building's set points based on outdoor temperature feedback and sensors, as well as altering new building load requirements resulted in an identified, measured, and verified 1,613,526 kWh of annual electricity savings.

The combined implementation cost of all measures was about $26,000, which included a controls contractor and in-house labor costs and resulted in a simple project payback of just four months. Retrocommissioning services were paid for in full by the ComEd program.

3.  Two Types Of Utility Incentives Can Help Optimize HVAC, Other Energy Use

Today's tip from Building Operating Management comes from David P. Callan and Kyle Hendricks of Environmental Systems Design: Two types of incentives can help optimize energy use by the HVAC system, as well as other building systems.

The two types of utility incentives offered for commercial buildings are service incentives and cash incentives. With the service incentive, the utility company pays an engineering firm or other service provider directly for their technical services, such as retro-commissioning or energy assessment. The incentives range any-where from 100 percent of services in cities like Chicago to 50 percent of services in others like New York.

In the case of the cash incentive, the utility provides the commercial building owner with a check based on the size or energy impact of the installation of energy efficient equipment.

Obtaining a utility incentive means working with the utility company or their corporate liaison hired to administer the program, or working directly with an industry professional, such as a consulting engineer, contractor or energy efficiency firm that is an approved provider with the sponsor utility.

Some utility programs offer incentives for retrocommissioning of existing buildings. Those incentives can help justify the cost of retrocommissioning. But retrocommissioning on its own often has a strong economic justification, even without incentives, as does commissioning of new buildings. A study by the Lawrence Berkeley National Laboratory found that:

  • The median whole-building energy savings from commissioning is 16 percent in existing buildings and 13 percent in new buildings.
  • The median payback time is 1.1 years in existing buildings and 4.2 years in new buildings.
  • Projects with a comprehensive approach to commissioning attained nearly twice the overall median level of savings, and five times the savings of projects with a constrained approach.

This has been a Building Operating Management Tip of the Day.

4.  Take a Hands-On Approach to Identifying Energy Waste

Managers looking to take a more hands-on approach to identifying energy waste in facility systems can consider a walk-through energy assessment. The approach has three components:

Understanding the building and building systems. Performing a walk-through survey gives managers and technicians a better understanding of the building's construction, equipment, and energy-using systems. During walk-throughs, managers and technicians can identify opportunities for equipment upgrades, as well as system modifications that might improve overall system performance.

Two examples of equipment upgrades are replacing existing motors with premium-efficiency motors and installing variable-frequency drives (VFD) to control cooling-tower motors. It also is important to identify these major energy-consuming systems and define the different functions within the building. Important questions to ask during the walk-through assessment relate to systems already in place, and steps technicians can take to improve their efficiency.

Understanding operations and maintenance practices. One essential element of energy assessments is having discussions with engineering and operations technicians regarding the operation and maintenance of a building's energy-consuming systems. These technicians handle the equipment every day and are familiar with the building systems. They can identify maintenance problems and propose changes to operations and maintenance practices that improve energy efficiency.

Reviewing building automation systems (BAS) can help managers further understand operation of the major energy-consuming system. This step is important because a large portion of the effort to optimize the operation of the building systems relates directly to how the building is conditioned and controlled.

Technicians also can use the BAS to test the operation of building systems in order to identify problematic energy-saving measures, such as faulty sensors or controllers, improper operation, and systems that have failed or are failing.

Analyzing a building's energy use. Benchmarking is a key step in evaluating energy efficiency. It gives managers a benchmark, and it provides hard data to take to top facility executives to build support for improvements.

One good place to start is with a review of the utility bills. The more utility bills managers can review the better. It is important to use these bills to understand the building's current energy consumption and, if possible, the trend of past energy use. Knowing where a facility was in terms of energy use, as well as where it is now, can help managers set goals for future performance.


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HVAC , chillers , maintenance

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