Building owners have a continual challenge of being able to maintain their buildings. From government agencies with numerous facilities to individuals or groups of people with only one building, the need to be on the cutting edge of the latest technologies for energy conservation while maintaining a quality indoor environment is essential.

Sustainable, highperformance buildings are at the fore front of new construction. Unfortunately, for the end use facility maintenance person, keeping up with the latest and greatest ideas for high performance buildings can present new challenges.

For many years, facility groups have attempted to standardize lighting, electrical gear, plumbing equipment and mechanical systems in an effort to stay on top of maintaining facilities. If the end-use maintenance person understands what the maintenance requirements are, there is a better chance that proper maintenance will take place. Many maintenance departments have an efficient process for things like air handling equipment filter change, bearing lubrication, winter drain downs, etc.

Too often, the maintenance process is reactive rather than preventive. Occupant complaints usually trigger a process whereby spaces that do not heat or cool correctly get maintenance attention. Roof leaks or plumbing leaks, for obvious, reasons fall into this category. There are however, many things that go unnoticed that may have major impact on the energy use/bills. For example, variable speed drives may not modulate like they should, occupancy schedules are lost from the building management system, erroneous outside air control signals, excessive air handler run times, non-important spaces dictating air handler control points, unnecessary simultaneous heating and cooling, etc. could slip under the radar and cause major problems.

With so many components required for mechanical and plumbing systems to operate efficiently, how does a maintenance staff stay on top of things, especially those that are not obvious to the building occupants or discovered by routine maintenance?

Staying in touch with the energy use/cost is a good way to discover problems that otherwise can go undetected.

• Establish a baseline monthly energy cost for each meter
• Review patterns and profiles
• Determine whether sudden differences are explainable
• Utilize the BAS to watch building space temperatures
• Adjust seasonal cooling to billing cycles
• Make sure modulating equipment actually modulates
• Make sure outside air is adequate, but not excessive
• Establish a way to turn things off

As previously mentioned, many times there is a disconnection between how the energy bills get paid and communication of concerns to the maintenance department. It is hard to prevent excessive energy use if you do not know where to start looking. In an ideal world, we could just change filters, lube the bearings, and assume that a complaint or work order will identify any other issues; but routine maintenance and responsiveness to complaints will not always find the smoking gun or hidden treasure in the energy bills. A watchful eye and basic knowledge of what to expect will help find both.

Most buildings have some way of establishing both energy use and cost; even campus situations served from central plants generally have some means of determining individual building use.

Establishing a baseline monthly energy cost for each meter is essential. If you do not know what you expect, you may not know that you are using and paying for more than is needed. If an owner has multiple buildings, he or she can compare one to another to help identify a target energy use profile. No two buildings will have equal characteristics, even if they are quite similar buildings. However, they usually share enough common ground to make some basic comparisons. Many times, differences can be explained intuitively; for instance, building age, orientation, operating hours, lighting strategies, and mechanical systems can play a role in the baseline energy.

Comparing similar buildings? energy use is a valuable tool but does not always tell a story. One thing you can count on is that you can always compare a building to itself. New buildings can be misleading. Sometimes the fine tuning/debugging process takes a while, or occasionally the building needs to go through all four seasons to get the bugs worked out. A formalized commissioning effort may minimize the problems, but some things cannot be totally replicated until real conditions exist.

Once the expected baseline is established, each monthly energy statement can be compared to the previous month and eventually to the same month of the previous year. If differences cannot be explained in these monthly statements, look deeper! Abrupt changes can be an indicator of a problem that needs attention, but they may not be obvious to the building users because they are disguised by a comfortable building with no complaints or obvious problems.

There are many problems that could be avoided if the time were taken to analyze monthly differences. Paying attention to space temperatures can help zero in on problem spaces that never reach a set point, especially if they are not critical spaces. Depending on the type of HVAC system, faulty temperature readings can cause an entire area of the HVAC system to run unnecessarily all day every day.

Depending on the building rate structure, knowing the billing cycle can occasionally be utilized to save the spike in demand charges by keeping mechanical cooling off in the early spring and turning it off in the late fall for only a few days. Obviously this can only be effective if appropriate space temperatures can be maintained, so watching the building temperatures and being familiar with how the building reacts to expected weather conditions is necessary.

Today?s buildings employ variable speed drives on most fans and pumps. In addition to periodically changing their filters, which is necessary to keep them running properly, trending each variable speed drive to make sure it is actually modulating can be a valuable tool. If the variable speed drive is running higher than needed, energy is used unnecessarily. Often new projects are left with variable speed drives being set to satisfy a worst-case balancing need rather than adjusting to the actual building needs, causing them to run that way for the life of the building. A close eye on resetting duct pressure, pump pressure and space temperature can be used to determine the minimum motor speed needed to satisfy building conditions.

Outside air is essential to provide ventilation for building occupants, make-up air for building exhaust, building pressurization and, in many cases, free cooling. Adequate outside air is needed to maintain proper indoor air quality. A popular strategy for reducing outside air is demand-controlled ventilation that senses carbon dioxide (CO2) either directly in the space or in the return air and reduces the amount of outside air when it is not needed. A watchful eye on CO2 sensor calibration and an expectation of how much outside air is needed can ensure good indoor air quality without using excessive energy. Outside air should never be closed off during occupied hours.

Something that has always held true is that the most effective strategy for saving energy is to turn things off. Lights and equipment that are turned off do not use energy. Proper illumination, thermal comfort and ventilation should not be sacrificed to save energy cost, but a close eye on diligence of turning things off pays dividends.

Incorporating energy bills into the preventative maintenance plan can not only help identify potential energy savings, but also help with corrective action on things that might otherwise go undetected.

A Principal of VBFA, Wade Bennion has over 30 years of engineering experience. He is known for his energy-efficient designs and for his excellence in client relations.