3 FM quick reads on energy conservation
1. Facility Policy Practices for Good IAQ
Sometimes a facility's HVAC system has remained largely untouched since it was installed 30 years ago. To help ensure the quality of the facility's indoor air, newer mechanicals might be a big help. But there's a lot you can do by making sure vintage mechanicals are not being operated under equally vintage policies.
First, review current energy conservation programs. Many energy conservation programs were started before concern over IAQ arose. One practice, indiscriminately closing outside air dampers, should be discontinued immediately.
In addition, the benefits garnered from energy-saving measures such as duty cycling, load shedding, raising chilled water temperatures and reducing hot water temperatures, should be evaluated in light of their effects on the indoor air environment.
Continuously document the operation of the HVAC system. Because the HVAC system acts as the lungs of the building, it is important to verify and document its operation periodically. Often HVAC system and component technology can assist in accomplishing this goal. For example, with air flow monitoring technology, it is possible to track the amount of outdoor air delivered down to each zone.
Also, develop an ongoing training program for building personnel. System operators and building managers need to be kept up to date on proper IAQ and their IAQ responsibilities. Trade journals, books, seminars and consultation with IAQ professionals are good starting points.
And last, don't be afraid to publicize proactive IAQ efforts to building occupants and potential tenants. A building's good IAQ is a market asset. Creating a newsletter, tweeting or updating the department's Facebook page to inform occupants and potential tenants on the latest IAQ developments and your building's IAQ program are some ways to capitalize on this asset.
2. Energy Model Can Improve HVAC System Energy Efficiency
Today's tip from Building Operating Management: Energy models are valuable in achieving high performance HVAC designs.
How efficient can a building's HVAC system be? To a very large extent, the answer depends on other factors in the building. The type of windows, the amount of insulation, the lighting system, the reflectivity of the roof — these factors and others like them can constrain the performance of the HVAC system by requiring it to work harder to heat and cool the building.
Today, it is possible to evaluate the HVAC impact of these other elements while the building is being designed. Powerful energy modeling software, available from a range of sources, enables the design team to estimate just how efficient a given set of design choices is, and then to compare other designs to identify the one that best meets the building owner's requirements.
For example, Option A may involve code-minimum insulation, ordinary insulated glass windows and a non-reflective roof. Option B, with more insulation, low-emissivity windows and a reflective roof, may initially cost more, but pay for itself in energy savings. What's more, savings associated with a smaller HVAC system can free up funds to cover the cost of those added efficiency measures. In some cases, the energy model may identify options that actually reduce the first cost of the project.
The use of an energy model is required to obtain federal tax deductions under Section 179D of the Internal Revenue Code. These are also known as EPAct tax deductions for the Energy Policy Act of 1995. To qualify for a deduction, an HVAC project must reduce energy costs at least 16.67 percent below the costs for a building designed to meet ASHRAE 90.1-2001. Energy modeling has to show the energy cost savings.
It's important to keep in mind that the energy model, as important as it can be at the design stage, is only an estimate. The actual energy efficiency of a building will depend on how the building systems are operated. A well-designed building can't overcome poor operation.
3. High-Performance HVAC System Requires an Integrated Design
Today's tip from Building Operating Management comes from Jeffrey Heiken, engineering design principal with Kling Stubbins: A high-performance HVAC system requires an integrated design.
Designing a high-performance HVAC system starts with understanding its end goals. It effectively serves the functional needs of the building and its occupants. It minimizes the use of resources by accurately "right-sizing" components and configurations. It is flexible in response to changes in use. And it employs design elements to capture waste heat, reduce material or energy use, or reuse materials wherever possible.
Across the spectrum of building types, high-performance HVAC systems provide more pleasant and satisfying work environments, and efficiencies which translate into lower owning and operating costs.
But a high-performance HVAC system is impossible without a truly integrated design team fully engaged and focused on project goals from the start. That's because so many aspects of design are interrelated and have to be considered simultaneously to achieve the goal of a high-performance HVAC system. For example, the HVAC design is affected by sustainability elements like daylight projection into the building, which helps drive building footprint and building aspect ratio (length to width dimensions) as well as solar orientation on a site. Daylighting also brings consideration of external shading devices and internal reflective light shelves to prevent glare and heat gain while bringing natural light to the occupied spaces. Internal shading (often mechanized and automated) in concert with computerized lighting control systems are also common energy conservation measures. With all of those factors affecting the HVAC design — not to mention the exterior wall construction, glazing, occupancy and utilization — it's clear that an integrated design approach is essential. From building siting to building envelope composition, the performance of all elements is enhanced.
HVAC can't be an afterthought once the shell of the building has been designed. Compared to the overall building life, the design process is brief and often fast-paced. Attention to HVAC performance at the earliest steps will be felt for decades. So will a lack of attention.