4 FM quick reads on
1. Benchmarking software can reduce energy use
Today's tip is to look at software-based benchmarking to improve energy efficiency. As sustainability and high performance green buildings gain momentum across the building industry, new tools continue to enter the market. Software-based benchmarking, energy dashboards and energy analytics can help meet green-building goals.
Benchmarking compares measurements against a standard, average or best practice to improve current practice. Although it can use a spreadsheet, software benchmarking tools provide some benefits: a database of buildings with similar characteristics is easily available, and it is not necessary to be an energy engineer to understand the process.
Two publicly available Web-based benchmarking tools are Energy Star Portfolio Manager and EnergyIQ. Portfolio Manager was developed by the U.S. Environmental Protection Agency and can be used to benchmark energy and water consumption at the whole building level, as well as to calculate the carbon footprint. Portfolio Manager produces a score from zero to 100 that compares the energy performance of a specific building to other similar buildings. Buildings receiving a score of 75 or greater can be recognized as Energy Star labeled.
EnergyIQ is a free, online benchmarking tool developed by the Lawrence Berkeley National Lab. EnergyIQ provides ways to quickly develop standardized graphs to compare whole-building-level and system-level energy performance. EnergyIQ can be used for more detailed benchmarking analysis than Portfolio Manager. Thus, it can be used to identify and prioritize energy efficiency opportunities.
"Benchmarking shines a spotlight on which buildings are not performing as efficiently as they potentially could," says Tom Reinsel, coordinator, energy management, at Fairfax County Public Schools. He says that benchmarking information can be used as a road map to help determine how to get the most energy savings with the least investment and time. For schools, with a wide range of design types, the most useful benchmark is thousands of British thermal units per square foot per year.
It is often possible to quickly determine the overall performance of the building, but remember what energy sources are used. For example, buildings that use electric resistance heating or hot water heat will create unequal comparisons. Unique characteristics must be carefully noted and addressed properly when comparing different buildings. As the weather varies annually and during the year, it is important that benchmarking data be normalized.
2. Security Film Offers Options For Windows
Today's tip is to consider security film for windows. Window security film is very different from solar film. Though some security film will block solar radiation, its primary purpose is to prevent shards of flying glass from injuring occupants if the window breaks.
At 4 to 14 mil, security film is significantly thicker than solar control film, which is generally 1.5 to 2 mil thick. While solar control film is applied only to the part of the window that is visible, security film is installed into the window system itself by a process known as anchoring.
Two types of anchoring are available, known as wet-glazed and mechanical installations. A wet-glazed installation involves removing the rubber around the window from the gasket and replacing it with a structural silicon sealant that fills the space between the window and the frame. A mechanical attachment involves overlapping the film around the edges of the window and securing the film with bolts to an internal frame. Both methods are meant to ensure that the film will hold glass fragments together and to prevent the entire window unit from becoming dislodged and sent into a building’s interior.
Shattered glass can be a risk to buildings that may not be a target for a bomb blast, but are in the vicinity of a building that is. If a threat assessment shows high-profile targets nearby, applying security film to the windows might make sense to protect against residual blast effects.
The value of security film has been recognized by the federal government, especially after 9/11, says Daniel Leclair, a security consultant with SAKO Associates. "All government buildings have some type of window film or protective glazing on the windows," Leclair says. "The majority of federal buildings have wet-glazed film application as a requirement.”
Security film is also a recognized benefit in hurricane-prone areas like Florida. The Protecting People First Foundation studied the performance of window film during recent hurricanes. Among the findings: In one high-rise condominium, some windows were protected by 8 and 12 mil security film; others had no film. None of the windows that had film were damaged, while some unprotected windows did sustain damage.
Most manufacturers' warranties are for five to 10 years. Check not only the length of the warranty, but also whether it covers removal of any failed product and reinstallation.
3. Open Work Spaces Require Careful Noise Management
Today's tip is to minimize extraneous noise in open office settings. Many organizations have found that a more open environment, with movable partitions and plenty of meeting places, is more conducive to productivity than the permanent offices that prevailed 30-some years ago.
But openness means that employees are likely to be distracted by other employees' conversations, cell phones ringing, etc. To get the benefits of open office designs while minimizing distractions, a range of acoustical goals come into play, says Jeffrey Fullerton, director of architectural acoustics with Acentech. These include controlling the noise in common areas, creating some level of privacy and sound absorption for workers at their desks, and creating private rooms for confidential discussions.
It's easiest to achieve specific goals when the building is designed with acoustics in mind from the start, says Raj Patel, principal with Arup, an engineering and consulting firm. Otherwise, the costs to remedy any noise problems tend to spike.
When developing the acoustical environment, the acronym ABC comes into play, says Fullerton. That is, you want to absorb, block and cover sounds. Absorption requires what might be called passive tools, such as sound-absorbing ceiling panels. "It may be a greater cost initially, but it requires no maintenance or additional changes," says David Joiner, principal with JaffeHolden. Without sound-absorbing ceiling panels, employees' conversations and similar sounds will reflect off the ceiling.
Effective sound-absorbing ceiling materials will have an NRC, or noise reduction coefficient, of .85 or greater, meaning that they remove 85 percent of the sound bouncing off the ceiling. Fiberglass ceiling tiles with a painted finish tend to have NRCs that are about 25 percent higher than what mineral fiber tiles provide, says Thomas Trask, senior associate with Newcomb & Boyd. Fiberglass "is more absorptive at the same thickness versus mineral fiber."
To offer tiles that both block sound from the plenum and also absorb sound from offices below, some manufacturers are developing tiles that combine fiberglass and mineral fiber, Fullerton says.
Another situation where sounds need to be managed both from above and below is in open plenum spaces, where the bottom of the exposed concrete deck reflects sound. One solution is to incorporate sound-absorbing material into the design. Ceiling system manufacturers have developed products specifically for open plenum spaces.
4. Tankless Water Heaters Can Provide Big Savings
Today's tip is to consider tankless water heaters for energy savings. Water-heating systems in institutional and commercial facilities typically consume more energy than any other system except HVAC. As a result, even small gains in efficiency can lead to large savings.
More manufacturers are offering a range of new tankless water heaters — also known as instantaneous or demand systems — that provide hot water only when necessary.
Tankless water heaters use highly efficient technology to transfer heat instantly to cold water as soon as demand occurs. When a building occupant turns on a hot water faucet, cold water enters the inlet of the tankless heater and flows through a copper coil, energizing the burner to provide temperature-controlled hot water.
Fueled by propane or natural gas, tankless water heaters offer operating costs that are 30 percent lower than natural gas storage-tank units and 40 percent less than electric storage-tank units. They also require less space, and stored water does not have to be reheated.
An electronic ignition lights the gas burner without a pilot light, so no gas is consumed when the system is dormant.
The typical capacity of a tankless water heater is 2-5 gallons per minute. For larger-capacity systems, a manifold arrangement links units. Condensing technology captures any exhaust gas heat and returns it to preheat incoming cold water, thereby increasing thermal efficiency to as high as 98 percent.
One new electric coilless, tankless heater comes with a rating of 2.5 gallons per minute at a 45-degree temperature rise or 1.7 gallons per minute at 65-degree temperature rise. Voltages for tankless water heaters range from 110 volts to 277 volts.
The necessary size of a unit depends on the user's water flow and the required temperature rise. Typical utility water is 60 degrees, and the typical desired temperature for hot water is 100-120 degrees. In this case, the temperature rise required would be from 40 degrees to 60 degrees. If the water heater serves a kitchen sink with a water flow of 1.5 gallons per minute, then the heater's required capacity is a maximum of a 60-degree rise at 1.5 gallons per minute.
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