Energy-Saving Opportunities

One particularly interesting session at the ASHRAE Winter Conference focused on how replacing or retrofitting rooftop units (RTUs) can result in significant energy savings. In “Advanced RTU Campaign: Accelerating Efficiency,” speakers discussed how contractors can help commercial building owners and operators evaluate their stock of RTUs, then encourage them to replace older units with high-efficiency ones, or else retrofit them with advanced controls that can help save money and energy.

Aging RTUs are considered a prime target for saving energy, said Amy Jiron, commercial buildings integration team, technology deployment program, Department of Energy (DOE), given that in the U.S. packaged units condition 40 billion square feet of commercial building floor space and consume 2,100 trillion Btu of primary energy annually. “Many RTUs are past their typical life span, functioning at much lower efficiency levels than new units, and are ready to be replaced.” As such, the DOE, along with industry partners, has issued the RTU Challenge, calling for the increased market adoption of highly efficient RTUs, with a goal of replacing 1,000 units in 2014.

This is the perfect time to think about replacing RTUs, said Dr. Michael Deru, section manager, National Renewable Energy Laboratory (NREL), as there is a large stock of aging equipment that is between 6-18 years old. Contractors who help owners and managers think proactively about replacing RTUs that are over 10 years old will help customers avert costly emergency replacements, allowing time to plan for energy-efficient upgrades.

And replacing an RTU can result in significant energy savings, said Deru, who gave an example of a 10-ton RTU that is 15 years old and runs an equivalent 3,600 full load hours per year in New York, where the average electricity rate is 15 cents per kWh.

“By now, the EER has degraded to 7.3, and it will cost almost $9,000 per year to run that unit. If we put in an 11 EER unit, it’s only going to cost $6,000 per year to run it, so right off the bat there will be a savings of $3,000 per year. In addition, a new unit will phase out R-22 in a building’s inventory, reduce maintenance costs, and usually provide better comfort, especially if a variable-speed unit is installed.”

Another seminar at the winter meeting focused on how a building’s façade can play an important role in energy savings. In “The Façade Odyssey: Solutions for Design of High-Performance Buildings,” speaker Kent Peterson, P.E., P2S Engineering Inc., Long Beach, Calif., noted, “Façade design is a vital aspect of buildings, largely controlled by architects as per wishes of building owners. However, based on green building design experience, it has been found that façade optimization can help reduce as much as 40 percent of building energy.”

Speaker John Swift Jr., P.E., Cannon Design, Boston, discussed the latest developments in high-performance façades in North America, including the use of simulation tools by integrated design teams to perform extensive and detailed analysis, while speaker Ashish Rakheja, P.E., COO, Spectral, New Delhi, India, focused on double façade, phase-change-materials, and green walls.

ASHRAE’s free public session also focused on energy efficiency. In “Trends in Building Energy Disclosure: Increasing Energy Efficiency Without Retrofits,” speakers discussed alternative approaches to saving energy, such as harnessing data from smart meters in order to provide feedback to building occupants on their energy consumption. As Dr. Rishee K. Jain, Center for Urban Science + Progress, New York University, noted, “Energy use reporting and open data have been shown to impact market behavior and drive energy efficiency in buildings.”

Jain described two tests that were developed to measure whether social influence could impact energy consumption behavior, and the results for both tests proved that point. As he explained, “Eco-feedback provided building occupants with information on energy use in their buildings and in others, so occupants could see how their energy use might compare to their neighbors — whose buildings might be more efficient.”

One of the challenges of this model is figuring out how to do it on a large scale, said Jain, but preliminary results suggest that social influence and network dynamics can be used as a tool to help manage energy consumption in buildings.

On the Floor

At the AHR Expo, energy-efficient products lined the aisles, including Trane’s new TruComfort system, which has the ability to change to over 700 speeds, saving energy and improving comfort. “TruComfort runs at the lowest output possible to meet the needs of the home, so its overall energy efficiency improves as the capacity output of the system lowers,” said Matt Barga, portfolio leader, air conditioners and coils, Trane.

Barga explained that as energy costs rise, consumers are increasingly interested in products that can deliver energy efficiency at a price point they can afford. “Trane has positioned TruComfort in the 17-21 SEER space, which enables a cost-effective, variable-speed solution that also delivers the ultimate in comfort. Many consumers have issues with hot and cold spots or high humidity in their homes, and the appropriate application of TruComfort variable-speed technology can address those comfort issues, as well as deliver energy efficiency.”

On the commercial side, Bell & Gossett introduced the Series e-1510 base-mounted, end-suction centrifugal pumps, which are designed for use in hot water heating and chilled water cooling systems. The pumps have been redesigned to optimize pump efficiency and offer a larger efficiency island that keeps the pumps operating at a high efficiency level over a broad range, said Mark Handzel, vice president, product regulatory affairs, and director of HVAC & commercial buildings business unit, Xylem.

“Building owners are becoming increasingly interested in energy-efficient products such as the Series e-1510, because they are looking to reduce what they spend on operating costs,” said Handzel. “In addition, regulations are having an impact, as ASHRAE Standard 90.1 continues to require the design of new buildings be more efficient. Initiatives like DOE’s Better Building Challenge and similar programs in cities throughout the U.S. are also forcing building owners to seek ways to save energy.”

Incentive programs are also driving interest in energy-efficient equipment, said Mark MacCracken, CEO, Calmac. “California has just put in place an incentive program for permanent peak-load reduction in buildings, which is what we do. Essentially, instead of creating the cooling instantaneously, like most buildings, we’re creating the cooling at night, so it is possible to separate when cooling is needed from when cooling is created.”

MacCracken likens the process to making ice cubes for a party. “You’d never consider starting to make the ice cubes when people walk in the door for the party — instead, you’d make them the night before. A building needs 200 times as much equivalent cooling per person as the amount of ice required for a person at a party, so it makes no sense to instantaneously cool a building and act like you don’t know people are coming. Creating the cooling at night is more efficient and much less expensive. It’s just a smarter way to cool a building.”

Whether attendees at the AHR Expo and ASHRAE meeting were looking to save energy in their homes or offices, they came to the right place to find the products and solutions that can save them money while keeping them more comfortable.

Publication date: 3/17/2014 

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