A Green Light for HVAC Efficiency
HVAC Installations Find New Ways to Incorporate Green Elements
Green projects are constantly underway throughout the nation and HVAC contractors have embarked upon a number of environmentally conscious efforts, showcasing innovative displays of green awareness that improve energy efficiency and are cost-effective.
A project completed by UV Resources in March 2012 at BayView Corporate Tower in Fort Lauderdale, Florida, included a UV-C lamp system for two cooling towers, three chillers (250, 430, and 750 ton), and 24 air-handling units (two per floor). The objective of the project was to provide tenants with cleaner, healthier air through modest upgrades to the building’s HVAC systems while also saving energy, reducing maintenance costs, and extending equipment life.
The BayView Corporate Tower, which was built in 1973 and houses 13 corporate tenants utilizing 412,000 square feet of space, chose to install the RLM Xtreme fixtureless UV-C lamp system in an effort to improve the 12-story building’s HVAC systems.
“There are many benefits of UV-C,” said Miki Minic, chief building engineer. “Most important is the improvement to IAQ levels so tenants enjoy cleaner, healthier air. Absenteeism due to the spread of unsafe microorganisms via HVAC systems is almost eliminated. Moreover, equipment life is improved; and downtime and preventive maintenance expenses, like cleaning the coils, drain pans, and the purchase of coil and drain treatments, etc., are significantly reduced.”
The building’s air-handling units were 25 years old and offered limited access to the evaporators. The UV-C lamp system retrofit was completed in four days by two installers. The UV-C project reduced enough energy use to pay for the upgrade in just three months and showed a reduction in both fan and refrigeration system energy consumption.
Bunnie Willis, senior property manager of the BayView Corporate Tower, said: “Following my research and meeting with other commercial property managers who had UV lighting installed, I was sold on the technology’s benefits. Within one month, we saw an immediate reduction in our energy costs, which has remained consistent since the installation. I believe so strongly in this improvement that we are getting ready to do it at one of our other properties in Doral, Florida. We are very satisfied with the decision to install the UV lighting.”
Houston DoubleTree Hotel
Houston-based Goes Heating Systems came up with an interesting solution to an energy-efficiency problem at a Houston DoubleTree Hotel in March 2013.
Hilton Worldwide, operator of the American DoubleTree hotel franchises, developed sustainability goals in 2009 to reduce energy consumption, carbon, and waste output by 20 percent within four years. As one of the hotel chain’s largest energy users, the Houston DoubleTree set out to meet those goals. Goes Heating approached the DoubleTree with a solution to energy-consumption concerns and a way to meet those lofty sustainability goals: an HVAC system that took advantage of newly available hydronics technology to “substantially reduce the heating energy requirements for the hotel,” said Jason Geagan, system designer, Goes Heating.
To comfortably heat all the hotel rooms throughout the morning, the hotel’s boilers needed to maintain a consistent operating temperature. In the afternoon, the boiler shut down as the cooling system engaged. The heat was then stored in the system and left to dissipate and essentially be wasted. A Caleffi HydoCal™ hydraulic separator was installed. The separator partitions the flow of heat on the source side, or supply side, from the load or heat distribution side. It then ensures the two sides don’t affect each other. The hydro-separator also protects the system from both dirt and unwanted air, thereby reducing installation costs and maintenance expenses down the road.
“I don’t think [natural gas usage] was as much of a hot button [issue] in 2013. The world is changing, and we have to keep up with that change as we do business with these Fortune 500 companies,” said Jim Mullins, employee, DoubleTree.
The case study is part of Eneref Institute's "Sustainable Hydronics" initiative to increase hydronics efficiency.
AdvancED Global Headquarters
Another project in the Southern U.S. highlighted how rainwater can positively impact rooftop air conditioning systems.
Two companies — JE Dunn Construction Group Inc., Kansas City, Missouri, and McKenney’s Inc., Atlanta — came together in late 2012 for modifications to three Trane Intellipak packaged rooftop air conditioning systems: a 60-ton unit and two systems offering 40 ton of cooling capacity at the AdvancED global headquarters in Atlanta. The objective was to achieve U.S. Green Building Council (USGBC) Leadership in Energy and Environmental Design (LEED)-Gold certification for use of the latest green products and materials, eco-friendly building designs, energy conservation techniques, and state-of-the-art technology including rainwater applied for energy reduction on a commercial scale.
Gregory Jeffers, senior project engineer with Atlanta-based McKenney’s Inc. — the commercial mechanical contracting firm chosen to handle the design/build aspects for the project’s plumbing and mechanical installations — specified an indirect system — an installation that now increases the energy efficiency of the air conditioning systems by about 15 percent. The rooftop units were modified to include metal-framed screen/filter-media membranes at condensing unit intakes. Each of these units is served with an attached spray nozzle. When condenser fans draw air into the large A-frame coils, the spray nozzles deliver a fine mist into the mesh screens. Moist, cooler air contacts the refrigerant coils, lowering the power draw from the compressors. Before delivery to the spray nozzles, rainwater is filtered to eliminate debris and also run through UV treatment to neutralize biological contaminants.
“The initial plan for HVAC systems at AdvancED called for small chillers, a cooling tower, and fan coil units,” said Reed Thomas, preconstruction director, JE Dunn. “But, thanks to the successful use of the coil-cooling technique at South Face’s headquarters building, and at McKenney’s own facility, we were excited to recommend coil cooling as an option to the far-more-expensive initial plan.”
“What we’re especially pleased with on this job, beyond the use of harvested rainwater for irrigation, is the link between rainwater and energy efficiency, said Eddie Van Giesen, policy director for BRAE, a Watts Water Technologies Co. “The use of rainwater to cool HVAC coils is something we should see much more use of here in the South, where cooling loads are so high. It’s an application with huge energy-saving potential.”
Guthrie Green Arts Complex
Efficiency on a large scale was the motivation behind a project at Guthrie Green, a public green space and arts complex in Tulsa, Oklahoma, in the fall of 2012. ClimateMaster Inc. installed 74 geothermal heat pump systems, a 200-ton closed-circuit fluid cooler, 120 500-foot-long geothermal boreholes, and 250 energy-efficient LED lights. The overarching goal of the project was to create a green, central gathering space for the blossoming Brady Arts District in downtown Tulsa. In 2009, the George Kaiser Family Foundation engaged Creative Community Builders, Minneapolis, to work with The Brady Arts District to help guide the development of the park and to inform the cultivation of commercial residential and nonprofit projects in the neighborhood.
Plans for the Guthrie Green project were unveiled in 2010. In addition to its example as an urban re-use project, Guthrie Green also serves as a testament to sustainability with numerous green and renewable elements incorporated into its design. A field of geothermal boreholes was drilled prior to the above-ground construction, which ties into a hybrid system of ClimateMaster geothermal heat pumps and a ground-mounted cooling tower that serve as the main mechanical systems for the Tulsa Paper Co. and Hardesty Arts Center buildings on the site. The geothermal borehole field, which is organized into 15 operating circuits, provides 600 ton of heating and cooling to both buildings, with the capability of reducing heating and cooling costs by approximately 60 percent.
“The 600 ton from the geothermal field is supplemented with a 200-ton closed-circuit fluid cooler, which was incorporated into the overall system design when taking the peak demand of all four end users into account,” said Justin Roush, project manager, Flynt & Kallenberger Consulting Engineers. “Each of the tenants has a water-to-water heat exchanger that enables them to use the loop water on one side while keeping their individual systems separated. That way, if they wanted to create chilled water or put equipment on the roof and use glycol, these elements can’t ultimately end up in the main loop water.”
Roush went on to say “they [ClimateMaster’s Geothermal heat pumps] have been up and running since the fall of 2012 and are functioning extremely well. In total, the borehole field supplies efficient heating and cooling to about 80,000 square feet of land. I consider the end result to be a success.”
Publication date: 9/29/2014