High-performance buildings exemplify the effectiveness of HVAC energy-efficiency retrofits
achrnews.com, July 17, 2017
HVAC systems in commercial buildings consume a lot of energy, which is why many building owners and managers are looking at replacing their older, inefficient equipment with new high-performing systems. The buildings discussed below offer a good representation of the types of energy-efficient retrofit projects that are currently taking place across the country.
BETTER BOILERS
A failing steam heating system posed many issues and challenges for facility services at Cornell College in Mount Vernon, Iowa. Retrofitting campus buildings with high-efficiency condensing boilers provided the solution needed for improved heating at the school.
Installed in the late 1800s, the original Cornell College heating system consisted of a steam central plant that supplied all of the buildings on the university grounds with steam heat. Originally using coal, the school’s boiler plant was converted to gas in the 1960s. Three 350-horsepower, gas-powered steam boilers handled heat for the entire campus.
Because of the age of the equipment, repairs were commonplace, and the old boilers and infrastructure from steam piping and condensate piping had deteriorated.
“We were experiencing numerous faults with our in-ground steam lines and constant maintenance work on the steam boilers,” said Joel Miller, director of facility services for Cornell College. “The steam lines were rusting, which required repairs from building to building.”
The decision was made to install more cost-effective high-efficiency boilers in campus buildings, and Pipe Pro Inc. in Cedar Rapids, Iowa, was selected to work with Miller to take the college off of the central steam plant and convert each building to a stand-alone high-efficiency boiler system with remote operation.
One of the first retrofit projects took place in the residence facility, Olin Hall, where the team installed five Weil-McLain Ultra® 550-MBtuh high-efficiency condensing gas boilers. Three units were configured as the main heating boilers, while the other two were set up for domestic water. As part of the retrofit, thermostats were installed in each student’s room, so they could regulate the temperature for optimal comfort.
The West Science Center also received an upgrade, and the team sought to replace the existing heat exchanger with a boiler that would fit into the same space. Two Weil-McLain SlimFit 750 Series gas boilers filled the bill and were installed in the building’s mechanical room. The building already had a steam-to-hot water converter, so the team installed new T’s off of the header and then connected the boiler. The building’s original pumps, piping, and plumbing were used for the retrofit.
In total, Pipe Pro completed eight boiler conversions at the campus. The boilers are configured to control each building individually and are connected through a web-based system for monitoring and control. Miller reported that students and teachers are extremely pleased with the climate of the classrooms and residences. “My phone does not ring as much since the changeouts,” he added.
NEW CONTROLS
With an enrollment exceeding 41,000 students, Kent State is one of the largest universities in Ohio. Being such a large school, energy management is very important, and much care is taken to ensure that every energy dollar is used as efficiently and cost-effectively as possible. To that end, the school asked Magnum Energy Solutions to devise an energy-efficiency strategy that would involve energy conservation, education, sophisticated building automation systems (BAS), and other new technologies, such as motion sensors and programmable thermostats.
That strategy has been successful, thanks in part to new BAS from Magnum, which has allowed Kent State to reduce its dorm room energy consumption by nearly 22 percent. To date, the technology has been included in 4,250 dorm rooms, which amounts to more than 22,000 wireless points of control on campus. The dorm rooms on campus have occupied/unoccupied control, a central access control for the HVAC, and full monitoring capabilities. The devices in the dorm rooms include wireless, battery-free motion sensors, wireless thermostats, controlled power strips, and window sensors.
The new dorm room controls solution from Magnum requires limited maintenance as there are no batteries to replace. This means that Kent State will save more than 300,000 batteries in the course of 20 years. The installation of the wireless solution also saved the university considerable money due to the system’s simplicity.
In an effort to be proactive with the latest technology, Kent State is also upgrading its HVAC and lighting controls throughout all of its dorm rooms to the latest 902-MHz frequency controls. These high-performance devices will now allow residents and personnel at the university access to low power usage with the wireless network reaching to the longest indoor wireless communication range possible with current technology.
A CASE FOR VRF
Originally built in 1872, The Foundry in Providence, Rhode Island, has a rich history dating back more than a century. Once the former manufacturing campus of industrial powerhouse Brown & Sharpe, the 13 brick buildings located on 26 acres at the edge of the downtown area have been restored into a mixed-use complex.
In the middle of the sprawling complex is the Sharpe Building, which served as a mill during the building’s manufacturing years. The goal for the renovation of the 157,500-square-foot, six-story building was to develop 196 loft-style luxury residences. Placed on the National Register of Historic Places in 2003, the Sharpe Building required a renovation that upgraded the functionality of the building while maintaining the historic design.
As far as the HVAC system was concerned, the project team wanted equipment that was energy-efficient, aesthetically pleasing, and as quiet as possible. The project’s mechanical contractor, Rumford, Rhode Island-based Peregrine Mechanical Inc., turned to Trumbull Campbell Associates to help them design an efficient solution that would allow for individually controlled heating and cooling in the building’s mix of metro, studio, and one- and two-bedroom units.
After carefully reviewing the requirements, Trumbull Campbell Associates recommended installing the LG Multi V™ IV variable refrigerant flow (VRF) heat recovery system. Using the VRF system would preserve the architectural integrity of the historic building while addressing space considerations by running small refrigerant lines throughout the building without using bulky ductwork.
In addition to the small refrigerant lines and compact equipment, the Multi V IV does not require a large mechanical room, so the Sharpe Building was able to repurpose that space for a gym and a theater for residents. On a large portion of the roof that would have been occupied by conventional HVAC equipment, the Sharpe building created an outdoor space overlooking downtown Providence for the residents.
To create a comfortable and appealing indoor environment, the Sharpe Building features a mix of indoor units, including ceiling cassettes and wall-mounted units, depending on the location. Selected for their minimal noise levels, the indoor units provide precise temperature control while operating library-quiet.
By using individual zones, the Multi V IV systems only engage when there is enough demand and then balance the load requirements across all spaces to use energy more efficiently. The system provides further energy efficiency through the heat recovery feature as heated return air is redistributed to the zones that need it rather than heating new air.
According to the building owners, the VRF system has helped the Sharpe Building experience significant cost savings per square foot since opening in 2015.