Arden Engineering Constructors used the Belimo Energy Valve™ to reduce chilled water demand in existing buildings so that Providence College would have sufficient capacity to accommodate new developments on its lower campus. As a result, the college avoided buying a new chiller and the extensive excavation to replace existing chiller lines—all while increasing energy efficiency.
Growing Pains
Founded in 1917, Providence College sits on an illustrious 105-acre campus in the heart of Providence, R.I. Since its inception, the campus has evolved and expanded to meet the needs of its enrolled base, which has grown to more than 4,000 students. For example, the college’s Campus Transformation initiative seeks to create a more unified, sustainable, functional campus. As part of that transformation, in 2013, the college purchased Huxley Avenue from the city so that the campus would no longer be bisected by a busy street, offering enhanced freedom of movement for both pedestrians and drivers.
Running beneath one of the recently renovated sections of the school, 12” chilled water lines provide cooling to several buildings on the lower campus. With additional buildings set to come online in the next two years, these lines and the central chiller plant are inching closer to full capacity.
One solution discussed by Providence College and Arden, its main mechanical and controls contractor, involved adding more capacity with the installation of a new chiller. However, this approach would require increasing the size of the chilled water line to handle the higher flows. An alternative was to reduce chilled water demand in existing buildings.
A Simpler Solution
Reducing demand for chilled water on the lower campus would effectively create spare capacity in the chiller plant and reduce water flow through the main line. In doing so, Providence College could forgo the installation of a fourth chiller (the plant already had three 1,000-ton chillers running in parallel). Moreover, the main line would not have to be excavated and replaced, which would have been a significant undertaking.
With around 20 Energy Valves already installed on campus, Arden and Providence College had an established relationship with Belimo and were familiar with the company’s range of products.
“Our plan was to essentially pick off the sections of the lower campus where the demand for chilled water was highest,” said Paul Carter, general manager at Arden’s sister company, Earthwise Energy Technologies, the controls contractor on the job. “Some of the technology in these buildings was very outdated and due for an upgrade. Having seen the advanced capabilities of the Energy Valve first-hand, we were confident it would be able to generate the flow savings we were looking for.”
The Energy Valve is a web-enabled, pressure-independent valve that measures and manages coil energy by using an embedded ultrasonic flow meter, along with supply and return water temperature sensors. With built-in power control and Belimo Delta T Manager logic, the Energy Valve monitors coil performance and optimizes available energy by maintaining delta T.
A key advantage of the Energy Valve is that the delta T setpoint can be matched to the design delta T of the coil. As the temperature sensors start to realize a lower differential temperature across the coil, the valve begins to close and the flow decreases, allowing for more efficient heat exchange and elimination of overflow. When delta T begins to stabilize, the valve increases flow back through the coil, thus maintaining optimal heat transfer.
The Energy Valve comes equipped with a suite of cloud-based services that can be used to benchmark coil performance, analyze glycol concentration, store energy data, send alerts, and commission for optimal performance. In addition to the standard analog signal and feedback wiring, the Energy Valve communicates its data to the building management system via building automation and control network (BACnet) master-slave/token passing (MS/TP) protocol or internet protocol (IP) as well as Modbus remote terminal unit (RTU) and Modbus transmission control protocol/internet protocol (TCP/IP). The built-in web server collects up to 13 months of data that can be downloaded to external tools for further optimization.
After careful evaluation, the decision was made to install 22 additional Energy Valves across the lower campus—with sizes ranging from ¾” to 2½”.
Significant Savings Anticipated
The retrofit project was completed in spring 2023, and now Arden and Providence College plan to begin collecting data to quantify the actual flow reductions. The reduction in pumping will lead to decreased electricity usage, which is in line with the college’s commitment to increase energy efficiency and improve environmental, social, and governance performance.
By allowing their cooling needs to be met with the existing chiller plant configuration, the school saved the cost of buying and installing a new chiller, amounting to an estimated $500,000-$1,000,000 in savings. This figure excludes the millions of additional funds and months of work that would have been needed to resize and replace the existing main chilled water line.
“While the construction of new buildings in the coming years may ultimately necessitate the installation of a new chiller, the Energy Valve will allow us to push that project further into the future and significantly increase the efficiency of the existing system,” said Matt Basile, lead design engineer for Arden.
Download Belimo’s Energy Savings Estimator to illustrate the annual dollar and energy savings you can expect by installing an Energy Valve: https://www.belimo.com/us/en_US/products/valves/product-documentation/energy-valve.
Basile continued, “Every Energy Valve we install gets a data connection to the cloud and to the campus central building management system. This provides us with visibility down to the individual air handlers, which is crucial for troubleshooting and identifying further opportunities for efficiency gains as we move forward with future capital improvement projects. It is now standard practice to flat spec the Energy Valve for any chilled water device over 10 gallons.”
Successful Track Record
The Energy Valve retrofit is one of several instances over the past three years in which Belimo, Arden, and Providence College have worked collaboratively to conserve water usage and drive energy efficiency.
“Belimo has a long-standing relationship with both Arden and Providence College and is proud to once again be part of a project that will help the college achieve its goal of creating a more efficient and sustainable campus,” said P.J. Qvarnstrom, RetroFIT+ business manager at Belimo. “We are eager to see the results of this Energy Valve retrofit and look forward to supplying cutting-edge technologies for future projects.”
In addition to the lower campus chilled water line, two other main lines come from the central chiller plant and provide cooling to separate sections of the Providence College campus. With additional buildings planned for these sections, the lower campus retrofit will serve as a demonstration project and may potentially pave the way for additional Energy Valve installations in the coming years.
“Belimo’s track record of providing superior products and service has fortified our professional relationship and made them a preferred supplier to the college,” added Steve Basile, supervisor of engineering at Providence College. “We look forward to leveraging innovative products like the Energy Valve in the future as we drive to continuously improve the efficiency of our facilities across campus.”
For more information, visit www.belimo.com.
