Submitted by Arden Building Companies
Providence College (PC) sits on a 105-acre campus in Providence, R.I. The campus has evolved and expanded to meet its enrollment needs, now over 4,000 students. In 2013, PC began the Campus Transformation Initiative, a plan to create a more unified, sustainable, and functional campus.
Beneath the recently renovated sections of the school are 12-inch chilled water lines, which provide cooling to several buildings on the lower campus. With additional buildings set to come online in two years, these lines and the central chiller plant are close to capacity.
One solution discussed by PC and its longstanding mechanical and controls contractors, Arden Engineering Constructors and Earthwise Energy Technologies, involved adding more capacity with the installation of a new chiller. However, this would require increasing the size of the chilled water line for higher flows. An alternative option was presented to reduce chilled water demand in the existing buildings, increasing capacity to accommodate growth. Recognizing this as the pragmatic solution, Arden/Earthwise and PC turned to the Belimo Energy Valve.
Project Overview and Motivation
Reducing chilled water demand on the lower campus would create spare capacity in the chiller plant and reduce water flow through the main line. In doing so, PC could forgo the installation of a fourth chiller (Currently, three 1000-ton chillers run parallel.), and the main line would not have to be excavated and replaced.
With approximately 20 energy valves already installed across the campus, Arden/Earthwise and PC had established a close working relationship with Belimo and were familiar with their range of products.
“Our plan was to pick sections of the lower campus where demand for chilled water was highest,” said Paul Carter, general manager at Earthwise. “Some technology in these buildings was outdated and due for an upgrade. Having seen the capabilities of the Energy Valve, we were confident it would generate the flow savings we were looking for.”
The Energy Valve is an IoT-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. Its built-in Power Control and Belimo Delta T Manager logic monitors coil performance and optimizes available energy of the coil 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 flow decreases, allowing 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 with a suite of cloud-based services that can 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, it communicates its data to the Building Management System (BMS) via BACnet MS/TP or BACnet IP as well as Modbus RTU and Modbus 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, ranging from ¾” to 2 ½”.
Energy Valve Savings and Benefits
The retrofit project is set for completion this spring, after which Arden/Earthwise and PC will collect data to quantify flow reductions. The reduction in pumping will lead to decreased electricity usage, which aligns with the college’s commitment to increase energy efficiency and improve environmental, social, and governance (ESG) performance.
“While future construction of new buildings may necessitate installation of a new chiller, the Energy Valves will allow us to push that project out and significantly increase efficiency of the existing system,” said Matt Basile, principal engineer I for Arden. “Every Energy Valve we install gets a data connection to the cloud and the campus’s central BMS. This provides visibility down to the individual air handlers, which is crucial for troubleshooting and identifying further opportunities for efficiency gains. It is now standard practice to flat spec the Energy Valve for any chilled water device over 10 gallons.”
“Belimo has a long-standing relationship with Arden/Earthwise and PC and is proud to be part of a project that will help the college achieve its goal of creating a more efficient and sustainable campus,” said PJ Qvarnstrom, retrofit business manager at Belimo.
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 campus. With additional buildings planned for these sections, the lower campus retrofit will serve as a demonstration project.
“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 PC. “We look forward to leveraging innovative products like the Energy Valve for future efficiency of our campus.”