Constructing college, university buildings wisely: Electrical, power, and lighting
Aravind Batra, PE, LC, LEED AP, Principal P2S Engineering Inc., Long Beach, Calif.
Craig Buck, PE, LEED AP, Associate, RMF Engineering, Charleston, S.C.
Jeffrey R. Crawford, PE, LEED AP, CCS, Vice President, Director of Higher Education & Research Market, Ross & Baruzzini Inc., St. Louis
Andre M. Hebert, PE, BEMP, LEED AP BD+C, Principal, Senior Mechanical Engineer, EYP Architecture & Engineering, Boston
Sergiu Pelau, PE, LEED AP, Principal, Syska Hennessy Group, New York City
Scott Robbins, PE, CEM, LEED AP BD+C, Senior Vice President, WSP | Parsons Brinckerhoff, Boston
CSE: Describe a recent electrical/power system challenge you encountered when working on a college/university.
Batra: The recent electrical/power system challenge we encountered was to design an automatic load-shed scheme for a university to provide the ability to keep their medium-voltage cogeneration system operational should they lose power from the utility. The project involved provision of microprocessor-based relays, load-shed processors, and real-time automation controllers to automatically shed nonpriority loads should the university lose power from the utility and the university demand exceeds the capacity of the existing cogeneration system.
CSE: What types of renewable-energy systems have you recently specified in a college/university?
Robbins: We have installed photovoltaics (PV) at a number of locations. Ground-source heat pumps are interesting. There are multiple installation options including small distributed heat pumps, large air-handling heat pumps, and central water-to-water heat pumps. All offer great value depending upon the building type. We’ve studied and successfully installed these options. Our experiences are only with closed-loop systems. Contractors have done a great job of understanding how to install the well fields, and costs have lowered as a result.
Crawford: We have designed several solar-PV and solar-thermal systems on recent college/university projects, as well as a few geothermal heat pump systems.
Batra: We have been specifying PV systems in our current designs. The primary reason is lower cost and shorter payback, virtually maintenance-free installation, lowered peak demand and thus operating costs, and reduced greenhouse gas emissions.
CSE: How do you work with the engineer, owner, and other project team members to keep the electrical/power system both flexible and sustainable at the same time?
Batra: We work with the owner and other project team members to understand their current and future needs and then design an electrical/power system that provides the required infrastructure for future growth, promotes efficiency, provides effective controls to offer flexibility to the users in tailoring the systems to suit their needs, and provides renewable-energy systems to not only offset energy consumption but also provide the owner with adequate capacity for future growth.
CSE: What types of smart grid or microgrid capabilities are owners demanding, and how have you served these needs? Are there any issues unique to college/university projects?
Batra: Smart grid and microgrid capabilities that are currently being demanded by the campuses include a combination of battery-storage systems, PV systems, fuel cell systems, cogeneration systems, and a front-end system that effectively coordinates and integrates these systems together to save operational costs for the campus. Related issues are lack of distributed-energy sources to achieve the integration of the various systems to form a smart grid system.
CSE: What unique lighting or lighting-control systems have you completed?
Pelau: Cornell CIS Gates Hall building uses the latest lighting technologies: LED lighting and digital distributed lighting control with a daylighting control system with a connection to the BAS. Multiple energy-smart modules, each with four dimming relays or four switching relays, are located in corridors along classrooms and connected by the communication bus with the light-management hubs. Perimeter spaces have daylight-harvesting zones with photocells connected to energy-smart modules. Low-voltage override switches, digital-programmed time clocks, and occupancy sensors make the building friendly around the clock and, at the same time, save energy. The building also has a unique feature designed for classroom flexibility by using a track plug-in busway with drop-cord outlets.
Robbins: These lighting options are no longer unique, but occupancy-sensor control and LEDs are now commonplace.
Buck: RMF Engineering installed efficient LED light fixtures throughout the Clemson Watt Innovation Center. The majority of the light fixtures are of a new power-over-Ethernet (PoE) technology. Each fixture is connected to both power and data over a single Ethernet connection to a PoE switch. The PoE switch, located above the ceiling local to the lights, has eight ports to power up to eight 30-W light fixtures and requires a line-voltage connection. The system allows for individual fixture addressability and controllability, including daylight harvesting, to accommodate the desired building flexibility. The LED light fixtures are inherently dimmable and have integral occupancy/light sensors. The lighting-control system consists of a computer in lieu of dimming/relay panel. When a room reconfiguration requires the lights to be controlled differently, it just requires a computer-program adjustment. The smart PoE system has eliminated the need for an electrician to manually rework the conduit, wiring, and connections. Because the power connection is a Cat 5 cable, the light fixture can be unplugged, moved to a different location, and plugged back in—just like moving a computer station. The data connection will also allow monitoring of power consumption. With this being such a new technology, there were a couple of problems that were overcome:
- The PoE switch was originally designed to be rack-mounted with a cord and plug. Unless specifically permitted in NFPA 70: National Electrical Code (NEC) 400.7, flexible cords must not be concealed by walls, floors, or ceilings, or located above suspended or dropped ceilings. Philips had to redesign the switch by removing the cord and plug and replacing it with a junction box for a hard-wired connection.
- The switch is not UL-listed for life safety. Line-voltage light fixtures were used for egress lighting.
Batra: The unique lighting and lighting-control systems that we have completed include LED lighting that has integrated dimming and sensor controls that offer daylight savings, occupancy savings, demand-control abilities, and user flexibility to adjust their footcandles based on individual tasks performed.