Energy audits, Cantor Art Center, Cecil H. Green West Library
System overhaul: Energy audits, Cantor Art Center and Cecil H. Green West Library; Salas O'Brien
Location: Stanford, Calif.
Firm name: Salas O'Brien
Project type, building type: System overhaul, art/museum venue
Project duration: 4 years
Project completion date: Nov. 2012
Project budget for mechanical, electrical, plumbing, fire protection engineering only: $367,800
The projects were challenging to implement in an operational facility. Each system had to be done one at a time so that the entire building was not affected. Because these historic buildings were not built in a humidity-controlled space, they dry out quickly once they are shut down and take a substantial amount of time (more than a week) to reach steady state again after start-up. This amplified the need to have redundancy in the new systems. Commissioning lasted several months as the new systems dynamics were learned by the in-house EMCS staff along with finding problems with existing equipment. This also was a cultural change given the learning of new sequences based on dew point instead of relative humidity.
Stanford University, as part of its energy program, targeted two historic buildings for energy audits—Cantor Art Center and Cecil H. Green West Library—due to their relatively high energy usage when compared to other buildings. The audit focused on a few energy projects and was followed by design and construction of these projects. Now that these have been installed for a full year, through measurement and verification, savings of over $500,000/year have been proven. Mechanical systems in the buildings consisted of constant volume central station air handling units (AHUs) with fixed outside air, humidification, chilled water, and reheat coils. These AHUs were controlled by an energy management and control system (Rosemont). The control sequences were standard for this type of application. Modulating the chilled water coil and heating coil depending on demand controlled zone temperatures, and modulating the chilled water for dehumidification and the steam-to-steam humidifier for humidification controlled zone humidification. Trending of this data revealed hunting of both temperature and humidity.