The Public Library of Charlotte & Mecklenburg County (PLCMC) and Children’s Theatre of Charlotte (CTC) each offered engaging and educational programs for young people, but both were running out of space. The executive directors for both organizations decided to create a combined solution into a single, new facility. Aesthetics became a vital part of the mechanical system design as unsightly panels and conduit have no place in a building designed to delight the eye as much as the mind. One of the biggest challenges was concealing as much equipment as possible.

An Alerton BACnet-based energy management system (EMS) provides energy efficient operation, including occupancy-based HVAC control, CO2 demand ventilation and more. Alerton’s Envision for BACtalk front-end software manages all the functions and seamlessly integrates third-party devices and systems such as lighting control and fire/life safety. Sophisticated control strategies–including supply air reset control, static pressure reset control, and fan speed modulation based on airflow measuring–effectively manage the vastly different heating and cooling needs of the library and the theater.

In addition to motion-based space sensors, ImaginOn uses precision controls to reduce its energy use and increase savings by ensuring no space is over- or under-ventilated. ImaginOn features electronically commutated motors (ECM), a high-powered, brushless motor that has less energy loss than permanent split-capacitor (PSC) motors, thereby reducing a facility?s energy consumption. An analog output on an Alerton unitary controller uses an ECM speed card to control variable air volume (VAV) box fan speed.

Hoffman Building Technologies, the controls contractor, established interfaces to a packaged Bell & Gosset pumping system for secondary chilled and hot water systems. Piping is classic constant volume primary and variable volume secondary with differential pressure control. Onicon BTU meters are in the hot water and chilled water systems for energy measurement and verification (M&V) purposes. The meters are connected to the EMS, and energy consumption is trended for review and analysis. Beyond peak efficient operations to help the facility achieve Leadership in Energy and Environmental Design (LEED) certification, ImaginOn building data had to be vigilantly tracked and verified. Integrated York chillers use an MS/TP trunk off an Alerton BACtalk Integrator (BTI), a BACnet-based global controller, picking up between 40 and 50 points and enabling the trunk to generate a great deal of building data. An integrated lighting control panel energizes lighting in a zone once it picks up an occupancy sensor contact.

For additional control, an Alerton Microtouch unit offers a push-button override option if the motion sensor doesn’t pick up the contact. Hoffman also tied in CO2 demand control ventilation (DCV), which controls the outdoor air intake, enabling the ImaginOn EMS to reduce the potential of over-ventilating a space during a period of low occupancy. The system still provides enough outdoor air ventilation, but decreases energy consumption in doing so. One of the ImaginOn project requirements was for the controls contractor to provide power to the combination fire-smoke dampers. The fire alarm contractor provided a contact and a p-tap station for each damper. Hoffman facilitated the coordination between the fire alarm contractor and the smoke alarm contractor to placing and concealing the power transformers that power the fire-smoke dampers and complete installation.