Standard Single-Loop Digital Controllers for HVAC Systems

Heating, ventilating, and air-conditioning HVAC control systems are uniquely designed for individual Army facilities. Since each facility has a different control system design and nonstandard hardware, Army Directorate of Engineering and Housing DEH personnel have a very difficult time operating and maintaining the systems correctly. DEHs need standard control systems designed and are constructed of reliable, interchangeable control hardware. The objectives of this research were to 1 evaluate single-loop digital controller SLDC technology to see if the SLDC is the optimum controller to be used in the standard control panel, 2 develop detailed product specifications, and 3 develop application guidance. Although SLDCs have typically been used only by the process control industries, they are suitable for us in HVAC control applications. Despite the fact that SLDCs are somewhat more expensive than other alternatives, they are simple, flexible, reliable, and maintainable, making them well suited for use in Army facilities. They are ideal for PID, reset, and economizer applications. Product specifications developed during this research were submitted to Huntsville Division for inclusion in documentation on HVAC control systems.