Читать книгу Automation of Water Resource Recovery Facilities - Water Environment Federation - Страница 157

Nonprocess systems are also included in facility automation design using the same techniques developed for facility treatment processes. One such example is WRRF heating, ventilation, and air-conditioning (HVAC) control systems. These systems, which have become more complex, are essential to many facility operations. Digester heating, for example, may require hot water for heat exchangers. Facility electrical and control rooms need a climate-controlled environment. Boilers fueled by digester gas that use natural gas or other fuels as backup need an HVAC system that coordinates well with the digester gas-handling system. Because such HVAC control systems use the same instruments, PLCs, DCSs, communication systems, and control panels as the treatment process I&C system, consulting engineers have begun using the same design tools for both systems.

Using P&IDs for all control systems, regardless of application, simplifies overall WRRF design. With the exception of system-specific requirements, design engineers can typically use the same specifications for both systems. As such, fewer types of hardware and software are needed. In addition, project documentation is easier to review and maintain (Gillman, 2010).