Case Study: Heat Recovery and Demand Controlled Ventilation in Industrial Kitchens

Industrial kitchens have high HVAC load requirements due to high exhaust rates from hoods. Especially in cold climates to heat the makeup air in winter requires high initial and - more importantly - high operating costs. Heat recovery always looks like an attractive alternative due to the high temperatures of hood exhaust air. However, since hood exhaust is quite dirty, heat recovery sections are clogged very fast. Heat recovery systems are established in six restaurants in Ankara, Turkey. Hood exhaust lines equipped with electrostatic precipitators (ESP) to keep heat recovery coils clean. Two of those six installations have ESP’s with self cleaning automatic washing systems and operating successfully. Four other installations have ESPs without self-cleaning automatic washing systems and clogged very fast. One of the successfully operating systems has temperature based demand control. The other one has manual fan speed control. Makeup air side fan speeds are interlocked with exhaust fan speeds. This study will show ESP’s with automatic washing system protects heat recovery sections and discuss the equipment, methods, results of the installed systems and user behaviors including maintenance and operation.