By properly designing the exhaust ventilation system for a new commercial restaurant, significant operational savings, energy efficiency, and environmental improvements can be achieved.

Summary:

At the outset of a new construction project, the building owner wants to limit design and installation costs. With budget constraints, the kitchen designer specifies ventilation hoods based on past experience that are adequate for capture and containment of cooking plumes without regard to energy efficiency. The mechanical engineer, in turn, strives for an effective but low cost HVAC (heating, ventilation, and air conditioning) system. Energy efficiency and energy costs are often of little concern to the design team. However, the energy efficiency of commercial kitchens is, in large part, directly related to the exhaust ventilation system.

The interaction between HVAC, makeup air, and exhaust systems is complex and until recently was not well documented. Recent research has demonstrated that hood type and local introduction of makeup air have a significant impact on exhaust and makeup air ventilation rates. These design elements are frequently not developed and specified by the same professional. Kitchen designers usually select the hoods while mechanical engineers design the HVAC and makeup air systems, often exchanging no more information than estimated exhaust rates. These design professionals may not fully understand the impact of their commercial kitchen ventilation (CKV) selections on energy consumption and occupant comfort.

These problems exist in part due to a lack of comprehensive design information for CKV systems. This design brief provides guidance to kitchen designers, mechanical engineers, and food service operators on commercial kitchen exhaust systems, and is intended to augment comprehensive design information published in the Kitchen Ventilation Chapter in the ASHRAE Handbook.

This brief focuses on methods of increasing the efficiency and effectiveness of the exhaust system while reducing the impact on the total building energy consumption and improving the kitchen environment. Key discussion areas include:

• The fundamentals of kitchen ventilation systems.
• The basics of hood selection and sizing.
• The influence and types of makeup air.
• Energy considerations for CKV systems.
• A summary of design strategies.
• A comparison of two CKV system designs.