ASHRAE Research Project 1480 Report - Food Service Technology ...

Introduction
Background
In commercial kitchens, exhaust hoods are used to remove the smoke, grease, moisture, heat, and
combustion products generated by the appliances and foods during idle and cooking operations.
These items are what are referred to as effluent. By removing air from the kitchen, the exhaust
hood also drives the need for replacement air to enter the kitchen to maintain a balanced room
pressure and an acceptable climate for the kitchen staff.
Optimal energy efficiency of the kitchen ventilation is achieved by minimizing the exhaust flow
while maintaining sufficient capture and containment of the effluents from the cooking process.
This airflow reduction usually leads to reduced HVAC loads for supplying and conditioning the
replacement air to the kitchen for either new construction or optimization of current kitchens. If
the minimized exhaust rate is applied at the design stage with an appropriate safety margin for
field adjustment, oftentimes the size of the fans, ductwork, and heating and cooling systems can
be reduced for additional energy and cost savings.
To drive improved commercial kitchen ventilation efficiency, more baseline data has been
needed to establish valid guidelines. In the past ten years, the Commercial Kitchen Ventilation
Laboratory in Wood Dale, Illinois completed three projects focused on the investigation of wallmounted
canopy hoods. These projects have focused on exhaust rates and heat gain to space
energy rates for wall-mounted canopy hoods. Sensitivity testing during one of the projects and
field experience by the industry has provided insight for the necessity of island hood research.
A study was conducted for the California Energy Commission [Ref 1], which evaluated different
methods of introducing makeup air for an 8-foot by 4-foot wall canopy hood. Sensitivity testing
was performed using the wall canopy as a rear-filter island hood by removing a portable back
wall. A significant difference between the wall-mounted and island hood performance was
found. However, the island hood data was limited due to the laboratory capacity and layout at the
time. The data from this project has been made publicly available as a report and design guides,
and has contributed to ASHRAE papers and the ASHRAE Handbook.
A recent ASHRAE study, RP-1202 [Ref 2], analyzed how appliance position and/or a mix of
appliances with different duty ratings affected the minimum exhaust rate needed to provide
capture and containment of all effluents under a 10-foot by 4-foot wall mounted canopy hood. To
compliment the data, a co-funded supplemental study was conducted to evaluate hood end
panels, operational diversity of a common heavy-duty appliance, two types of shelving under the
hood, appliance accessories, hood height, and the distance from the appliance to the hood.
Another recent ASHRAE study, RP-1362 [Ref 3], determined the capture and containment
exhaust rates and heat gain to space for over 80 commercial foodservice appliances. Most tests
were conducted underneath a 10-foot by 4-foot wall mounted canopy hood to complement data
from previous studies. Furthermore, determination of the exhaust rates required for capture and
containment of hooded appliances was augmented with the funding assistance from Pacific Gas
and Electric’s Food Service Technology Center. The expanded research project not only
provided accurate heat gain information for load calculations, but also the ventilation rates
1-1
RP-1480