Best Practice Guide

Local Governments

Introduction

Planning an Energy Program

Funding and Approval

Education

Lighting

Central HVAC System

Procurement Policy

Building Envelope

Demand Response

Distributed Generation

Water Use

Motors

Food Service

Tips for Energy Savings

Buying and Operating Equipment

Insulation

Sanitation and Water Use

Heating and Cooling Systems

Ventilation

Resources and Appendices

Lessons Learned


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Food Service

Ventilation

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An unbalanced or poorly designed kitchen exhaust system can spell trouble both for your cafeteria’s air quality and for your utility bills. Get ahead of the game by enlisting the help of an expert to design an optimized exhaust setup.

Catch all that you can. At least in principle, kitchen ventilation is a straightforward art with a simple goal: Capture and contain as much cooking effluent—the combination of grease, smoke and heat that emanates from each appliance—as possible. In practice, however, the task is much more challenging. Cross drafts and misaligned appliances can allow heat and smoke to spill into the kitchen. Spillage leads to a hot, uncomfortable working environment and higher energy bills if you air-condition your kitchen. Cut down on spillage by adding inexpensive side panels to hoods that are failing to capture, and push each appliance as far back against the wall as possible to maximize hood overhang and close the air gap between the appliance and the wall.

Rebalance your act. If you have not performed an air balance recently, it’s time to call a contractor. Time, maintenance, broken belts, and poor commissioning all lead to kitchen exhaust systems that are out of balance—moving too much or too little air, spilling and costing you money. This tip applies to your dining room HVAC as well; outside doors that are hard to open because of suction or that blow open by themselves are a sure sign that it’s time to order an air balance.

Consider variable-speed exhaust. Typically, kitchen exhaust hoods have two settings: “off” and “on”. Naturally, “off” is ideal for when the kitchen is empty, and “on” may be great for the frenzied dinner rush—but neither is quite right for the afternoon lull, the post-dinner wind down, or any other situation when the kitchen isn’t operating at full capacity. Variable-speed, demand-based exhaust controls get around this problem by using sensors to monitor your cooking and varying the exhaust fan speed to match your ventilation needs.  Demand ventilation controls typically reduce the cost to operate an exhaust system by anywhere from 30 to 50% and can be installed on either new installations or retrofitted to existing hoods.

Maximize overhang. A four-foot deep hood is somewhat typical for cafeteria exhaust, but you’ll capture more smoke and heat with a five- or six-foot deep hood.

Group heavy-duty appliances together. If you’re designing a new kitchen, try to group your heavy-duty appliances (e.g., broilers, wok ranges, salamanders) together in the middle of your appliance lineup. You might also consider placing the broiler under a separate dedicated exhaust hood with a higher exhaust rate and leaving the light-duty equipment under the original hood at a lower rate.

Learning more about kitchen ventilation
If you’re getting ready to design a new kitchen or renovate an old one, check out “Improving Commercial Kitchen Ventilation System Performance,” a two-part kitchen ventilation design guide written by the experts at PG&E’s Food Service Technology Center. www.fishnick.com/ckv/designguide/