Presentation on theme: "Demand Ventilation Control Systems for Commercial Kitchens NEBB February 24, 2012 Presented By: Mike Dean."— Presentation transcript:
Demand Ventilation Control Systems for Commercial Kitchens NEBB February 24, 2012 Presented By: Mike Dean
What is DVC for CKV? Demand Ventilation Controls for Commercial Kitchen Ventilation True “demand ventilation” control system designed specifically for commercial kitchens. A controls package that can be “retro-fitted” to a commercial kitchen exhaust hood, or designed into a “new construction” application. Controls the grease exhaust and make-up air unit fan motors for each exhaust hood system. VFD’s modulate exhaust fans based on a controlled input, exhaust air temperature, and make-up air fans are then controlled proportional to exhaust.
History Traditional kitchen ventilation systems have been controlled by basic electro-mechanical interlocks for years. NFPA 96 required grease exhaust duct velocities of 1,500- 2,500 fpm up until This forced mechanical engineers into constant volume designs for many years January 2002 NFPA issued Errata changing Section to read “ The air velocity through any duct shall be not less than m/min (500 ft/min)”
History This single revision allowed the traditional constant volume kitchen ventilation system to enter into the world of variable volume 2004 first Melink Intelli-Hood system installed in California Energy conservation became trendy…..and…..more openly subsidized
Codes/Standards ASHRAE Section Kitchen Exhaust Systems If a kitchen/dining facility has a total kitchen exhaust airflow rate greater than 5,000 cfm then it shall have one of the following: a)At least 50% of all replacement air is transfer air that would otherwise be exhausted. b)Demand ventilation system(s) on at least 75% of the exhaust air. Such systems shall be capable of at least 50% reduction in exhaust and replacement air system airflow rates, including controls necessary to modulate airflow in response to appliance operation and to maintain full capture and containment of smoke, effluent and combustion products during cooking and idle. c)Listed energy recovery devices with a sensible heat recovery effectiveness of not less than 40% on at least 50% of the total exhaust airflow
Codes/Standards ASHRAE Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings Variable-Speed Fan Control for Commercial Kitchen Hoods. In addition to the requirements in Section of ANSI/ASHRAE/IESNA Standard 90.1, commercial kitchen Type I and Type II hood systems shall have variable-speed control for exhaust and make-up air fans to reduce hood airflow rates at least 50% during those times when cooking is not occurring and the coking appliances are up to temperature in a standby, ready-to-cook mode. All exceptions in Section of ANSI/ASHRAE/IESNA Standard 90.1 shall apply. Why is this important? Changes to Standards, and Codes, show a growing trend towards the adoption of the technology across the board
Now What? Melink Intelli-Hood (OEM by: Greenheck, Accurex Kees, Gaylord) CaptiveAire EMSplus Spring Air TruFlow Halton MARVEL
PG&E Food Service Technology Center
Allen Bradley PowerFlex or ABB ACH550 Series VFD’s Intelli-Hood I/O Processor Interface Keypad Temperature Sensor Air Purge Unit Infrared Optic Sensor
Variable Frequency Drives The heart of variable volume controls
Melink Intelli-Hood Video
So, now we have a new demand ventilation control system. How do we incorporate existing HVAC systems and proper air balance Commercial Kitchens and Restaurants are typically very “leaky” facilities and present different air balance challenges: Diner’s entering and exiting the main doors Competing ventilation systems. i.e. Dining area air conditioning Versus kitchen ventilation (and now modulated hood exhaust) Receiving doors blocked open “House” ventilation transferred to kitchen as additional make-up air DVC systems operate dynamically between their preset minimum fan speeds and maximum ventilation system design airflows. Balance at full speed Verify airflows at minimum fan speeds Let the systems modulate and save energy
Our Top 5 1. Avoid degrading exhaust hood capture and containment at all costs! Verify capture and containment at minimum design speeds 2. Control exhaust and make-up air whenever possible 3. Pre-balance all retro-fit projects. Will typically uncover existing underlying problems 4. Integrate with building EMS systems so that the individual systems work together 5. Commission, commission, commission!
Ultimately, a properly balanced ventilation system with proper capture and containment at the exhaust hood creates a happy customer
Proper Capture and Containment – Our Ultimate Goal Schlieren Video
OK, Now The Real World
Exhaust Hood Capture Problem – Palo Alto Restaurant OK, Now The Real World Frayed Belt Cat Litter Pool of Oil Fan Not Attached To Base
OK, Now The Real World Noise and Velocity Issue at Zagat Rated Restaurant in San Francisco
Perfect World Application for DVC – matched systems
Demand Ventilation Controls Save Energy! Several Utilities offer direct incentives for these systems in both “Deemed” and “Calculated” energy efficiency measures: PG&E SMUD Southern California Edison SoCal Gas SDG&E Silicon Valley Power City of Palo Alto Utilities
Mike: x801 Constant Volume Kitchen Ventilation Systems Waste Energy!