Kitchen Ventilation Systems
There are particular objectives, which the kitchen ventilation has to achieve. The general ventilation has to provide sufficient air for complete combustion at burning appliances, otherwise chronic debilitating carbon monoxide poisoning could occur...
Ventilation is the single most important factor in the design, construction and operation of commercial kitchens. Without adequate ventilation and an ample supply of clean makeup air, no kitchen will operate efficiently. There are particular objectives, which the ventilation has to achieve. The objectives include the following:
1. The general ventilation through the kitchen has to introduce sufficient clean, cool air and remove excess hot air for the occupants to breathe adequately and remain comfortable.
2. The general ventilation has to provide sufficient air for complete combustion at burning appliances, otherwise chronic debilitating carbon monoxide poisoning could occur.
3. The general and local ventilation has to dilute and remove products of combustion from gas and oil fired appliances.
4. The general and local ventilation has to dilute and remove odours, vapours and steam from the cooking processes.
5. Local ventilation has to protect against particular hazards to health arising from some cooking fumes, such as those involving direct application of heat to the food.
6. The local ventilation has to be capable of being kept clean from fat residues to avoid loss of efficiency and fire risks.
7. The system has to be quiet and vibration free. The amount of ventilation required in a particular cooking area depends on various factors: the type of product(s) being cooked, the structure which houses the cooking area, the type of equipment used and local code regulations. And, depending on your location, the building heat source may also play a factor.
The growth of the service industry and the need for more control over the air quality inside difficult to maintain areas such as commercial kitchens has created a boom in the market for kitchen ventilation equipment. This equipment is becoming increasingly more critical to the safety and comfort of employees within kitchens located in retail restaurants, cafeterias, stadiums and nearly any other type of building complex.
The nation’s leading manufacturer of commercial kitchen ventilation systems had built a reputation on providing fast, reliable service, and was looking to further capitalise on this reputation to grow its business across the nation. In the process, it wanted to focus on its internal mechanisms for controlling costs while maintaining the quality of its systems and its reputation as the vendor of choice for integrated kitchen ventilation packages that include hoods, exhaust fans, electrical controls, direct-fired heaters and utility distribution systems.
The customer’s core business with independent restaurants, national chains and other public and private institutions continued to show signs of solid growth, which gave the organisation the opportunity to improve their business by focusing on key product offerings and leveraging the economies of scale this success would provide.
Areas that they decided would be most advantageous to them and their customers’ success included:
• Standard electrical, controls and automation products on a single vendor to minimize support issues
• Reduce inventory expense by minimising on-hand and replacement parts
• Decrease the reliance on custom built vendor parts integrated into the design of their products.
Duct Temperature Sensor
Typically one per hood installed above the duct collar. Thermistor or RTD type sensors can be used.
Hood Differential Pressure
This measurement is used for multiple purposes: detection of clogged or very dirty fi lters, detection of a missing filter, and calculation of air flow.
VFD – Variable Frequency Drive
Adding a Variable Frequency Drive (VFD) to a motor-driven system can offer potential energy savings in a system in which the loads vary with time. VFD’s belong to a group of equipment called adjustable speed drives or variable speed drives.
Variable speed drives can be electrical or mechanical, whereas VFDs are electrical. The operating speed of a motor connected to a VFD is varied by changing the frequency of the motor supply voltage. This allows continuous process speed control.
Kitchen Space Temperature Sensor
Measures the ambient temperature in the kitchen.
User Interface Control
A hood usually has the following control components:
This light is activated when any alarm condition is detected. Most common alarm conditions are: filter missing, filter clogged, fi re suppression system activated, duct temperature dangerously high, sensor failed, or VFD is in fault. The easiest way to diagnose problems is by using the Konsole™ Diagnostic Software remotely.
This is an audible alarm that is activated at the same time as the alarm light.
Pressing this button accelerates the exhaust rate to 100% for a pre programmed period of time (default 1 minute). Pressing and holding the button for 3 seconds starts the hood if it has been overridden by a schedule or an “off” state. In this event, the system will start in idle mode and operate normally for the specifi ed override interval. The default override time is 1 hour.
Fan Control Device Override Switch
The Fan Control Device Override Switch is used only in emergency situations to override the control system entirely. This switch should be located inside the VFD cabinet.
• Space humidity (i.e., room humidity)
• Outdoor temperature
• Outdoor humidity.
Infrared Radiation Index Sensor (IRIS) (Optional)
Typically, there are 1 to 4 IRIS sensors per hood. The sensors are installed inside the hood in such a manner that each of them views a cooking surface.
The final solution enabled the customer to meet its objectives and achieve several key financial, service and product advantages including:
• Consolidating on a single supplier for all major components to minimise cost and service confusion
• Eliminating the need to maintain inventories of control and automation products
• Gaining the freedom to choose alternative breaker products to improve performance and functionality
• Eliminating solution components by selecting a new breaker, Automation Controllers, VFD’s etc. that provided a broader range, by reducing both space requirements and cost.
AUTHORS CREDIT & PHOTOGRAPH
Schneider Electric India