A SIMPLE SOLUTON TO KITCHEN EXTRACT ODOUR CONTROL

Nuisance odours from commercial kitchen exhausts are a very common problem that can lead to complaints and hinder planning permission for new restaurants. Cian Flood, Director at Extechnology explains how the next generation of UV-C technology can offer an easily maintained solution for contractors.

According to recent data, the number of complaints regarding odours from commercial kitchen extraction systems is rising. As a result contractors are being increasingly asked to provide odour control solutions for kitchen exhausts. Traditionally contractors have opted for carbon filters since they are regarded by many as a tried and tested solution. However, a raft of factors is now driving clients to ask contractors for odour control alternatives.

Firstly, increased fuel costs are motivating clients to take a hard look at their buildings' operating costs, including the expense of running kitchen extraction systems. Energy efficiency can be an issue when using carbon filtration for odour control, since the filters are installed inside the extraction system and trap the odour contaminants as the air passes through them. As a result an extraction system using carbon filtration will require larger fans to overcome the associated resistance posed by the filters - not a very energy efficient option. Another down side of using carbon filtration is that it does not provide grease control. This is an important point to consider when opting for carbon filtration in kitchen extract systems. In this environment excessive levels of grease are present which clogg up the carbon filters rendering them ineffective as an odour control solution. The built up grease on the filters also puts further pressure on the extraction system, increasing pressure drops and wasting additional energy.  This brings us onto the next issue which clients have with carbon filters which is maintenance.

Carbon filters generally need to be changed on a monthly basis to assure they are working effectively and control extract odour. However, in reality unless a client has secured a service and maintenance contract carbon filters are often fitted in commercial kitchens as a odour solution and then just ignored - out of sight, out of mind. That is of course until the next odour complaint via Environmental Health.

However, another significant driver which is preventing clients replacing carbon filters - is expense. In the current financial climate many clients are focused on the bottom line and may be tempted to take a chance and not replace their carbon filters in order to make a saving of possibly upwards of £500 a month.

Lastly the desire to be seen as environmentally considerate is also leading to clients questioning using carbon and so asking contractors for alternatives.

So what alternative can contractors offer their clients? Well in fact, there is a simple well established solution to odour control that contractors will be familiar with - UV-C technology.

Used in a variety of air cleaning applications for more than 20 years, UV-C technology works by oxidising the odour and grease particulate, permanently destroying and altering the compounds. In kitchen ventilation UV-C technology has traditionally been used in an inline application within the extract ductwork or canopy. An arrangement of UV-C light tubes is fitted in the ductwork close to the canopy hood. The air is then extracted from the kitchen through the canopy into the ductwork where it passes through the UV-C tubes. Here the odours and grease are broken down into harmless compounds through the presence of ozone and hydroxyl free radicals. The compounds are then carried out with the exhaust air flow, leaving significantly cleaner ducts and reducing odours where the air is discharged.

Although, despite offering, in theory, an effective alternative to carbon filters, applying UV-C technology in this way has its drawbacks, and certainly does not fully utilise its potential for the benefit of the contractor or the end-user. Because the UV-C tubes are installed ‘inline' as the cooking effluent flows past them, the tubes require frequent cleaning since in practice the cooking grease tends to adhere to their surface. This growing accumulation gradually inhibits the performance of the inline UV tubes as well as causing pressure drops which affect the energy efficiency of the air movement system in a similar way to carbon filters.

However, contractors will be pleased to know that in response to these problems, and to maximise the high performance, easy maintenance benefits of UV-C technology, Extechnology has developed a patented solution, the Extechnology EXE 12 which offers the next generation of UV-C odour and grease control in kitchen extracts - thus providing a real alternative to carbon filters.

The major difference with the Extechnology application is that the UV-C tubes are mounted outside the ductwork or canopy in a separate, self-contained chamber that is linked to the ductwork or canopy via two spigots. The Extechnology EXE 12 unit is therefore easier to install and connect into the ductwork or canopy, especially when retrofitting. It is also possible to specify where the spigots are located to aid fitting on different applications and there's no need to change the canopy or the extract fan either which may be necessary with inline applications or carbon filters.

Within the Extechnology unit UV-C tubes produce ozone which significantly reduces odour and grease within the extract system. The process is further enhanced through the production of hydroxyl free radicals. The ozone and free radicals are drawn into the extract system through the two spigot connections, mixing with the extract air so removing odour and grease from the airflow before it is discharged. Any residual ozone not used up in the process is then reconverted back to oxygen before being exhausted to atmosphere.

Since the Extechnology EXE 12 unit is not located within the air flow of the extraction system it offers an energy efficient solution to odour and grease control because there is no air flow resistance. As a result the extraction system does not suffer from any of the pressure drops associated with inline applications or carbon filters. This means that by opting for the EXE 12 contractors can specify smaller fans, thus saving their client valuable energy and money. Applying UV-C technology in this way also ensures the tubes remain clean, working efficiently without the need for a continuous cleaning regime.

The only maintenance required by this new type of system is tube replacement every 12000 hours, instead of a regime of continuous cleaning that is needed with inline units or the monthly replacement routine demanded by carbon filters. This reduction in maintenance saves the contractor and client time and money. Meanwhile, for the contractor locating the tubes outside the ductwork has the added advantage of making installation and maintenance simple. With maintenance it is easy to access the tubes via a panel on the chamber rather than having to access the duct as with inline applications or carbon filters.

UV-C technology is proven to combat nuisance odours and grease making it the ideal solution for contractors and clients alike. However, it's the latest generation of Extechnology UV-C products which really opens up the kitchen extract market for contractors, especially retrofit opportunities. More and more contractors and catering chains are seeing the benefits of this approach, where air cleaning performance is excellent and the maintenance, hassle and running costs of such a system are also significantly reduced.

UV-C Technology

Extechnology has developed a unique UV-C application which overcomes many of the barriers preventing traditional UV-C technology from operating effectively. The Extechnology UV unit sits outside the airflow and is attached to a canopy or duct via two connecting spigots.    

The Extechnology process works through the production of ozone. The Extechnology UV tubes are specially designed to maximise the generation of ozone. (Ozone is a powerful oxidant which interacts with most pollutants such as odour, bacteria, mould, mildew and grease.)  The ozone produced in the Extechnology unit is introduced into the extract system and a breakdown of the polluted molecules results in permanent oxidation and a conversion of the grease and odour molecules into harmless compounds such as water vapour and carbon dioxide.

The results being achieved by the Extechnology unit can be seen in over 150 installations throughout the UK.