Substantial savings for Claridges

Luxury hotel Claridges in London is benefiting from a 30% reduction in energy costs after the installation of two 11kW ABB variable speed drives (VSDs) to control air supply and extraction in its kitchen.

The VSDs were installed by ventilation control system specialist Food Industry Technical (FIT) to lower energy costs and reduce CO2 output as part of the hotel’s total kitchen refit. The upgrade will see total energy savings of over £10,000 per year.

FIT supplied a cooker hood system that automatically reacts to conditions in the kitchen, ramping up extraction during busy times and reducing flow in quieter times. By controlling the extraction and supply fans to match the needs of the application, significant energy savings are achieved.

Previously the cooker hood system was consuming over 450kWh per day, but after the installation of FIT’s system incorporating ABB drives, energy consumption fell to 315kWh per day. The installation will save the hotel just under 50 tonnes of CO2 per year and achieve return on investment in 1.8 years.

The fans were running at 100% at all times prior to the installation of the FIT system. However this method wastes energy, and using VSDs to control fan speed brings more accurate control and uses less energy. VSDs match the speed of the fan to the demands of the application so just enough energy is supplied to extract and supply fans at all times, saving money.

FIT installed its Cheetah cooker hood extraction system into the kitchen. At the heart of the system are two 11kW, IP54 ABB standard drives for HVAC controlling the extraction and supply fans. The system incorporates a range of sensors measuring temperature, smoke, steam and airflow in the extract and supply ducts in order to determine the fans optimum flow rates, enabling conditions in the kitchen to remain constant at all times. To enhance safety the system also incorporates a gas isolation module for cutting off the gas supply in case of emergencies.

“The sensors measure activity in the kitchen and constantly send signals to the drives adjusting the fans to meet demand,” says Peter Evans, Sales Director for FIT. “As a safety measure, the system also monitors flow in the exhaust duct and supply duct. If the extract or supply duct loses air supply, the gas isolation module automatically shuts down the gas supply, ensuring that gas levels do not build up in the kitchen.”

The system also features a fail safe mechanism to further enhance safety – in the event of a control cable being severed, or a sensor failing, the drives will automatically ramp up to 100% and stay there until the fault is rectified, ensuring air supply to the kitchens remains at safe levels.

“The installation represented a huge challenge,” adds Evans. “We had six hours to fit our system before the kitchen opened up to customers. Using ABB drives here offered a significant advantage as the drives are extremely easy to configure because the built-in keypad tells you exactly what parameters you are setting without having to reference them. With competitor models, the drives have numbers that represent each parameter and the engineer has to refer to an instruction manual to see what the numbers mean, resulting in a significantly increased installation time.”

“With the introduction of the 17th edition of the new Building Regulations (Part F & L), variable speed drives are now mandatory for the control of extraction fans,” says Gary Busby, Sales Engineer for ABB drives. “Claridges will benefit from a considerable reduction in energy costs whilst making a contribution to cutting their CO2 output – a legal requirement under the new Carbon Reduction Commitment (CRC) Energy Efficiency Scheme.”

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