Two 11kW ABB variable speed drives (VSDs) have reduced energy costs at London’s Claridges Hotel by 30%, after they were installed to control air supply and extraction in its kitchens. The VSDs have been installed by ventilation control system specialist Food Industry Technical (FIT) as part of the hotel’s kitchen refit. The upgrade will see total energy savings of over £10,000 per year, as the VSDs will control the extraction and supply fans to match the needs of the application.

Previously, the cooker hood system was consuming over 450kWh per day, but after the installation of the VSDs, 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.

Prior to the installation, the fans wasted a lot of energy as they were running at 100% at all times. However, VSDs match the speed of the fan to the demands of the application so just enough energy is supplied to the extract and supply fans at all times, thus offering increased control and saving money.

FIT installed its Cheetah cooker hood extraction system into the kitchen, with the two 11kW, IP54 ABB standard drives for HVAC at the heart of the system. 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.

“The sensors measure activity in the kitchen and constantly send signals to the drives, adjusting the fans to meet demand,” said Peter Evans, sales director, FIT. “As a safety measure, the system also monitors flow in the exhaust and supply ducts. If the extract or supply ducts lose 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 a safe level.

“The installation represented a huge challenge,” added Evans. “We had six hours to fit our system before the kitchen opened up to customers. Using ABB drives here offered a significant advantage – 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.”