• Energy saving for London hotel

Energy saving for London hotel

The installation of seven Mitsubishi Electric WR2 heat recovery air conditioning units into the Zetter Hotel in Clerkenwell is helping the stylish conversion provide the right environment for its guests, while using the natural underground lake deep below the city streets as a cooling source to save on energy consumption.

The air conditioning system, which was supplied by Mitsubishi Direct’s Bristol office, was put together by a design team from engineering consultancy, Buro Happold and Gratte Manly Mechanical Services and installed by J C W Air Conditioning of Bristol. It was selected as the option that not only allowed for a sustainable and energy efficient design, but also avoided losing valuable roof space that has now been used for penthouse suites.

“If we had installed standard air conditioning units we would have lost at least one penthouse suite, which earns valuable revenue for the hotel,?explained Todd Billo, maintenance manager at the 59-bedroomed hotel.

The refurbishment was designed by architects Chetwood Associates, using sustainable materials and environmentally responsible principles with the main atrium providing natural ventilation and the air conditioning cooled by water pumped from the bore-hole which sinks 130m below the building.

The 19th Century warehouse in the heart of Clerkenwell is within walking distance of Sadlers Wells, the Barbican, Smithfields, St Pauls and the City and has a modern Italian restaurant on the ground floor with stylish, comfortable bedrooms above.

The bedrooms include seven rooftop studios with patios providing panoramic views over London. All rooms have giant sash windows and are reached via the dramatic five-storey atrium.

The refurbished building will probably need very little heating requirement, although this is also a feature of the versatile and energy efficient WR2 system, which can supply simultaneous cooling and heating to up to 16 individual indoor units from each condensing unit, which are sited in small service rooms on each floor.

Along with this capability to free up vital roof space, the WR2 is also ‘unique?in its ability to link to a building’s water loop and transfer heating or cooling energy between them. This allows the units to offer efficient double heat recovery, producing heat recovery from indoor units on the same refrigerant circuit in addition to using the water circuit to transfer energy between different WR2 circuits.

The 18-month conversion project has retained many of the building’s original features and scars while blending the traditional and the modern, to create an unpretentious urban space in which to sleep, eat and meet.

The building’s large sash windows for example, are a dominant feature of every room and particularly on the south side of the building, this can leave rooms hot as the guests walk in, so it is vital that the air conditioning is able to cool quickly to a comfortable level.

The air conditioning is controlled by Mitsubishi Electric’s G50 system which links to the overall BMS, although each room has an individual controller. When a guest enters the room and places their VIN card (room key) in the slot, which controls all lights and services, the air conditioning will come on and will automatically switch off when the room is vacated.

The system is also connected to sensors on the sash windows so that if they are opened, the air conditioning will switch off to stop energy being used when it is not needed.

“The system has been so well set up that it practically runs itself and we are now fine tuning it so that we can get maximum efficiency,?says Mr Billo adding that the user-friendly G50 is easy to pick up and understand.

Water has figured largely in the history of Clerkenwell, whose name derives from a well used to bring water up to medieval London from the underground reservoir. In addition to using this water to take away excess heat from the air conditioning systems, the Zetter Hotel also filters it and offers it to guests in the form of still or sparkling bottled spring water.