Butterfield Business Park, Luton

Client: Easter Developments Ltd
DB&P's Services: Design and Build Consultants

Butterfeild business park

Description of Works:

In many respects, the Offices constructed at the Butterfield Business Park are relatively simplistic in terms of the well proven and established mechanical services intent. The buildings constructed to accord with the latest Part L2 Regulations, are inherently energy efficient. This nett energy efficiency is significantly enhanced with control features including automatic operation of the openable glazed louvres deigned to promote air movement through the buildings in response to increased room temperatures.

However, the most innovative aspect of the building is the introduction of thermal earth ducts, designed to provide a source of passive heating and cooling through the building.

Operation of the Earth Ducts: Operating under the suction pressure created by the supply air handling unit, fresh air is drawn through a series of cylindrical turrets located around the site. The air is subsequently entrained through the 900mm dia. x 100m long earth ducts respectively buried at a depth of 2m. As the entrained air passes through the ducts, the surrounding soil held at a constant 13oC provides a degree of pre-heat or colth to the ventilation system.

During the winter months, the temperature of the pre-heated fresh air, mixed with a degree of recirculated air, is boosted via conventional LPHW heater batteries. This tempered air is injected into the pressurised floor plenum and subsequently discharges into the occupied office space via a series of swirl diffusers. During the summer months, with the fresh air maintained at a temperature of circa 14 / 15oC, there is no requirement for mechanical cooling.

ButterfieldIn essence the earth duct system provides "free pre-heat" and "free comfort cooling" – with energy savings calculated to be in the region of 75%

Extent of Mechanical Services:

• Incoming utilities

• LPHW Heating – trench heating operating in conjunction with supply ventilation system.

• Mechanical Ventilation – operating in conjunction with natural / passive ventilation systems.

• Domestic Hot and Cold Water Services

• Automatic Control Systems