- Building Design and energy efficiency
- The external building envelope
- Energy efficiency measures for the mechanical and electrical services
Building Design and energy efficiency
Where possible buildings are sited to reduce solar gain whilst at the same time providing good natural lighting. The introduction of brise soleil and the selection of solar glass help to control solar gain.
The main entrance of buildings will be positioned so as to maximise its visibility when entering the site to create a clear sense of arrival. A Canopy is usually provided to the main entrance to emphasize the entrance and protect building users from adverse weather. The canopy also provides shading to the reception area and reduce solar gain.
Building materials are chosen to accommodate cost, longevity, appearance, maintenance, site continuity and environmental performance: the ability for materials to be recycled after their use in the building is also considered and timber materials used are from sustainable sources.
The external building envelope
Office and laboratory buildings are designed to reduce the building mass by lightening the upper areas of the façade by the introduction of a ribbon of lightweight high-pressure laminate rainscreen, which is manufactured from a bi-product of a milling process to form other products. Wastage is minimal and this element has been designed to utilise the standardised modules of manufacture to further reduce waste generated during construction.
Windows and curtain walling to offices and laboratories are manufactured in aluminium and offer the same benefits as the aluminium rainscreen. Aluminium products have a 70/100-year life and are completely recyclable.
Windows at high level under eaves overhangs are provided to factories and warehouses rather than rooflights. These windows introduce natural light into the building and reduce the need for artificial light and thus reducing CO2 emissions. Wall and roof cladding are also manufactured in aluminium offering the same benefits with a 70/100-year life and are completely recyclable. Office roof coverings can also be in clay tiles and natural slate which offer similar benefits to the clay facing brick façades.
Energy efficiency measures for the mechanical and electrical services
The mechanical and electrical services are designed to reduce running (maintenance and energy) costs and achieve operational flexibility for the building users.
A number of energy efficiency measures are utilised in the building design.
Where office heating and cooling (comfort conditioning) is adopted a refrigeration system generically titled "variable refrigerant flow" (VRF) is used. The system selected has been awarded eligibility for tax rebate/s under the Government's "Enhanced Capital Allowance Scheme". Significant elements of the system are as follows.
- The system incorporates energy efficient heat-pumps.
- The refrigerant gas used is R410A, a hydrofluorocarbon (HFC) with zero ozone depletion potential (ODP). R410A also has a lower total equivalent warming impact than its competitors due to its greater operating efficiency.
- The compressors in the refrigeration cycle are high efficiency "scroll" compressors.
- The management of the compressors is by micro-processor controlled inverters, which vary the compressor speed to match the duty, thus resulting in major power saving at part load.
- Appropriate parts of the comfort conditioning system also incorporate local heat recovery, in the form of "BC" control boxes which re-direct heating and cooling to trade-off local imbalances.
The fresh air ventilation systems incorporate heat recovery.
Churchmanor are actively reviewing the option of using boreholes, buried water loops or an open loop aquifer to link the comfort conditioning system to a renewable source of pre-heated or cooled water to reduce the energy consumption and achieve COP's as high as 7.5. This renewable energy source when used in conjunction with products such as the Mitsubishi Electric inverter driven WR2 system provides a significant impact on the 10% renewable energy requirement set out in Governments targets.
All ventilation ductwork is to be optimally insulated for operational energy efficiency and reduced running costs.
The hot water installations incorporate optimal thermal insulation, together with electric trace heating and localised blending at each tap/outlet. This solution is a proven safeguard against the growth of legionella in the pipework, minimises water wastage due to a reduction in stagnant cold water, and results in lower running costs than comparable hot water return pipework systems.
The urinals, and their attendant flushing systems, shall be designed to operate under the control of automatic PIR detectors which only consume water when the facilities have been used. Churchmanor are also reviewing the use of waterless urinals to further reduce water usage in the building.
The lighting design incorporates low energy control gear and lamps, which benefit the whole installation in both increased efficiency and lower energy usage. Significant elements of the lighting installation are as follows:
- The lighting installations will be designed to incorporate full lighting controls with timed on, and automatic off control, and local override switching.
- Lighting installation utilises high frequency control gear & energy efficient lamp technology, with resultant energy reduction, and lower running costs.
- Lighting control systems permits various programmes including "reduced lux levels" for security, and cleaning facilities, by switching on/off pre-selected fittings only, with resultant energy savings.
- The lighting installations, and ventilation, within all WC's/toilet cores are controlled by PIR's, to yield further energy reductions.
By way of summary, the intention on all schemes is to design the office M&E installations so that when audited against the current Part L2 Section of the Building Regulations they will yield a rated score well within the maximum permitted rating.
Churchmanor are also reviewing the use of solar photovoltaic panels and solar water panels for augmenting the electric supply and the hot water installations.
Churchmanor are also investigating the use of wind turbines to provide a contribution to the office lighting and power requirements.
