Low-carbon cooling for refurbished buildings
Chilled ceilings and beams can often provide effective comfort cooling when refurbishing existing buildings — as John Staunton explains.
Refurbishing existing building stock is essential to meet the UK’s target of reducing greenhouse gas emissions by 80% by 2050 — simply because the annual rate of construction for new buildings is only 1 to 2% of the stock. This point is emphasised by the former president of the British Council for Offices, Gordon Carey, commenting that the ‘retention and improvement of existing building stock is one of most sustainable and energy-efficient methods that can be explored’.
The environmental performance of an organisation’s built assets is a key factor in its sustainability credentials and carbon footprint. Architects and M&E consultants are seeing chilled ceilings, chilled beams and integrated service modules (ISMs) as part of the solution to meeting organisational sustainability targets.
A solution that adds to a building’s ‘sustainable credentials’ and reduces ‘whole life costs’ is now increasingly demanded by end users, specifiers and architects. With higher chilled-water temperatures of 14 to 17°C, chilled ceilings, chilled beams and ISMs offer a cost-effective, energy-efficient and low-maintenance alternative to traditional air-conditioning systems.
As a result, specification can lead to a reduction in energy consumption and the size and cost of the central plant. Owing to their increased energy efficiency, chilled ceilings, chilled beams and ISMs can help achieve good EPC (Energy Performance Certificate) and DEC (Display Energy Certificate) ratings as well as help a building achieve a higher BREEAM and LEED (Leadership in Energy & Environmental Design) ratings.
A recent report undertaken by Cyril Sweett for the Investment Property Forum stated, ‘the advent of EPCs means commercial landlords can no longer ignore the inefficiency of existing stock.’ It went on to highlight an example of refurbishment, where the ‘replacing of fan-coils units with [a] chilled beam installation’ could reduce annual CO2 emissions by 11.2 kg/m2.
A solution that provides a flexible means of delivering excellent comfort control and low energy consumption in a discreet way and without the space-demanding duct work associated with air conditioning is highly attractive.
The installation of an all-water chilled ceilings and passive chilled beams system does not require the bulky ductwork associated with all-air systems. This results in an installation tight to the soffit, maximising the floor-to-ceiling height. Current guidance from the British Council for Offices recommends a minimum floor-to-ceiling height of 2700 mm.
ISMs on the other hand can leave large areas of the soffits exposed. As a result the maximum floor-to-soffit height and feeling of space is achieved.
While not appropriate for every project, there is no reason why this technology cannot be applied to most new and refurbished commercial developments, as well as within projects in sectors such as education, healthcare and transport.
