Historic harmony in Pembroke Library Case Study, Heritage
When the Old Library at Pembroke College, Cambridge required a new heating and air conditioning system as part of a comprehensive refurbishment, the building services consultants and engineers were faced with this challenge. This has been met with the Invisible.AC system as part of the complete solution.
The Old Library is nowadays used for functions, meetings, lectures and dinners. Its refurbishment project included making critical repairs to its late 17th century ornate and intricate masterpiece ceiling, full redecoration, the installation of secondary glazing, a new lighting scheme and the specification of a new closely controllable HVAC system.
As a result of the refurbishment, the building would be much more tightly sealed with no real natural ventilation. Apart from the risk of humidity build-up and condensation which might have a detrimental effect on the precious interior décor, the main issue was the personal comfort of occupants when some 200 people may gather at any given time for functions.
The bespoke HVAC system design integrates a heat recovery unit, a gas fired boiler and condenser to provide a complete, highly energy efficient centralised solution. When it came to the air delivery system, it was essential that it was totally compatible with the system, easy to install and visually sympathetic with the historic interior of the Old Library.
The Invisible.AC mini-duct air distribution system can deliver heating, cooling, fresh-air and dehumidification without impacting on the visual appearance of a property. It is also designed to link to heat recovery systems and as such was perfectly suited to the Old Library project.
The system uses flexible, easy to install space saving short lengths of ducting with just a 105mm external diameter. The ready insulated, sound-attenuating mini-ducts distribute the conditioned air from the heat recovery unit in the basement, winding through the building’s restricted headroom space below the Old Library’s floor and into the room itself. The ducting features manually adjustable Volume Control Dampers (VCDs) to control the flow of air in order to maintain energy efficiency and keep occupant comfort at the desired level.
Discreet, quiet and unobtrusive Invisible.AC linear floor outlets run around the perimeter of the room and integrate perfectly with the Old Library’s interior architecture. They are the perfect alternative to the installation of unsympathetic grilles, wall or ceiling units and radiators.
The complete system has fulfilled the aim of dramatically improving ventilation and the indoor air quality. It has a heat recovery efficiency as high as 96%, ensuring significant energy cost savings and with no compromise whatsoever on the visual impact of the Old Library.