Moducel controls environment for China’s Terracotta Army
Images supplied courtesy of the British Museum
Moducel air handlers are providing a controlled environment at the British Museum for China’s world famous terracotta army. The exhibition ‘The First Emperor: China’s Terracotta Army features the largest group of terracotta figures ever lent by China (20 complete figures) and is housed in the historic Round Reading Room, the first time this space has been used for a temporary exhibition.
As the British Museum is a Grade 1 listed building permission had to be sought to convert the Reading Room for a temporary period.
Protective boxes were built over the desks and a temporary floor approximately two metres above the Reading Room’s floor bridges over them to provide exhibition floor space and an accessible void for engineering services to the display cases and exhibition media.
The Chinese Authorities required tightly controlled environmental conditions for the display of the artefacts with temperatures of 22°C + 2°C and humidity levels of 45% RH + 8%. The challenge was to design a means of maintaining these conditions irrespective of the variation in load presented principally by display lighting and up to 400 visitors each hour. Ventilation would also need careful consideration given the high concentration of visitors in the enclosed Reading Room.
Images supplied courtesy of the British Museum
The Reading Room was already equipped with a mechanical ventilation system installed at the time of the Great Court development. Two air-handling units were installed in the “Spider”, a series of passageways radiating from the centre beneath the Reading Room’s floor. These units deliver a mixture of fresh air from the Great Court primary plant and re-circulated air from the Reading Room via ductwork to linear grilles fitted in the desks themselves.
To overcome the ventilation problem, the units have been temporarily converted to provide full fresh air using surplus capacity designed into the primary plant.
In the exhibition area, eight custom built Moducel LKP units are providing the air conditioning. Four units are identical fresh air units comprising filters, chilled water-cooling coils (with a bypass arrangement), supply fan and discharge plenum with an air volume of 1.0 m³/s for each unit. The other four air handlers are identical recirculation units comprising filters, chilled water cooling coils, LPHW (Low Pressure Hot Water) heating coil, Vapac electrode type humidifiers, fan section, discharge plenum and air volume of 1.55 m³/s.
Images supplied courtesy of the British Museum
The cooling coils in the fresh air handling units make use of high by-pass technology to maximise dehumidification without reheat. This achieves the necessary latent removal without undue dry bulb depression and a clever way of keeping costs down and saving energy.
The re-circulating units pressurise the void beneath the exhibition floor with air supplied via floor mounted swirl diffusers.
Return air is drawn back to the under-deck plenum through grilles around the perimeter enclosure via air handling units including cooling, re-heat coils and integrated Vapac humidifiers to achieve the necessary temperature and humidity control at all times.
Extensive environmental trials were carried out before the exhibition opened to ensure that temperature and relative humidity criteria were being maintained.
Moducel worked closely with TGA Consulting Engineers and Romec who co-ordinated much of the work, to design the most appropriate solution. Moducel is proud to be associated with such an historic and high profile exhibition and is the latest in a number of projects it has undertaken at The British Museum.