IAQ 2000, Presentation 19:
Tadj Oreszczyn*, Nigel Blades* and May Cassar+
Bartlett School of Graduate Studies, University College London *
Resource: The Council for Museums, Archives and Libraries +
Universities and Museums: an account of work in progress - the UK DETR-funded research project' Energy Efficient Pollution Control in Museums and Galleries'
The UK Partners in Technology project 'Energy Efficient Pollution Control in Museums and Galleries' was carried out with the aim of improving the energy-efficiency of environmental control in museums and galleries by developing sustainable pollution control strategies. The study was a collaborative one, involving a university, five museums, and a filter manufacturer, all as active partners.
OUTLINE OF WORK
The objectives of the project were met by the following programme of work:
- Monitoring pollution concentrations in five buildings - two naturally ventilated (Dreadnought Study Collection Centre of the Horniman Museum and The Manchester Museum), two air-conditioned (Museum of London and the Theatre Museum) and one with a mixture of air-conditioned and naturally ventilated galleries (Victoria & Albert Museum).
- Producing a hierarchy of potential improvements to the building fabric and services to reduce pollutant levels while monitoring the implications these have for energy use.
- Performing intervention studies within four (Horniman Museum Dreadnought Study Collection Centre, Museum of London, The Manchester Museum and Victoria & Albert Museum) of the five buildings.
- Developing methods and prototype components to reduce pollutant concentrations by passive and active techniques.
- Produce design guidance for the heritage sector and the building services industry on how to choose the most appropriate pollution control strategy. (Guidance document to be published in December 2000. Details on how to obtain a copy are at the end of this abstract).
- Monitored pollution levels in several naturally ventilated storerooms at the Horniman Museum Dreadnought Study Collection Centre were found to be as low as in air-conditioned galleries with carbon filtration, such as those at the Museum of London.
- Internal surface deposition of pollutants reduced internal pollution concentrations by up to 90% in naturally ventilated storerooms, such as those at the Horniman Museum Dreadnought Study Collection Centre.
- Novel materials, such as the carbon-impregnated fabric tested at The Manchester Museum may act as passive pollution scavengers, reducing internal pollution concentrations in a naturally ventilated gallery or storeroom. More research is required to confirm this result.
- In air-conditioned carbon-filtered buildings, for pollution control to be effective the system must be correctly operated and maintained, and filters must be replaced with high-quality units at appropriate intervals.
- Air-conditioned buildings often operate at higher ventilation rates than naturally ventilated buildings and hence if they are not equipped with carbon filtration, higher internal pollution concentrations than in naturally ventilated buildings will occur.
- Localised carbon filtration can control internal pollution concentrations significantly even in buildings with high ventilation rates. The power consumption of one unit tested was 10.5 W m-2 of conditioned area, based on an area of 64 m2. The annual cost to run this, assuming continuous operation would be 5870 kWh. This is 1% of the estimated energy cost of a full museum air-conditioning with filtration system. Clearly, where it is necessary to control only a few localised zones it is more economic to install local units rather than a central system.
- Monitored external concentrations of nitrogen dioxide can be up to 50% higher at the front of a roadside building compared to the rear.
MAJOR CONCLUSIONS ARISING FROM THE PROJECT
- The main method of pollution control in current use i.e. centralised carbon filtration, is not the only viable method of reducing pollution in many museum buildings, although it is often perceived as such.
Current guidance for building services engineers does not take into account surface deposition, which can significantly reduce the need for active pollution control.
The measured energy consumption of air-conditioned museums is approximately twice that of naturally ventilated museums per m2 of display area. We estimate that approximately 25% of the energy consumed by the air-conditioning fans in a system such as the Museum of London's is expended in overcoming the pressure drop caused by the filter bank. Clearly, there is the opportunity for large energy savings, reduction in maintenance costs and plant size through the use of alternative pollution control strategies, as described in the technical report ('Energy Efficient Pollution Control in Museum s and Galleries Milestone 6: Closing Technical Report', March 2000).
Localised filtration can provide highly effective pollution control for smaller galleries and rooms in an energy-efficient manner. It would be most appropriate to use this method in situations where it is important to provide clean air to a few critical zones. The energy cost per zone treated (based on a room area of 64 m2) could be as low 1% of the cost of a fully centralised system. If it is necessary to treat a large number of zones, diminishing returns apply as penalties in terms of maintenance and capital cost come into play. In this situation a centralised system may be the better option.
The naturally-occurring process of surface deposition, either to existing surfaces, or to purposely-introduced absorbing materials will significantly reduce reactive pollutant concentrations, provided the ventilation rate of the room or gallery is low, ideally below 0.5 air changes per hour for effective control of nitrogen dioxide. This approach has no energy or maintenance costs but some capital costs in terms of the absorbing materials and measures that may be necessary to reduce air infiltration and achieve a low ventilation rate. This approach can be made to work well in stores, archives and perhaps some less visited galleries. It is less appropriate for galleries with large numbers of visitors, which require a high ventilation rate for human comfort.
These conclusions are not only important to museums and galleries. They are equally relevant to other heritage buildings, such as libraries and archives. They are also important conclusions for designers and operators of more mainstream building types such as commercial and domestic premises.
For further information please contact:
Resource: The Council for Museums, Archives and Libraries
16 Queen Anne's Gate, London SW1H 9AA, U.K.
Phone: 020 7233 4200
Fax: 020 7233 3686
Prof Tadj Oreszczyn
Bartlett School of Graduate Studies, (Torrington Place Site), University
Gower Street, London WC1E 6BT, U.K.
Phone: 020 7679 5906
Fax: 020 7916 3892
Dr Nigel Blades
Bartlett School of Graduate Studies (address as above)
Phone: 020 7679 5965
Fax: 020 7916 3892
The guidance document developed from this project, "Guidelines on pollution control in heritage buildings", will be published as a special supplement to the journal Museum Practice, and will be sent free to subscribers in December 2000. Further copies are available at a cost of £15 from: The Secretary, Bartlett School of Graduate Studies, (Torrington Place Site), University College London, Gower Street, London WC1E 6BT, UK.
Index of presentations at IAQ2000 meeting
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