Green Cost Savings
Microclimates are Green!
Many artefacts in museums need constant, or near constant humidity levels, and the costs of maintaining these conditions in many museums can be astronomically high. Buildings must be built or modified to safely maintain appropriate environmental conditions, as the costs of energy constantly increase.
Energy costs for humidity control alone can be a substantial portion of an institution's energy expenses*. In a recent master's thesis done at the University of Pennsylvania, under the guidance of Michael C. Henry and Richard Kerschner, David Artigas concluded "the results show that energy costs and consumption decrease exponentially as the variance of the indoor conditions increases." With each halving of limits on allowable humidity variations, the costs of environmental control double. Allowing your limits to increase (say from +/- 6% RH to +/- 12% RH) could halve your energy costs!
Active and passive microclimate environmental control techniques have been a fixture of museum display technologies since the 1960's. These systems can provide steady, reliable climate control to the display cases exclusively. Clearly, it is more efficient to maintain constant humidity levels in relatively small, tightly sealed display cases than it would be to maintain similar levels in a cavernous gallery. Energy costs, both financial and carbon loading can be substantially reduced.
In addition, as many artefacts need differing environments for optimal storage and display, these conditions cannot be met by a single room environment. Microclimate humidity control can efficiently compensate for temperature changes, modifying the moisture content of the air to maintain constant relative humidity levels, even as temperatures change, and regardless of the ambient gallery humidity levels.
From the earliest studies of showcase environmental control, microclimate control was seen as a generator of cost savings for museums. Over forty years later, with steadily increasing energy costs and a new concerns for the dangers of carbon emissions, microclimate control techniques are now specified for their "Green" aspects alone, with energy savings driving the project rather than artefact safety.
Click here for a study demonstrating Energy Savings in Te Papa
Click here for a Master's thesis by David Artigas on Comparing Energy Costs in Museums. One conclusion was that energy costs decrease exponentially as humidity setpoints are loosened.
*Even worse, every visitor and employee in the building is generating CO2, and stale air must be exhausted from the building and replaced with fresh air. While heat can sometimes be recaptured in a heat exchanger, the energy used to adjust the humidity content of the air (usually accomplished by generating steam at substantial costs) is lost with the exhaust air.