Low-Energy Museum Storage

The energy needed for climate control in a museum storage building can be greatly reduced by allowing a moderate annual temperature cycle. The energy saving is achieved partly by abandoning heating or cooling and partly by a less strict humidity control. Temperature moderation can be provided by the building itself. The proposed system is a highly thermally insulated building envelope with an uninsulated floor directly on the ground. The inside temperature is allowed to vary freely, buffered by the large heat store of the ground. Such a structure will completely even out the daily temperature variation and reduce the annual temperature amplitude to about half the average outside cycle. In a northern European temperate climate, the inside temperature will span less than 10°C. The relative humidity is buffered by hygroscopic materials or controlled by mechanical dehumidification. This climate control strategy relies on an almost airtight building with an air exchange rate of less than one air change per day and consumes annually as little as 1 kWh per cubic meter space. Relative humidity is easily controlled within the 40%–60% range, which is acceptable for most materials and conforms to all standards. Mechanical failure caused by this temperature variation is unlikely for most objects. However, some standards propose contradictory temperature limits. The reason might be due to recommendations that are intended for both storage and exhibition spaces, whereas temperature constancy is mainly for the benefit of human comfort and should be implemented only in permanently occupied buildings.