Displacement ventilation in the museum environment: a case study

The indoor climate in a recently renovated Dutch museum* does not meet design criteria and specifications for preservation although an extensive climate system is installed. Furthermore indoor air quality is poor during high occupancy. Eindhoven University of Technology (TU/e) performed measurements regarding temperature and relative humidity (Rh) on 20 locations throughout the museum. Also computer modeling was used to research optimizations. Results show problems partly are caused by malfunctioning of the humidification system. Also the dehumidification system is too low in capacity. Comparing results with the original design parameters based on the strict former guidelines by the Netherlands Institute for Cultural Heritage, indoor climate is only for about 60% of time within limits of the guidelines. These guidelines are comparable to ASHRAE A. Comparing the data with guidelines as given in ASHRAE, which can be considered fair for such a building, more satisfactory results are found. In that case about 80% of time indoor climate conditions in the galleries are within limits. Literature and measurements show that the used method of ventilating, Variable Air Volume (VAV) combined with displacement ventilation, is not capable to create and maintain stable and homogeneous indoor climate conditions and therefore is an incorrect design choice for a museum. From literature it is known that displacement ventilation causes hygrothermal stratification over the height of the room and therefore over large artifacts. Furthermore VAV is known for its poor humidity control and possible low air quality. Given the fact that renovating the system technically as well as financially is not an option, it is recommended to optimize the current system. Despite the incorrect design choice, reasonable acceptable climate conditions are achievable this way, without too large hygrothermal stratification. *the museum is anonimized on reques