Improved HVAC operation to preserve a church organ

The common operation of heating systems installed in churches in the Netherlands has led to typical building physics problems directly related with heating. One of the main problems is the drying related shrinkage and damage to (monumental) wooden organs under cold winter conditions. The paper presents an integrated heat, air and moisture model including modelling components for: the indoor climate of the church, the heating systems and operation, and the moisture distribution in wood. The modelling components are validated with measurements. Two types of control strategies are discussed. The first type is a limited indoor air temperature changing rate. The second type is a limited indoor air relative humidity changing rate. This preliminary study shows that a limitation of indoor air temperature changing rate of 2 K/h can reduce the peak drying rates by a factor of 20 and a limitation of the relative humidity changing rate of 2% per hour can reduce the peak drying rates by a factor of 50. The second strategy has the disadvantage that the heating time is not constant and therefore more difficult to implement in relation with early start-up.