Climate control simulation in Härnevi church : moisture storage analysis of a medieval stone wall

This thesis examines how the moisture content of a stone wall from the 15th century varies with different types of climate control. The simulations in this report is based on measured data from sensors placed inside and outside Härnevi Church north of Enköping. The measured data are processed to simulate different climate control strategies in the church porch. The simulated climate control strategies are temperature control and air-dehumidification, the systems are controlled against either a mold risk curve or a fixed maximum value for the relative humidity. The simulations are performed with the program WUFI Pro 6.1; which performs onedimensional hygrothermal calculations of building component crosssections and is an alternative to the traditional Glaser-Method.Many climate simulations have been performed, though only four are fully accounted for in this dissertation. Simulations that have not resulted in surface conditions below the mold risk curve LIM I has not been included in the investigation process. Simulation results are based on climate controls against "fixed relative humidity max 71%" and "mold risk curve LIM I-10 percentage points". The results show that the desorption process of the wall is similar to all four simulations but provides different absorption processes, control against the mould risk curve allows the wall a faster water content build up. The simulations show that control against the mould risk curve results in a greater moisture storage in the wall during the winter months; compared to control the climate against a constant relative humidity. During summertime there is no significant difference in moisture storage between the various climate control simulations. The operating time to control against the mould risk curve for one year is roughly 1000 hours less than control against constant relative humidity. When considering the results in this report together with Härnevi church's current heating system, this dissertation recommends a climate control based on temperature control against a mould risk curve. The results also show the importance of investigating the difference between the mold ratio in the air and on the surface of the wall to perform a proper and safe climate control