Tor Broström

Climate for Culture: assessing the impact of climate change on the future indoor climate in historic buildings using simulations

BackgroundThe present study reports results from the large-scale integrated EU project “Climate for Culture”. The full name, or title, of the project is Climate for Culture: damage risk assessment, economic impact and mitigation strategies for sustainable preservation of cultural heritage in times of climate change. This paper focusses on implementing high resolution regional climate models together with new building simulation tools in order to predict future outdoor and indoor climate conditions. The potential impact of gradual climate change on historic buildings and on the vast collections they contain has been assessed. Two moderate IPCC emission scenarios A1B and RCP 4.5 were used to predict indoor climates in historic buildings from the recent past until the year 2100. Risks to the building and to the interiors with valuable artifacts were assessed using damage functions. A set of generic building types based on data from existing buildings were used to transfer outdoor climate conditions to indoor conditions using high resolution climate projections for Europe and the Mediterranean.ResultsThe high resolution climate change simulations have been performed with the regional climate model REMO over the whole of Europe including the Mediterranean region. Whole building simulation tools and a simplified building model were developed for historic buildings; they were forced with high resolution climate simulations. This has allowed maps of future climate-induced risks for historic buildings and their interiors to be produced. With this procedure future energy demands for building control can also be calculated.ConclusionWith the newly developed method described here not only can outdoor risks for cultural heritage assets resulting from climate change be assessed, but also risks for indoor collections. This can be done for individual buildings as well as on a larger scale in the form of European risk maps. By using different standardized and exemplary artificial buildings in modelling climate change impact, a comparison between different regions in Europe has become possible for the first time. The methodology will serve heritage owners and managers as a decision tool, helping them to plan more effectively mitigation and adaption measures at various levels.

A Method to Assess the Potential for and Consequences of Energy Retrofits in Swedish Historic Buildings

Abstract The Swedish research project ‘Potential and Policies for Energy Efficiency in Swedish Historic Buildings’ aims to investigate the interdependency between political energy targets and effects on the built heritage. The first part of this paper presents an iterative and interactive method to assess the potential for and consequences of improving the energy performance in a stock of historic buildings. Key elements in the method are: categorisation of the building stock, identifying targets, assessment of measures, and life-cycle cost optimisation. In the second part of the paper, the method is applied to a typical Swedish building. The selected case study shows how the method allows for an interaction between the quantitative assessment of the techno-economic optimisation and the qualitative assessment of vulnerability and other risks. Through a multidisciplinary dialogue and iteration it is possible to arrive at a solution that best balances energy conservation and building conservation in a given decision context.

Adaptive ventilation for climate control in a medieval church in cold climate

ABSTRACT Old medieval churches hold objects of great historical and cultural value: organs, altars, paintings. But they have no systems for indoor climate control or the church may be heated only at services. These conditions are inadequate for the preservation of cultural heritage. The objective of this paper is to assess an adaptive ventilation (AV) solution in a church for reduction of the relative humidity (RH) in an unheated church to prevent mould growth and disintegration of wooden parts. The operation principle of the system is to ensure ventilation in the church when water vapour content in the outdoor air is lower than that indoors, to lower the RH in the church. A case study in Hangvar Church in Gotland, Sweden, was conducted to test the performance of AV to reduce the RH in the church. Field measurements showed that AV has a positive impact on the indoor RH of the church. During the measurement period without climate control, the RH in the church was higher than 70% of 98% of the time; with AV, the indoor RH was higher than 70% only 78% of the time. Building simulation was carried out to test the performance and energy consumption of AV under different conditions. The simulations showed that auxiliary heating and airflow rate both have high impact on the system performance. The higher the heating power, the more effective the system is; thus, lower airflow rates are needed. Infiltration has also high impact on the system performance: the lower the infiltration rate, the better the AV performance is.

Indoor hygrothermal condition and user satisfaction in naturally ventilated historic houses in temperate humid continental climate around the Baltic Sea

Indoor climate and user satisfaction were analysed by field measurement and a questionnaire in 67 traditional rural houses in Estonia, Finland and Sweden. Our findings showed that the indoor climate in all the investigated historic rural houses needs improvement. The room temperature was mainly too low during winter. Leaky houses had also a larger vertical temperature difference. The relative humidity in the unheated and periodically heated houses was high during winter and caused risk for mould growth in 17% of all houses and 33% of unheated houses. Significant differences of indoor humidity loads in different houses were revealed depending on the living density and usage profile. During the winter period, the design value of moisture excess was 4–5 g/m3 and the average moisture load was 2–3.5 g/m3. The indoor humidity load in historic houses was similar to that in modern houses. The results of the questionnaire showed that main problems were related to unstable or too low temperatures. At the same time, inhabitants rated the overall indoor climate as healthy and no statistically important relations were found between average indoor temperature and complaints about too cold or too warm indoor temperatures.

Standardizing the indoor climate in historic buildings: opportunities, challenges and ways forward

ABSTRACT Standardization for indoor climate control in historic buildings has recently taken a new direction with standards and guidelines that focus more on decision processes than outcomes. The objective of the paper is to explore and discuss how standards can evolve to both fit and guide decision processes to facilitate a sustainable management of historic buildings. Interviews with engineers and heritage professionals in the Church of Sweden in combination with indoor climate monitoring were used to understand the technical and organizational context. The results show that the development of process standards solves some of the problems related to the conventional outcome-oriented approach by opening up for a wider set of solutions. However, available guidelines are difficult to apply and integrate in the existing management of churches. A stronger focus on strategic feedback and an increased use of local guidelines are suggested.