Umeå University's logo

Weather-based damages in housing insurance correspond to 23 % of all insurance claims in Sweden and include damages from fungi. Some fungi could cause health risks to the tenants, while others can cause rapid structural failure for the building itself, like the dry-rot fungus Serpula lacrymans.

The study aims to analyse a possible connection between the increased rate of insurance claims related to S. lacrymans fungi and climate change. This study uses historical data of 2446 damaged properties from insurance companies and current and future climate data. In addition, eight geographical areas within Sweden with 567 damaged properties were analysed in relation to changes in outdoor temperature over a decade. Finally, a full onsite inspection of 20 infected properties by S. lacrymans fungi was conducted to evaluate common conditions for fungi infections.

The results of this study showed that the S. lacrymans fungus is expected to spread to the northern parts of Sweden even in areas where it could not exist before, while the rate of infected buildings in the southern part of Sweden might decline but not drop to zero. Wooden buildings older constructed before 1980 with chimneys and self-ventilation are at higher risk of infection. Economic implications are significant, with high repair costs rendering some buildings economically unviable, particularly in rural areas. Insurance reimbursement is typically limited to market value loss, indicating location, design, and maintenance status as crucial factors. The results may raise a concern for insurance companies and property owners, especially related to locations in the sparse parts of North of Sweden.

The use of pit thermal energy storages (PTES) enables higher solar fraction in district heating networks by counteracting the mismatch between heat demand and production in solar district heating (SDH) installations. Capital costs linked to land areas with site-specific geological conditions are the deciding factors for PTES constructions. This study investigates non-technical and technical factors for the implementation of PTES in Swedish district heating networks. Having several SDH and PTES installations in operation the country of Denmark is used as a reference. This study, based on literature review, discusses the drivers and challenges for the use of PTES in district heating networks.

This study investigates primary energy use and CO₂ emission reduction potential resulting from the integration of solar thermal heating in biomass-based district heating systems in high-latitude regions. A newly commissioned solar thermal system based on parabolic trough collectors for an existing district heating network in Häarnösand, Sweden, is used as a case study, and its hourly one-year measured data are used as inputs for the analysis. The changes in operation and fuel use for local district heat production are extended to a regional context, considering the short- and long-term perspectives of the energy system. The results show that during the studied period, the solar water heating system provided 335 MWh of heat to the existing district heating system with a supply/return temperature of approximately 80/45 °C. Consequently, 339–382 MWh of biomass fuel consumption could be reducedannually with such an installation, depending on the district heat production technologies being substituted. An annual CO₂ reduction of 65.3–189 tons can be achieved in an overall energy system perspective when the saved biomass substitutes fossil fuels. The reduction of CO₂ emission depends on the fuels being substituted and energy conversion technology.

Currently, companies in the solar heating sector may choose from a wide range of tools for modelling and simulating solar thermal power. However, due to the deviant design of some collectors, conventional simulation tools may be inadequate in correctly assessing the performance of such collectors. This study aims to test and validate an in-house simulation model for T160 PTC collectors developed by the company Absolicon Solar Collector AB by comparing measured data with simulated results. A solar district heating (SDH) plant in Härnösand, Sweden featuring 192 parabolic trough collectors (PTC) is used as a case study for the validation. Operational data such as weather data,solar heat production and collector loop/ambient temperatures were collected from the facilities of Absolicon. The data was compiled and simulated using a Python model developed for the T160 collectors. The study shows anacceptable correlation between simulated and measured data during periods with high DNI where a relatively highamount of heat is delivered to the district heating. Deviations are present during periods of low DNI and can bederived from inadequate assessments of heat losses from the piping of the installation in addition to inaccurate measurement data. 

Many schools in Sweden lack a proper indoor environment due to, e.g., poor thermal-envelope properties, overcrowded classes, poor visual appearance and insufficient ventilation. This study aims to explore the integration of a large number of indoor green plants into classrooms’ environments. This case study consists of three parts: measurements of the indoor environment including a final energy model, a questionnaire to the pupils with questions about their well-being and qualitative interviews with teachers. The case was two classrooms in a secondary education facility in central Sweden with an average annual temperature of 3◦ C and a long and dark winter period with snow. The results showed 10% lower CO2 and slightly higher and more stable temperatures due to the green plants. Worries about climate change and war among the pupils decreased after several months with the plants and worry about infectious disease increased. The teachers experienced fresher air from the plants and used the plant stands for a flexible classroom design. The conclusion is that indoor plants have the potential to contribute to a better indoor environment, but due to the high number of uncontrolled variables (including the effect of COVID-19) in measurements of real-life conditions, more studies are needed.