Low-Emissivity Window Films as an Energy Retrofit Option for a Historical Stone Building in Cold Climate

Saman Abolghasemi Moghaddam,Magnus Mattsson,Manuel Gameiro Da Silva,Nuno Simões,Jan Akander,Arman Ameen

doi:10.3390/en14227584

Saman Abolghasemi Moghaddam, Magnus Mattsson + Show 4 more

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https://doi.org/10.3390/en14227584

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Journal: Energies	Publication Date: Nov 12, 2021
Citations: 18	License type: CC BY 4.0

Affiliation: University of Coimbra, University of Gävle

Abstract

Low-emissivity (low-E) window films are designed to improve the thermal comfort and energy performance of buildings. These films can be applied to different glazing systems without having to change the whole window. This makes it possible to apply films to windows in old and historical buildings for which preservation regulations often require that windows should remain unchanged. This research aims to investigate the impacts of low-E window films on the energy performance and thermal comfort of a three-story historical stone building in the cold climate of Sweden using the simulation software “IDA ICE”. On-site measurements were taken to acquire thermal and optical properties of the windows. This research shows that the application of the low-emissivity window film on the outward-facing surface of the inner pane of the double-glazed windows helped to reduce heat loss through the windows in winter and unwanted heat gains in summer by almost 36% and 35%, respectively. This resulted in a 6% reduction in the building’s annual energy consumption for heating purposes and a reduction in the percentage of total occupant hours with thermal dissatisfaction from 14% (without the film) to 11% (with the film). However, the relatively high price of the films and low price of district heating results in a rather long payback period of around 30 years. Thus, the films seem scarcely attractive from a purely economic viewpoint, but may be warranted for energy/environmental and thermal comfort reasons.

Highlights

The results of the simulation for the base model, presented in Figure 9, show that the highest and lowest share of the building’s annual energy consumption are 215,500 kWh and 6300 kWh for heating purposes and domestic hot water, respectively, which are both supplied by the district heating network
The comparison between the simulation results of the base model and the energy bills revealed a 3% difference between them, indicating a reasonable validity of the IDA Indoor Climate and Energy (ICE) base model
It was found that the application of the tested low-emissivity window film helped to reduce heat losses through the glazed parts in winter by about 36%, resulting in a 6% reduction in the annual district heating-related energy consumption of the building

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Around 25% of the existing buildings in Europe were built prior to the middle of the last century and are a living symbol of Europe’s rich cultural heritage and diversity. Based on their age, integrity and significance, some of these buildings are recognized as historic and have been registered at the local, state or national level [1]. Old and historic buildings are mostly energy-inefficient [2,3], and generate more emissions than new buildings [4]

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