Zero Emission Building Envelopes: The Effect of Insulation and Thermal Masson Greenhouse Gas Emissions

Abstract

In a sustainable world, the use of non-regenerating natural resources is in balance with what nature is able to provide in long term. Our way of living has resulted in enormous usage of resources, and it is time to change our attitude and regain the balance. In this context, the main focus the latest years have been global warming caused by greenhouse gas (GHG) emissions. It is therefore important to reduce the GHG-emissions from buildings, not only from the operational phase, but from the whole life cycle.

This thesis presents six papers, where the building envelope has been studied, with main focus on thermal insulation and thermal mass. The advanced products Vacuum Insulation Panels (VIPs) and Phase Change Materials (PCMs) have been given special attention. The basis for the work has been a single-family house with a lightweight wood frame construction, which is a common Norwegian building. The house has been studied at three different levels and in a life cycle perspective:

1. Component level, i.e. the thermal performance of insulation, thermal mass and studs which is part of wall/floor constructions.

2. System level, i.e. the thermal performance of wall/floor constructions.

3. Building level, i.e. the energy performance of the building.

4. Life cycle, i.e. greenhouse gas emissions (GHG) during the life cycle of the house.

The work presented in the papers can briefly be summarised with: Different wall constructions have been tested in a hot box to measure the thermal transmittance (ref. paper I a and I b) and to investigate the effect of thermal mass (ref. paper III). The hot box measurements have been compared with numerical simulations.The relationship between insulation thickness in a house and greenhouse gas emissions have been studied using a building energy simulation program and calculations of life cycle GHG-emissions (ref. paper II).The relationship between different thickness of thermal mass and the energy demand of a house have been studied using building energy simulations (ref. paper IV). The effect of changing the climate and the type of thermal mass was also studied.The relationship between different thickness of thermal mass in a house and the greenhouse gas emissions have been studied using building energy simulations and calculations of life cycle GHG-emissions (ref. paper V). The effect of changing the climate and the type of thermal mass was also studied. Two case studies have shown (ref. paper II and V) that there is an optimum thickness for insulation and thermal mass, where the life cycle GHG-emissions are minimized.