In a net zero energy building (nZEB), the energy demand from the operation of the building is met by renewable energy generated on site. Buildings require energy both in the form of heat and electricity, and solar energy utilization is important in order to reach a net zero energy balance. In projects with ambitious energy targets or limited available areas for local energy generation, solar thermal and photovoltaic (PV) installations will eventually compete for space on roofs and facades. Hybrid photovoltaic-thermal (PV/T) modules, in which heat and electricity is generated simultaneously, are therefore an interesting technology for building applications, which can potentially lead to a higher total efficiency and lower use of space. This paper describes a comparative simulation study of different solar energy solutions for a Norwegian residential building concept aiming for a net zero energy balance. Separate PV and solar thermal systems are compared to PV/T systems, and the resulting energy balances analyzed. The results show that the building with only high-efficiency PV modules comes closest to reaching a zero energy balance, but that the results depend greatly on the nZEB definition, the boundary conditions and the design of the building"s energy system.

The objective of this work is to present, evaluate and discuss the calculation methodology and embodied greenhouse gas (GHG) emission results from zero emission building (ZEB) case studies from the Norwegian ZEB research centre, to extract design drivers and lessons learnt. In all, two virtual models, and five ZEB pilot buildings are assessed; consisting of three residential, two office and two school buildings. The embodied GHG emission results show that the building envelope (ca. 65%) and production and replacement of materials (ca. 55-87%) are the main contributors to total emissions across the Norwegian ZEB case studies. Although difficult to draw definitive conclusions, this work builds upon the current body of knowledge on embodied GHG emissions in Norwegian ZEBs, and provides some practical indications for embodied GHG emission calculations and reduction strategies in future Norwegian ZEB and zero emission neighbourhood (ZEN) projects.

Service lifetimes applied for technical components are given in Table A1 and construction materials in Table A2. It is assumed that the building service lifetime is 60 years. Main construction materials such as concrete, metals, insulation and timber are assumed to have the same service lifetime as the building, 60 years. Service lifetimes of windows, doors, solar thermal panels and heat pumps are based on the previous Norwegian concept studies (Dokka et al., 2013b). Inner wall coverings, such as plywood panels or gypsum, are assumed to have the service lifetime of 60 years according to (FPInnovations, 2013

No abstract

Printed by NTNU Grafisk senter i This thesis concerns the use of solar energy in energy efficient buildings. More precisely, the topic is photovoltaic-thermal (PV/T) solar energy systems, and how these can be used to provide renewable energy in zero emission buildings. PV/T modules are a hybrid between photovoltaic (PV) modules and solar thermal collectors, and therefore generate electricity and thermal energy simultaneously. The objective of the thesis was to investigate the potential of PV/T systems to minimize the life cycle greenhouse gas emissions of a residential building.The building sector accounts for around one third of the global energy use and about half of the electricity use, and is therefore a key area to focus on in the effort to mitigate climate change and to create more sustainable societies in the future. The environmental impact of buildings need to be lowered by reducing the energy demand during construction and operation, but also by replacing polluting energy sources with renewable ones. The European Union has demanded of its member states that all new buildings shall be nearly zero energy buildings by 2020.Solar energy is well-suited to use in buildings, and can supply electricity, lighting, heating, and cooling. Once installed, a solar energy system supplies energy without pollution, is silent, have few or no moving parts, and can also be integrated into the building itself. In order to do investigate how PV/T systems can best be used in buildings to minimize life cycle emissions, the systems have been studied both in terms of energy performance and in terms of greenhouse gas emissions.The main research method in this thesis has been simulation of solar energy systems in buildings. Using simulations, PV/T systems have been compared to other solar energy systems with separate PV modules and solar thermal collectors. The simulation studies were performed in the simulation programs Polysun and PVsyst, and were based on commercial solar energy products available on the current market. The use of heat pumps, air-source and ground-source, in combination with solar energy systems was also studied.Two case buildings, the ZEB residential concept and the Living Lab, have been used in the simulation studies. The buildings are two of the pilot buildings of the Norwegian Research Centre for Zero Emission Buildings (the ZEB Centre). Both buildings are single family residential buildings located in Central or Southern Norway, and are designed to meet the Norwegian passive house requirements.The embodied emissions of the solar energy systems were determined using elements of life cycle assessments (LCA). A review of previous research found few studies of the environmental impact of PV/T modules, especially using industrially produced modules. The embodied emissions of such a PV/T module was therefore determined in this thesis, based on a combination of data from databases and information from module producers. The embodied emissions of the case buildings and the other solar energy systems studied were d...