Maria Wall

Distribution of solar radiation in glazed spaces and adjacent buildings. A comparison of simulation programs

Energy simulation programs are commonly used to calculate the climate and energy requirements in glazed spaces and adjacent buildings. However, these programs have usually been developed to study buildings with ordinary window sizes. Comparisons of four simulation programs were carried out for a sunspace with an adjacent room. The distribution of solar radiation between the glazed space and the adjacent room as well as the portion of short wave radiation lost to the outside were studied. The programs show very large differences. The more simple calculation methods overestimate the utilization of solar radiation. This means that the temperature in the glazed space and also cooling requirements will be overestimated. In addition, heating requirements will be underestimated. The investigation shows that simulations of glazed spaces must be based on a geometrical description of the buildings, taking into account transmission through windows, reflection and absorption.

Architects' design process in solar-integrated architecture in Sweden

Architects can play a key role in future solar-integrated architecture as they are involved in the building process from the beginning. Solar-integrated architecture takes both passive and active use of solar energy into account. The aim of this research was to gain insight into the actual design processes of solar-integrated buildings. Therefore, semi-structured interviews were conducted with Swedish architects who designed such buildings. Results showed that teamwork was experienced as crucial and building performance simulation tools were hardly used by the architects themselves. Results from these interviews serve as input for the development of new architectural guidelines for designing solar-integrated architecture as part of IEA-SHC Task 41: Solar Energy & Architecture.

The impact of urban design decisions on net zero energy solar buildings in Sweden

Planning for future energy-efficient and energy-producing buildings requires specific knowledge during the design process. Many design decisions taken by urban planners –form, density, roof type and orientation – have a significant effect on the conditions of such buildings, although urban planners might not always be aware of the effect of their design. This study examines the effects of important design decisions on the solar energy potential of net zero energy solar buildings. Typical Swedish building blocks with varying form, density, roof type and orientation were used to simulate the annual solar irradiation and energy production, and to calculate the load match for heating and electricity under Swedish conditions. Results of this study show that the urban density is the most influential parameter on the solar potential of building blocks. Furthermore, flat roofs often returned the highest load match value, while the effect of orientation on the solar potential turned out not to be that straightforward. With the results of this study, urban planners can make better informed decisions, while it also provides a ground for the net zero energy solar buildings discussion by exposing the boundaries of such buildings in the urban environment.

Towards zero-energy buildings and neighbourhoods – A combination of energy-efficiency and local renewable energy production:

The development of high performance buildings and urban areas is important due to increased environmental goals. In many cases, it is a voluntary development by different actors in the building industry and by municipalities that strive to reach sustainable solutions for cities and neighbourhoods. So many things have been developed and learnt from, but still we have a long way to go. Although I am collaborating in international projects, my working platform is based in a Nordic country (Sweden), which will influence the discussions below. After the oil crisis in the 1970s, energy issues became important when new buildings were planned. In Sweden, as example, also existing buildings were renovated by changing to better windows with lower U-values and making the building envelope more airtight. Often more insulation was added in the roof construction of the building and sometimes also in exterior walls. The eagerness to reduce energy losses caused sometimes a not so good side-effect; buildings with ‘natural’ ventilation that depended on a leaky building envelope, suddenly did not get sufficient ventilation. This was bad marketing for energy-efficiency measures. In cold countries like Sweden, mechanical ventilation systems with heat recovery became more frequently used to ensure sufficient ventilation rates without causing high energy losses. Since then a system approach with less sub-optimization has been growing when designing buildings. In the 1980s, engaged developers, architects and other stakeholders planned and built low-energy buildings. Low-energy buildings were not necessarily what we mean by energy-efficient buildings. An energyefficient building means that the building uses less energy than a standard building, while maintaining the building’s quality/function such as thermal comfort, air quality, etc. A low-energy building simply means that the building is using less energy than a standard/ reference building. However, this could be, e.g. due to a reduced or increased indoor temperature outside the comfort zone, or by causing a poor indoor air quality as mentioned above. Thus, a reduction in energy use could mean a reduction in quality and performance in a worst case scenario.

Experiences from the urban planning process of a solar neighbourhood in Malmö, Sweden

Abstract Many cities have set ambitious goals regarding the production of renewables within cities using advanced energy planning. The crux of those ambitious plans and goals is to put them into action using different legislative instruments, like a zoning plan. In this article, the experiences of an action research project with the aim to support local urban planners developing a zoning plan that creates favourable conditions for solar energy in Malmö, Sweden, are described. The Swedish planning process, national legal framework and financial conditions for PV systems are described first. Then, different scenarios for optimising the zoning plan were studied, using mainly the economic performance as a key indicator. The results showed that the detailed development plan does create both barriers and drivers for the implementation of PV systems in new buildings. At the same time, it also became clear that the legal and financial framework are equally decisive. By describing the lesson learnt, the method can be applied to other (inter)national contexts.

State-of-the-Art of Education on Solar Energy in Urban Planning - Part 2: Solar Irradiation Potential Tools in Education

This booklet describes an interdisciplinary summer school on solar energy in urban planning. Teaching methodologies and results are shown as an applied example of successful collaboration between teaching, research and practice, to serve as inspiration and encouragement for educators.