Insolation analysis in sustainable architecture design
Case study: Creative canopy design for optimal insolation utilization in the car dealership project
Never before architects and designers has to pay so much attention to designing buildings which would deliver great indoor comfort while at the same time achieve a high sustainable score. The right amount of natural light, fresh air, consistent temperature, exciting view of the outside environment, as well as sometimes view to the inside of the building, are all important factors of modern design.
Aldo weather, sunlight, and temperature are all dynamic forces of nature, they all can be addressed by static elements of a building. There are many reasons to control an amount of sunlight that is admitted inside a building. In warm climates excess solar causes overheating issues, which can lead to high energy consumption. In cold climates, solar heat gains may reduce a need for conventional space heating. In some areas, both are the case, one in the summer and other in the winner respectively. In all climates controlling diffusion will result in better daylighting.
Passive solar heating
Passive solar heating is one of the strategies composing passive design. Philosophy of passive design is to take advantage of the climate (rather than fighting it) to create a comfortable indoor environment. This strategy usually leads to reducing the energy consumption of a building.
In passive solar building walls and floors are made to collect and store solar heat energy when window, reflectors, and shadings control and distribute solar irradiation. It is crucial to consider very careful placement and sizes of glazing, thermal insulation, thermal mass, and shading.
Energy efficiency challenges
Car dealership building usually features large glazed facade with very high ceiling area behind it. This usually leads to issues with overheating in the cooling season and heat losses during the heating season. Uneven distribution of temperature inside can also cause issues with indoor microclimate.
In this case, designers decided to use passive solar heating approach to address those issues. Large glazed facade of exposition space was made to work in conjunction with shading canopy to reduce heat gains in summer. Shading is designed in such a way so it let thru solar thermal energy during the heating season and large tiled floor of the exposition area can act as thermal mass.
Optimization process with Shadow Analysis and SketchUp
To optimize the shape of the canopy architects use Shadow Analysis plugin for SketchUp. Designers started from the box-shaped building of modular structure which offers low construction cost. Next, they went through a series of iteration examining different sizes of glazed facade and depth of the canopy.
To find optimal solution designers used trial and error method. Combination of Shadow Analysis and SketchUp allowed for very quick modeling and evaluation of each concept. On average, it took few minutes to check new possible solution. Hole optimization process took one day and produced a very interesting outcome from an aesthetic perspective as well as energy efficient one.
Shadow study (below) shows an impact of the designed canopy on a glazed facade. During the heating season windows are exposed to sunlight, this will have a positive impact on heating and lighting requirements of this space. In the cooling season, canopy casts a shadow over glazed elevation, this reduces cooling requirements as well as reduce light level (daylight during summer is usually to intensive for comfortable interior conditions). By designing well-optimized shading canopy designers managed to reduce negative impacts of solar radiation (overheating in summer, heat loses in winter) and enforce positive aspects of it.
The case study of car dealership shows how Shadow Analysis can be incorporated into green building design process. Solar heating, thermal storage and daylighting are very important in sustainable design and in acquire energy efficient building certificates like LEED or BREEAM.
Shading is a crucial factor in passive solar design. It can be designed to allow sunlight and heat into a building in winter and reject it during summer months. The simplest method involves the concise distribution of windows around a building and horizontal shading of well-optimized shape which allows sunlight during winter when the sun is at a lower angle. Shading can also be provided by landscaping and trees or other buildings. In all of those cases, Shadow Analysis provides very detailed and easy to understand information for optimizing the design.