Buildings must be responsive to solar orientation on the site. The sun is at a low angle during the winters and to the south of east-west axis. During summer, its path is at a high angle and slightly north to the east west axis. The alteration in path affects solar radiation penetration patterns during different seasons and consequently, heat gain and loss in a building.
Form and orientation constitute two of the most important passive design strategies for reducing energy consumption and improving thermal comfort for occupants of a building. It affects the amount of sun falling on surfaces, daylighting and direction of winds. Towards net zero energy goals, form and orientation have significant impact on building’s energy efficiency, by harnessing sun and prevailing winds to our advantage. Thus they play a pivotal role in NZEB design approach as these strategies are one time interventions and their potential benefits should not be missed.
Building designs vary according to context of its location and climate. However, the underlying principle remains the same, maximising amount of solar radiation in winter and minimizing the amount in summers. In predominantly hot regions, buildings should be ideally oriented to minimize solar gains, the reverse is applicable for cold regions. Orientation also plays an important role with regard to wind direction.
The building form determines the volume of space inside a building that needs to be heated or cooled. Thus, more compact the shape, the less wasteful it is in gaining/losing heat. In hot & dry regions and cold climates, building’s shape needs to be compact to reduce heat gain and losses, respectively.
Orient buildings to take advantage of prevailing wind. In case of multiple buildings on a site, they must be arranged to avoid built forms falling in the wind shadows created by other buildings on the site.
Cooling for hot regions
Mutual shading of built forms and compact forms i.e. forms with low surface area to volume (S/V) ratio and low perimeter to area (P/A) ratio are ideal for extreme climates. Compact forms gain less heat during daytime and lose less heat at nighttime.
Heating for cold regions
Service cores can act as thermal buffers against heat gain and loss. Optimal locations for building service cores are in the east and west.
Online Resources
Publications
Tools
Autodesk Ecotect Analysis
Autodesk Ecotect Analysis is an environmental analysis tool that allows designers to simulate building performance from the earliest stages of conceptual design. It combines analysis functions with an interactive display that presents analytical results directly within the context of the building model.
http://usa.autodesk.com/ecotect-analysis/
Climate Consultant
A graphic-based computer program that displays climate data in dozens of ways useful to architects, builders, contractors, and homeowners, including temperatures, humidity, wind velocity, sky cover, and solar radiation in both 2-D and 3-D graphics for every hour of the year in either Metric or Imperial units.