The Simulation of Four Seasons in Aladdin

By Charles Xie

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Unlike many other CAD software programs that you may have used, one of the unique features of the Aladdin CAD software is that it has a built-in time dimension. This is because Aladdin needs to model the change of the position of the sun at any time on any given date in any given place on our planet. This is clearly illustrated by the built-in heliodon that allows you to animate the movement of the sun across the sky relative to an observer on the ground. As seasonal changes are important to building energy and renewable energy, we must take them into account. In this article, I will show you how four seasons are simulated in Aladdin.

Weather data and weather modeling

Weather changes as time changes throughout a day and season changes throughout a year. To calculate the energy usage of a building or the energy output of a solar panel, we need to set weather factors such as air temperature at any given time (because the heat transfer across the building envelope is determined by the temperature difference and the efficiency of a photovoltaic solar panel is affected by the temperature). As of October 2022, Aladdin has incorporated weather data from more than 800 locations in the world. If the location that you are designing for is not included, Aladdin will use the weather data from the nearest available location.

Weather data graphs that show changes in 12 months

The temperature at a given time during a day is determined from the average lowest and highest temperatures by using a model (in the future, we may switch to using the actual fine-grained minute-by-minute data). Currently, Aladdin provides two options: the sinusoidal model and the more accurate Parton-Logan model.

Diurnal temperature graphs for a summer day and for a winter day in Boston

Seasonal changes of landscape

The landscape changes from season to season and plays a role in energy modeling. For example, trees have a large impact in building energy. Aladdin also accounts for their effects in the seasonal simulation. The following set of images shows this.

Landscape changes in four seasons

Click HERE to view and edit the above model

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