LOCATION
General Characteristics of this climate
Stockholm’s climate falls under the humid continental climate (Dfb) category according to the Köppen-Geiger classification.
This means it experiences cold, snowy winters and mild to warm summers. Precipitation is distributed fairly evenly throughout the year, though summers tend to have more rainfall. Winter temperatures in Stockholm can drop below freezing, while summer temperatures typically range between 20–25°C. The “Dfb” classification indicates that Stockholm has cold winters, no dry season, and warm summers.
ENVIRONMENTAL POTENTIALS
Analysis of Psychrometric Chart
The Psychrometric Chart is a very efficient instrument to assess the requirements of a specific location regarding thermal comfort. By overlying Givoni´s bioclimatic strategies, the best combination of passive and active measures can be extracted. Integrating these strategies represent the essence of a climate conscious design approach. By focusing on the extremes, the summer and winter periods, the following strategies can be derived:
1.Integrate heating systems (active)
2.Make use of passive solar heating (passive)
3.Make use of internal gains (passive)
4.Enhance natural ventilation (passive)
5.Mass cooling (passive or active)
6.Mass cooling + Night ventilation (passive or active)
SOLAR OPTIMIZATION
Analysis of solar Radiation
The maximum solar radiation is present during the summertime and comes from the south at low sun altitudes. From this the following strategies can be derived:
- As the main issue in this climate is heating, the maximum solar yield on the facades.
- Horizontal sun shading is necessary for the south facades.
- For the East/West facades vertical shading elements are more effective.
- Renewable energy from the sun can be collected from roofs but also from south facades. Optimal inclination for PV-yield is 45° to the south.
- As the main issue in this climate is heating, the maximum solar yield on the facades.
WIND OPTIMIZATION
Analysis of Wind
The wind optimization is driven on the winter period. The main purpose is to optimize the outdoor comfort by creating spaces with reduce wind in the winter. Fortunately, the protected location of the building does not require the modification of the geometry to optimize the wind conditions. The natural ventilation inside the building will be optimized through the layout design, allowing cross-ventilation and using night flushing if needed.
DAYLIGHT OPTIMIZATION
Our next step is to go inside of the building. For this we evaluate here the spatial daylight autonomy. By Increasing or decreasing the Window-to-wall ratios and by adjusting the depth of the window frames, a pretty good daylight autonomy of 47% is achieved. By locating the cores with Service facilities and optimizing the programming of the spaces, the spatial daylight autonomy of the building can increase to nearly 90%. Of course, this setting is not realistic. For this Window-to-wall ratios of over 90% should be aimed, which create a not so efficient glass box in terms of energy. Next steps could include a multi-objective optimization including cooling and heating demands to reach a balanced outcome.
OUTLOOK
Enhancing solar energy performance in buildings, specially in the north hemisphere can aim for high reductions of the operational emissions.
In this last optimization, we focused on generating energy by maximizing the solar yield of the roof.
