How to heating and cooling need feature on the PreDesign seasons page
In any PreDesign study, you'll notice that there is information about the likely heating and cooling need for a study that looks something like this:
In this help article, we'll explore how to use this and where the information comes from.
How to use this information
The goal of this information is to help you get your head around the extent to which the building type you are considering will need heating and cooling of some description in this climate, by season. Specifically it can help designers:
- Understand the relative usefulness of architectural solutions aimed at reducing heating or cooling energy
- Understand the relative merits of more efficient heating and cooling systems.
To help with this, the information provides, seasonally, 2 pieces of information:
- Frequency of heating and cooling. This is how many days that season the heating or cooling would typically need to be switched on with a standard design
- Energy Demand. This offers a relative assessment by season as to how much energy is likely to be needed for heating and/or cooling.
Some ways to think about this information:
- Each level of improvement in insulation or air-tightness can take a flame away from each season. So if you have flames in each season, small improvements in insulation might have a much bigger bang for their buck than really big improvements.
- Each level of improvement in shading and/or glazing control or reduction in glazing ratio can be assumed to take a snowflake away from each season. Again, smaller improvements will have a really big impact when you see snowflakes in multiple seasons.
- Frequency of heating or cooling helps you see how concentrated the demand for heating or cooling is. If the frequency is low, it might be an opportunity to discuss whether systems are necessary, or whether the client should consider temporary options.
How do I address a heating demand architecturally?
Heating can be reduced architecturally by considering improving facade insulation and reducing infiltration. Generally speaking, the smaller the floor plate size relative to the envelope and the lower the ventilation requirements of your project, the more important these improvements will be. That said, the presence of lots of flames in all buildings should lead to contemplation of better insulated designs.
If you're designing a building with large floor plates and/or with high ventilation requirements, it's likely the heating will also be required for the ventilation air. Lots of flames should tell you that things like heat recovery ventilation systems will be more useful.
Use the glazing ratio feature to help measure the value of changing the types of insulation you use. The % shown can be taken as a proxy for the relative merits of each design option.
How do I address a cooling demand architecturally?
Cooling demand can be met with both mechanical and architectural solutions (or a combination of both). Limiting solar gain by incorporating shading and/or better performing glazing will help effectively reduce the number of snowflakes.
For buildings with narrower floor plates, natural ventilation could be a great way to reduce the number of snowflakes as well. It could even be an acceptable solution instead of air conditioning, especially if you don't have any seasons with 4-5 snowflakes or if your client is more relaxed about the types of indoor temperatures you want to maintain.
Use the glazing ratio and shading features to help identify which facades would benefit from shading and how useful different approaches are.
