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System design days for climate changes

asked 2024-02-19 12:02:15 -0500

romemeek's avatar

updated 2024-02-19 15:14:30 -0500

Has anyone thought about system design days being recalculated for more extreme climate patterns (warmer summers, colder winters, etc...)? If so, where have you received information or guidance to account for extreme climate changing conditions?

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answered 2024-02-23 21:37:38 -0500

updated 2024-02-23 21:38:30 -0500

I use the future weather files generated by WeahterShift. You can upload your EPW file and define the climate change scenario (RCP - gas concentration scenario of 4.5 and 8.5) and the future time period (up to 2100). They use morphing techniques to estimate future climate scenarios based on the provided historical data (TMY). The major adjustments are made to the dry-bulb temperature and insolation. I have purchased and used these files previously and might need some cleaning before use in EnergyPlus, but nothing major:

Here is the link:

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what is the spatial resolution of the WeatherShift files? Last time I looked, it was not very good, and they only had files for a few major cities.

yolotom's avatar yolotom  ( 2024-02-28 00:40:21 -0500 )edit

I'm not quite sure what you mean by spatial resolution, but they either use the location provided through the uploaded EPW file (e.g., a TMY file) or if a location is selected that has no weather files, they interpolate between the four nearest grid points in the GCM models. This service might not be available in the future, and uploading a specific EPW file will be the only option.

There are other open access tools such as CCWorldWeatherGen, but I haven't used them before.

Ehsank's avatar Ehsank  ( 2024-02-28 11:22:44 -0500 )edit

spatial resolution refers to the minimum grid size that the climate model can calculate, e.g. 10 km vs.100 km grid.

This makes a big difference in urban areas vs. suburban & rural due to urban heat island effect, esp. for nighttime temps. London has separate files for different UHI areas in the city.
Also, areas near large bodies of water or in highly variable elevation can have big microclimate differences. However, current weather files are from weather stations at airports, which are usually in more rural, flat areas. They can also be affected by local cooling by ag irrigation

yolotom's avatar yolotom  ( 2024-02-28 11:47:39 -0500 )edit

Got it. How did you check that in the WeatherShift files? The files that I work with are standard TMY CSV files and I'm not sure if that's where you could see the spatial resolution is not very good or if there is a different source. Thanks for sharing your experience.

Ehsank's avatar Ehsank  ( 2024-02-28 11:53:44 -0500 )edit

answered 2024-02-26 07:30:38 -0500

Andy Tindale's avatar

You can obtain design year weather data for a range of future climate scenarios from the DesignBuilder Climate Analytics website: https://climateanalytics.designbuilde...

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The link doesn't work for me and says "Forbidden You don't have permission to access / on this server." Not sure if it's a geo-filter. I'm trying to access it from the U.S. Could you please double-check?

Ehsank's avatar Ehsank  ( 2024-02-28 11:25:10 -0500 )edit

answered 2024-02-21 14:33:16 -0500

(not a complete answer, as the related literature is quite abundant).

When it comes to "extreme" design conditions, you could first go over the (updated) ASHRAE Climatic Design Information (Chapter 14, Fundamentals). More specifically the Extreme Annual Design Conditions (e.g. n-Year Return Period Values of Extreme Temperature). You can sift through the References section (at the end of the Chapter) for a deeper dive.

Depending on the location of interest, you may find precompiled "future weather" files (EPW format), like here (Canadian locations). In this case however, the design day conditions remain those of Fundamentals 2017. Yet one could pre-process the actual "future weather" file and extract monthly min/max values and reconstitute design day conditions.

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thx. Yes, PCIC future files are used in the BC overheating assessment. I am not sure how good their spatial resolution is.

yolotom's avatar yolotom  ( 2024-02-28 00:39:04 -0500 )edit

answered 2024-02-26 02:02:48 -0500

yolotom's avatar

Hi Denis: looks like you are in Canada, so check out future weather file resources for Canada & elsewhere, in my BC CDC / NCCeH webinar and slide deck:

-- Keeping our cool: Preventing overheated buildings in the climate crisis (Phillips, 2023 webinar). National Collaborating Centre for Env. Health, Healthy Built Environment Forum, Canada.

-- Preventing Indoor Overheatiing (NCCEH 2023). Subject guide: summary and resources for health, planning, and building professionals.

-- Overheating and Passive Survivability Standards and Guidelines: A Brief History and A Look Ahead (Phillips, Aug. 2022).

As I recall, the BC Energy Step Code uses morphed (future T-shifted) weather files, from a Canadian climate center NGO. NRC Canada might have morphed weather files too. Climate files usually require 20 or 30 year averages.

Note that the climate models do NOT do a great job yet in predicting extreme events, such as the PNW heat dome, but this is now a hot research area.

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BTW, a few caveats: -- some weather files have very low spatial resolution, which is a problem if your local climate differs a lot vs. the area average or weather station used in the climate model. -- climate projections can vary a lot among the various models, and some models do a beter job of predicting hot climates. -- morphed files usually only shift the daily (or monthly) max T, but wind and humidity are also projected to change significantly in some areas. And nighttime temperatures (daily minimum T) are increasing faster than max T.

yolotom's avatar yolotom  ( 2024-02-26 02:16:45 -0500 )edit

For the US, check with Argonne Natl Lab CCRDS Program,, Tom Wall, They have some future weather files (hourly) for Public Use Microdata Areas. They plan to add some for the contiguous US this spring. I don't know what spatial resolution they have.

yolotom's avatar yolotom  ( 2024-02-28 00:57:05 -0500 )edit

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Asked: 2024-02-19 12:02:15 -0500

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Last updated: Feb 26