Calculator #014Climatic & environmental design conditionsERA5 · CERRA · NASA POWERIEC 60721DXF · Word

Climatic and Environmental Design Conditions

Two levels, kept apart on purpose. Level 1 is the site itself: its general information, its climatic statistics, and the environmental and natural-hazard design conditions that act on it. Level 2 is what a particular plant needs — a PV plant, a wind farm onshore or offshore, a conventional plant or a substation, with an overhead line added when there is one — assembled from the same site data rather than gathered again.

Nothing has to be typed in. The design wind and the return-period rainfall are fitted to the annual maxima by the Gumbel method of IEC 60826 Annex D, the distance to the coast is walked out on a terrain model, the site pollution severity follows IEC 60815-1 Table 5, the soil thermal resistivity IEC 60287-3-1 Table 2, the terrain category IEC 60826 Table 5 and the terrain complexity IEC 61400-1 Table 4. The primary data source is NASA POWER, which has no request budget to run out of.

A reanalysis statistic and a design action are different things, and this module never lets one pass for the other. Every row carries its type, its source, reference period, height or depth, averaging time and return period; where a design value needs a code, a hazard map or a study that no service can answer, the row says so and names it instead of asking you for it. That is what the last section of the report is.
Scope the application decides the Level 2 block and the flags

Nothing else is asked for. The array tilt is found by transposing the hourly irradiance of the record onto a plane at every tilt from 0 to 60° and keeping the best; the azimuth is equator-facing; the wind profile is referred to the 100 m level the data carries and the terrain complexity is evaluated there; the design temperature is the one an equipment rating is referred to, with every other candidate reported beside it. The hourly detail period follows the source: the whole reference period on NASA POWER, which has no request budget, and the last ten years on Open-Meteo, which has one.

Where click the map to place the point · drag the bottom edge of the map to make it taller

These go on the title page of the Word report and into the running head of every page. All of them are optional — a quick check of a site needs none, an issued document needs them all.

Basemap: OpenStreetMap, an Esri street map with English labels, or Esri satellite imagery with latin place labels drawn over it — from the selector on the map. Drag to pan, wheel or double-click to zoom about the cursor, ⌖ centres the view back on the point. The scale bar, the ground resolution and the coordinates are drawn on the map itself.

What goes in the report

— off by default: the report carries the conditions it establishes, and a value nobody established is never printed as one.

Overrides optional — nothing here has to be filled in

Every value in the report is worked out automatically. This panel exists only so that a figure from a national map, a utility specification or a survey can replace a derived one: type it in and the row switches to your value and your source. Rows that no dataset and no standard method can answer — a lightning flash density, a measured ESDD, a seismic hazard map outside the United States — are not asked for here either; they appear in the report's list of required studies.

Show the override fields

Site climatic summary — ten parameters for a drawing or another section

A long report is not what a drawing needs. These are the ten values a general arrangement, a specification cover sheet or an equipment schedule is annotated with, in one small table that can be pasted straight in. It is available whichever tier you are on; where one of the ten is a design condition rather than a statistic of the record, a free run shows what it is and that a licence supplies it, instead of quietly leaving it out.

Monthly climatological statistics
Through the year
IEC 60721 environmental classification
Conditions that change a specification
Hazard assessment what the numbers mean for this site

A table of design conditions does not say which of them governs. This reads the site's own figures and states, hazard by hazard, what the exposure is, which value governs it, what it drives in the design, and where the figure is not a design value at all but a screening level or a missing study. Nothing here is an opinion added on top: every statement names the row it comes from, and where the evidence does not support a statement, none is made.

Charts in the report

The Word report carries the monthly charts, the wind rose, the wind speed distribution, the plane-of-array sweep against tilt and the horizon profile, drawn as vector graphics rather than screenshots, so they stay sharp at any size and print black on white.

Project data and studies required