Typical meteorological year (TMY). 8 760 hours of representative weather assembled from real years — for annual energy, not for sizing. Running a year.
A typical meteorological year is 8 760 hours of weather assembled month by month from a run of real years — each month chosen as the most representative of its kind in the record, then stitched together — so that a simulation against it sees a normal year rather than any particular one. It carries dry-bulb temperature, humidity, wind and the solar components, and the European PVGIS service publishes one free for any point on the map, from which this site's weather library is drawn. Its purpose is annual energy and comfort: how many hours a machine runs, cycles, or falls short, and what the year costs.
It is not a sizing tool. Design conditions — the 0.4 % or 1 % dry bulb and wet bulb a machine is selected at — are percentiles of the whole record, and a typical year may not contain the design day at all; a machine sized on the year's own peak is sized on one year's luck. One trap in the data: PVGIS labels its hours in UTC, and a year used unrotated puts every occupancy schedule a time zone away from its sun, which this library corrects on the way in. A synthetic design year, built from the design conditions, is the other kind of year the Simulate tab runs.
Open the builder — the examples in the Design tab's sources list include a machine of this kind, and the Simulate tab runs it against a year of weather.
DOAS — dedicated outside-air system · SZVAV — single-zone variable air volume · VAV terminal box · Economiser · Waterside economiser · Demand-controlled ventilation · Face-and-bypass · Head-pressure control · Humidity ceiling and floor · Cycling and modulation · Coupling · Priority · Category · Nested system · Design point and TMY year · Superheat · Subcooling · Sensible heat ratio (SHR) · Bypass factor · Wet-bulb temperature · Dew point · COP and EER · Compressor map · Evaporating and condensing temperature · Range and approach · Heat-recovery (three-pipe) VRF