# EPW: checks and interpretation

The first release covers NASA POWER annual EPW, one continuous range of complete
years, TMY and DDY. Outputs include provenance, hashes and machine-readable
checks. The actual result passport declares its sources and transformations.

## Distinct kinds of evidence

1. Format and integrity: headers, 35 fields, hourly grid, period bounds, gaps,
   duplicates, ranges and units. Period output checks every complete year,
   leap days and one continuous calendar.
2. Physical consistency: temperature/moisture relations, pressure, solar
   components and solar geometry. Pass/fail applies only to the declared checks;
   missing fields and unsupported checks remain visible.
3. Independent observations: local climate accuracy needs separate comparison
   against observations. Passing the first two levels does not establish it.

Reading an EPW and actually using DDY cases in EnergyPlus sizing are separate
tests. The public DDY protocol covers a fixed reference. The website does not
run a visitor's building model or give every new job a passed EnergyPlus status.

## Year, period, TMY and DDY

Annual output preserves its real calendar. Period output joins complete years
without averaging or repeating a year, with years in DATA PERIODS. EnergyPlus
requires Begin Year/End Year and Treat Weather as Actual=Yes. Annual analytics
must not be applied silently to a multiyear sum.

TMY is a synthetic typical year assembled from selected historical months,
not an observed calendar year or an extreme-load year. Its passport records
month origins and solar-component transformations. DDY uses the entire historical
series before TMY selection and requires at least 20 complete years.

The first continuous-period mode supports NASA POWER without supplementary
ground histories. A first year's monthly GROUND TEMPERATURES header is not
reused as the history of every year. Ground temperatures in any EPW do not
validate floor heat losses; that belongs to the building model.

## Continuous-period reference

EnergyPlus 26.1 read a manufactured 2023–2024 period: 17,544 hours, including
24 hours on 29 February; temperatures were 12 °C in 2023 and 16 °C in 2024,
without daylight saving time. The native run had no severe errors and one
expected warning about coordinates (0, 0). The initial SQL verifier wrongly
excluded rows with WarmupFlag=NULL. Both the failed original receipt and the
successful reinspection of the same SQL are preserved. The reinspection
checks every actual timestamp and rejects missing or extra hours; EnergyPlus
was not rerun. This verifies calendar interoperability, not NASA POWER
observations or local climate accuracy.

## Reference and visitor files

Reference protocols remain public with their version, date and SHA-256. They
contain no visitor jobs; dates identify the verified snapshot. Visitor files
are temporary and accessible only by their owner. The account shows their
deadline; running jobs can stop when required temporary inputs expire.
Registration, downloading and email delivery do not raise scientific validity.