Dataset of subatmospheric pool boiling of water on copper surfaces

This dataset contains 30 transient saturated pool-boiling experiments with deionized water on flat copper, straight-microchannel copper, and square-micropillar copper surfaces at nominal vapor-space pressures of 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 kPa. One transient is provided for each surface-pressure combination. In each standard test, a single electrical-heating step was applied until a CHF-related thermal excursion was identified, after which the heater was turned off and the cooling/recovery response was recorded. The archive includes native thermocouple and pressure records, processed thermal histories, reconstructed surface temperature, heat flux, wall superheat, heat-transfer coefficient, selected boiling-event fields, side-view high-speed videos, NumPy data archives, and selected image-derived BubbleID quantities. The data support analysis of CHF, post-CHF recovery, boiling hysteresis, thermal history, pressure effects, and surface-structure effects. The boiling-hysteresis ratio used in the companion manuscript is $H=q''_{NBR}/q''_{CHF}$, where NBR denotes the sustained return to the nucleate-boiling branch. Reconstructed thermal quantities and event labels are derived outputs, while projected vapor fraction and bubble counts are side-view image metrics rather than volumetric void fraction or wall dry-area measurements. The dataset is not a replicated performance database and should be analyzed with condition-aware methods because pressure sequence, surface history, and run order were not fully randomized. The companion analysis and figure-generation workflow is available in BoilingLab (https://github.com/UARK-NED3/BoilingLab/tree/main/manuscripts/boiling_hysteresis_subatmospheric).