Envelopes of Operating Conditions for Acceptable Crew Comfort at Low Space Station Ventilation Velocities

It was shown in a previously-published study, that for the light crewmember activity levels applicable to Space Station, ventilation velocities could be lower than 15 feet per minute, and still provide for crew comfort. However, the previous calculations to determine the effects of ventilation velocity upon heat flux were conducted only for nominal values of other environmental parameters. As described in this paper, the study has been expanded to establish envelopes of operation in terms of five main independent variables: crewmember activity levels (metabolic rates), cabin air temperatures, cabin air relative humidities, ventilation velocities, and levels of clothing. The results are presented in terms of data tables, such that the boundaries for achieving acceptable crew comfort can be determined for combinations of the five independent variables over realistic ranges. Using these tables, sets of operating conditions might be chosen as alternatives to the most power-intensive (high velocity) one, to achieve the required heat flux for comfort.