Abstract: Steam heating apparatus for heating air introduced into a building in which the heat of condensate under pressure which otherwise would be wasted is converted into flash steam and is used in auxiliary heating means to supplement the heat of the primary heating system. The heating system operates at a predetermined steam pressure unless the incoming air temperature falls below some predetermined minimum at which additional steam temperature is required. In that case, automatic temperature responsive controls increase the steam pressure to increase the steam temperature.

Abstract: Apparatus for conditioning air of the constant volume type in which air gates are provided at the outlet ends of heat exchange passages and bypass passages to regulate the proportion of air passing through each of the pair of passages and therefore the temperature of air downstream from the air gates.