DOE-2 Reference Manual Version 2.1 - DOE2.com

common strategy is to specify COOL-CONTROL = RESET with a COOL-RESET-SCH, aRESET-SCHEDULE, and a DAY-RESET-SCH.When the hourly values specified in the SCHEDULE that is referenced byINDUC-MODE-SCH are negative (see left side of Fig. IV.6), the zone coils arein the heating mode and the central coil is in the cooling mode. In this modeof operation, the program resets the central cooling coil to MIN-SUPPLY-T(unless COOL-CONTROL = CONSTANT, in which case the central cooling coil isreset to the temperature specified in COOL-SET-T).During winter operation (that is, when the hourly values in the SCHEDULEreferenced by INDUC-MODE-SCH are negative), the cold outside air is used forcooling any zone that requires cooling and the zone coils provide addedheating. During the summer, the central coil provides cool dry air and thezone coils provide any extra cooling that may be necessary.SYSTEM-TYPE Equals FPIUThe Four Pipe Induction Unit (FPIU) SYSTEM-TYPE is physically identicalto the TPIU except that the FPIU has two pipe loops, one for cooling and onefor heating. Depending upon the COOLING-SCHEDULE and the HEATING-SCHEDULE,either cooling or heating, or both, are available at all times to the ZONEs.That is, the FPIU SYSTEM-TYPE permits some ZONEs to be cooled while other ZONEsare being heated. The changeover from cooling to heating, and vice versa, isautomatic. The INDUC-MODE-SCH capability is not available, nor necessary, forFPIU.SYSTEM Cooling Mode for TPIU and FPIU:The method for setting the temperature of the cold air stream leaving themain cooling coil is determined by the value specified (or defaulted) for thekeyword COOL-CONTROL in the SYSTEM-CONTROL subcommand.For SYSTEM-TYPE = TPIU, the most commonly used strategy is to specifyCOOL-CONTROL = RESET (with an associated COOL-RESET-SCH, RESET-SCHEDULE, andDAY-RESET-SCH). This strategy resets the primary air temperature each hourbased upon the outdoor dry-bulb temperature and the user's input for thekeywords SUPPLY-HI, SUPPLY-LO, OUTSIDE-HI, and OUTSIDE-LO in the DAY-RESET-SCHcommand. Figure IV.6 shows example air temperatures for winter and summeroperation.IV.156 (Revised 5/81)