DOE-2 Reference Manual Version 2.1 - DOE2.com

6. Thermostat SimulationThe discussion in this subsection is related to the simulation of variouszone temperature control strategies and the SOL input data required to specifyeach of them.The simulations for PROPORTIONAL and TWO-POSITION types of thermostats(see keyword THERMOSTAT-TYPE in ZONE-CONTROL subcommand) are essentially thesame, except that the program automatically selects a very narrow throttlingrange for the two-position type of thermostat to simulate on-off operation,thus negating the necessity to enter data for the keyword THROTTLING-RANGE(see ZONE-CONTROL subcommand). The REVERSE-ACTION type of thermostat (seeTHERMOSTAT-TYPE) is applicable only for variable air volume systems, and then,only when appropriate. This thermostat allows the supply air flow rate (forheating as well as cooling) to rise above the design minimum flow rate, asdefined in MIN-CFM-RATIO.The keywords HEAT-TEMP-SCH and COOL-TEMP-SCH are used to reference SCHEDULEinstructions that specify the heating and cooling temperature control setpoints of the zone. Note that all schedules may change hourly and seasonally,thus allowing summer/winter, and day/night, or even finer adjustments of setpoints.Almost any imaginable thermostatic control scheme can be simulated. Theuser should take care that the scheme specified is physically possible withthe HVAC system being modeled; The program does not make such a check.The user should avoid throttling range overlap when simulating sequentialcontrol of heating and cooling. If the user inadvertently specifies overlappingthrottling ranges, the program will move the cooling and heating setpoints until they are one throttling range apart.A number of different thermostatic control options and the SOL input datarequired for the simulation of each are shown in the examples that follow.There is no priority or preference intended; Case 1 through Case 9 arepresented in order of increasing difficulty.Case 1 - TWO-POSITION Heating/Cooling Thermostat Operation (with deadband)Figure IV.8 depicts the operation of a TWO-POSITION dual-set pointthermostat (or two single-set point thermostats) that provides on-offoperation of the system heating component, whenever zone temperature fallsbelow 68°F, and on-off operation of the system cooling component, wheneverzone temperature increases above 78°F.No heat is either added to or extracted from the zone when zonetemperature is between these set points. If a single thermostat is beingsimulated, it is the type that has two independently adjustable set points(dual-set point). The program simulates a thermostat with narrownonadjustable differential. This thermostat should not be used formultizone and dual duct systems.IV.164 (Revised 5/81)