DOE-2 Reference Manual Version 2.1 - DOE2.com

The central cooling source for RESYS is controlled by the user input forCOOL-TEMP-SCH for the control ZONE (plus its associated SCHEDULE). ThesublONEs, if they exist, do not have control of their own cooling; therefore,the subZONEs may be overcooled or undercooled, which is not uncommon with thisSYSTEM-TYPE.The central heating source for RESYS is controlled by the user input forHEAT-TEMP-SCH for the control ZONE (plus its associated SCHEDULE). ThesubZONEs, if they exist, do not have any control of their own heating, unles~they have the optional baseboard heaters with BASEBOARD-CTRL = THERMOSTATIC.With this option, it is possible to prevent underheating of the subZONEs, butnot overheating.At calculated control ZONE temperatures above the coolingTHROTTLING-RANGE, the cooling unit and supply air fan run continuously. Atall calculated control ZONE temperatures within the small coolingTHROTTLING-RANGE, the cooling unit and fan cycle on and off. The cooling unitruns just long enough, during the simulation hour, to extract the correctnumber of Btus to cool the ZONE. As the control ZONE temperature drops intothe dead band, the cooling source and fan are turned off. As the calculatedcontrol ZONE temperature drops into the top of the heating THROTTLING-RANGE,the heating source and fan cycle on. At control ZONE temperatures below theheating THROTTLING-RANGE, the heating source and fan run continuously.The calculated temperatures in the subZONEs of a multizone residence maynot be acceptable if the wrong ZONE is chosen as the control ZONE. This isnot surprising and is quite indicative of this SYSTEM-TYPE in real life.There are several solutions to this problem; however, a less obvious solutionis the following. The user can intervene in the automatic process ofcalculating the design flow rate by specifying values for ASSIGNED-CFM,AIR-CHANGES/HR, or CFM/SQFT (see ZONE~AIR subcommand) for those subZONEs thatare improperly conditioned. Often, however, such a correction for heating inthe winter will be detrimental to the cooling process in the summer.RESYS is the only SYSTEM-TYPE in DOE-2 that is capable of Simulatingcooling by natural ventilation through openable windows. The naturalventilation cooling is simulated based on the user input for NATURAL-VENT-SCH,VENT-TEMP-SCH, and NATURAL-VENT-AC (see SYSTEM-AIR subcommand). The usershould note that natural ventilation cooling is specified at the SYSTEM level,which means that the input will apply to every ZONE in the SYSTEM. The lowerlimit (on ZONE air temperatures) for cooling by natural ventilation isspecified via the keyword, VENT-TEMP-SCH. At calculated control ZONE temperatureswithin the cooling THROTTLING-RANGE (T-R = .5) and down to the temperaturesspecified (or defaulted) via VENT-TEMP-SCH, the residence may be put intothe natural ventilation mode for cooling. If NATURAL-VENT-SCH is-5pecifiedsuch that the occupant is at home and wishes to ventilate the residence (thatis, if the hourly values in the referenced DAY-SCHEDULE are either 1 or -1),the following will occur. The windows will be opened and closed by theoccupant, if the act of doing so will help keep the control ZONE temperaturebetween the-top of its cooling THROTTLING-RANGE and the temperatures specified(or defaulted) via VENT-TEMP-SCH. If the occupant does not wish to ventilatethe residence, or cannot ventilate the residence because he is not at home atthe time, that should be reflected in the NATURAL-VENT-SCH (that is, theIV.142 (Revised 5/81)