DOE-2 Reference Manual Version 2.1 - DOE2.com

'.Warning: The following keyword is not to be confused with a keyword bythe same name in the SYSTEM command. T~two are related, but not the same.SIZING-OPTIONInput for this keyword is a code-word that indicates if theuser wishes the program to adjust the system equipment sizeto account for certain temperature differences in LOADS andSYSTEMS:(1) If the constant space temperature specified in LOADS(see keyword TEMPERATURE in the SPACE-CONDITIONSsubcommand) is between the zone DESIGN-HEAT-T andDESIGN-COOL-T (in the ZONE-CONTROL subcommand inSYSTEMS), the peak loads will be overestimated forcooling and heating. Consequently, the calculated airflow rate for the zone will not exactly correspond tothe actual air flow rate necessary to meet the heataddition rate or heat extraction rate at the peaks.(2) In the LOADS program, unconditioned spaces and plenumsare assumed to be at constant temperature. In fact,the temperature is not constant because thetemperature of an unconditioned zone is allowed tofloat and the temperature in a plenum is determined bythe blend of return air temperatures and flow rates.As a result, there is no contribution to the peakloads of conditioned zones from interzone hea-t--­transfer with adjacent unconditioned zones.To account for these two effects or not, the user mayspecify a code-word from Table IV.32.l. This assumes thatthe user does not specify the equipment size but ratherallows automatic equipment sizing by the program.Code-WordFROM-LOADSADJUST-LOADSTABLE IV.32.1SIZING-OPTIONThe automatic sizing of equipment to heat or cool thiszone will not consider the two previously listedeffects. ThlS is the default value.The automatic sizing of equipment to heat and coolthis zone will consider the two previously listedeffects. An adjustment will be made to the peakheating and cooling loads to account for a differencebetween the value specified for TEMPERATURE (in LOADS)and DESIGN-HEAT-T and DESIGN-COOL-T (in SYSTEMS).Also, a steady-state adjustment will be made toaccount for thermal conduction through interior andexterior walls. Note that DESIGN-HEAT-T andDESIGN-COOL-T should also be specified for unconditionedand plenum zones. Infiltrationloads will also be adjusted.(Revised 5/81)IV.201.1