DOE-2 Reference Manual Version 2.1 - DOE2.com

TILTRules:solar radiation is absorbed by the floor; the remaining 40per cent will be distributed to the other surfaces (excludingwindows), according to their surface areas. Ifthere is no floor, the full 100 per cent will be distributedto the surfaces (excluding windows), according to theirsurface areas. To override this default procedure, the usercan explicitly specify SOLAR-FRACTION values for all the surfacesor part of the surfaces. If the latter approach istaken, the program will sum the values specified and distributethe balance (up to 1.0) to the other surfaces. Thus, ifthe user specified SOLAR-FRACTION = .7 for the floor only,the program will distribute the remaining :3 to the walls andceiling, according to their surface areas.The distribution of absorbed solar radiation depends, ofcourse, on the space geometry and surface absorptances, aswell as on the hourly varying position of the sun relativeto the space. It also depends on the hourly varying proportionsof direct and diffuse solar radiation entering thespace.Since the user can enter only one set of SOLAR-FRACTIONs fora SPACE, the SOLAR-FRACTIONs should be chosen to represent atime-average over the intended RUN-PERIOD of the analysis,with emphasis given to those times of day and seasons of theyear when solar gain is greatest.Note: SOLAR-FRACTION is not affected by MULTIPLIER. Itapplies to the surface area after multiplication.is the inclination of the interior wall from the Z axis ofthe space coordinate system (see Sec. A.5 of this chapter).The program uses this value to determine if this surface isan interior floor, or not. If it is, the program uses thefloor area to calculate the effects of furnishings on theCustom Weighting Factors. If the surface being described istruly a floor, the user should specify TILT = 180. If it isa ceiling, specify TILT = O.1. The associated SPACE instruction must precede any INTERIOR-WALLinstruction.2. Before an INTERIOR-WALL instruction is specified, the user mustspecify either (a) Custom Weighting Factors or (b) a CONSTRUCTIONinstruction having a U-value keyword.3. It is important not to input INTERIOR-WALLs twice. This is usuallydone by accidentaTTy specifying the same interior wall under twoadjacent SPACEs. If the user specifies the same U-name in both SPACEsfor the same INTERIOR-WALL, the program will abort with a diagnosticmessage. If, however, different U-names are specified, in the twoSPACEs for the same INTERIOR-WALL, the program will accept the dataIILll5 (Revised 5/81)