The TC 4.7 simplified energy analysis procedure (SEAP) does not consider thermal mass, and its predictions differed substantially from those of a major hourly simulation program when solar influences were substantial (Brotherton et al. 1987). ASHRAE Research Project RP-564 was initiated to improve the thermal mass and solar performance of the SEAP. A method for treating thermal mass and an improved solar treatment for the SEAP are described in companion papers (Claridge et al. 1992. Valdon et al. 1991). This paper compares the performance of the SEAP incorporating these modifications with the original SEAP and with the hourly simulation program DOE-2 for 45 different cases in each of four climates. The modified SEAP shows better results in more than 80% of the cases examined. In the remaining cases, comparison to DOE-2 predictions are similar or have worsened.

KEYWORDS: comparing, computer programs, buildings, heavy, lightweight, calculating, solar radiation, solar heat gain, accuracy, performance, climate