Analysis of the Effects of Wall Thermal Properties and Insulation Location on CTSF and Heat Gain

Abstract

In Korea, the RTS-SAREK program, developed by the Society of Air-Conditioning and Refrigerating Engineers of Korea (SAREK), is widely used to estimate the peak cooling load of non-residential buildings. This program is based on the ASHRAE Radiant Time Series (RTS) method and incorporates a Conduction Time Series Factor (CTSF) to account for the time lag effect of heat transfer through building envelopes. However, the CTSF data provided by ASHRAE are derived from foreign envelope compositions and may not accurately reflect the thermal characteristics of Korean buildings. This discrepancy can lead to errors in cooling load calculations. To address this issue, this study classifies data from various domestic non-residential buildings and proposes a CTSF derivation process tailored to local conditions. An analysis of a sample Korean wall, compared with a similar ASHRAE wall, confirmed the necessity of a separate CTSF library that accurately reflects local envelope characteristics. Furthermore, the study investigated the impact of insulation position, thermal capacity, and thermal resistance on CTSF and heat gain behavior.