Guildlines for Reduction of Overall Thermal Transfer Value and Roof Thermal Transfer Value Case Study: Natural History Museum Building, Khon Kaen University

Abstract

This research study aimed at examining Overall Thermal Transfer Values (OTTV) and Roof
Thermal Transfer Value (RTTV) of Natural History Museum Building Khon Kaen University. The present
internal physical conditions of the building were surveyed in order to collect the data for calculate
OTTV value and RTTV value, based on Building Energy Code version 1.0.6 program. The results
showed that OTTV value had been 52.45 watt/sq.m, which does not meet the criteria set in the
ministerial law at 50 watt/sq.m. Meanwhile, RTTV value had been 3.68 watt/sq.m, which passes the
ministerial law criteria of not being over 15 watt/sq.m. A means of improving the building’s OTTV
value was determined. The southern and eastern walls were modified since both walls had shown
an OTTV value of over 50 watt/sq.m. The approaches selected for the real situation had a highly
possible to renovate and also would have a minimal impact on the interior usage. The target aimed
at was having an OTTV value of 49.54 watt/sq.m. for both walls. Four approaches were implemented
as follows: reducing the area of transparent wall by increasing 0.10 m. lightweight concrete wall
(wall no.1) area; or reduce WWR value (Approaches #1 and #2) had lower costs and less space
requirements than Approach #3 is changing 0.10 m. lightweight concrete wall (wall no.1) by lining
it with 3-inch EPS foam sheet and 9 mm. normal type gypsum board; and Approach #4 is replacing
transparent wall with 6 mm. solartag glass SG 110. Approach #1 used the smallest area (30.00 sq.m.)
and had the lowest required cost for renovation (19,850 baht). This would allow for a savings 14,713
baht in electricity costs per year with a payback period of 1.35 years.