การปรับปรุงตึกแถวพักอาศัยเพื่อความสบายทางด้านอุณหภูมิ แสงสว่างและการระบายอากาศ / วรนุช ฤกษ์เสริมสุข = The rehabilitation of a resident shophouse for thermal, lighting and ventilation comfort / Woranuch Roeksermsook
The objective of this research is to rehabilitate a resident shophouse for thermal, lighting and ventilation comfort. The research process is to study factors that affect each human comfort, survey, measure and evaluate existing comfort conditions and ventilation flow rates of a case study shophouse according to tropical living standards and Thailand's building code to analyze and determine discomfort factors. The case study is a 5-storey, center unit shophouse located in a high density district of Bangkok. It was 4x20 square meters and 17 meters height. Calibrated building simulation model by computer program ENER-WIN 97.2000, Lightscape 3.2 and 2D CFD (Heat-X) were used as tools to evaluate building performance of each architectural improvement strategy. The conclusions of evaluation by survey and measurement of the existing shophouse in 2002 exposed that indoor dry bulb temperatures in summer and winter were about 26-34 ํC when indoor relative humidity was 54-86 %RH in summer and 47-58 %RH in winter. Mean radiant temperature (MRT) was lower than air temperature in daytime about 1-2 ํC and higher about 1 ํC in nighttime. This excludes the 4th floor where MRT was close to indoor air temperature all day in summer. Average indoor wind velocity was lower than 0.1 m/s which will cause no human response. Thermal comfort in the case study by computer simulation (ENER-WIN 97.2000) breakdown had average thermal comfort of 7,417 hours/year (84.6% of year) which is within themal comfort (24.5-30.8 ํC). Effective daylight at 300 lux illuminance was 46 sq.m. (14% of total area). For most of the building, passive ventilation was under air flow standards. Only 2 zones that compose inlet and outlet areas are much higher than standard. (about 84 sq.m. or 27% of total area). From the study, a basic improvement that reaches fresh air exchange standards is to open a door that connects the zone t a outlet area. However flow path still causes an Eddy effect which is dust and pollution collection. Three rehabilitation strategies were purposed. The first strategy was to improve material and window to wall ratio of the building envelope, with minimum horizontal and vertical internal opening related to existing construction. The results from simulation: average thermal comfort was 8,602 hours/year (98.19% of year), effective daylight at 300 lux illuminance was 219 sq.m. (76.8% of total area), average indoor wind velocity was 0.2-0.5 m/s. This strategy lost 8.5 sq.m. indoor area and 9.5 sq.m. outdoor area. Inertial cost was 525,250 baht with a return period of 4 years and 2 months. The second strategy was to improve the same building envelope with minimum horizontal and vertical internal opening not related to existing construction. Rearranged function and circulation with longitudinal stairway and a 1x3 sq.m. main vertical opening of 4-storey height at the center of building with covering slab, as well as a reconstructed mezaanine floor in front of the building. The results from simulation: average thermal comfort was 8,622 hours/year (98.43% of year), effective daylight at 300 lux illuminance was 200 sq.m. (65.8% of total area), average indoor wind velocity was 0.5-0.8 m/s. This strategy lost 13.5 sq.m. indoor area and 21.5 sq.m. outdoor area. Inertial cost was 644,300 baht with a return period of 6 years and 6 months. The third strategy was to set building content to recent building code: 15 meters height, set back 3 meters from rear boundary, 10% of maximum floor area vertical opening and mezzanine floor area 40% of room area. Those were building envelope improvement and internal wall opening as well as rearranged function and circulation with cross stairs and a 7.2 sq.m. main vertical opening of 4-storey height at the center of building without covering and reconstructed mezzanine floor in front of the building. The results from simulation: average thermal comfort was 8,652 hours/year (98.78% of year) effective daylight at 30 lux illuminance was 185 sq.m. (66.8% of total area), average indoor wind velocity was 0.6-1 m/s. This strategy lost 20.5 sq.m. indoor area and 44 sq.m. outdoor area. Inertial cost was 747,030 baht with a return period of 6 years and 7 months. This research set 3 criteria for consideration of a suitable improvement strategy for an urban resident shop house. These are building performance in term of thermal lighting and ventilation comfort according to standards, maximum functional area and economic analysis. The best strategy of comfort criteria is the third strategy, but the best strategy for maximum area or short-return period is the first improvement strategy.