| Summary: | 碩士 === 國立臺北科技大學 === 冷凍空調工程系所 === 93 === Taking the external roof construction of a building as the research target, this study uses the ventilating heat-insulation layer for reduction of cooling load surrounding the building. This study makes a computer simulation analysis of the results of heat insulation test. Taking the analysis as the basis for calculation of load, this paper investigates the effects of this heat-insulation technology on the predicted mean vote (PMV) and predicted percentage of dissatisfaction (PPD) of people.
The research approach of this study is to construct firstly the ventilating heat-insulation layer at the roof construction according to the general heat-insulation projects of buildings. The solar radiation heat is brought out via the natural ventilation environment of the external air. Then a temperature sensor and an anemograph are installed at the heat-insulation layer on the roof. The temperature distribution, airflow speed, air circulation of the roof construction with the ventilating heat-insulation layer, and different indoor environmental parameters (including the temperature, barometer of environmental wind field, humidity and solar radiation strength) are recorded at the site for further reviews and analysis.
After improvement, it is found that this insulation technology can effective decreases the solar radiation and cooling load surrounding the building. The total heat transmission coefficient reduces from the original 3.91W/㎡℃ to 0.40W/㎡℃. The external heat radiation and cooling load are even decreased by 90% when compared with the original construction.
Numerical analysis is made on the total heat transmission coefficients resulted from this study, via the computer program HvacLoadExplorer V1.0. The error between the cooling load and the actual measurement result is within 5%. Thus in the later days, computer calculation and numerical analysis can be adopted to know the heat insulation effects. The PMV and PPD indices are also improved from the original average of 3.01 and 91% to 2.0 and 85% respectively This heat-insulation technology of ventilating heat-insulation layer designed by the study for the roof of building has very sound heat-insulation performance. It is really a workable measure of energy saving.
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