Hsien Te Lin

Analysis of and control policies for light pollution from advertising signs in Taiwan

Densely installed advertising signs have become a common source of light pollution in Asian countries. Due to mixed land use, there is a question as to whether or not the sign luminance limits set by the CIE are effective in preventing light trespass from these signs. Light trespass from advertising signs was comprehensively analysed by field measurements and software simulations. The results show that, in Taiwan, although the luminances of almost all of the signs are much lower than the limit set by the CIE, they still cause serious light trespass due to their large coverage area, high density distribution and improper installation. From an urban planning point of view, control policies are recommended as models for other countries with similar environmental problems.

Buoyancy Ventilation Efficiency Analysis of a Conference Hall

This study focuses on the efficiency of passive solar chimney in natural ventilation performance. A case study is conducted for the conference hall at the Magic School of Green Technology (MSGT) in Tainan, Taiwan. The efficiency of the passive solar chimney is evaluated using both computational fluid dynamics (CFD) and full-scale model tests. Simulation and experimental results demonstrate that without the thermal resources of people in the conference hall. The air exchange rates were 5.15ACH and 4.92ACH. With the thermal resources of 200 people in the conference hall, the air exchange rates were as high as 8.62ACH. When the external temperature is lower than 28°C, the internal temperature in conference hall is still in acceptable and comfortable scope. By using the passive solar chimney in the conference hall, the air-conditioning system can be shut off for 4 months and energy consumption can be reduced by roughly 27% annually in Taiwan.

A Study on Energy Saving and Light Pollution of LED Advertising Signs

Lighting advertising signs not only play an important role in outdoor lighting environment in Taiwan, but also become the main factor of energy consumption in urban areas at night. Light-emitting diode (LED) has been gradually used in advertising signs due to its advantages. However, in order to be conspicuous and legible in the daytime, signs that are excessively bright may result in considerable light pollution and energy waste at nighttime. Therefore, this research aims to measure the luminance of LED signs and traditional internally lighted signs, and analyze the light trespass from each signage. Based on the research results, the energy consumption from a LED full color screen is 12 times more than a traditional internally lighted sign per day. Statistically, all kinds of LED signs are much higher than traditional internally lighted signs in the percentage of excessive brightness and average luminance value. As for the light trespass, since the vertical illuminance on facade facing the signs increases with the increase of the sign area or the decrease of the distance between the sign and the facade, the vertical illuminance on facade facing the signs would exceed the limit of CIE even if the luminance of the signs achieves the standard of CIE in terms of the general conditions in Taiwan. This happens to LED full color screens in particular and thus results in considerable obtrusive light. To sum up, in order to reduce unnecessary energy consumption and improve the nighttime lighting quality for outdoor environment, this research recommends the luminance limitation for light dimming of LED advertising signs should refer to the zoning, time period, and sign area.

A study on the performance of stratified air conditioning design in assembly halls - A case study at the Dazhi cultural center in Taiwan

This study focuses on the performance of air conditioning design at the Dazhi Cultural Center and uses a computational fluid dynamics (CFD) simulation to discuss the differences in wind velocity and ambient indoor temperature between all-zone air conditioning design and stratified air conditioning design. The results have strong implications for air conditioning design and can improve the indoor air quality of assembly halls.

Energy-saving techniques of full-scale green building analysis research - Taiwan's first zero-carbon green building

This research is based on Taiwan’s first zero-carbon green building-Magic School of Green Technology in National Cheng Kung University. Actual energy consumption will be measured to explore benefits of energy-saving. The design origin for this building encompasses 13 green energy-saving techniques. United States Department of Energy dynamic building energy analytical software, eQUEST, is used to execute the strictest energy consumption analytical assessment. It is forecasted to reach an energy-saving efficiency of 65% with energy use intensity (EUI) of 43 kWh/m².yr for the whole building, far below that of 169 kWh/m².yr found in Taiwan low/mid-rise office buildings. This building has begun operation in 2011, through actual readings from Building Energy Management System (BEMS) during January to June, first-half-year accumulated EUI of 19.3 kWh/m².yr against eQUEST analytical assessment of 22.5 kWh/m².yr for the same period. Actual energy consumption analysis for air conditioning, lighting, socket outlet, and power equipment, respectively recorded 41.7%, 11%, 22.3%, and 25% in June. Demonstrating that eQUEST analytical assessed value is very consistent with building’s actual energy consumption readings. The energy consumption standard in the experimental research behind the Magic School of Green Technology stands at world class.

Energy Saving and Payback Period for Retrofitting Air Conditioning Systems in Taiwan

In Taiwan, AC systems in buildings with central air conditioning account for over 45% of the total electricity consumed. Inefficient and poorly designed AC systems in existing buildings waste considerable amounts of money and energy. Therefore, retrofitting AC systems has become a widely adopted strategy to save energy while maintaining a comfortable indoor thermal environment. This study analyzes the potential energy savings and payback period of retrofitting AC systems in public buildings. In addition to the required Building Energy Management System (BEMS), several measures are introduced to reduce energy consumption during retrofitting. The main measures include testing, adjusting, and balancing (TAB) of existing AC systems; replacing over-designed chillers with chillers with smaller capacity; installing frequency conversion in original systems, such that they become variable water volume (VWV) and variable air volume (VAV) systems; and utilizing CO2 concentration control and pre-cooling air systems. Based on analytical results, we conclude that AC system retrofitting can reduce total energy usage by 11.75%, while the average payback period for a retrofit project is 4.71 years, demonstrating that AC system retrofitting in Taiwan is economically sound.

Electricity Consumption Benchmark and Ranking System for Office Buildings in Taiwan

Energy use intensity (EUI) is a significant index for energy management in the building sector; however, previous research that determined an EUI benchmark for a type of building resulted in serious problems. Such earlier EUI benchmarks cannot fairly evaluate office buildings with different proportions of parking areas and different numbers of floors, becoming an obstacle for energy management. Therefore, this study proposes an area-weighted office building EUI benchmark that calculates according to office areas and parking areas. This study subsequently surveys the electricity consumption of 58 office buildings in Taiwan to determine the office area EUI benchmark that depends on the number of floors in a building, and suggests a reasonable parking area EUI benchmark. Finally, this study promotes a fairer EUI benchmark and ranking system for office buildings in Taiwan. Such a benchmark and ranking system act as a reference for the promotion of the building energy certificate system in Taiwan.

Analysis of Natural Ventilation Efficiency of a Passive Solar Chimney in a Conference Hall of the Magic School of Green Technology

This study focuses on the efficiency of passive solar chimney in natural ventilation performance of the conference hall at the Magic School of Green Technology (MSGT) in Tainan, Taiwan. The air exchange rate in the conference hall was between 5.73 ACH and 9.11 ACH, which exceeded the minimum air ventilation rate required in Taiwan. This shows that a passive solar chimney can effectively applied to the conference hall to meet indoor ventilation and air exchange requirements without using air conditioning.

Simulated and actual energy use of a green building: A case study on the magic school of green technology

This is a case study on the Magic school of Green Technology (MSGT), the first zero-carbon building in Taiwan. This study simulated the energy performance of the MSGT by using eQUEST, a tool for simulating building energy, before the construction was complete. This study compared the simulated energy use with the actual energy use of the MSGT in 2011, and determined that the actual energy use was lower than the simulated energy use. Based on this comparison, the study proved that the MSGT consumed 65% less energy than do similarly sized buildings with the same functions.

A Study on Light Trespass of Dynamic LED Advertising Sign Flickering on Adjacent Residents at Night

Nowadays, with the growing popularity of dynamic LED advertising signs, the light trespass caused by these signs is being taken more and more seriously. This study analyzes experimentally how various flickering cycles affect the visual fatigue of residents who read in the room adjacent to these signs. According to the results of the research, an increase in the flickering cycle of the sign corresponds with a decrease in the degree of disturbance to adjacent residents. Moreover this study suggests that the flickering cycle of a dynamic LED advertising sign should be set above four seconds to ensure minimal discomfort.