This study evaluated the potential of toplighting systems in the hot and humid tropics by using Bangkok, Thailand (latitude 13.7°N) as a test location. The analysis tested both the thermal and lighting performance of three toplighting systems. Toplighting, designed for use in one-story buildings or on the top floor of taller buildings, yields a uniformly distributed light throughout a space. However, in lower latitude locations, where there is no heating period, heat gain is a critical design issue since it significantly affects the annual energy consumption of the building. Accordingly, the decision to use toplighting in these locations needs to be carefully examined before any design considerations occur. In this study, the thermal and lighting performance of three toplighting systems were compared. For the thermal performance, total cooling loads, heat gains and losses, and interior temperature were evaluated. The lighting performance parameters examined were daylight factor, illuminance level, light distribution, and uniformity. EnergyPlus was used as the thermal analysis tool, and RADIANCE, along with a physical scale model, was used as the lighting performance analysis tool. The sky conditions tested were overcast, clear sky, and intermediate sky. Results have shown that, for locations with hot and humid climates with variable sky conditions such as Bangkok, Thailand, the roof monitors perform better than the other two systems in terms of the thermal and lighting performance. With similar cooling loads, the roof monitor provides better illuminance uniformity than the skylights and lightscoops, with adequate illuminance level (at mostly higher than 500 lux).

The purpose of this research is to develop methods that reduce energy consumption in a residential building in a hot and humid climate region (Thailand) using efficient architectural building components and renewable energy (solar energy) to produce electricity, domestic hot water, and supplemental cooling by night sky radiation. Improving the architectural building components, including building materials, is an option to reduce energy consumption in a building. Using renewable energy sources is another option to reduce the consumption of non-renewable energy. In residential buildings, solar energy has been utilized for space heating and domestic hot water using active solar collector systems and for generating electricity using photovoltaic (PV) systems. One photovoltaic system, the hybrid photovoltaic-thermal (PV-T) collector system, has been developed by several researchers over the last 20 years. The hybrid photovoltaic-thermal (PV-T) collector system is a combination photovoltaic (for producing electricity) and solar thermal collector (for producing hot water). Theoretical and experimental studies of this collector have highlighted the advantages of the hybrid PV-T collector system over separate systems of PV and solar collector in term of system efficiency and economics. Unfortunately, very little experimental data exists that demonstrates the advantages of a combined system. Therefore, one of the objectives of this study conducted was an experimental study of this system as an auxiliary energy source for a residential building. Night sky radiation has also been studied as a cooling strategy. However, no attempt so far could be found to integrate it to a hybrid PV-T collector system. The night sky radiation strategy could be operated with the hybrid PV/T collector system by using existing resources that are already present in the solar system. The integration of the night sky radiation into the hybrid PV-T collector system should yield more productivity of the system than the operation of the Hybrid PVT system alone. The research methods used in this work included instrumentation of a case-study house in Thailand, an experimental PV-T collector system, and a calibrated building thermal simulation. A typical contemporary Thai residential building was selected as a case-study house. Its energy use and local weather data were measured and analyzed. Published energy use of Thai residential buildings was also analyzed as well to determine average energy consumption. A calibrated computer model of the case-study building was constructed using the DOE-2 program. A field experiment of the thermal PV system was constructed to test its ability to simultaneously produce electricity and hot water in the daytime, and shed heat at night as a cooling strategy (i.e., night sky radiation). The resultant electricity and hot water produced by the hybrid PV-T collector system helped to reduce the use of non-renewable energy. The cooling produced by the night sky radiation also has to potential to reduce the cooling load. The evaluation of the case-study house and results of the field experiment helped to quantify the potential reduction of energy use in Thai residential buildings. This research provided the following benefits: 1) experimental results of a hybrid PV-T solar collector system that demonstrates its performance compared to typical system of separate photovoltaic and solar collector, 2) results of night sky radiation experiments using a photovoltaic panel as a radiator to demonstrate the performance of this new space cooling strategy, and 3) useful data from the case-study house simulation results and guidelines to assist others in transferring the results to other projects.

This study evaluated the potential of toplighting systems in the hot and humid tropics by using Bangkok, Thailand (latitude 13.7°N) as a test location. The analysis tested both the thermal and lighting performance of three toplighting systems. Toplighting, designed for use in one-story buildings or on the top floor of taller buildings, yields a uniformly distributed light throughout a space. However, in lower latitude locations, where there is no heating period, heat gain is a critical design issue since it significantly affects the annual energy consumption of the building. Accordingly, the decision to use toplighting in these locations needs to be carefully examined before any design considerations occur. In this study, the thermal and lighting performance of three toplighting systems were compared. For the thermal performance, total cooling loads, heat gains and losses, and interior temperature were evaluated. The lighting performance parameters examined were daylight factor, illuminance level, light distribution, and uniformity. EnergyPlus was used as the thermal analysis tool, and RADIANCE, along with a physical scale model, was used as the lighting performance analysis tool. The sky conditions tested were overcast, clear sky, and intermediate sky. Results have shown that, for locations with hot and humid climates with variable sky conditions such as Bangkok, Thailand, the roof monitors perform better than the other two systems in terms of the thermal and lighting performance. With similar cooling loads, the roof monitor provides better illuminance uniformity than the skylights and lightscoops, with adequate illuminance level (at mostly higher than 500 lux).

The aim of this thesis is to investigate to what extent regulated office clothing affects the perception and adaptation of office workers to the thermal conditions surrounding their work environments, focusing on the city of Enugu in South Eastern Nigeria which has hot humid climatic conditions. Clothing, regarded as a second skin, allows us to adapt or adjust to the thermal conditions in our immediate surrounding environment. It also affects our perception of the thermal environment. In some offices however employees are expected to wear regulated clothing or uniforms, during the working day; for various corporate identity reasons. Field studies were undertaken in office spaces in Enugu involving the behavioural and environmental analysis of thermal comfort conditions in six typical case study office spaces, at the Federal Radio Corporation of Nigeria (FRCN) and Federal Road Safety Corps (FRSC). The thesis adopted a mixed‐mode methodological process; combining a quantitative and qualitative approach to data collection and analysis. The field research analysis found that all office spaces analysed were in compliance with the adaptive thermal comfort component of the ASHRAE Standard 55‐2013. The results however did not comply with the adaptive thermal comfort of CEN/EN 15251‐2007. The thermal sensation component of the results suggests a neutral temperature of 28.80C, with 80% thermal satisfaction, in a comfort range of between 25.40C and 32.20C. The thermal comfort vote indicates that approximately 85% of office workers with flexible clothing policy were comfortable at that comfort range, whilst only 55% of workers who had to adhere to a strict uniform policy voted that they were comfortable. The key research findings were: Firstly, the field observations and semi-structured interviews undertaken indicated that the strict uniform policy of FRSC office workers contributed substantially to the limited adaptation of staff to their workspace thermal conditions. Also, of all the thermal variables recorded during the field survey, clothing insulation had the strongest correlations to the thermal sensation of participants in the survey compared to indoor operative temperature, outdoor air temperature, relative humidity or metabolic rate. Furthermore, it is possible for workers in naturally ventilated office buildings in the hot humid climate zone of Enugu to achieve thermal comfort in higher temperature conditions through clothing adaptation.

This research seeks to find a design solution for reducing the energy usage in high-rise office buildings in Singapore. There are numerous methods and techniques that could be employed to achieve the purpose of designing energy efficient buildings. The Thesis explores the viability of double-skin fa??ades (DSF) to provide natural ventilation as an energy efficient solution for office buildings in hot and humid environment by using computational fluid dynamic (CFD) simulations and case study methodologies. CFD simulations were used to examine various types of DSF used in office buildings and the behaviour of airflow and thermal transfer through the DSF; the internal thermal comfort levels of each office spaces were analyzed and compared; and an optimization methodology was developed to explore the best DSF configuration to be used in high-rise office buildings in the tropics. The correlation between the fa??ade configurations, the thermal comfort parameters, and the internal office space energy consumption through the DSF is studied and presented. The research outcome of the Thesis has found that significant energy saving is possible if natural ventilation strategies could be exploited with the use of DSF. A prototype DSF configuration which will be best suited for the tropical environment in terms of its energy efficiency through cross ventilation strategy is proposed in this Thesis. A series of comprehensive and user-friendly nomograms for design optimization in selecting the most appropriate double-skin fa??ade configurations with considerations of various orientations for the use in high-rise office buildings in the tropics were also presented.

Water is the most important resource on Earth. Climate and land cover changes are two important factors that directly influenced water resources. This research provides important information for water resources management and contributes on understanding of the responses of water resources to climate and land cover changes in two different climates. The Neches River watershed located in a humid subtropical climate had a 0.7 °C increase in temperature and a 16.3 % increase in precipitation. Developed and crop land covers increased whereas vegetation cover decreased, as a result of human activities. Hydrologic responses to climate and land cover changes resulted in the increases of surface runoff (15.0 %), soil water content (2.7 %), evapotranspiration (20.1 %), and a decrease of groundwater discharge (9.2 %). Surface runoff had an increasing trend with precipitation whereas soil water content was sensitive to changes in land cover, especially human intervention. The Canadian River watershed, a semi-arid watershed, experienced a 0.9 °C increase in temperature and a 10.9 % decrease in precipitation. Land cover was converted from developed and crop lands into barren land and grass covers, as a result of the decrease in human activity. The change of grass and forest covers into bush/shrub cover is thought to be linked to climate change. Surface runoff, groundwater discharge, soil water content, and evapotranspiration were all decreased by 10.2 %, 10.0 %, 7.7 %, and 9.4%, respectively. Hydrologic parameters generally follow similar patterns to that of precipitation. The trend in water resources followed a similar trend of precipitation for the two watersheds with different climates; a humid watershed and a semi-arid watershed. The humid climate watershed, the Neches River watershed, experienced increasing trends in temperature and precipitation. Groundwater discharge was sensitive to changes in land cover caused by human activities. The semi-arid watershed, the Canadian River watershed, had an increase in precipitation and a decrease in precipitation. Conversion of developed and crop land covers into barren and grass land covers was thought to be the result of the decrease in human activity. The volume of soil water was relatively offset by a combination of precipitation changes and land-cover changes.

This research seeks to find a design solution for reducing the energy usage in high-rise office buildings in Singapore. There are numerous methods and techniques that could be employed to achieve the purpose of designing energy efficient buildings. The Thesis explores the viability of double-skin fa??ades (DSF) to provide natural ventilation as an energy efficient solution for office buildings in hot and humid environment by using computational fluid dynamic (CFD) simulations and case study methodologies. CFD simulations were used to examine various types of DSF used in office buildings and the behaviour of airflow and thermal transfer through the DSF; the internal thermal comfort levels of each office spaces were analyzed and compared; and an optimization methodology was developed to explore the best DSF configuration to be used in high-rise office buildings in the tropics. The correlation between the fa??ade configurations, the thermal comfort parameters, and the internal office space energy consumption through the DSF is studied and presented. The research outcome of the Thesis has found that significant energy saving is possible if natural ventilation strategies could be exploited with the use of DSF. A prototype DSF configuration which will be best suited for the tropical environment in terms of its energy efficiency through cross ventilation strategy is proposed in this Thesis. A series of comprehensive and user-friendly nomograms for design optimization in selecting the most appropriate double-skin fa??ade configurations with considerations of various orientations for the use in high-rise office buildings in the tropics were also presented.

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The commercial buildings sector in the United States used 18 percent (17.93 Quads) of the U.S. primary energy in 2006. Office buildings are the largest single energy consumption category in the commercial buildings sector of the United States with annual energy consumption around 1.1 Quads. Traditional approaches used in commercial building designs are not adequate to save energy in both depth and scale. One of the most effective ways to reduce energy consumption is to improve energy performance of HVAC systems. High-performance HVAC systems and components, as well as application of renewable energy sources, were surveyed for buildings in hot and humid climates. An analysis of performance and energy saving potential estimation for selected HVAC systems in hot and humid climates was developed based on energy consumption simulation models in DOE-2.1E. A calibrated energy consumption model of an existing office building located in the hot and humid climate conditions of Texas was developed. Based on this model, the energy saving potential of the building was estimated. In addition, energy consumption simulation models were developed for a new office building, including simulation of energy saving measures that could be achieved with further improvements of HVAC system above the energy conservation codes requirements. The theoretical minimum energy consumption level for the same office building was estimated for the purpose of evaluating the whole building energy efficiency level. The theoretical minimum energy consumption model of the office building was designed to provide the same level of comfort and services to the building occupants as provided in the actual building simulation model. Finally, the energy efficiency of the building that satisfies valid energy conservation codes and the building with an improved HVAC system was estimated based on theoretically minimum energy consumption level. The analysis provided herein can be used for new building practitioners and existing building owners to evaluate energy reduction potential and the performance of innovative technologies such as dedicated outdoor air system, displacement ventilation, improved cooling system efficiency, air source heat pumps and natural gas heat pumps.

Thermal mass can be successfully implemented in the hot‐humid region of Austin, TX especially when well designed and with supplementary aids like nightcooling and day‐lighting. This study shows that in some situations thermal mass can be actually more beneficial at reducing electricity demands in hot‐humid regions than in the hot‐dry regions that are so emphasized in the literature. / text