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Solar shading devices, such as Venetian blinds, are effective in controlling heat and light gain in buildings. This study focuses on developing an Artificial Neural Network (ANN) to automate the management of Venetian blinds in order to find a balance between energy savings and visual comfort. Typically, automatic control strategies rely on cut-off angles or maintaining appropriate indoor illuminance. However, finding the optimal trade-off between solar gain and daylight is challenging, particularly in regions with temperate or tropical climates. To this end, this paper proposes a novel approach to identify the best slat arrangement. The optimal angle is determined by simulating all possible slat angles using EnergyPlus and selecting the one that maximizes an objective function. The ANN is trained to recognize this angle as a function of variables that can be easily measured in situ. The resulting building's behavior is tested on EnergyPlus using the output provided by the ANN. The results demonstrate that the target angle can be identified with high reliability, even for windows with different orientation and in other cities. The energy savings for heating/cooling are up to 37.7 %/38.7 %. The UDI 200-800 increases by up to 38.5 % at the expense of a slight increase in lighting consumptions (13.5 %). [ABSTRACT FROM AUTHOR]

This paper deals with a global approach in the thermal and airflow design of new dwellings and specially low-cost housing built in the French tropical overseas islands. The sizing of passive cooling techniques has been evaluated thanks to a simulation code. The solutions have been edited in a reference document that serves as work-base for the design of dwellings developments in the French tropical territories. An experimental and sociological survey has been carried out over two years (from 1998 to 1999) in order to validate the impact of these passive cooling specifications on the comfort of tenants and to have an immediate feedback and correct the solutions if necessary. The paper presents the implementation, the experimental survey and the results for the two first housing projects built according to the passive design specifications. This step is important because the aim of the public utilities is to expand the ECODOM specifications on a much broader scale and to prepare to future housing thermal regulations. The results indicated that the solar protection of the roof remains one of the main points in the thermal design of buildings in a tropical climate as well as the natural ventilation. The sociological study showed that the tenants were globally satisfied with their flat as far as the thermal aspects are concerned. However, dissatisfaction resulted from the bad acoustic design of the flats. [Copyright &y& Elsevier]

To move to holistic indoor environmental quality (IEQ) assessment methods of residential building performance in Australia, a relevant evidence base on the comfort behaviour and preferences of contemporary households is needed. A lack of information on the environmental conditions, behaviour and preferences relevant to dwellings in Australia’s hot humid climates has been revealed as an area of ongoing policy and research interest. This paper explores the cooling practices of households living in predominantly naturally ventilated dwellings in Darwin, the Northern Territory through a survey of behaviour, preferences and dwelling construction (n = 102) and a 12-month longitudinal thermal comfort study in 20 houses (n = 2535). The results show that these households employ a range of adaptive behaviours in response to warm and hot conditions. The houses were almost always naturally ventilated, with the assistance of ceiling fans for approximately 50% of the time. The limited use of air-conditioning in these houses is more strongly associated with indoor humidity levels than temperature. These patterns of comfort behaviour provide a basis for the enhancement of building simulation models for the performance assessment of dwellings in naturally ventilated mode in hot humid climates in Australia. [ABSTRACT FROM AUTHOR]

Increasingly compact high density urban development in cities has allowed urban heat island effect to take root and increase the energy consumption of commercial buildings to cool its interior. Although the extensive use of glass façade has allowed these buildings to harness daylight to light up the building interior, it has also allowed substantial solar energy to enter and heat up the building. This is especially critical in hot and humid tropical regions, where reducing solar heat gain, while minimizing heat loss are equally important. The evaluation of glass performance is often conducted using active measurement, which make use of known radiant source. However, this type of setup cannot be applied for testing under non-controlled weather. Though a passive test procedure can be conducted under actual weather conditions using the outdoor test chamber, it is not suitable for a large-scale testing and fast on-site characterization. In addition, this test is limited to the fabricated glazing and thus could not predict potential issues in the design stage. Advances in simulation techniques have enabled building professionals to evaluate the glass façade of a building at the design phase. However, the typical simulation tools are unable to integrate the high performance glazing description, which is generated thanks to advances in coating technology, using the existing glass models. Furthermore, these tools are often lack of local weather models that plays an important role in accurately assess the solar heat gain admitted into the building. This paper provides useful information on different high performance glass façades and assesses their applicability for green building in a tropical country like Singapore. The research effort encompasses an improvement in the methodology used to predict solar irradiance through building glass that incorporates seamlessly the advanced glass models into the solar irradiance simulation. In addition, this will show how to effectively estimate the actual sky behavior via a measured data-based optimization process. A comparison of the simulation results with the measurements from an outdoor climatic test chamber under tropical climate will be performed. An assessment based on the typical glass performance metrics (e.g. U-value and Solar-Factor) together with measured energy savings obtained with the use of different high performance glass façade compared to clear float glass as a control will also be presented. [ABSTRACT FROM AUTHOR]

Located near the equator, Singapore has a tropical rainforest climate with high temperature and high humidity. In hospitals of Singapore, the subsidized patient wards are designed to be naturally ventilated, considering the affordability for patients. However, due to the high occupant density of the patient wards and the hot humid climate, occupants may feel discomfort, especially in the older hospital wards which were not well designed for natural ventilation. In this paper, the thermal comfort level of occupants at Singapore's Changi General Hospital (CGH) is evaluated based on both in-situ measurements and modeling analysis. Against this backdrop, several low energy solution concepts that potentially improve the thermal comfort level of occupants in patient wards are analyzed and simulated using detailed building thermodynamic and airflow simulation. We found that this approach of combining thermodynamics, computational fluid dynamics, and thermal comfort level models was effective for analyzing and comparing the thermal comfort impact of alternative, low-energy building retrofit concepts. We also found that passive solutions to ventilation could be used effectively for a patient hospital ward, even in the tropical warm climate of Singapore. [ABSTRACT FROM AUTHOR]

From field monitoring, it has been observed that in readymade garments (RMG) production spaces, thousands of workers have been worked day long and might have probability of different thermal perceptions. As thermal comfort is the crucial phenomenon for workers, for the reduction of excessive indoor heat, using HVAC cooling strategies are the most critical segments in energy consumption. This paper describes an experimental study about assessment of different indoor environmental steps to evaluate the acceptable adaptive thermal comfort range for the workers considering typical summer climate in tropics. Tests were carried out in a climate chamber designed to represent typical RMG factory worker’s (sewing) working station and analyses were carried out under pre-conditioned air temperature, wind speed, and relative humidity. During the experiments, all subjects wore typical summer clothing and needed to answer questionnaires according to ASHRAE comfort scale. This current study only focused on tropic’s different summer temperature and humidity steps to explore the adaptive comfort range. Finally, this research was specified that indoor temperature range 25–26 °C and humidity 60 ± 5% with significant air movement (0.25–0.30 ms −1 ) indicated the acceptable in combination and 25.6 °C represented the best fitted condition for the sewing activity. [ABSTRACT FROM AUTHOR]

Daylighting is perceived to be a potential measure for energy conservation in commercial buildings. In Thailand where the sky is highly luminous and daytime is long throughout the year, daylighting is however neglected by the use of heat reflective glasses to prevent excessive solar gain from windows. To address the issue, this paper investigates the energy performance of the daylighting from a window with horizontal slats located between two panes of glasses (slat window). The slats can shade the intense beam radiation, but allow penetration of the diffuse daylight for interior illumination. In the study, a model was developed to determine the thermal gain from the slat window. By using the thermal model together with the daylight model developed earlier, the simulations were performed and the results show that the slat window, when used with typical office room, can save 25–70% of the total electrical energy of air-conditioning and lighting in the same room equipped with heat reflective glass window. [ABSTRACT FROM AUTHOR]

This paper presents two grid-connected photovoltaic (PV) systems (monocrystalline silicon, c-Si; copper–indium–diselenide; CIS) situated on the rooftop of the solar lab building in the National University of Malaysia, southwestern Malaysia. Various parameters were used to analyze the system performance; including array yield, final yield, capacity factor, and performance ratio. The recordings were noted down under the actual climatic conditions for an entire year. The variables of energy cost and payback period were also considered to calculate the economic feasibility of the system. Variations in the final yield of CIS were as low as 2.98 h/day in July to the highest value of 4.31 h/day in March. The final yield for c-Si power plant ranged from 2.92 h/day in July to 4.14 h/day in March. The calculated capacity factors for CIS and c-Si power plants were 15.6% and 14.4%, respectively, in July as the worst value, and 21.12% and 20.2%, respectively, in March as the best value. In the case of CIS power plant, the performance ratio ranges from 63.8 in July to 84.12 in March, and for c-Si power plant, it ranges from 59.92 in July to 79.14 in March. The energy cost and the payback period of the suggested system were evaluated as 0.045 USD/kWh and 28.44 years, respectively. Finally, this study provides valuable information for those who are interested in PV system installation in the tropical zones. [ABSTRACT FROM AUTHOR]

This paper evaluates the influence of key design parameters on the thermal behaviour of a naturally ventilated building with Double Skin Façade (DSF) under tropical climate conditions. Using a reference model of a conventional office building in the city of Rio de Janeiro and two groups of design parameters, dynamic thermal simulations are systematically applied to optimize design options with the aim to maximize the annual acceptable thermal comfort levels within the occupied spaces. This study not only defines the dimensional parameters to maximize the system airflows, but also investigates the significance of design decisions such as thermal mass and shading devices on the system performance. Options to avoid unintentional reverse flow on the upper floors and maintenance of balanced horizontal airflow rates across the floors are also addressed. Two optimized naturally ventilated building models with DSF are developed and evaluated in terms of thermal performance. Results show that acceptable thermal comfort levels can be met for nearly 70% of the occupied hours. Although the office building will still require other means of cooling during peak summer periods, the incorporation of DSF as part of a mixed-mode ventilation strategy can potentially have a significant impact on annual energy consumption. [ABSTRACT FROM AUTHOR]

• At the mean temperature of 26.9 °C, 79% of the surveyed felt 'cool' or 'slightly cool' • At the mean operative temperature of 30.4 °C, 45.7% of the surveyed felt 'neutral' • Higher slopes of adaptive comfort equations than the standards was predicted. • The neutral temperature of 27.4 °C and 30.3 °C was predicted for AC and NV mode. • Minimum saving of 56% on cooling energy consumption could be achieved. Adaptive comfort considerations and passive design are crucial in tropical, hot and humid climates where the straightforward response to discomfort in this climate, such as in Ghana, has been the adoption of air conditioners and mechanical cooling. This approach, along with following the provisions of current international comfort standards, has resulted in higher electricity demand and excessive emissions of greenhouse gases into the atmosphere. This paper presents an adaptive thermal comfort field study in library buildings in the tropical Aw climate of Kumasi, Ghana considering naturally-ventilated (NV) and air-conditioned (AC) buildings. The proposed models in this study are compared with existing studies and current international standards. Using the Griffiths coefficient of 0.5, the mean neutral temperature of 27.4 °C and 30.3 °C were predicted for AC and NV mode, respectively. Although Fanger's predicted mean vote (PMV) method overestimates the extent of changes in thermal sensation votes (TSV) by indoor operative temperature in AC mode, the neutral temperature predicted from PMV (27.8 °C) is analogous to the one estimated using TSV. The adaptive equations for Kumasi's hot and humid climate predict higher slopes of 0.17 K−1 and 0.41 K−1 in AC and NV modes, respectively, than the standards; this indicates that the Ghanaian respondents were more sensitive to the outdoor temperature changes. The average difference of 2.1 °C in AC mode and 1.8–3.3 °C in NV mode were estimated when comparing the proposed model with those in the international standards [ABSTRACT FROM AUTHOR]

This paper focuses on the modelling of occupant behaviour in the case of a non-residential mixed-mode building on the tropical island of La Réunion. For such areas and types of buildings, occupants can operate passive solutions to achieve comfort while energy-consuming ones can offer alternatives during the hottest months. Yet, compared to other climatic zones, specific knowledge on occupant comfort and behaviour is limited, making the work of engineers difficult during the design phase. In this work, occupants' operations on hygrothermal comfort controls, such as windows and fans, were first measured and analysed. Secondly, these behaviours were modelled using two deterministic methods based on machine learning techniques and a probabilistic graphical model. A model was also implemented to estimate the number of people, using the power demand of the electrical outlets. The estimation ability of the behavioural models was evaluated and led to F1 scores greater than 0.7. A two-classifier model was proposed to estimate the level of ceiling fan use. This combined model slightly improves the F1 scores by more that 2%, which demonstrates the necessity of taking into account the links between the different controls. [ABSTRACT FROM AUTHOR]

Abstract: In the tropics, daylighting from a side window requires shading to intercept direct sunlight from the window whilst allowing penetration of daylight from sky. In this paper, daylighting from a double-pane glazed window with enclosed horizontal slats (slat window) was investigated for which it is situated on either north or south wall of a room. Full-scale experiments and simulations were conducted to characterize distribution of the interior daylight from the slat window under a real tropical climate. Performance of the slat window was evaluated in terms of the “useful daylight illuminance” (UDI), interior daylight availability and light power density (LPD) of an integrated dimmable lighting system. Empirical formulas were developed for determining annual average LPD values of the dimmable lighting system over its served area. The LPD value can be used with a reduced form of the energy equation of Thailand's building energy code to evaluate the reduced annual electrical energy consumption for accreditation of the daylight use in a building. The analysis of life cycle cost proved that the daylighting from the slat window integrated with the dimmable lighting system is cost effective. [Copyright &y& Elsevier]

Abstract: In the last recent years, research in thermal comfort during summer has induced a significant increase in electricity consumption in buildings due to the notable use of mechanical vapor compression air conditioners. Solar cooling systems are an attractive alternative to overcome this problem. The development of these systems requires a fundamental approach with the development of numerical models to predict the behavior of the whole installation. The ultimate goal is to estimate the comfort, the refrigerating power, the power consumption and the overall performance of the facility based on external factors (solar radiation, outside temperature, occupancy in the building). For this, we chose the EnergyPlus environment that is proving to become a reference tool in the field of building simulation. This simulation tool facilitates the coupling of energy systems to the building with a wide range of models (solar thermal collectors, absorption chiller, stratified storage tanks, cooling tower). In this paper, we present the modeling of the solar cooling installation “RAFSOL” within the EnergyPlus environment at the Technology University Institute (IUT) of Saint Pierre in La Reunion. The simulations are then discussed and compared with data extracted from our experimental platform. Then, the model is used to propose a solution to improve the seasonal performances of the installation. [Copyright &y& Elsevier]

Abstract: Hainan province is the only tropical and island province in China, with the unique climatic and geographical features. It has a different energy performance in public buildings from those in the inland areas. This paper investigated the current situation of energy consumption of the sampled public buildings, including 26 hotels, 24 office buildings and 7 department stores, through analyzing utility billing data, on-site survey and measurement, and site operational records. The breakdowns of energy consumption found out that the electricity dominated the energy consumption for all the sampled buildings and the air conditioning system played a key role in the energy consumption of major building services. By analyzing the main factors for building energy consumption, the annual average energy use indexes were calculated to be 141.63kWh/m2, 87.70kWh/m2, and 166.95kWh/m2 for hotels, office buildings and department stores, respectively. Besides, the comparison between Hainan province and other areas revealed that the building energy consumption of this tropical province was at a low level. Because indoor environment quality can influence the health and work efficiency of humans in buildings, field tests on the indoor environment quality were also carried out, and the performance of indoor environment quality was rated. [Copyright &y& Elsevier]

Abstract: Thermal comfort conditions in residential buildings vary according to the designs, modifications of the house and adaptations of the occupants. The purpose of this paper is to examine thermal performance of terrace housing in tropical climate by exploiting internal courtyard. A case study of a terrace house was chosen, where field measurement was conducted during a three-day recording in naturally ventilated spaces of the house. Results from field measurement were used to develop a baseline model for computational experiment. Subsequently, the effects of introducing an internal courtyard on thermal comfort performance of the building were investigated using ECOTECT software. The results from simulation analysis indicate that, applying internal courtyard in the terrace house will improve natural ventilation and thermal comfort in spaces with openings to the outside environment. It shows that the influence of the internal courtyard on the thermal condition has a strong reliance on the envelop openings. This study suggests that the internal courtyard of a terrace house can affect improvements in thermal conditions of the courtyard''s surrounding spaces, provided sufficient and efficient openings with shading devices are suitably incorporated. [Copyright &y& Elsevier]

Abstract: In the last few years, thermal comfort research in summer has significantly increased the electricity consumption in buildings. This is mainly due to the use of conventional air conditioning systems operating with mechanical vapor compression. Solar cooling systems appear to be an interesting solution to solve this problem. But the understanding of this technology has to be refined through fundamental studies by developing numerical simulations. Moreover, the study of pilot plants is a practical method to gain experience by analyzing all the processes behind solar cooling technology. This paper presents an experimental study of a solar cooling absorption system implemented in Reunion Island, located in the southern hemisphere near the Capricorn Tropic. The particularity of this project is to achieve an effective cooling of classrooms, by a solar cooling system without any backup systems (hot or cold). The aim of this experimental study is to define the limits of the use of such system under tropical climate conditions without setting a set point temperature. Indoor thermal comfort is achieved by a self-stabilizing operating system that maintains the indoor temperature 6°C below the outdoor temperature. During some critical periods of the year, when the outdoor temperature is very high and when the solar cooling system cannot provide enough refrigerating production, thermal comfort inside the building is achieved by using ceiling fans. Firstly we will present the installation and the choices we made in the control and design process. In the second part, an analysis of the experimental results will be presented. [Copyright &y& Elsevier]