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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]

Temporary prefabricated houses (PHs) can be effective in providing disaster victims with a temporary living place quickly whenever there is a natural disaster, and are also widely used in providing construction workers with living places. However, there are very limited studies on indoor thermal environment inside PHs, with their inadequacies. Therefore, an experimental study on the indoor thermal environments in an experimental PH located in the subtropics is reported in this paper. The study results suggested that at closed door and window situation, the air temperature inside the experimental PH was very high at daytime in summer, but very low at nighttime in winter. In addition, the variation of the air temperature inside the PH appeared synchronously with that of outdoor air temperature at daytime in summer, suggesting insignificant thermal mass of envelope to store solar heat gain. Furthermore, in both winter and summer, indoor air temperature stratification was observed. At daytime, indoor air temperature was increased with the height but at nighttime, decreased with the height. Finally, external roof temperatures in both winter and summer time were lower than outdoor air temperature, reflecting sky cooling effects for the experimental PH. The measured thermal environments inside the experimental PH, clearly demonstrated that the thermal environments inside PHs are highly unacceptable for long term occupation and that appropriate measures should be taken to improve the thermal environments in PHs. [ABSTRACT FROM AUTHOR]

In building energy simulation, researchers commonly use weather data obtained from the software database or (meteorological) MET station. However, this method leads to disparity of urban-rural temperature condition, hence the input weather data do not characterize the on-site condition. This paper highlights the importance of generating and implementing the urbanized weather data, primarily on the ambient temperature. A parametric approach was used to create hundreds urban layouts of the hypothetical office block plan. An annual temperature profile was generated for each scenario using the Screening Tool for Estate Environment Evaluation (STEVE) tool. It was found that the local average temperature ( T avg ) and peak afternoon period ( T max ) from these scenarios could differ 1–2 °C and 1.2–3.5 °C respectively as compared to the MET station data. Using Integrated Environmental Solutions (IES) to simulate the thermal load performance, this temperature difference can lead to an approximately 8% difference in the predicted cooling load, 20% in external conduction gain, and 17% in fresh air intake gain. These numbers can be deemed substantial in simulating building performance, especially cooling load due to changes in the external condition. Furthermore, the comparison proves to be significant in term of enhancing the simulation result and representing the studied area. [ABSTRACT FROM AUTHOR]

In the subtropics, air conditioning (A/C) for a bedroom in residential buildings commonly serves to provide an appropriate indoor thermal environment at nighttime for sleeping. During daytime when A/C is not provided, a large amount of thermal energy can be stored in the thermal mass in its envelope components, in particularly its external walls. The energy stored would be gradually released, contributing significantly to the total space cooling load in the bedroom at nighttime. Therefore, this paper reports a simulation study on the impacts of daytime external envelope heat gain/storage on the nighttime cooling load in a hypothetic west-facing bedroom and the related mitigation measures in the subtropical Hong Kong. The study results showed that, among all envelope components, the west-facing external wall contributed most significantly to the total nighttime cooling load, because of its direct exposure to solar radiation, thus the heat gain and storage in its thermal mass. In addition, adding an air gap in the west-facing external wall can reduce remarkably the hourly total nighttime cooling load for the first hour (21:00–22:00) and the total cooling load for the 10-h A/C period. However, while varying the width of either the air gap or inside/outside concrete layers would not reduce cooling load further, ventilating mechanically the air gap can further increase the cooling load reduction and improve the flatness of load variation profile at the expense of consuming additional electrical energy. Finally, adhering aluminum foil to both sides of the air gap can further remarkably reduce nighttime cooling load, and improve the flatness of the load variation profile. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study relating to thermal comfort in 28 buildings and schools, in the coastal and central areas of Cameroon. This research was conducted during the dry and rainy seasons, employing the adaptive approach, in naturally ventilated buildings, in accordance with ASHRAE 55/2004, ISO 7730 and ISO 10551. Wind speed, air temperature, relative humidity and CO 2 levels were measured, and 2650 questionnaires were distributed simultaneously. The results revealed that 76.7% of the voters in Douala found the results environmentally acceptable, as against 82.6% in Yaoundé. On average, 74.6% of the respondents found that these were within the comfort range, while 25.3% were neutral. When the local thermal comfort factor was analysed, it was found that the percentage of dissatisfied persons exceeded 40% in both cities, Yaoundé in particular, due to its higher average temperature. [ABSTRACT FROM AUTHOR]

Abstract: In general, a proper balance of temperature and humidity control is essential for efficient datacenter operation and is integral to protecting the significant investment in computer and network technology in datacenter facilities. However, the rising costs of energy and the drive to be green are resulting in a greater demand to conserve energy. One method of reducing facility costs for a chilled water plant is by adding an economizer. The purpose of this study is to develop energy models of the most common economizer systems. A normal chiller plant with an air-side economizer and a water-side economizer are compared. Results show that outdoor conditions influence facility energy consumption. This paper provides terminology and definitions for the two different types of economizer modes and compares their energy performance against key datacenter attributes in temperate or subtropical regions. The electrical end use breakdown and the Power Usage Effectiveness (PUE) value for a typical year were estimated. The water-side economizer made it possible to achieve a maximum energy performance improvement of about 16.6% over the reference base cooling system, whereas the air-side economizer made it possible to achieve about 42.4% improvement. [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]

Field studies conducted in tropical climates have found that the International standard for indoor climate, ISO7730 based on Fanger’s predicted mean vote (PMV/PPD) equations, does not adequately describe comfortable conditions. This paper presents some of the evidence and suggests ways in which International standards are failing and how they might be complemented using adaptive comfort standards derived from the results of local comfort surveys. In particular the implications of air movement and humidity for adaptive comfort standards are considered. [Copyright &y& Elsevier]