Buildings In Tropical Climate Research Articles

A Comparative Simulation Study of the Thermal Performances of the Building Envelope Wall Materials in the Tropics

The building walls which form the major part of the building envelope thermally interact with the changing surrounding environment throughout the day influencing the indoor thermal comfort of the space. This paper aims at assessing in detail the different aspects (thermophysical properties, thickness, exposure to solar heat gain, etc.) of opaque building wall materials affecting the indoor thermal environment and energy efficiency of the buildings in tropical climate (in the summer and winter days) by conducting simplified simulation analysis using the Integrated Environmental Solutions Virtual Environment (IES-VE) program. Besides, the thermal efficiency of a number of selected wall materials with different thermal properties and wall configurations was analysed to determine the most optimal option for the studied climate. This study first developed the conditions for parametric simulation analysis and then addressed selected findings by comparing the thermal responses of the materials to moderate outdoor temperature and energy-saving potential. While energy consumption estimation for a complete operational building is a complex method by which the performance of the wall materials cannot be properly defined, as a result, this simplistic simulation approach can guide the designers to preliminary analyse the different building wall materials in order to select the best thermal efficiency solution.

Single Objective Optimization of Net Zero Energy Residential Building in Tropical Climate

The Building sector is the largest consumer of energy worldwide. Net Zero Energy Residential Building (NZERB) is one of the prudent approaches to reduce pressure on primary sources of energy. The main objective of this study is to use Taguchi simulation based on orthogonal arrays approach to optimize thermal envelope of a building, SEER value of HVAC system, lighting power density, and ventilation level to reduce the Building Energy Intensity (BEI) 50% lower than the base case building according to International Energy Conservation Codes 2015. In this study whole building energy simulation was performed by Hourly Analysis Energy Program and PVWatts calculator was used to estimate the size of the PV system for balancing the energy demand of the house. The results of Taguchi simulation approach show that by decreasing the U value of wall, windows, roof, floor to 0.1, 0.8, 0.1, 0.2 W/m2. °K respectively and ventilation rate 0.15 l/s-m2, lights of 110 lm/W and SEER of the HVAC system 4 (W/W option) reduce BEI from 147.78 kWh/m2/year for base case building to 67.085 kWh/m2/year for optimal design case. PV system size estimation was performed with PVWatts calculator. PV Watts recommended the size of 13kW DC rating system (open rack type) of 15% efficiency for the weather of Johor Bahru to meet the annual energy demand of the proposed optimal building design.

The effects of microclimate and air-infiltration on energy and long-term thermal comfort in high-rise buildings in tropical climate

An increase in the number of high-rise buildings in most developing cities affects the surrounding microclimate. In this study, the influence of microclimate due to height variations and air infiltration were investigated for a building’s energy and long-term thermal comfort performances. A 20-storey high-rise office building with full glass façade in a hot and humid climate of Malaysia was studied using EnergyPlus to simulate the energy performance and RStudio programme for thermal comfort performance analysis. It was found that the building energy consumption reduced up to 2% when the air infiltration was removed from the building. However, the effect of microclimate showed insignificant reduction in energy consumption, but it had a significant difference in discomfort hours up to 17%. Air infiltration had less effect on thermal comfort with only 3 % reduction in discomfort hours. Microclimate should be considered to accurately evaluate the building performances in the densely built with high-rise buildings area. Removal of air infiltration from space helped in providing comfort and at the same time reduced the building energy consumption.

Influence of environmental factors favorable to the development and proliferation of mold in residential buildings in tropical climates

Among the possible pathologies in buildings, one of the main occurrences in humid climates is the appearance of mold. The mold growth on envelope inside surfaces is not exclusively due to failure on building execution and waterproofing. Factors such as, the air relative humidity, inside air temperature, and surface condensation, are aspects that could cause the mold emergence. In this context, the present research was carried out in order to understand the influence of the use of thermal insulation and the solar orientation of the walls in the mold growth in naturally ventilated residences. This study is developed in the humid temperate climate (Köppen Cfa) of Florianópolis, Brazil, located in South America. For this, simulations in the EnergyPlus software, version 8.8, were performed. The residence was simulated by varying the use of thermal insulation in external walls: thermal insulation on the internal side of the wall, insulation on the outer side of the wall and wall without insulation. Two solar orientations were adopted, being north and south. Based on the results found, it was observed how the constructive parameters affect the periods of occurrence of ideal conditions for formation and growth of the mold. It was found that when the rooms were facing north, fewer occurrences of long periods satisfying the conditions for the appearance of the mold occurred. It was also observed that the non-use of thermal insulation reduced these occurrences when the performance among construction systems was compared. This effect also occurred due to the increase in air changes in this model.

Experimental study on the impact of facade design on indoor thermal environment in tropical residential buildings

This paper presents an experimental study on the indoor air temperature near residential facades in naturally ventilated buildings in tropical climate of Singapore. Four residential sites (Site A-D) with different design features were selected for investigation. Indoor measurements were conducted at locations 30-cm away from the façades.Field measurement results showed that windows are of great significance to indoor thermal environment. In vacant units, the peak indoor air temperature reached 44 °C near a large west-facing window at Site A on sunny afternoon, when windows were kept closed and window-to-wall ratio (WWR) was 0.9. Air temperature near the closed window was lowered by 4.1 °C in the afternoon when WWR was reduced from 0.9 to 0.6. Moreover, window openings can effectively lower the indoor air temperature. At Site B, indoor air near a closed window was 7.6 °C hotter than that near an open window with the same orientation and window, and the average temperature difference reached 3.2 °C during daytime (7:00–19:00). In occupied units, air temperature near the north-facing façade was found 4.7 °C higher than that near the east-facing façade in July at Site D, due the sun path in Singapore. The percentages of time with indoor comfortable conditions were evaluated using the criterion for Asian residential buildings in summer. It was found that the acceptable time percentages were no less than 80% for indoor locations with daytime or occasional window ventilation. Façade design recommendations were proposed to reduce indoor air temperature and improve indoor thermal comfort in tropical climate.

Energy performance of PV integrated office buildings with fan-assisted double skin façades under tropical climates

ABSTRACTBuilding upon the knowledge accumulated from a comprehensive research program on double skin façades (DSFs), this study explores two design enhancements for buildings in tropical climates. Thermal and energetic benefits of the inclusion of mechanical ventilation within the DSF cavity and electricity generation from the PV systems have been determined across a wide spectrum of Brazilian climates. Using computational simulations, DSF models with two fan configurations, placed solely at the top of the DSF and distributed along the height of the cavity, are evaluated. Annual distribution of thermal comfort acceptance and impact on energy demands from HVAC systems and contribution from the PV systems is analyzed. Results demonstrated wide variations of energy performance in relation to the climatic conditions. The ‘Cool’ climate zone presented most significant benefits from the proposed design enhancements resulting in electricity surplus. On the other hand, electricity generated from PV in the moderate climate zone can only cover about 30% of the HVAC energy consumption, whereas energy savings in the ‘hot’ zone are the lowest with only 15% of electricity contributed from the PV systems. The results of this paper contribute to the early stage of design when considering the adoption of DSF in tropical climates.

Life cycle energy assessment of university buildings in tropical climate

Abstract In recent years, there is a strong emphasis on embodied energy due to its significance in all buildings life cycle stages. Previous studies on embodied energy showed that building embodied energy ranges between 2% and 80% of total building energy. Singapore's Nanyang Technological University (NTU) has committed to achieve the vision of being the world greenest campus through various green initiatives. These include technological implementations on campus buildings to reduce its operational energy intensity. With improvement in operational energy intensity, the share of embodied energy increases. This study focused on the life cycle energy assessment of NTU's 22 academic buildings, making NTU the first university campus in Singapore and the Asia Pacific to conduct a large-scale life cycle energy investigation. Based on an assumed lifetime of 40 years, the average embodied energy for material, construction, transportation, maintenance and end of life stages constitute 1179.5 kWh/m2 or 29.5 kWh/m2 per year. The average operational energy is 11033.4 kWh/m2 or 276 kWh/m2 per year. Operational energy constitutes 90% of total life cycle energy while the remaining 10% is from embodied energy. The results provide suggestions to building professionals on ways to reduce the share of building embodied energy. These suggestions include material reusing and recycling, importing building materials from neighbouring countries and use of low carbon building materials.

Effect of the double skin façade material on the thermal performance of the educational building in tropical climate

ABSTRACTThis study aimed to compare the thermal performance of university building models with Double skin façade (DSF) made with glazing and perforated metal sheet under tropical climate conditions. Building models with alternative DSF outer layer fabric material, perforation rate and colour were developed and compared through dynamic computational simulations in the tropical climatic conditions of Rio de Janeiro. Results indicate that, differently from the case made with glazing, cases having perforated metallic screen presented similar ascending cavity airflow rates over the year as the wind pressures have major impacts on the system ventilation. Annual levels of thermal comfort reached up to 75% indicating that real buildings may require other means of cooling under summer conditions. Results also include airflow rates through the different levels of the building and solar heat gains on the DSF cavity. This study contributes to the DSF design when considering its adoption in tropical climates as a sustainable solution.

Envelope design strategies: TROPICAL CLIMATE | KOMTAR building

The main objective of this study is to assess the role of building envelope design strategies on reducing the energy consumption of typical high-rise office buildings in tropical climates. For this purpose, the KOMTAR building was selected as a typical case building, and the energy usage pattern prior to and after the refurbishment was compared through a computer simulation. Through the simulations, the effect of each strategy was quantified as the percentage of reduction or increase in the total energy usage compared to the reference model. However, to have a better understanding of how retrofitting strategies can contribute to energy-saving, the effect of each strategy on cooling and lighting energy demand will be discussed additionally. In some cases, in order to apply a new strategy, there is a need to change the floor plan configuration, which means a different floor area of the conditioned space. In order to make different strategies comparable, the total energy consumption per conditioned area was used as an indicator.

Ecological footprint reduction of built envelope in India

Built envelope significantly influences the environment during construction as well as the operational phase of the building. The present study examines environmental impact reduction of a building in tropical climate through low environmental impact materials and the reflective roof. Ecological Footprint (EF) analysis has been done for two different design models: (1) Model I based on conventional design, (2) Model II based on modified design. It has been observed that modified design reduces the EF of the built envelope significantly, simultaneously, improved the thermal comfort inside the built envelope. In this study, experimentally has been examined the thermal characteristics of the external wall/roof structure as well as analyze the EF (constructional & operational) of the built envelope in the different climatic zone of India.The constructional EF of the external wall surface of Model I and Model II are 0.0074 and 0.0053 gha/m2, respectively. However, roof constructional EF of both models does not significantly differ, it's 0.0074 and 0.0073 gha/m2 for Model I and Model II, respectively. The annual operational EF reduction potential of the external wall and roof of the Model II as compared to Model I are 21.9% & 15.5%, respectively. The constructional cost per unit external wall surface area of the Model II is 3.6% lower than the cost of the conventional external wall (Model I), while the constructional cost of reflective roof (Model II) does not significantly high than conventional roof (Model I).

Ecological Footprint Reduction of Building Envelope in a Tropical Climate

Built envelope (external wall and roof) significantly influences the environment during construction as well as operational phase of the building. The present study examines environmental impact reduction of a building in tropical climate through low-impact materials and green roof. Ecological footprint (EF) is a globally recognized assessment tool that assesses the environmental impact of the human activities. EF tool was used in this study on two different design models: conventional design (Model I) and modified design (Model II). It was observed that modified design reduces the EF of the built envelope significantly. By taking the built envelope as the research object, this study experimentally examines the thermal characteristics of the external wall/roof structure and analyzes the materials used in Indian buildings for a modified design. For external wall surface area, the constructional EF of the Model I and Model II is 0.0091 and 0.0049 gha/m2, respectively. For roof surface area, the constructional EF of the Model I and Model II is 0.0064 and 0.0071 gha/m2, respectively. The monthly operational EF reduction potential of external wall and roof of the Model II as compared to Model I is in the range of 25–30.1% and 61.9–67.1%, respectively. The constructional cost per unit external wall surface area of the Model II is 10% higher than the cost of conventional external wall (Model I), while the constructional cost per unit green roof surface area of the Model II is 15.6% higher than conventional roof of the Model I.

Building Healthy and Comfortable House in Equatorial, Tropical Climate Indonesia

This study aims at providing information on the factors that must be considered in building a house in accordance with the climate of Indonesia. The research method used related studies and supporting theories about buildings in tropical climates and interviewed the lecturer who teaches building physics in one of the private universities in Bandung. The results obtained from this research were the creation of a healthy and comfortable house that adapted to the equatorial tropical climate in Indonesia. Considering thermal comfort factors such as wind direction, indoor air temperature, humidity influenced by climate in Indonesia, radiation temperatures entering the house and human physique that will stay in the house and the factors of the creation of a healthy house with attention to the comfort of humans live and indulge in it by applying the concept of sustainable architecture. Human Friendly is a house built according to function and character, Environmentally Friendly is environmentally the friendly house and renewable energy is a house that can produce its own energy or a house that is not wasteful of energy in its use.

Open windows for natural airflow and environmental noise reduction

ABSTRACTFor buildings in tropical climates, the use of open windows for natural ventilation can not only provide low cost and low energy comfort but also provide thermal delight for occupants. However open windows let in environmental noise. The size and location of windows in walls are key but this study set out to determine whether there are any window forms that can effectively reduce the level of sound ingress into a building. A top-hung window was chosen for this study looking at the dimensions of the window opening and its orientation in relation to the environmental noise source. The top-hung form was selected for its potential to balance the functions of allowing airflow while potentially blocking and reducing noise levels with its window pane angle. The window pane was tested in a laboratory at three opening angles: 0° (closed), 5°, and 10° to let the outdoor air in. The angles were also tested in three different orientations in relation to the noise source position: perpendicular, sideways 60°, and sideways 90°. The test was conducted at 1/3 octave band frequency as specified by ASTM E90-09 to obtain the transmission loss, then ASTM E1332-90 was referred to calculate the outdoor-indoor transmission class (OITC) of the specimens. The study revealed that window orientation and extent of the openings and window pane angle have little effect on noise reduction. The paper concludes with a discussion of how higher levels of natural ventilation can be achieved, particularly in noisy urban areas. The top-hung window, once open, barely blocks environmental noise. However, when the window was closed, the perpendicular orientation offered more noise reduction when compared windows placed sideways to the noise source. The adjustable pane-angle of a top-hung window placed perpendicular to the airflow, and thus the noise source, seemed to have the most potential to balance the functions of allowing airflow when opened and reducing significant noise when closed. Nonetheless, an open window that through its design alone can significantly reduce the ingress of ambient noise into a building is still an issue.

An Investigation of Thermal Comfort and Adaptive Behaviors in Naturally Ventilated Residential Buildings in Tropical Climates: A Pilot Study

This article presents a pilot study of thermal comfort and adaptive behaviors of occupants who live in naturally ventilated dormitories at the campus of the National University of Singapore. A longitudinal survey and field measurement were conducted to measure thermal comfort, adaptive behaviors and indoor environment qualities. This study revealed that occupants living in naturally ventilated buildings in tropics were exposed to higher operative temperatures than what American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) comfort standards recommend for naturally conditioned spaces. However, they still felt that such conditions were acceptable. Two behavioral adjustments were found to have profound impacts on occupants’ acceptance of the imposed heat stresses: (1) increasing the indoor air velocity by turning on mechanical fans and opening the door/windows for cross ventilation, and (2) reducing clothing insulation by changing clothes and dressing in fewer clothes. Higher indoor air velocities were also associated with greater satisfaction with indoor air quality. The future study should develop a statistical model to correlate adaptive behaviors with temperature variations for tropical climates.

Envelope design strategies

The main objective of this study is to assess the role of building envelope design strategies on reducing the energy consumption of typical high-rise office buildings in tropical climates. For this purpose, the KOMTAR building was selected as a typical case building, and the energy usage pattern prior to and after the refurbishment was compared through a computer simulation. Through the simulations, the effect of each strategy was quantified as the percentage of reduction or increase in the total energy usage compared to the reference model. However, to have a better understanding of how retrofitting strategies can contribute to energy-saving, the effect of each strategy on cooling and lighting energy demand will be discussed additionally. In some cases, in order to apply a new strategy, there is a need to change the floor plan configuration, which means a different floor area of the conditioned space. In order to make different strategies comparable, the total energy consumption per conditioned area was used as an indicator.

Simulation and economic analysis of solar cooling for building in tropical climate of Surabaya, Indonesia

The possibility of solar cooling technologies is simulated and discussed in this work. Cooling system application for a six-floor university building in Surabaya Indonesia was taken as a case study. Two different solar technologies systems were designed and compared: (i) photovoltaic powered cooling system, and (ii) solar thermal absorption cooling system. Economic analysis was carried out based on the economic key-figures as well as the CO2 emission analysis. Based on the results gained in the profitability analysis, the most economically feasible system is solar thermal absorption cooling system due to the good agreement between solar radiation andcooling demand. Besides, this systems allows the maximum CO2 emissions savings.

Passive Cooling Using Phase Change Material and Insulation for High-rise Office Building in Tropical Climate

Buildings consumed 40% of the world’s primary energy consumption. In hot climate countries, more than 50% of building’s energy was spent on the cooling system. Aimed to reduce building’s cooling load in a tropical country, this study compares building’s construction configuration for two types of air-conditioned rooms in a high-rise office building. The two types of air-conditioned rooms are: (a) air conditioned rooms operating during office hours and (b) IT rooms and data centre with 24hours cooling. Six scenarios were compared using four building’s configurations (baseline, adding insulation, adding phase change material (PCM), and adding both insulation and phase change material) to evaluate the most efficient construction and cooling settings for both room types. It was found that for air conditioned rooms operating during office hours, adding PCM with melting point 29°C and force night time ventilation is the most effective in reducing cooling load. Meanwhile, for a room with 24hours cooling load, adding insulation material is the most efficient. PCM was only fully effective when night time ventilation was introduced which allows the PCM to discharge. High thermal conductivity walls have the potential to create a mould problem in the building (due to differences in moisture pressure at night time between the internal and external of the building) which can be eradicated by using night time ventilation or adding insulation to the wall. PCM installation reduced the sensible cooling load but not the latent cooling load. Hence, mechanical cooling or dehumidifier is still required.

Predicting integrated thermal and acoustic performance in naturally ventilated high-rise buildings using CFD and FEM simulation

The study of ventilation windows for both natural ventilation and noise mitigation has drawn significant attention recently. This paper presents the numerical approaches to analyse the integrated thermal and acoustical performance of ventilation windows, for a residential building in tropical climate which employs double-layer noise mitigation window for natural ventilation. Given a set of outdoor wind conditions, the distributions of indoor flow and temperature fields are simulated using Computational Fluid Dynamics (CFD) model. The thermal comfort is evaluated using statistical Predicted Mean Vote (PMV) method. For the acoustic performance, noise radiation from road traffic is assumed as the noise source, and the sound insulation of building facade is simulated using Finite Element Method (FEM). From the simulation results, it is found that the thermal satisfaction response is closely related to the inlet wind temperature and speed, and the window opening size greatly affects the ventilation performance. From the case study in Singapore, during certain season, day/night time and with sufficient wind flow, the ventilation window can provide enough fresh air, maintain adequate thermal comfort and quiet acoustic environment for the occupants. The numerical approaches presented in this paper are applicable to general window design studies, and the simulation findings can be incorporated into green building planning. The advantages of using simulation approaches are highlighted and their limitations are discussed.

Influence of orientation and the impact of external window shading on building thermal performance in tropical climate

Energy saving in buildings is a high-priority in developed countries as buildings are responsible for a substantial part of the energy consumption. Typically heating, cooling and artificial ventilation systems of a building are major consumer of energy. A validated Fortran 77 compiler program has been used to elaborate the influence of building orientation on building energy consumption. The amount of heat influx through windows on different oriented vertical walls for various direction has been compared and it has been found that heat gain through south oriented windows is maximum followed by East, West and North bound windows in a tropical climate of northern hemisphere. An experimentally designed, Programmable Logic Controller based movable exterior window shading device linked with sun path has been introduced through a validated TRNSYS building model to show the reduction in cooling load of a hospital building in tropical climate. The simulation study shows that maximum energy savings can be achieved in the month of June i.e. 14.9% and average energy savings is 9.8% annually by movable exterior window shading for a building in tropical climate. Through an economic analysis it has been established that the proposed exterior shading device is financially viable and the payback comes within 6 months. This study is useful for professionals who are responsible for decision-making during the design phase of energy-efficient buildings and can show a path for sustainable building design.

Buoyancy-Driven Ventilation Generated by the Double-Skin Façade of a High-Rise Building in Tropical Climate: Case Study Bandung, Indonesia

High-rise buildings in tropical region is identical to the use of mechanical Air Conditioning in massive scale. Nevertheless, there is an encouragement to high-rise buildings to reduce its energy consumptions, since they consume quite large amount of energy. This challenge can be overcome with various of strategies, one of them, by means of reducing the cooling load of mechanical Air Conditioning in high-rise building. Prospects come from the modern tall building design strategies, for example the use of double-skin facade to give addition of building skin which could provide indoor temperature protection from outside. Double-skin facade system has continued to increase in buildings in a tropical region such as in Indonesia. However, there is another potential of double skin facade, which is the possibility to increase the buoyancy effect in the air gap between the skin and building envelope. The possibility needs to be studied in order to give a proper way in designing double-skin facade of a high-rise building, especially on Bandung-Indonesia tropical climate. This paper explores the potential of double-skin facade in driving the air inside the facade to generate natural ventilation for a high-rise building in Bandung climate condition. Two parameters are used in exploring the buoyancy force, the width of double-skin facade and the temperature of the skin facade. In general, double-skin facade of a high-rise building in tropical climate can generate buoyancy driven ventilation for the building, it relates strongly to the distance between of the double-skin facade and the building envelope.