Buildings In Tropical Regions Research Articles

Selecting suitable passive design strategies for residential high-rise buildings in tropical climates to minimize building energy demand

Passive design strategies (PDS) are a fitting solution to reduce the ever-growing energy cost of residential high-rise buildings in tropical regions. However, PDSs’ building energy saving potential significantly varies with local climate conditions, but it has been sparsely investigated. Hence, this study investigated the energy-saving efficiency of eight common PDSs integrated into a typical residential high-rise building in three sub-climates: extremely hot humid (0A), very hot humid (1A), and warm humid (3A) defined by ASHRAE for the tropical climate. This study developed a Building Performance Analysis (BPA) workflow with a BIM-based simulation framework and local and global sensitivity analyses for the building energy analysis. The global sensitivity analysis revealed that low e-coating on glasses is the most influential PDS for 0A and 1A climates, but it has a negative effect in the sub-climate zone 3A. The low-conducting exterior walls are the most effective PDS in the sub-climate zone 3A, but they are poorly performed in the other two sub-climate zones. Based on the energy calculation and sensitivity analysis, this study proposes the best PDS groups, saving up to 40.1%, 63.5%, and 31.7% of average annual building consumption in the sub-climate zones, 0A, 1A, and 3A climates.

Building Information Modeling (BIM 6D) and Its Application to Thermal Loads Calculation in Retrofitting

The purpose of this study is to propose optimal actions to improve the energy efficiency of large office buildings in tropical regions with cooling systems, while ensuring the users’ comfort at a reasonable cost. In tropical climates, the building envelope plays a crucial role in saving thermal energy as buildings are exposed to significant climatic impacts and require a significant amount of energy to achieve optimal indoor comfort conditions. In this context, BIM-3D simulation is considered to be effective since it can provide results very similar to those of its physical counterpart, which can be useful for decision making. For this purpose, a public building in Costa Rica is used as a case study, which is modeled in Revit 2019 to obtain a BIM-3D model and simulate its thermal behavior using the BIM tools of the referred software. The architectural characteristics are evaluated in the climatic context of the building, and results are simulated with different configured materials. The obtained results lead to the conclusion that simulation together the previous economic analysis is a valuable decision-making tool for design, enabling significant savings during construction and subsequent building use.

Indoor Thermal Environment in Different Generations of Naturally Ventilated Public Residential Buildings in Singapore

This study aims to evaluate and compare the indoor air velocities and thermal environment inside different generations of public residential buildings developed by the Housing and Development Board (HDB) of Singapore and analyze the impact of façade design on the indoor thermal environment. To achieve this goal, several case studies were carried out, namely, five typical HDB blocks built in different generations from the 1970s to recent years. Firstly, these five blocks with different façade design features were simulated to obtain the indoor air temperatures for both window-closed and window-open scenarios by using the EnergyPlus V22.2.0 (U.S. Department of Energy) and Design-Builder v6 software(DesignBuilder Software Ltd, Stroud, Gloucs, UK). Meanwhile, the computational fluid dynamics (CFD) simulations were conducted to obtain the area-weighted wind velocities in the corresponding zones to evaluate the indoor thermal comfort. Accordingly, the effects of façade design on indoor air temperatures under both the window-closed and window-open conditions were compared and analyzed. Positive correlations between the facades’ window-to-wall ratio (WWR) and the residential envelope transmittance value (RETV) and Ta were confirmed with statistical significance at a 0.05 level. Furthermore, the indoor thermal comfort based on the wind open scenarios was also investigated. The results indicate that the thermal environment can be greatly improved by implementing proper façade design strategies as well as opening the windows, which could result in an average 3.2 °C reduction in Ta. Finally, some principles were proposed for the façade design of residential buildings in tropical regions with similar climate conditions.

Indoor Thermal and Ventilation Indicator on University Students’ Overall Comfort

Thermal comfort (TC) and CO2 concentration significantly influence the overall indoor comfort sensations of building occupants. However, few studies have focused on educational buildings regarding both TC and CO2 concentration in tropical regions, and they also lack guidelines for short-term evaluation, which is essential for university classrooms. In this study, a mechanically ventilated university classroom was selected to investigate the 5 min-averaged comfort ranges for indoor parameters and the impacts of TC and variation of CO2 on student overall comfort. The real-time indoor environmental parameters were monitored, including indoor air temperature (Ta), mean radiant temperature (Tm), relative humidity (RH) and CO2 and air velocity (va); the operative temperature (Top) was calculated. Moreover, an online-based questionnaire survey related to thermal sensation (TS) and CO2-related air sensation (AS) was carried out. Linear and nonlinear regression models of comfort sensation predictions were obtained based on the questionnaires and corresponding measured indoor environmental data. The 5 min-averaged comfort ranges for Top, CO2 and RH are 21.5–23.8 °C, <1095 ppm and 47–63.5%, respectively. The comfort range of the TS and AS are 2.3–3.1 and 1–1.55, respectively. The result shows that students prefer a relatively cold indoor environment, as this improves their ability to tolerate bad indoor air quality (IAQ) with high CO2. A regression analysis indicated that AS is the most critical aspect, with a weight of 0.32, followed by TS, with 0.18. Finally, it was also found that individual weighting coefficients were not equivalent and differed across geographical locations and building types. Thus, obtaining the prediction models for a particular building is necessary. The results can give meaningful suggestions to adopt the appropriate operations for HVAC and improve indoor environmental quality in university buildings in tropical regions.

Energy and performance analysis of solar solid desiccant cooling systems for energy efficient buildings in tropical regions

Due to Malaysia's high ambient humidity, the majority of buildings suffer from over-cooling and high-energy consumption of conventional cooling systems. This study investigated the feasibility of solar desiccant cooling systems as alternatives to conventional cooling systems for energy-efficient buildings in Malaysia. The performance of a fan coil unit (FCU) and three solar desiccant cooling systems for use in a seminar room with a high latent load has been compared and evaluated. The FCU performance was evaluated using an energy audit, while desiccant cooling systems were simulated using TRNSYS and validated by experimental measurements. The energy audit results showed that FCU could not provide thermal comfort conditions since the room's relative humidity (77.2%) was more than 50%, while the greatest energy usage (37%) was consumed for the dehumidification process. The simulation outcomes demonstrated that the solar hybrid desiccant cooling system with 17.3% energy-saving potential was feasible for buildings with a high latent load. The two-stage solar desiccant cooling system in ventilation and recirculation modes provided 27.9% and 33.9% energy saving, while the room temperature and relative humidity could be brought closer to 25.5 °C-25 °C and 61%-66% respectively. It was found that the solar hybrid desiccant cooling system with COP and the solar fraction of 0.84 and 0.615, respectively, was able to reduce 256.4 kg CO2 emissions per month.

Transition to Zero Energy and Low Carbon Emission in Residential Buildings Located in Tropical and Temperate Climates

Different methods to achieve zero-energy and low carbon on the scale of a building are shown by most of the research works. Despite this, the recommendations generally offered by researchers do not always correspond to the realities found during the construction of new buildings in a determined region. Therefore, a standard may not be valid in all climate regions of the world. Being aware of this fact, a study was carried out to analyse the design of new buildings respecting the “zero-energy and low carbon emission” concept in tropical climatic regions when they are compared with a base case of temperate regions. To reach this objective, the comparison between real and simulated data from the different buildings studied was developed. The results showed that the renovation of existing residential buildings allows for reducing up to 35% of energy demand and a great quantity of CO2 emissions in both climate types. Despite this, the investment rate linked to the construction of zero-energy buildings in tropical zones is 12 times lower than in temperate zones and the payback was double. In particular, this effect can be related to the efficiency of photovoltaic panels, which is estimated to be, at least, 34% higher in tropical zones than temperate zones. Finally, this study highlights the interest and methodology to implement zero-energy buildings in tropical regions.

A developed method to measure and calculate the solar albedo of discrete-particle layers

Albedo is an important parameter for many research fields, including solar energy, building energy conservation, road engineering, regional and global climate, environmental protection, and other fields. The solar albedo of rough surface is always lower than the reflectance of homogeneous and flat surface due to the irregular and nonuniform surface properties. It is difficult to determine the solar albedo of rough surface in laboratory, especially for the surface with large particle sizes or cavities. Here a method was developed to measure the solar albedo of rough surface layers based on discrete-particle model in consideration of particle sizes, diurnal variations, and solar and season conditions. Besides, the solar albedo was theoretically studied by the discrete-particle model with and without cavities, which shows good performance. The relationship between the solar albedo of rough surface and the reflectance of flat surface was also studied. This developed methods can be applied to many engineering fields, such as the crushed-rock layers of embankments in permafrost regions and the cool roofing of buildings in tropical regions. The results also showed that the rough surfaces with higher reflective coatings can increase the solar albedo with greater values, which may be expected to raise the cooling performance of above engineering applications.

Critical components of Environmentally Sustainable Buildings Design Practices of office buildings in Ghana

Sustainable building design practices has in recent times become a topical issue among researchers and practitioners. However, in tropical built environment, particularly office buildings, there is inadequate empirical knowledge on practices that should be considered at the design stage of sustainable buildings. This study examines the critical components of environmentally sustainable building practices at the design stage for office buildings in the tropical built environment. Using quantitative research method five hypotheses were tested. The views of 250 professionals in the building industry were elicited using structured questionnaire. A confirmatory factor analysis (CFA) based on Structural Equation Model (SEM) was used to validate the hypotheses. The findings suggest that the five major components that is energy efficiency and conservation, water efficiency and conservation, material conservation, waste reduction, reuse and recycling and humane adaptation all positively influence sustainable design practices of office buildings in tropical regions, specifically Ghana. This finding suggests the critical components for environmentally sustainable building design practices for tropical regions which other tropical countries can emulate. The finding may be useful for professionals during design stage of projects to preserve the environment and its resources.

Lowering Emissivity of Concrete Roof Tile’s Underside Cuts Down Heat Entry to the Building

Buildings in Southern China widely use a double-skin roof to reduce heat entry through the roof to the building interior during summertime. Concrete roof tiles are preferably installed as the outmost layer of the double-skin roof due to their resistance to hail and wind damages and their attractive price. However, after construction, the tile’s top tends to be darkened by dust deposit and algae growth, increasing the heat entry through the roof to the building. Here, we show that this heat entry can be curtailed by lowering the emissivity at the tile’s underside. Temperatures and heat fluxes at different elevations of a double-skin roof with concrete tiles as the outmost layer of the roof are monitored. The underside of each concrete tile is coated with a specific paint to get a unique emissivity. Observations reveal that lowering the emissivity of concrete roof tiles could cut down the summer heat gain of buildings in tropical regions.

Influence of the types of fuel and building material on energy savings into building in tropical region of Cameroon

This study aims to investigate the influence of the combination of different types of fuel and building material on energy savings into buildings. The yearly cooling transmission loads of the building were determined using the degree-day’s concept. The optimization was based on a life cycle cost analysis. Five different fuels (fuel oil, hydroelectricity, liquefied petroleum gas (LPG), natural gas and solar energy), six insulation materials (foamed polyvinyl chloride and polyurethane, expanded and extruded polystyrene, rock and glass wool) and five wall structures (sundry earth block (SEB), hollow concrete block (HCB), compressed earth block (CEB), heavyweight concrete block (HWCB), and stone) were considered in calculations. The optimum insulation thicknesses, energy savings, and payback periods for different combinations were determined. As a consequence the result show that the optimum insulation thickness varies between 0.2 and 14cm, energy cost savings shift between 3 and 155$/m2, and payback periods change between 0.66 and 6.11years depending on the fuel type, the insulation material and the wall type. The highest energy saving has been obtained by using hydroelectricity (86.7%), while de lowest was reached by using natural gas (13.8%) and the combination using solar energy was found to be more economic.

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.

Performance Assessment of Dedicated Outdoorair Systems for Office Building in Thailand

Ventilation is necessary for good indoor air quality (IAQ) in air-conditioned buildings. However, the ventilation causes a substantial load and resulting energy consumption of the air-conditioning system particularly for buildings in tropical region. To address the issue, this paper investigates the dedicated outdoor air system (DOAS) for the energy-efficient ventilation. In the study, performance of various DOAS configurations is evaluated for a typical office building under the hot and humid climate of Thailand. The results from the simulations using TRNSYS software show that the DOAS of the combination of a cooling coil, a run-around coil and an enthalpy wheel is the most energy efficient by which it offers the smallest total air-conditioning loads in obedience with the Thai's ventilation standard requirement.

Combined use of design of experiment and dynamic building simulation in assessment of energy efficiency in tropical residential buildings

Energy consumption has become an increasingly controversial issue in the modern world. Among the widest range of energy consumers, residential buildings consume the largest amount of energy most of which is consumed by air conditioning systems in tropical countries. This paper attempted to examine energy saving in building elements such as walls, floors, windows, roofs, and ceilings and how the integration of such optimized elements in conjunction with effective air quality factor can contribute towards an ultimate energy efficient design. A typical two-storey terraced house in Kuala Lumpur, Malaysia was chosen to model energy usage by means of dynamic building Simulation. A case study was modeled using Revit Architecture software and analyzed using energy analysis software. Current energy consumption patterns were identified and the optimal level of energy usage was determined by replacing components with new energy efficient materials. Afterward, a Design of Experiment (DOE) method was used and the best combination of factor was identified. The results indicated that in residential buildings in tropical regions, changing ceilings and ceiling materials are the most effective way to reduce energy consumption; moreover, wall materials and inside temperatures were in the next levels of significant factors respectively. These results can be used to help building designers achieve optimum cooling load savings.

Evaluation of Impact of Shading Devices on Energy Consumption of Buildings in Tropical Regions

The aim of this paper is to demonstrate the role of shading devices in the improvement of energy efficiency of buildings in hot dusty and dry tropical regions. The effect of shading in reducing the energy consumption of buildings is investigated by considering a case study of a guest house chosen because of its logical design approach to reduce thermal loads. The building plan, measurements, and details on schedules of building usage activities have been used as input data to a simulation program of the building. Based on the inputs, a thermal building model is developed in trnsys 17 simulation program and the effect of external shading on the building has been explored. It is seen that building design and orientation determine the effectiveness of shading. Movable shading over windows has a significant impact reducing temperatures by about 1.5 °C in each thermal zone. The difference in thermal energy loads of the building calculated from modeling simulations of the base case and the control case utilizing movable shading devices is approximately 8%. A programmable logic controllers (PLC)-based movable shading device has been designed to facilitate optimal shading control. The results enable us to draw inferences regarding the additional contribution of the shading factor in energy saving techniques for buildings.

DESIGN GUIDELINES FOR THE UTILIZATION OF TILTED FAÇADES TO ENHANCE BUILDING ENERGY PERFORMANCE

Intense solar radiation is one of the key design problems for buildings in tropical regions. The recommended practice is to install shading devices, particularly to protect glazing systems. However, many design factors do not allow shading devices to be implemented in all cases; shading devices may not be appropriate to particular design concepts. To serve the designers' preference, alternative solutions should be provided. This study aims at investigating the performance of a new design alternative—the tilted façade. By simply tilting a wall downward, solar radiation can be minimized in the same way as a shading device. The state-of-the-art energy software, eQUEST, was used to simulate energy performance of buildings in Bangkok, Thailand. At the same time, simulated results were confirmed by using experimental data monitoring from specially customized test cells. A wide range of WWR (Window to Wall Ratio) was tested against different façade orientations, glazing types, and shading devices with similar projected lengths. Tilted façades can be most effective for all orientations except for the north. Also, tilted façades allow designers to use more glass without any additional energy consumption. Based on these results, a set of design guidelines for using tilted facades are proposed. Designers can not only utilize these guidelines to effectively adjust façade angle but also optimize the glazing size for the best energy performance.

A Field Study on Thermal Comfort of Occupants and Acceptable Neutral Temperature at the National Museum in Malaysia

A field study was conducted to investigate the thermal environment and occupants’ comfort in the National Museum of Malaysia. The occupants’ thermal perceptions in the museum were measured and characterised. The response of the occupants has indicated that the thermal conditions inside the museum did not satisfactorily fulfil the ASHRAE Standard 55, because only 78% of the occupants were satisfied with their environment. Besides, actual mean vote (AMV) and predicted mean vote (PMV) were compared. The Fanger’s model gave a neutral operative temperature of 22.2°C from the PMV, whereas the questionnaire data used in the mean thermal sensation vote (MTSV) of the present study gave a higher value (22.5°C) for the neutral operative temperature. The preferred operative temperature was found to be 22.3°C. The minimum air temperature in three galleries was below the lower limit of the temperature range of 18–22°C as recommended by Museums Australia Victoria. The mean indoor humidity was too high compared to the optimal range of 55 ± 5% relative humidity (RH). The mean air velocity, ≤0.15 m·s−1, in each gallery was satisfactory. Findings of this study are very useful for designing heating, ventilating and air-conditioning (HVAC) systems with energy-saving methodology for museum buildings in tropical regions.

The Effects of Orientation, Ventilation, and Varied WWR on the Thermal Performance of Residential Rooms in the Tropics

Building orientation is a significant design consideration, mainly with regard to solar radiation and wind. In predominantly hot humid regions like Malaysia which receives sunlight all year around, buildings should be oriented to minimize solar gain and maximize natural ventilation. This paper describes an investigation into the effect of building orientation in view of solar radiation absorptance of exterior wall, varied area ratio of glazed window to wall and the effect of natural ventilation on the thermal performance for residential building in tropical region. The FAJAR BAKTI building (postgraduate student residential building) which is oriented in the east west directions, and a located in USM Campus, Penang. The selected case study are two rooms, the first one is facing east direction while the other faced west. The differences in in/out door air temperature and air velocity of both rooms have been measured from the field directly using the comprehensive datalogger BABUC/M, this data have been analyzed and investigated. The results shows that east windows have more obvious effect on increasing indoor air temperature than west windows, that is applicable for ventilated or unventilated rooms.

A resistance approach to analysis of natural ventilation airflow networks

Many buildings in warm humid climates, particularly in tropical regions, rely for much of the time on natural ventilation from prevailing breezes for indoor thermal comfort. Much effort in recent years has been directed toward the use of computational fluid dynamics in evaluating airflow through buildings based on the solution of Navier-Stokes equations incorporating a turbulence model. This approach requires extensive data preparation and a reasonably powerful computer to yield results within an acceptable computation time for both numerical solution and simulated flow visualisation. Quantitative evaluation of natural ventilation through many low budget buildings in tropical regions is not evaluated due to a lack of suitable simple computer programs. What is needed are programs that can run on modest personal computers and be used quickly to compare the relative natural ventilation performance of alternative building layouts for prevailing breeze directions during the preliminary design stage. Smaller buildings are often designed for cross ventilation by prevailing breezes with flow entering a windward opening and exhausting through a leeward opening. Such flow through a limited number of openings in series can be calculated very quickly on a personal computer using an orifice flow approach based on estimates of pressure differences and discharge coefficients of openings. When buildings have external ventilating openings in a number of rooms and flow branches within the building, it is no longer possible to calculate directly the airflow in the various branches of the airflow network. Flow in such networks can be analysed iteratively on a personal computer by repetitive solution of simultaneous equations for flow rates in branches at nodes and conservation of mass flow through the network. The procedure described in the paper uses the Hardy Cross method of balancing flows at network nodes until errors throughout the network are acceptably small. Sources of data on wind pressure distributions over building walls and shielding influence of nearby buildings are provided together with a detailed description of a procedure for solving network airflows sufficient for readers to write their own computer code.