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Net zero-energy buildings have become one of the flagships in the path towards the decarbonisation of cities. Even though heating systems, especially in existing buildings, are currently the main consumer in many areas of the world, cooling needs are gaining relevance in several countries, and this is expected to be kept in the focus in the context of increasing temperatures, according to the climate projections identified by the IPCC. This has also additional implications on thermal comfort conditions (and, indirectly, on the derived health issues) in areas where no cooling systems are installed in residential buildings. This research work aims to evaluate the design of shading elements as a design strategy in the path towards net-zero residential buildings in diverse Colombian climates. A parametric analysis is developed, considering a combination of different shading solutions applied in residential buildings. Their effectiveness is evaluated in different climate zones in Colombia considering both the current climate data and future climate data expected according to the projections proposed by the IPCC. A reference building in Bucaramanga (Colombia) was selected for detailed monitoring, and the collected data were used to validate a simulation model developed in DesignBuilder. Almost 1000 alternative scenarios were established and parametrically evaluated, resulting from the combination of different shadings solutions, orientations and climate conditions. The results are evaluated considering two different approaches: cooling demand assuming a standard indoor temperature profile and indoor comfort when no cooling devices are used in the building, showing that some strategies, such as overhangs, involve significant improvements in terms of indoor thermal comfort and a reduction in cooling demand (reaching in some cases savings up to 30%) in the different climate conditions considered; as well, their effectiveness remains similar when future climate projections are considered. [ABSTRACT FROM AUTHOR]

This study investigates the application of dynamic window technologies in condominiums located in hot and humid climates, focusing on Thailand. The research integrates both passive and active window designs aimed at reducing energy consumption by maximizing natural ventilation and daylight, while minimizing heat gain. Dynamic windows, equipped with shading devices, automated controls, and stack-effect ventilation, can achieve significant energy savings by decreasing the need for air conditioning and artificial lighting. The energy performance was assessed through simulations based on Thailand's Building Energy Code (BEC), resulting in a potential reduction in energy consumption by 3.29 kWh/m2 annually or approximately 1.6% annually. Moreover, economic analysis showed that applying dynamic windows in condominiums could save up to 506.38 baht per room per year. The lifecycle cost analysis supports their long-term financial viability, achieving payback within 18.4 years and generating further net savings post-payback. The study concludes that dynamic windows are both scalable and sustainable, offering a viable solution for urban developments in tropical regions. [ABSTRACT FROM AUTHOR]

Thermal energy storage (TES) is an innovative technology that can help mitigate environmental problems and make energy consumption in air conditioning systems more efficient. TES also helps to decouple the production and use of cooling. In this work, a mathematical model was used to obtain the thermal loads of the environment based on Brazilian standards and to simulate the operation of an air conditioning system integrated with TES. A refrigeration system capable of providing cooling capacity for the selected environment was used. It simulated the operation of refrigeration systems to evaluate the coefficient of performance of the refrigeration cycle and the refrigeration system, including the TES, for the city of Teresina, in the northeast region of Brazil. On each day, the efficiency of the air-cooled chiller coupled with a TES that used paraffin with phase change material was verified. Based on the data obtained from the mathematical model, the reduction in energy consumption achieved by coupling TES with the air conditioning system varied between 10.6% and 1.3%. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to explore how building design requires consideration of both energy consumption and environmental impacts of the construction and maintenance processes. The increasing energy consumption and construction waste are concerning trends within the building industry. In response to this issues, the concept of circular economy has gained prominence, emphasizing the need to restore, rebuild, and regenerate resources in a sustainable manner. This research focused on Bio-Cooling Façades (BCF) in tropical climates through the assessment of four parameters including the biomaterial, cooling façade, energy consumption, and building circularity. This was conducted through a comparative analysis of existing and eight proposed BCF configurations designed to reduce energy consumption and increase building circularity. The results show that applying BCF at a glazing size of 40% reduces solar heat radiation, lowers building energy consumption, and minimizes potential construction material waste in countries with tropical climates. These findings assist architects and the industry in defining the optimal building façades for cooling, ultimately reducing energy consumption. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to explore how building design requires consideration of both energy consumption and environmental impacts of the construction and maintenance processes. The increasing energy consumption and construction waste are concerning trends within the building industry. In response to this issues, the concept of circular economy has gained prominence, emphasizing the need to restore, rebuild, and regenerate resources in a sustainable manner. This research focused on Bio-Cooling Façades (BCF) in tropical climates through the assessment of four parameters including the biomaterial, cooling façade, energy consumption, and building circularity. This was conducted through a comparative analysis of existing and eight proposed BCF configurations designed to reduce energy consumption and increase building circularity. The results show that applying BCF at a glazing size of 40% reduces solar heat radiation, lowers building energy consumption, and minimizes potential construction material waste in countries with tropical climates. These findings assist architects and the industry in defining the optimal building façades for cooling, ultimately reducing energy consumption.

The aim of this review was to present the breeding status of pure or crossbreeds of European cattle with African indigenous cattle in order to improve milk yield in African tropical conditions. As the African indigenous breeds are characterized by small size, low body weight (300–450 kg) and low production performances (less than 1000 kg per lactation), short lactation length (205–240 days), etc., the crossbreeding with pure European cattle was done in order to ameliorate production performances especially milk and beef production. As results, it was seen that F1 offspring improved output productions than their parents of tropical origin. Also, it was seen that F1 offspring showed disease and heat resistance than their parents of temperate climate origin. However, at different degrees of crossbreeding, it was seen that the offspring can demonstrate bad production performances than their parents and therefore, the crossbreeding has to respect a certain degree. Other consequences are that the crossbreeding of local and pure European cattle breeds has resulted in calving complications in African local cattle. In African indigenous cattle, the selection as an improvement tool was given less emphasis as a solution to improve output production. That is why, the implementation of a well-prepared selection programs could be practiced in African indigenous cattle in order to preserve African cattle genotypes, as they are endangered of extinction due to various crossbreeding with exotic cattle breeds. [ABSTRACT FROM AUTHOR]

Abstract Overview Dengue fever, a viral illness transmitted by the Aedes mosquito, is capable of causing a range of serious complications, including fulminant hepatic failure, renal dysfunction, encephalitis, encephalopathy, neuromuscular and ophthalmic disorders, seizures, and cardiomyopathy. Case description This report details the case of a 30-year-old lactating woman with no notable medical history who presented to the emergency department with symptoms of high-grade fever, altered mental status, and seizures. Upon imaging, bilateral infarcts in the thalami and cerebellar hemispheres were observed, consistent with cerebellitis and dengue encephalitis. Patient treatment and outcome The patient was admitted to the intensive care unit and received appropriate treatment. Following a critical phase and successful patient stabilization, she was transferred to a high dependency unit for a week before being discharged with recommendations for follow-up care. Conclusion This case illustrates the broad spectrum of complications that can arise as a result of dengue infection and the importance of timely diagnosis and management in improving patient outcomes. Further investigation is required to better understand the mechanisms underlying these complications and to formulate specific guidelines for the prevention and treatment of dengue shock syndrome.

The rapid increase in the population, which has been concentrated mainly in urban areas, has caused an environmental imbalance over the years since the built environment developed as a foreign element to the ecosystem, which prevents having resilient environments capable of adapting to the challenges posed by climate change. This research aims to provide an updated knowledge base of bio- inspired strategies emulated in hot and humid climates to achieve an efficient built environment, restoring resources, and bringing nature closer to cities. A systematic review is conducted based on keyword selection to answer i) what has been achieved in built environments to be more efficient and sustainable (including tropical climates) and ii) how natural patterns, strategies, and models are mimicked. Implementing these strategies is very little in regions with hot and humid climates. Bio-inspired approaches are concentrated in those that try to emulate the functions of nature, followed by approaches that imitate the form of nature, biomimicry, and biomimetics being the most used approaches, leading to the development of efficient and resilient cities. [ABSTRACT FROM AUTHOR]

This work investigates the feasibility of terrestrial Optical wireless communication links under tropical and subtropical regions which are characterized by high precipitation. The impact of rain on propagating optical radiation is observed under controlled rainfall conditions using a laboratory testbed. Link degradation in terms of rain specific attenuation (RSA) is calculated experimentally and using known empirical models. A worst case analysis in terms of fade margin is carried out using measured and recorded data from Indian Meteorological Center to estimate the free space link feasibility for Indian tropical/subtropical climates. [ABSTRACT FROM AUTHOR]

In this study, the suitability of various Cement Asphalt Mortar (CAM) mixtures for bridge expansion joint applications in tropical climates was quantitatively assessed. A comprehensive analysis encompassed key properties, including mixing stability, flowability, unconfined compressive strength, expansion characteristics, and resistance to acidic and alkali environments. The influence of high-temperature exposure on unconfined compressive strength and the microstructural features were also examined. The results revealed a discernible trend: lower cement content, in conjunction with anionic Asphalt Emulsion (AE) or epoxy resin, significantly enhanced mixing stability and flowability while contributing to improved unconfined compressive strength and chemical degradation resistance. Notably, epoxy resin emerged as a valuable component in mitigating high-temperature-induced strength reduction, indicating potential promise for CAM mixture design. SEM analysis visually supported these findings by highlighting the microstructural distinctions among CAM mixtures. Quantitatively, the findings indicated that CAM mixtures with a 25% cement content and 75% anionic AE exhibited an 11% improvement in mixing stability, along with a 13% enhancement in flowability, relative to the control mixture with 100% cement. Additionally, CAM mixtures incorporating epoxy resin (at various percentages) with anionic AE exhibited a significant 15% resistance to high-temperature-induced UCS reduction, surpassing other mixtures. The SEM micrographs visually confirmed the superior microstructural connectivity achieved with epoxy resin, further validating the observed enhancements. These quantitative results offer a robust foundation for tailoring CAM mixture compositions to optimize their suitability for rigorous infrastructure projects in tropical climates. [ABSTRACT FROM AUTHOR]

Urban vegetation makes cities more liveable, provides essential ecosystem services, and is relevant for sustainable development. We investigated the public perception of urban vegetation in the metropolitan area of Costa Rica, Central America. Through an online survey, we collected 1264 responses from Costa Rican residents on their attitudes and opinions towards urban vegetation's environmental services and disservices. After selecting those participants residing in the Greater Metropolitan Area and applying a data cleaning process, we derived 811 valid responses. Poststratification techniques were employed to fit the sample to the general population distribution. We found that the majority viewed urban vegetation favorably, with 80 % believing that urban greenery contributes more benefits than negative effects to air quality, shading, and wildlife. In contrast, up to 20 % think urban greenery is harmful, asserting that it encourages crime, promotes pests, and damages infrastructure. Perceptions changed according to demographic variables such as gender, age group, and education level. We compared our results to a previous study in Singapore, Southeast Asia, which showed similar trends despite cultural and economic differences. This paper offers a starting point for priority-setting and decision-making in city planning by delivering insights into how people in the tropics perceive urban vegetation.

The maximum specific pollutant loads of nutrients and carbonaceous organic matter of the effluent—in an initially oligotrophic or mesotrophic state artificial run‐of‐river reservoir—should be studied in order to serve as a basis for future hydroelectric in tropical regions. Two different hydrological scenarios in the central tropical region of Brazil are analyzed; a historical and a synthetic one. The maximum specific load that the artificial run‐of‐river reservoir of a hydroelectric power plant supports is evaluated in order to meet the environmental limits defined by national resolution. An analysis of lateral and vertical dispersion between epilimnion and hypolimnion is performed. The maximum permissible loads for the historical hydrological scenario with a long‐term average flow of 247.2 m3 s−1 are 70.017 kg BOD hm−3 d−1, 0.131 kg Ptotal hm−3 d−1, and 2.626 kg Ntotal hm−3 d−1. For the synthetic hydrological scenario with a long‐term average flow equaling 140.4 m3 s−1, the maximum permissible loads are 55.576 kg BOD hm−3 d−1, 0.096 kg Ptotal hm−3 d−1, and 1.925 kg Ntotal hm−3 d−1. The proposal of this study is to provide an aid to the decision‐making process of environmental managers and consultants in artificial run‐of‐river reservoirs in tropical regions with similar hydrological regimes. [ABSTRACT FROM AUTHOR]

The present study has analyzed the allelic-specific expression in Purebred Sistani (Bos Indicus) and their crossbreed with Holstein, Simmental, and Montbeliarde breeds (Bos Taurus). The blood samples were taken from the caudal vein of purebred Sistani cows and crossbreed Sistani’s with Holstein, Simental, and Montbeliarde (4 treatments). We discovered 152,496 (Purebred Sistani), 134,285 (Sistani × Simmental), 163,362 (Sistani × Montbeliarde), and 177,042 (Sistani × Holstein) SNPs on the assembled transcriptomes. In the Purebred Sistani, 8295 (5%), Sistani × Holstein crossbreed 11,900 (7%), Sistani × Simmental crossbreed 13,187 (10%), and Sistani × Montbeliarde crossbreed 16,666 (10%) number of SNPs were identified as ASE-SNPs. In the present study, 12 SNPs types identify, of which four were transition and eight were transversion. The most common SNPs were transition types. These SNPs were present in purebred Sistani 71.84%, Sistani × Holstein crossbreed 72.65%, Sistani × Simmental crossbreed 72.60%, and Sistani × Montbeliarde crossbreed 71.94%. Ontology analysis of the expressed genes in these cows revealed the involvement of these genes in different Biological classifications. Conducting such studies in parts of the world, such as the Sistan region, where it is not possible to record accurate records of cows, is a suitable and economical method for identifying genes with different expressions. [ABSTRACT FROM AUTHOR]

In this study, the suitability of various Cement Asphalt Mortar (CAM) mixtures for bridge expansion joint applications in tropical climates was quantitatively assessed. A comprehensive analysis encompassed key properties, including mixing stability, flowability, unconfined compressive strength, expansion characteristics, and resistance to acidic and alkali environments. The influence of high-temperature exposure on unconfined compressive strength and the microstructural features were also examined. The results revealed a discernible trend: lower cement content, in conjunction with anionic Asphalt Emulsion (AE) or epoxy resin, significantly enhanced mixing stability and flowability while contributing to improved unconfined compressive strength and chemical degradation resistance. Notably, epoxy resin emerged as a valuable component in mitigating high-temperature-induced strength reduction, indicating potential promise for CAM mixture design. SEM analysis visually supported these findings by highlighting the microstructural distinctions among CAM mixtures. Quantitatively, the findings indicated that CAM mixtures with a 25% cement content and 75% anionic AE exhibited an 11% improvement in mixing stability, along with a 13% enhancement in flowability, relative to the control mixture with 100% cement. Additionally, CAM mixtures incorporating epoxy resin (at various percentages) with anionic AE exhibited a significant 15% resistance to high-temperature-induced UCS reduction, surpassing other mixtures. The SEM micrographs visually confirmed the superior microstructural connectivity achieved with epoxy resin, further validating the observed enhancements. These quantitative results offer a robust foundation for tailoring CAM mixture compositions to optimize their suitability for rigorous infrastructure projects in tropical climates.

One method in terms of architectural technology used to minimize the negative impact of overheating is to design a building with double skin façade and integrating it with electrochromic glass. The purpose of this research is to reveal whether the use of a double skin façade and the application of electrochromic glass would be preferable for buildings in tropical climates, in terms of obtaining aesthetic points while not having to sacrifice thermal comfort nor committing energy waste at the same time. The data in this research is obtained with qualitative - descriptive comparative method, which is applied for room temperature measurement with a computer simulation software, based on pre-existing theories, reference standards and material specifications from existing manufacturers. The results of this study conclude that the application of double skin façade in a building does make a significant contribution to achieving thermal and lighting comfort. Both profiles of space reduction with the use of electrochromic glass in buildings in tropical climates are able to reach ideal temperatures in comparison to when ordinary glass material is applied. And third, it is proven that the double skin façade technology and applying electrochromic glass on a building can provide significant energy efficiency for long-term projects. [ABSTRACT FROM AUTHOR]

Tropical region such as Darwin has similar weather patterns throughout the year, thus creating higher energy demands in residential buildings. Typically, buildings consume about 40 per cent of the total energy consumption for indoor heating and cooling. Therefore, building envelopes are linked with design strategies such as the use of thermal energy storage and phase change materials (PCM) to minimize this energy consumption by storing a large amount of thermal energy. Primarily, PCMs are targeted by researchers for use in different components of buildings for thermal efficiency; thus, this study aimed to provide a suitable PCM to optimize indoor thermal comfort and minimize the cooling loads of residential buildings in tropical climates through simulation of a tropical climate building and provide optimum thickness for the selected material. Microencapsulated PCM mixed with gypsum in wallboards were used to reduce the cooling load of a building located in Darwin. The cooling load of the building was calculated using Revit software. A comparison of the cooling load of the building was carried out using PCM-incorporated wallboards of thicknesses of 0 cm, 1 cm and 2 cm in Energy Plus software. The total cooling load decreased by 1.1% when the 1-centimetre-thickness was applied to the wall, whereas a 1.5% reduction was obtained when a 2-centimetre-thick PCM layer was applied. Furthermore, the reduced cooling loads due to impregnation of the PCM-based gypsum wallboard gave reduced energy consumption. Ultimately, the 2-centimetre-thickness PCM-based gypsum wallboard gave a maximum reduction in cooling load with a 7.6% reduction in total site energy and 4.76% energy saving in USD/m2/year. [ABSTRACT FROM AUTHOR]

Temperature is known to influence the operational efficiency of enhanced biological phosphorus removal (EBPR) systems. This study investigated the impact of thermal stress above 30°C on the properties of an EBPR community established with tropical inoculum. The results confirmed the stability of the 30°C EBPR system with high P‐removal efficiency over 210 days. Accumulibacter was abundant in the community. When the EBPR sludge was subjected to a sudden temperature increase to 35°C under multiple cycles of anaerobic‐aerobic phases, each lasting 4 h, high P‐removal was maintained over 2 days, before gradually failing when the Competibacter appeared to outcompete Accumulibacter. These data suggested that the EBPR capacity is robust when subjected to occasional thermal stress. However, it could not be maintained even for a short time under temperature stress at 40°C. Thus, the threshold temperature for tropical EBPR failure is between 35°C and 40°C. Practitioner Points: EBPR was stably maintained at 30°C with Accumulibacter being dominant.Good EBPR activities persisted for a short period at 35°C.EBPR was deteriorated at 40°C.The threshold temperature for tropical EBPR failure is between 35°C and 40°C. [ABSTRACT FROM AUTHOR]

High ambient temperature negatively affects gas turbine performance, especially in a tropical climate. Cogeneration improves fuel utilization by taking advantage of the energy discharged as waste heat in the exhaust gases. This case study assesses the effects of high ambient temperature on the performance of a natural gas-based cogeneration plant in Barranquilla, Colombia, a location with a hot and humid tropical climate throughout the year with an annual average temperature of 27.4 °C. The cogeneration plant encompasses gas and vapor turbine generation, supplementary fire, waste heat recovery, and process heat exchange. Validated ASPENHYSYS® simulation allows comparing gas-turbine-alone indicators with those at ISO conditions, i.e., 15 °C and 101.3 kPa. Ambient temperature reduces gas turbine power output by up to 22% and decreases thermal efficiency by around 0.06% for every °C rise above ISO conditions. Cogeneration with and without supplementary fire increases power output by 17% and 5% compared to gas-turbine-alone operation. The energy utilization factor increases by 27–37% without supplementary fire and above 37% with supplementary fire. Results give insight into the challenges of cogeneration plants in a tropical climate. Further studies should include the effects of high humidity on power plant performance and the potential benefits of cooling inlet air.

Nineteenth-century British and Caribbean sources show that European colonists were constantly struggling to maintain their health in a little-understood tropical climate; they engaged in frequent discussion and the exchange of advice on the preservation of their health. This article reveals that the maintenance of a specific group of temporary migrants, those in the armed forces, was a significant concern for the British authorities. It analyses medical reports and information in the contemporary press, which illustrate how heightened concerns about preservation of the army’s health led to an alternation between two different diets, one based on preserved food imported from the British homeland and the other on fresh local food.

The objectives of this experiment were to calculate energy (ME) and crude protein (CP) requirements of Arabic chicken hens in the tropical climates during the early laying period by a choice feeding method. One hundred and thirty-eight of 22-week old Arabic chicken hens were allotted into 12 sheltered pens with 10-14 chicks each. The no free-choice group hens fed a standard diet conforming with the Hy-line Brown Commercial Management Guide, whilst the free-choice group hens fed with a standard diet, an energy-protein rich diet, an energy-rich diet, a protein-rich diet, and an energy-protein poor diet. Feed consumption, energy and protein consumptions, energy (kcal of ME/kg) and protein (g of CP/kg) dietary concentrations were recorded weekly, and egg production was recorded daily. All performance data were taken repeatedly during the first 28 weeks of egg production and were analyzed after summarizing weekly data into seven 28-d periods using the Mixed Procedure in SAS. The dietary treatments had no clear effect on feed and protein consumption but had a significant effect on energy consumption, energy and protein concentrations, and egg production. Energy consumption of the no free-choice group hens was lower than those in the free-choice group hens (1580 vs. 1718 kcal of ME/kg/hen; p

The spectral impact on various PV materials –amorphous silicon (a-Si), CdTe, CIGS, single crystalline silicon (sc-Si) and multi crystalline (mc-Si)– in two nearby cities of Southeastern Brazil is presented. For every PV technology studied, the values of the spectral mismatch factor on instantaneous, monthly and annual basis were computed by means of spectra recorded over a 12-month experimental campaign carried out in São Paulo and São José dos Campos. A blue-biased however seasonal spectrum prevails in both cities, which leads to annual spectral gains of up to around 6% and 2% exhibited by a-Si and CdTe, respectively. On the other hand, CIGS, sc-Si and mc-Si show negligible annual gains that lie between around −1% and 0%. These results are well aligned with previous findings obtained using both experimental and modelled spectra in other low-latitude sites with tropical climate. Consequently, spectral effects cannot be ignored in such sites, especially when modelling the outdoor behavior of larger bandgap PV devices. Last, a quasi-linear relationship exists between the monthly average photon energy and the monthly spectral mismatch factor for all the PV materials under scrutiny. This conclusion is in good agreement with previous works carried out in mid-latitude sites. Image 1 • Spectral impact on PV in two southeastern Brazilian sites investigated. • Twelve-month horizontal spectral irradiance datasets collected at two nearby sites. • Blue-biased prevailing spectra with seasonal behavior. • Annual spectral gains: up to ∼6%/down to −1% for large/small bandgap PV materials. • Results obtained well aligned with previous experimental and modelled findings. [ABSTRACT FROM AUTHOR]

Researchers have used passive strategies, such as the implementation of thermal insulation and the use of phase change materials (PCM), in several studies, but some problems have not yet been solved. It is the case of showing the real effect of external shading combined with thermal insulation and phase change materials to improve the thermal performance and energy efficiency of office buildings in tropical coastal areas. Another pending problem to be solved is to define the impact produced by passive strategies on the performance of workers in office buildings in coastal zones. It is with a view to answering all these questions that this study was envisaged with the main objective of evaluating, analyzing, comparing, and discussing the effect of thermal insulation and phase change materials on thermal comfort and energy demand in coastal areas of hot and humid tropical climates located in the island of Madagascar. In this sense, hourly climate data for the past 30 years have served as the basis for assessing environmental conditions of future climate. It was found that the PCMs have a more significant effect on the coastal zone of hot climates than humid tropical climates. The results of the statistical analyses showed that the application of passive strategies stabilizes indoor air temperatures to between 23 °C and 28 °C in the offices, which is the recommended comfort range in these regions. In the coastal regions of Madagascar, up to 30% of cooling energy is expected to be reduced by combining the introduction of thermal insulation and PCM materials. [ABSTRACT FROM AUTHOR]

In an effort to support carbon footprint reduction in housing development, one approach is designing energy efficient housing. Issues such as cost efficiency and minimum environmental impact should be thoroughly considered when designing this type of housing. One of concepts found to be cost-effective and to increase the energy performance of a house is the near Zero Energy House (nZEH) concept. This concept enhances the use of natural resources, for example, sunlight exposure, climate conditions, and wind, that can minimize the use of fossil fuel energy. Housing in a tropical climate where sun exposure is year round, such as in Indonesia, can benefit from the nZEH concept. This research aimed to identify design parameters of nZEH and its best practices in tropical climates, including Indonesia. The identified design parameters will be used in the next step of the research, finding a combination of cost optimum design parameters. This study was conducted by consulting recognized experts, which included government, private sector, and academicia, who have expertise in the field of building design and energy. The results showed that the design parameters of nZEH in tropical areas include passive design, fenestration, indoor lighting arrangements, and the use of photovoltaic panels (PV).

Graphical abstract Highlights • A financial model to determine the feasibility of cogeneration systems was applied. • The influence of the partial load of the cogeneration system was investigated. • A cogeneration system for tropical climate conditions was characterized. • The environmental feasibility by using the microturbine on the system was better over the engine. • The payback time was of up to 8 years when the equipment was resized to meet the demand. Abstract In countries with tropical climates there is a great need for air-conditioning in buildings. This is due to the high temperatures and high humidity in the tropics and sub-tropical regions such as Northeast Brazil. Overall, electricity bills show that an excessive amount of money is spent on achieving thermal comfort using regular air-conditioning systems to remove heat from buildings. The electricity consumed by such systems can represent about 50% of the total electricity bill. This paper proposes using a cogeneration system in the rectorate building of a university campus. A cogeneration system comprises a reciprocating engine as the prime mover, a back-up boiler, an accumulation tank and a single-effect absorption chiller to remove excess heat. The main advantage of using this kind of system is that increasing the production temperature of cold water improves the overall efficiency of the system as the residual heat is at a lower temperature. This solution is applied to the rectorate of the Federal University of Paraíba (UFPB) in João Pessoa, Northeast Brazil, where the demand for cool temperatures is intense and the consumption of energy is extremely high since the average annual relative humidity and the dry bulb temperature are about 75% and 27 °C, respectively. [ABSTRACT FROM AUTHOR]

Researchers have used passive strategies, such as the implementation of thermal insulation and the use of phase change materials (PCM), in several studies, but some problems have not yet been solved. It is the case of showing the real effect of external shading combined with thermal insulation and phase change materials to improve the thermal performance and energy efficiency of office buildings in tropical coastal areas. Another pending problem to be solved is to define the impact produced by passive strategies on the performance of workers in office buildings in coastal zones. It is with a view to answering all these questions that this study was envisaged with the main objective of evaluating, analyzing, comparing, and discussing the effect of thermal insulation and phase change materials on thermal comfort and energy demand in coastal areas of hot and humid tropical climates located in the island of Madagascar. In this sense, hourly climate data for the past 30 years have served as the basis for assessing environmental conditions of future climate. It was found that the PCMs have a more significant effect on the coastal zone of hot climates than humid tropical climates. The results of the statistical analyses showed that the application of passive strategies stabilizes indoor air temperatures to between 23 °C and 28 °C in the offices, which is the recommended comfort range in these regions. In the coastal regions of Madagascar, up to 30% of cooling energy is expected to be reduced by combining the introduction of thermal insulation and PCM materials.

The understanding of concentration and emissions distribution of gases such as ammonia (NH3) in agricultural installations is of growing importance due to its effect on health and productivity of animals and workers. The objective of this study was to use validated Computational Fluid Dynamics (CFD) model as a tool to predict NH3 concentration distribution and mass fluxes in a non-insulated broiler chicken installation with natural ventilation, typically found in subtropical and tropical countries. Results from this study indicated that simulation with CFD can be used to predict NH3 concentration distribution and mass flux inside similar installations with incident winds from different directions of entrance at the lateral opening of the installation. The most direct application of the proposed model would be to help improving the existing buildings and also to help in the conception of new ones, and may also apply the model to help in the development of NH3 emission inventories

A two‐week‐long intervention study was performed in two classrooms in an elementary school in Costa Rica. Split‐cooling air‐conditioning (AC) units were installed in both classrooms. During the first week, the air temperature was reduced in one classroom while in the other (placebo) classroom the fans were operated but no cooling was provided. During the second week, the conditions were exchanged to create a 2 × 2 crossover design in which each pupil was their own control. A total of 37 children performed tasks similar to school work and completed questionnaires reporting their thermal sensation and perceptions. Operating the AC units reduced classroom temperature by about 5 K, from about 30 to 25°C. Thermal sensations changed from hot to neutral and slightly cold, and the percentage of children rating the thermal conditions as acceptable increased significantly. Neutral temperature was estimated to be about 27°C. The 11‐year‐old children performed the language and logical‐thinking tasks significantly better in terms of speed at the lower temperature, while the less able pupils performed better on all tasks at the lower temperature. There were no significant effects on accuracy. These results confirm published findings from moderate climates and extend their validity to the tropics. They indicate that acclimatization can increase the optimal temperature for learning. [ABSTRACT FROM AUTHOR]

Mainstream partial nitritation/anammox (PN/A), coupled with excess biological phosphorus removal, in a 200,000m3/d step-feed activated sludge process (Train 2) in the Changi Water Reclamation Plant (WRP), Singapore, has been studied and reported. This paper presents an overview of process performance and the microbial community during the period from 2011 to 2016. The site data showed that, along with the reduction of dissolved oxygen (DO) from 1.7 to 1.0 mg O2/L in the aeration zones, the concentrations of ammonium and nitrate of the final effluent increased, while nitrite decreased, resulting in an increase of 2.4 mg N/L of total inorganic nitrogen. Autotrophic nitrogen removal was higher than heterotrophic biological nitrogen removal under higher DO concentration conditions, but decreased under low DO operating condition. These macro-scale changes were caused by shifts of the nitrogen-converting microbial community. The ammonia oxidizing bacteria (AOB) population abundance was reduced by 30 times, while the nitrite oxidizing bacteria (NOB) population abundance and specific activity increased significantly with a shift of dominant genus from Nitrobacter to Nitrospira. The ratio of AOB and NOB specific activities were reduced from 12.8 to 1.6, and the ex situ nitrite accumulation ratio reduced from 76% to 29%. Changes in the microbial community and overall process performance illustrated that, compared to the excellent NOB suppression under high DO conditions, NOB were more active after the DO concentration reduction despite still being partly suppressed. This case study demonstrated, for the first time, the influence of DO reduction on the nitrogen conversion microbial community and PN/A process performance for a suspended growth system. Its relevance to biofilm and hybrid PN/A processes is also discussed. [ABSTRACT FROM AUTHOR]

Demand baseline estimation (BE) is key to the impact assessment of a demand response event in a power system. While many BE techniques exist in literature and are implemented by utilities, these are either inaccurate, or computationally intensive, and only provide point estimates of the demand baseline. This study presents a simple, single‐stage, similarity‐based BE technique. The authors posit a new definition of similarity that includes weather covariates, and therefore eliminate the need for a subsequent adjustment. A novel growth rate assumption for the demand, combined with an optimised exponential smoothing technique results in a higher accuracy for the proposed BE technique. Additionally, an L ‐order iterated bootstrap is used to generate confidence intervals to account for prediction uncertainties. The proposed BE technique is tested for the Singaporean National Electricity Market, and is shown to be consistently more accurate than other conventional BE techniques. [ABSTRACT FROM AUTHOR]

Palm diversity in present-day Africa is much less than in other tropical regions such as the Americas and Southeast Asia but comprises several endemic genera, including Sclerosperma. The origin and evolution of this small Arecaceae genus are still enigmatic, and every new fossil discovered helps fill the void in its palaeophytogeographic history. In this article, we report five different pollen morphologies assigned to Sclerosperma from the earliest Late Eocene (early Priabonian) of southeast Kenya, Africa. These pollen grains represent the earliest fossil records of Sclerosperma so far and add a new geographic region and time slot to the palaeophytogeographic history of this genus. The morphological variability observed in the fossil pollen suggests that the diversification within Sclerosperma was already underway by the onset of the Priabonian, c. 37 Ma. Detailed analysis of the distribution of the three extant Sclerosperma species shows that this genus occurs only under Equatorial/Tropical climates with MTCM ≥ 18 °C, such as fully humid Rainforest (Af), Monsoonal (Am), and winter dry Savannah (Aw) climates. Sclerosperma is also conservative when it comes to vegetation biomes and only occurs in three different but closely related biomes, the Tropical & Subtropical Moist Forests Biome, the Tropical & Subtropical Grasslands, Savannahs & Shrublands Biome, and the Mangroves Biome. No current outliners pinpoint to a wider ecological tolerance of this genus in the geological past. This suggests Sclerosperma to be an exceptionally reliable taxon for palaeoclimate estimations and when assigning palaeofloras to major vegetation biomes. • Eocene Sclerosperma pollen grains are the oldest fossils from this enigmatic palm. • Pollen morphotypes suggest intrageneric divergence prior to the Late Eocene. • Fossil records of Sclerosperma suggests they were always endemic to tropical Africa. • Sclerosperma fossils can be used to estimate paleoclimate and past vegetation biomes. [ABSTRACT FROM AUTHOR]

In an effort to support carbon footprint reduction in housing development, one approach is designing energy efficient housing. Issues such as cost efficiency and minimum environmental impact should be thoroughly considered when designing this type of housing. One of concepts found to be cost-effective and to increase the energy performance of a house is the near Zero Energy House (nZEH) concept. This concept enhances the use of natural resources, for example, sunlight exposure, climate conditions, and wind, that can minimize the use of fossil fuel energy. Housing in a tropical climate where sun exposure is year round, such as in Indonesia, can benefit from the nZEH concept. This research aimed to identify design parameters of nZEH and its best practices in tropical climates, including Indonesia. The identified design parameters will be used in the next step of the research, finding a combination of cost optimum design parameters. This study was conducted by consulting recognized experts, which included government, private sector, and academicia, who have expertise in the field of building design and energy. The results showed that the design parameters of nZEH in tropical areas include passive design, fenestration, indoor lighting arrangements, and the use of photovoltaic panels (PV). [ABSTRACT FROM AUTHOR]

In Thailand, the delivery of adequate low-income housing has historically been overshadowed by politics with cost and quantity being prioritised over quality, comfort and resilience. In a country that experiences hot and humid temperatures throughout the year, buildings need to be adaptable to the climate to improve the thermal comfort of inhabitants. This research is focused on identifying areas for improving the thermal performance of these housing designs. Firstly, dynamic thermal simulations were run on a baseline model using the adaptive thermal comfort model CIBSE TM52 for assessment. The three criteria defined in CIBSE TM52 were used to assess the frequency and severity of overheating in the buildings. The internal temperature of the apartments was shown to exceed the thermal comfort threshold for these criteria throughout the year. The internal operating daily temperatures of the apartment remain high, ranging from a maximum of 38.5 °C to a minimum of 27.3 °C. Based on these findings, five criteria were selected to be analysed for sensitivity to obtain the key parameters that influence the thermal performance and to suggest possible areas for improvement. The computer software package Integrated Environmental Solutions--Virtual Environment (IES-VE) was used to perform building energy simulations. Once the baseline conditions were identified, the software packages SimLab2.2 and RStudio were used to carry out the sensitivity analysis. These results indicated that roof material and the presence of a balcony have the greatest influence on the system. Incorporating insulation into the roof reduced the mean number of days of overheating by 21.43%. Removing the balcony increased the number of days of overheating by 19.94% due to significant reductions in internal ventilation. [ABSTRACT FROM AUTHOR]

The elderly are particularly vulnerable to heatwaves and this research investigates the degree of thermal stress they experience and identifies a suitable index, using Thailand as the case study location. Several global heat stress indices were evaluated for their ability to predict thermal stress in the tropics: Universal Thermal Climate Index (UTCI), Heat Stress Index (HSI), Tropical Summer Index (TSI), Wet-bulb Globe Temperature Index (WBGT) and Discomfort Index (DI). The UTCI, WBGT and DI group tropical conditions in the zone of greater thermal stress, while the HSI and TSI are clustered in the lower stress categories and are more similar to the thermal sensation vote (TSV) and thermal comfort vote (TCV) definitions. Most indices correlated with the TSV, while only HSI and WBGT show a correlation with TCV. The research concluded that the HSI is the most suitable thermal stress index, although it still does not completely explain tropical heat stress conditions. [ABSTRACT FROM AUTHOR]

High temperatures and the intensive use of air conditioning are considered the main drivers of the increase in Brazil’s electricity demand in the summer, which has been causing major power cuts due to insufficient supply to meet peak demand. This paper analyses the techno-economic aspects of Ice Thermal Energy Storage (ITES) in Brazil, as a technology that can be used to shift building cooling load to off-peak time. ITES is assessed in five cities and five archetypes of commercial buildings, using two different operation strategies and two types of chillers, for new installations and retrofits. Results have shown that ITES can effectively shape peak demand in commercial buildings, generating economic gains for building owners but also losses in some cases. Although the climate plays an important role, the electricity tariffs vary significantly from city to city and this determined the economic feasibility of ITES. The technology’s potential to shape demand in Brazil’s commercial sector can encourage policy makers, regulators, grid operators and utilities in considering ITES as an option to reduce peak demand, increase security of supply and support the integration of intermittent renewable generation. [ABSTRACT FROM AUTHOR]

Substantial modifications have been made to the expressions for calculating distance factor and extrapolation techniques in the latest ITU-R P.530-14. However, its performance has not been rigorously evaluated in the tropical and equatorial climates. In this article, the new ITU-R method and three prediction models are validated using measurement data from tropical Malaysian climate. The data were collected on six geographically spread terrestrial microwave DIGI MINI-LINKs operating at 15 GHz. When tested against measurements, the Da Silva Mello model yields a significant improvement for the prediction of rain attenuation distributions. The prediction errors observed in the ITU-R model suggest the need for more data campaign in the afore-mentioned climates. [ABSTRACT FROM AUTHOR]

Separating dehumidification and cooling loads in air-conditioning systems has been proven to be a potential strategy to reduce electricity consumption if the dehumidification of air is mostly performed by heat-powered system components. Referring to experimental experiences in Singapore, this paper presents a novel electricity-efficient air-conditioning system consisting of a membrane unit, an evaporatively cooled sorptive dehumidification system (called ECOS system) and a high-efficient conventional cooling unit. The dehumidification of air is performed by a combination of the membrane unit and the ECOS system, and the sensible cooling of air is accommodated by a high-efficiency conventional chiller and in part by the membrane device. In order to find an optimized balance of the three air-conditioning components, an optimization-based simulation approach using a genetic algorithm is developed. The optimization is based on a simple objective function that comprises operating and investment costs. The optimization results reveal that an integration of a relatively large membrane unit, a small ECOS unit and a chiller operating at an elevated evaporation temperature is the most cost effective combination meeting comfort criteria. The resulting optimized combination has potential to save more than 50% of the system's lifetime operating cost compared to conventional systems supplying 100% fresh air. [ABSTRACT FROM AUTHOR]

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Energy consumption in the building sector is a major concern, especially in tropical climates where high temperatures and humidity force occupants to use electro-mechanical ventilation. Passive design strategies, in particular the application of natural ventilation, are one of the main techniques to moderate temperatures in buildings. Furthermore, many studies have shown reduced operating costs, better thermal comfort and indoor air quality, to be some of the advantages of the application of natural ventilation in buildings. Although existing studies support the efficiency of natural ventilation, the efficiency and practicability of architectural elements to maximise ventilation in buildings remains problematic. This study reviews studies on natural ventilation with other passive design strategies in tropical climates in order to support the argument for the application of natural ventilation in tropical climates. Through a review of studies on the operation of natural ventilation in buildings, it also identifies the most effective architectural elements and techniques in building façades and ventilation openings. The results indicate that ventilation shafts, window-to-wall ratio and building orientation should be applied in future construction. This study also identifies some further specific elements that are worth further investigation, including the shape of louvered windows, different forms of apertures and vernacular elements. [ABSTRACT FROM AUTHOR]

Research in the field of atmospheric science and epidemiology has long recognized the health effects of seasonal and meteorological conditions. However, little scientific knowledge exists to date about the impacts of atmospheric parameters on human mortality in tropical regions. Working within the scope of this systematic review, this investigation conducted a literature search using different databases; original research articles were chosen according to pre-defined inclusion and exclusion criteria. Both seasonal and meteorological effects were considered. The findings suggest that high amounts of rainfall and increasing temperatures cause a seasonal excess in infectious disease mortality and are therefore relevant in regions and populations in which such diseases are prevalent. On the contrary, moderately low and very high temperatures exercise an adverse effect on cardio-respiratory mortality and shape the mortality pattern in areas and sub-groups in which these diseases are dominant. Atmospheric effects were subject to population-specific factors such as age and socio-economic status and differed between urban and rural areas. The consequences of climate change as well as environmental, epidemiological and social change (e.g., emerging non-communicable diseases, ageing of the population, urbanization) suggest a growing relevance of heat-related excess mortality in tropical regions. [ABSTRACT FROM AUTHOR]

The semi-empirical method recently proposed by Silva Mello and Pontes (SMP) for the prediction of rain attenuation in slant paths is investigated in this letter. The SMP method uses the simplified model of equivalent rain cell and the concept of an effective rain rate. However, substantial deviations were observed in SMP predictions when compared to the rain cell diameters derived from experimental data. The measured rain rates and attenuations were obtained from three tropical climates (Australia, and USM and IIUM both in Malaysia). The measured rain attenuation complementary cumulative distributions (CCDs) were also compared to SMP and the Rec. ITU-R P. 618-11. The test results show that the ITU-R model performs much better compared to SMP method in the three tropical climates. [ABSTRACT FROM AUTHOR]

An improved method for predicting slant path attenuation in tropical climates is presented in this paper. The proposed approach is based on rain intensity data R0.01 (mm/h) from 37 tropical and equatorial stations; and is validated by using the measurement data from a few localities in tropical climates. The new method seems to accurately predict the slant path attenuation in tropical localities, and the comparative tests seem to show significant improvement in terms of the RMS of the relative error variable compared to the RMS obtained with the SAM, Crane, and ITU-R prediction models. [ABSTRACT FROM AUTHOR]