Tropical Buildings Research Articles

Eco-Resorts in Tropical Coasts: Design and Comfort

The argument presented in this paper is based on distinctive and exploitable differences which merit putting eco-tourists, eco-resorts and the coastal tropics into categories of their own. Such differences should inform planning and design process when working in this environment, which is both very sensitive and valuable. The paper aims to describe the main characteristics of the coastal tropics as a climate targeted by eco-tourism. Differences between eco-tourists and residents are presented through definition of comfort. Climatic and other factors influencing comfort limits are at the core of discussion, in which passive design is seen as the most appropriate response to challenges of the tropical coast setting. The design opportunities for the desirable climate modifications in eco-friendly resorts together with some passive design features are briefly presented. These architectural design solutions are set against theoretical principles specific to tropical coastal regions. The focus is on human responses to environmental factors, and on their implications. The paper concludes with a few recommendations aimed to deliver indoor conditions consistent with climatic preferences of itinerant environmentally conscious users of buildings in the coastal tropics. Such an approach is expected to minimize impacts the facility will make on the environment.

Using heat pipe heat exchangers for reducing energy consumption of treating ventilation air in an operating theatre in a tropical climate: a simplified model

This study applies the software package Transient Systems Simulation Program (TRNSYS), to estimate the air state and the energy consumption of a typical operating theatre located in a tropical building. For the simulation, typical meteorological year (TMY) data for the Kuala Lumpur area (Malaysia), and an operating theatre located in the University of Malaya Medical Centre (UMMC) (Kuala Lumpur), are used. The current heating, ventilating and air conditioning (HVAC) system for the operating theatre was found to be inherently energy-inefficient and could be improved with heat pipe heat exchangers (HPHXs). The impact on energy consumption of a custom-built air handler unit (AHU) was simulated with one or two 6-row HPHXs installed in the HVAC system, compared to a pre-cooling heat exchanger installed in the same system. Based on this investigation, it is recommended that a double HPHX system (Plant C) be applied in tropical HVAC systems for the reduction of energy consumption and dehumidification enhancement. Practical Applications: The analysis described in this paper enables necessarily comparison between possible HVAC system types on the year-round impact on energy consumption and dehumidification in an operating theatre located in a tropical area to be predicted before actual retrofitting is done to the space’s conditioning system. The results of this work could be used as a general guide for mechanical and electrical (M&E) engineers and researchers who are intending to apply HPHXs as ‘coolness’ recovery and dehumidification devices in HVAC systems operating in tropical countries, particularly, HVAC systems operating in hospital environments.

Application of a heat pipe heat exchanger to dehumidification enhancement in a HVAC system for tropical climates—a baseline performance characteristics study

In Malaysia, humidity control is a common problem in built environments in tropical hot and humid climates as it is an important aspect of the maintenance of comfortable and healthy conditions within a controlled airspace. An 8-row thermosyphon-based heat pipe heat exchanger (HPHX) for tropical building HVAC systems was studied experimentally. This research was an investigation into how the sensible heat ratio (SHR) of the 8-row HPHX was influenced by each of three key parameters of the inlet air state, namely, dry-bulb temperature, relative humidity and air velocity. On the basis of this study, it is recommended that tropical HVAC systems should be installed with heat pipe heat exchangers for dehumidification enhancement.

03/01964 The performance study of a wet six-row heat-pipe heat exchanger operating in tropical buildings: Yau, Y. H. and Tucker, A. S. International Journal of Energy Research, 2003, 27, (3), 187–202

03/01964 The performance study of a wet six-row heat-pipe heat exchanger operating in tropical buildings: Yau, Y. H. and Tucker, A. S. International Journal of Energy Research, 2003, 27, (3), 187–202

The effects of ventilation operations in determining contributions of VOCs sources in air-conditioned tropical buildings : Zuraimi, M. S. et al. Building and Environment, 2003, 38, (1), 23–32

The effects of ventilation operations in determining contributions of VOCs sources in air-conditioned tropical buildings : Zuraimi, M. S. et al. Building and Environment, 2003, 38, (1), 23–32

Daylighting as a passive solar design strategy in tropical buildings: a case study of Malaysia : Zain-Ahmed, A. et al. Energy Conversion and Management, 2002, 43, (13), 1725–1736

Daylighting as a passive solar design strategy in tropical buildings: a case study of Malaysia : Zain-Ahmed, A. et al. Energy Conversion and Management, 2002, 43, (13), 1725–1736

The performance study of a wet six-row heat-pipe heat exchanger operating in tropical buildings

The overall effectiveness of a wet six-row wickless heat pipe-heat exchanger (HPHX) for tropical building HVAC systems was simulated using a computer simulation program. This computer program, utilizing Fortran source code, was developed based on the effectiveness-NTU method together with the ridge model for predicting the film condensation and uses the concept of iteration to predict the temperature distribution across the HPHX and its overall effectiveness. The effects of inclination angle and inlet evaporator relative humidity on heat transfer coefficient for the HPHX were determined using TRNSYS Type98 component. The wet HPHX effectiveness and relative humidity were also studied in this research experimentally. Copyright © 2002 John Wiley & Sons, Ltd.

Daylighting in the tropics

Traditional adaptations of tropical/sub tropical buildings to high ambient irradiance from high elevations are outlined. Generally, these adaptations result in severe shading of window apertures, greatly reducing access to daylight. Some examples of optical systems designed to improve daylighting in tropical buildings are discussed. These include angle selective glazing, light guiding shades, vertical and horizontal light pipes, switchable glazing and angle selective skylights. The simulation of these devices within packages such as RADIANCE is also discussed.

An Analysis of the Bio-climatic Effects of Roof Cover of Domestic Buildings in the Equatorial Tropics

The thermal comfort effects of “Calicut” clay tiles, Corrugated fibre-cement roof sheet and half-round tiles-on-fibre/cement roofs are tested with no-ceiling, fibre-cement sheet ceiling and timber ceiling in an 8.1 x 5.3m (26′-6″ × 17′-6″) experimental hut. Real time measurements of ambient air temperature and relative humidity are made within the hut and at a reference station. Analyzing the bio-climatic differences between the indoor and the outdoor, the paper shows that the roof systems studied lead to significant thermal comfort differences in small domestic buildings in the tropics. Contrary to popular expectations, cheaper roof alternatives such as corrugated fibre-cement roofs and tile roofs with ceilings achieve the same thermal comfort regime as the more expensive tiles-on-fibre/cement roofs in tropical domestic buildings.

Daylighting as a passive solar design strategy in tropical buildings: a case study of Malaysia

The use of daylighting in buildings and architecture is not new. Natural lighting became out of vogue due to the availability of cheap electricity, the predictability and the ability to control illumination levels due to artificial lighting. However, the alarm over rapid depletion of energy resources and the environmental effects of their applications have led designers to reuse daylighting strategies in buildings in order to minimise energy use for lighting and air conditioning as a result of heat gains from the daylight sources and the electrical fixtures. This paper describes a study on the savings achieved by using daylight in passive solar design of buildings and, in this case, the size of windows. Simulated exterior illuminance levels based on long term measured solar irradiation and cloud cover data were used to estimate interior illumination on normal working planes using simple building configurations. Illumination on these planes decreases the need for artificial lighting, thus energy can be saved. A simple algorithm was then used to calculate the overall cooling load to ascertain that the daylighting strategies used do not invoke an increase in thermal gains through walls and glazings. The findings from this study show that at least 10% savings can be produced from simple daylighting strategies.

The effects of ventilation operations in determining contributions of VOCs sources in air-conditioned tropical buildings

This study analyses the findings of volatile organic compounds (VOCs) levels found in two tropical office buildings (a 1 year old and a 6 year old building) under different conditions of ventilation operations. The geometric concentrations of 11 target VOCs and TVOC have been measured under two scenarios—(1) normal occupancy with ventilation system operating and (2) when the ventilation system has completely shut down. Under the first scenario, the VOCs emission rate determined through mass balanced modeling is due to the buildings, occupants and their activities and ventilation systems. The emission from the second scenario is purely due to the building materials. Majority of the VOCs rose in concentrations after the ventilation system has shut down with exceptions for benzene, benzaldehyde and tridecane that are attributable to outdoor and occupant related activities and ventilation systems. The indoor–outdoor ( I/ O) ratio method of determining source contributions has been found to be a crude method for this case study. Instead, utilizing the ventilation-resolved mass balanced model method to evaluate contributions of sources (SER) from outdoors, building materials, occupants, their activities and ventilation systems have yielded relatively good and accurate results.

Theoretical determination of effectiveness for heat pipe heat exchangers operating in naturally ventilated tropical buildings

The thermal performance of wickless thermosyphon based heat pipe heat exchangers (HPHEs) for naturally ventilated buildings was simulated using a computer simulation program. This computer program utilizing Microsoft Visual Basic 6.0 software was developed on the basis of the effectiveness—number of heat transfer units (NTU) method and uses the concept of iteration to predict the temperature distribution across the HPHE and its thermal performance. The overall effectiveness of HPHEs was also studied in this research.

Higher space temperatures and better thermal comfort — a tropical analysis

In tropical buildings, it is not uncommon to find low space temperatures around 23 °C and high relative humidity levels in the order of about 70–75%. The present paper explores the possibility of operating at space temperatures close to 26 °C with relative humidity around 60%. The study is based on acceptable thermal comfort conditions in the space by resorting to ASHRAE comfort chart and comfort diagrams. The psychrometric challenge, as a consequence of higher space temperatures, is illustrated in the paper and an alternative method of air conditioning to overcome the problem is demonstrated. The analysis also reveals the potential savings in energy that could be obtained as a result of reduced space cooling loads due to higher space temperatures.

Cool tropical buildings: Lessons from old-style designs

Data to estimate human thermal stress levels were taken inside and outside 24 old-style buildings in the Bangkok, Thailand area. Interior coolness was found to be enhanced by: (a) shading from direct-beam solar radiation, (b) prevention of high temperatures on interior wall and ceiling surfaces, and (c) maximizing natural wind velocities inside the building. Any one factor having an undesirable status could negate the effects of many others having a highly desirable status.

The fungal problem in buildings in the humid tropics

Studies over the past three years have shown that internal walls of buildings and houses, whether painted or wallpapered, ceiling boards and glass panels, frequently become infested by moulds. Mould growths result in fouling. biodeterioration and discolouration of these substrata. Buildings affected by fungi have yielded 28 identified species. Among them are species of Aspergillus, Cephalosporium, Cladosporium, Curvularia, Fusarium, Penicillium, Pithomyces, Trichoderma, Verticillium and a number of sterile non-sporing isolates. The most widely occurring genera were Aspergillus, Cladosporium and Penicillium, with the former two very abundant wherever they occurred. The most abundant and most often encountered was Aspergillus fumigatus, followed by Cladosporium cladosporioides, and then Curvularia lunata. Fusarium decemcellulare was abundant on ceiling boards and F. solani on wallpaper. Tests carried out with local commercial antifungal paints showed that most were not resistant to fungal growth. Screening tests on the fungicides commonly used by paint manufacturers showed that only one was completely effective and six moderately effective in inhibiting the growth of the moulds.

Thermal Roof Insulation in Tropical Buildings

Model huts were constructed for tropical studies of the heat penetration of painted and unpainted galvanised steel roofs in combination with various commercial under-roof insulations. The results showed that a white painted roof and unpainted roofs with various insulations had similar resistances to heat penetration, but the white roof case allowed interior heat to escape faster and thus was superior for thermal comfort purposes. However, a combination of white paintedness and under-roof insulation was much better than either measure alone for overall insulating performance. It was concluded that dust buildup on upward facing, reflective under-roof insulating surfaces degrades their performance significantly compared to other cases. Measurements were made of the relative emittance and absorptance of weathered and unweathered steel roofs. The quotient of these surface optical properties was found to correlate with the heat penetration and thus provides a means of evaluating heat penetration of old roofs by in situ measurement of these properties. It is predicted that moderate weathering will have little effect on the heat penetration of white painted or unpainted galvanised steel roofs.

Thermal Insulation of Low-Cost Housing in Egypt

A common fault of architects and building designers in Egypt has been to produce buildings, particularly at the low-cost end of the market, with little regard to the climatic conditions that prevail. Satisfactory internal condi tions are achieved by using mechanical systems which in crease the initial capital cost of the building. In low-cost hous ing, artificial control over energy gains by means of air- conditioning is clearly not feasible on economic grounds. This paper discusses the criteria for thermal comfort in hot climates and reference is made to the BRE method of com putation of internal temperatures in tropical buildings, which has been validated by observations in Egypt. The effects of thermal capacity and insulation in buildings in hot climates are also discussed.

A statistical study of the population of the tropical mound building termiteOdontotermes redemanni (Wasmann)

A statistical analysis of the population of the tropical mound building termite,Odontotermes redemanni, shows the existence of significant peaks in the populations of worker, soldier and nymphs in different phases during June to September. The population trends of the sexual nymphs and others show a close parallelism and this associationship is quite significant from a biological point of view. The population structure within the mounds is intimately associated with the multiplicative phase of the mounds and the peak in the overall population mostly occurs when sexual nymphs are produced in large numbers. These sexual nymphs develop into alates and fly out to establish new colonies. The ability of the de-alate sexuals in the mounds to produce the sexual nymphs and other castes in large numbers during the multiplicative phase of the mounds is probably genetically determined. Various statistical tests have been tried to interpret the biological factors associated with the population dynamics of this termite.

Remarks on daylight of buildings in the tropics taking sunshine into consideration

We can now state some preliminary conclusions: (a) We shall not involve ourselves in big errors if we handle the problems of building construction in the tropics by taking the sky illumination alone into account. (b) When the sun shines we shall have an enormous surplus of illumination and the basic difficulty will be to handle the problems of glare and brightness distribution which result. These problems can be solved with suitable shading devices which have to be designed taking into consideration the need to solve thermal problems as well.