Malaysian Climate Research Articles

Quantification and Characterization of Allicin in Garlic Extract

Garlic (Allium sativum) is a plant well known for its extensive use in traditional and modern medicine. Its healing properties are attributed to thiosulfinates, compounds formed through an enzymatic reaction when garlic cloves are crushed. One of the most prominent thiosulfinate found in garlic is diallyl thiosulfinate or allicin. The condition in this research mimics Malaysian climate conditions. This allows allicin to be studied and characterized for its uses in the local agricultural sector as potential urea inhibitor. A spectophotometric method is used in this research to quantify allicin found in garlic extract. L-cysteine is used to react with allicin in garic extract with the knowledge that one molecule of allicin reacts rapidly with two molecules of cysteine to form two molecules of S-allyl mercaptocysteine. 5,5’-dithiobis-(2-nitrobenzoic acid) (DTNB) is added to the mixture so that spectrophotometrically active 2-nitro-5-thiobenzoate (NTB) is formed after residual cysteine reacts with DTNB. Quantification of allicin is done at 30°C with garlic extract concentration ranging from 0.005 g/mL to 0.03 g/mL. This is followed by tests on allicin stability at pH 4 – 8 at 30°C and effects of temperature on allicin from 30°C to 85°C.

CLIMATE CHANGE MITIGATION AND VOLUNTARY DISCLOSURE IN MALAYSIA’S LISTED PROPERTY COMPANIES

Climate change mitigation is a challenge faced by most nations of the world. The task is even more challenging in Malaysia considering the occurrence of sequence of floods within the past and the need to be a part of the developed economy by 2020 which needs environment protection. This paper examines the state of climate change mitigation and the practice of voluntary carbon disclosure in sustainable development practice among listed Property companies in Malaysia. Consequently the paper analyses policies and programs on-going in Malaysia to create an enabling environment for the implementation of climate change mitigation. From the studies, it can argued that Malaysia has made significant progress in setting up legal framework for the implementation of climate change mitigation and voluntary environmental disclosure, but critical mass is yet to be achieved. This was achieved as a function of Malaysia’s membership to United Nation Framework Convention on Climate Change (UNFCCC), and ratifying the Kyoto Protocol and also participates in the Clean Development Mechanism; and further establishes nationwide ecological protection laws which are implemented in the government’s Development Plans and development industry master plan. Lastly, the impetus given to the free market sector to be participants in mitigation through the Bursa Malaysia listing requirement that specifies corporate social responsibility reporting as part of the annual reports, with measurement, disclosure and management of emission integral part. The review allows us to infer that the Malaysia voluntary environmental disclosure and climate change mitigation practice in the property sector has made initial progress but there is need for more market driven motivation to be introduced so that more companies especially those in carbon-intensive practice would be involved.

Tracking collector consideration of tilted collector solar updraft tower power plant under Malaysia climate conditions

SUPP (Solar Updraft Tower power plant) is a technology in the power generation sector. The power productivity and efficiency represent important performance characteristics of SUPP. In the present work a mathematical model was developed to estimate the performance of SUPP based on tracking solar collector consideration in Malaysia. The objective is to verify the suggested model and to optimize the slope angle of tilted tracking solar collector. Basically, the hourly solar data were analysed considering solar azimuth angle for tracking case calculation to determine the solar energy incident on the collector. Then, the useful energy gain was calculated based on heat transfer relations. The model was validated with experimental work and well agreement was achieved. Results revealed that the SUPP of slope collector angle of 10° can produce higher power generation over the whole the year. Also, the tracking solar consideration enhanced the performance characteristics especially the power productivity by around 3.5 kW over that of fixed collector. The maximum collector and SUPP efficiencies of 51% and 0.165% respectively were obtained.

Minimization of Embodied Carbon Footprint from Housing Sector of Malaysia

The reduction in embodied carbon footprint is one of the major concerns in the construction industry. Among many other adopted techniques, the use of recycled materials is one of recommended method to lower the environmental effects of construction materials. However, the potential of recycled materials to offset the embodied carbon footprint from conventional Malaysian housing construction requires to be evaluated. The main focus of study was to perform a comparative analysis for minimization of embodied carbon footprint from the conventional materials used Malaysian housing industry by using recycled materials. A typical double story semi-detached house commonly constructed in Malaysian tropical climate was selected as case study. The model of the house was generated in a virtual environment using Building Information Modelling (BIM) process. The results highlighted that with incorporation of recycled materials within a range of 0 % to 100 %, the embodied carbon footprint offset potential varied up to 18 % as compared to conventional construction.

Development of Dual Axis Solar Tracking System Performance at Ulu Pauh, Perlis

Theoretically, the solar tracking system describe as the device to get the optimize amount of sunlight according to sun movement. So, the shading effect issues can be minimized. This paper is presents the finding of photovoltaic (PV) harvesting energy via dual axis tracking system. The operation of two direct current (DC) motors motion was programme using PIC kit SK40C by using the Lab View Programming software. The first motor system delay timer is set at 15° rotation per hour and second motor system delay timers is set to rotate 180° after 12 pm. The field testing was initially set up at Perlis, Malaysia climate. An actual testing was used to collect the daily data. The result shows that, the output voltage with solar tracking system is 12.93% higher than without tracking system in the sunny day condition.

Study of Solar Driven Silica gel-Water based Adsorption Chiller

In this study, a dynamic behaviour of a solar powered single stage four bed adsorption chiller has been analysed designed for Malaysian climate. Silica gel and water have been used as adsorbent-refrigerant pair. A simulation program has been developed for modeling and performance evaluation of the chiller using the meteorological data of Kuala Lumpur. The optimum cooling capacity and coefficient of performance (COP) are calculated in terms of adsorption/desorption cycle time and regeneration temperature. Results indicate that the chiller is feasible even when low temperature heat source is available. Results also show that the adsorption cycle can achieve a cooling capacity of 14 kW when the heat source temperature is about 85°C.

Total Harmonic Distortion Assessment of 17kWp Grid Connected Photovoltaic Systems

This paper presents prediction of total harmonic distortion (THD) on Grid Connected Photovoltaic (GCPV) power systems towards Malaysia climate variations (solar irradiance) by using Mathematical approach. The actual and prediction data measurement were analyzed on three types of solar cell technologies; monocrystalline, polycrystalline and thin film. Each PV array works with different types of inverters which are located at Green Energy Research Center (GERC), University of Technology MARA (UiTM) Shah Alam, Selangor. The prediction and detail analysis of total harmonic distortion is carried out by using MathCAD software. The results obtained show good agreement between prediction and actual data.

Sustainable potable water production using a solar still with photovoltaic modules-AC heater

Solar energy as a sustainable energy source can be harnessed to produce potable water using solar stills. In this work, effort was made to evaluate the performance of a double slope solar still integrated with a 500W heater to produce potable water. The heater was powered by six photovoltaic modules, which can produce 1.5 KWp and then connected to four batteries with capacity of 150 Ah each. The experiments were conducted over several days in the tropical climate of Malaysia. A black painted steel trough with length 90 cm, width 45 cm, and depth 8 cm was used as the basin of the glass covered double slope solar still. A comparison of the cumulative water production between the conventional solar still (CSS) and solar still with PV-Heater (CSSPVH) was done. The CSSPVH was found to be more effective; producing about six times the amount of water produced by the CSS. Mathematical models derived based on energy balance studies of CSSPVH, were used to carry out simulations to verify the experimental findings. The energy balance equations of condensing cover and the basin water of CSSPVH were developed as well. A good agreement was found between numerical and experimental productivities of CSSPVH. An expected increase in water production of up to 16 kg/m2 per 24 h was obtained using CSSPVH. Therefore, CSSPVH is an effective design to produce sustainable potable water, even in areas with very low daily solar radiation intensity, due to its ability to store solar energy. In addition, some tested water quality parameters indicate that water produced from solar stills meet the WHO standard for potable water.

Preliminary Overview on Thermal Performance of Green Roof

Green roof has shown potential contribution on improving the functional performance of buildings by lowering the roof exterior surface temperature, which is indirectly, could potentially reduce the energy demand. In addition, it is likely to provide important ecological services to urban areas through lowering of urban heat island (UHI) temperatures, increasing storm water retention and improves the biodiversity. This paper will then present the initial outcomes of the joint initiative between Malaysia Agricultural Research and Development (MARDI) and Universiti Tun Hussein Onn Malaysia (UTHM) in promoting this green technology in Malaysia. As green roof technology is still emerging, there is limited technical data available at present in Malaysian climate. The study aims to provide initial observation on the thermal performance of green roof and its effect towards surrounding and associated significant environmental benefit. In order to achieve the goal, the thermal performance of green roof system in experimental plot at MARDI had been monitored. The green roof experimental plot has been set up on two flat roofs in Horticulture Research Centre, MARDI, Serdang, Selangor and the treatments consists of two green roof system known as conventional system and self-watering system. The substrate depths were 50 mm and 100 mm. In addition, some observation on the attracted wildlife to the green roof was initiated. Based on the initial results, it is interesting to report that the temperature reduction for the green roofs on Roof 1 and Roof 2 were in averages of 6.1°C and 10°C, respectively. In conclusion, this joint study between UTHM and MARDI may facilitate the development of roof top gardening system in greening the urban area. With more studies, it will possibly highlight the engineering significance, furthermore promoting the application of green roof technology in Malaysia.

A REVIEW OF GROUND HEAT EXCHANGERS FOR COOLING APPLICATION IN THE MALAYSIAN CLIMATE

The ground heat exchanger (GHE) is one of the energy sources that has been identified since the 1970s which is able to produce sustainable energy for cooling which is in passive side. GHEs are widely implemented around the world, especially in European countries and a few Asian countries. In Malaysia, application of GHE is still considered as a new passive cooling approach in building energy reduction. Therefore, this paper reviews several important ways of implementing GHE in order to supply passive cooling for any application. The review covers general implementation of the GHE for thermal comfort and agricultural greenhouse cooling. The ground temperature variation used in different researches is also reviewed in this paper as an important part of identifying potential GHE implementations. Design and performance aspects of the GHE are also reviewed. Finally, this paper summarizes the potential and benefit of GHE implementation in the Malaysian climate for cooling applications to reduce the energy used in buildings and greenhouse gas emission.

Effective Solar Chimney Cross Section Ventilation Performance in Malaysia Terraced House

In hot and humid country, ventilation and thermal performance could be improved by effective natural ventilation strategies. However, the climatic conditions of the tropical countries are mainly distinguished by high air temperature and relative humidity as well as low wind velocity which are the main factors that reduce the comfort level of occupants, especially in the terrace house. The use of solar chimney in terrace house is one of alternatives to increase the thermal and ventilation performance of the indoor environment. This study initiated with field measurement in a selected case study house located in Kuching, Sarawak, Malaysia for software validation. Validation study of CFD in DesignBuilder software was done by compared with field measurement data, with the deviation ranges from 7.2% to 18%. The optimizations of solar chimney cross section were carried out. The results of CFD were observed in order to study the optimized length and width gap of solar chimney that could induce optimum air velocity and thermal performance in the indoor environment. The results show that the effective width gap for 36m3 room ranged from 0.6m to 1.0m while the length from 1.5m to 2.0m, whereby the induced air speed ranged from 0.04m/s to 0.223m/s. Based on the findings, the study has shown that the effective gap and length of solar chimney could increase the air velocity of indoor environment that creates a cooling effect on human body, especially for terrace house in Malaysia climate.

Application of Passive Cooling Techniques in Vernacular Houses to Modern Urban Houses: A Case Study of Malaysia

The main purpose of this paper is to determine potential vernacular passive cooling strategies for improving thermal comfort of modern urban houses in hot-humid climate of Malaysia. Field measurements were carried out in two traditional timber Malay houses and two traditional masonry Chinese shophouses to investigate their indoor thermal environments and passive cooling techniques. The results of the former showed that the indoor air temperatures were higher than the outdoor air temperatures by 1°C during daytime under open window conditions and 2°C at night under closed window conditions on average. The results of the latter revealed that indoor air temperatures adjacent to small courtyards were lower than immediate outdoors by up to 5-6°C during daytime; at night, the indoor air temperatures maintained values similar to the outdoors. The small courtyards were effective to enhance night ventilation and nocturnal radiant cooling in the high mass shophouses. When assessed using an adaptive thermal comfort equation for hot-humid climates, the periods of indoor operative temperatures exceeding the 80% comfort upper limit in the Malay houses, Chinese shophouses, daytime ventilated and night ventilated terraced houses were 47%, 7-8%, 91% and 42%, respectively on fair weather days. By comparing these evaluations and relationships between indoor and outdoor thermal conditions of all houses, potential passive cooling strategies for the existing terraced houses including night ventilation, roof/ceiling insulation, window/wall shading, courtyard/forced ventilation, and microclimate and urban heat island mitigation were discussed.

Drinking Water Production Using Passive Solar Stills with Different Absorbing Materials

Solar stills as the cheapest options used to desalinate brackish water in areas having freshwater availability limitation. The purpose of this work is to investigate the water production improvement of double slope solar stills using heat absorption materials in the basin. Three similar shapes double slope passive solar stills were constructed to conduct the experiments in tropical climate of Malaysia. Each solar still had a stainless steel trough and a transparent polythene film as basin and cover respectively. Three basins each having 50 cm length, 30 cm width and 8 cm depth were used to keep the fed lake water. 2 cm depths of black soil and sea sand were added in two solar still basins respectively, while the last solar still had only stainless steel trough as basin. Experimental investigations on the solar stills performance showed that the solar still with black soil had a highest output as compared to the solar still yield using sea sand layer in basin or conventional solar still using only stainless steel basin respectively. Some water quality parameters of lake water and produced distilled water were also tested in the laboratory and indicated that the treated water met the WHO standard for drinking.

Combinations of building construction material for residential building for the global warming mitigation for Malaysia

Global warming mitigation is used as a key to devise built environment strategies and sustainable policies in developed countries that aim to reduce the rate of carbon emissions. The goal of this research is to mitigate global warming from building construction by suggesting an alternative building scheme for Malaysia. A problem related to the building industry is releasing carbon dioxide emission. Use of timber for construction has less impact on the environment due to less carbon dioxide emissions, thus making wood the best material for wall construction. However, as the Malaysian climate is hot and humid, wood encounters many defects and deteriorates. Presently, most buildings in Malaysia are built from other materials such as concrete or brick. In the last 40years, wood materials in building schemes in Malaysia have dropped from 60% to almost 5%. This research proposed a new approach to minimize the effect of CO2 emission for buildings as well as to improve their structural stability for a longer lifespan because these would encourage the Malaysian construction industry to use wood components in their building schemes. In this study, SIMAPRO Software was used to assess CO2 emissions caused by seven different types of building schemes in wall constructions. The results from a simulation of three time frames of twenty, one hundred and five hundred years showed that timber scheme is the best choice for construction. To promote the use of timber, a new building scheme that would solve the problem of timber wood structure in Malaysia were proposed. The alternative building scheme has combined precast concrete and timber (H8) to improve the timber scheme deficiency while releasing less CO2 emissions compared to other systems. Therefore (H8) could replace current building schemes. This research can facilitate decision-maker to choose the most flexible scheme for Malaysian housing. Thus, this system could be positively and widely used in the Malaysian construction industry.

Comparative assessment of vernacular passive cooling techniques for improving indoor thermal comfort of modern terraced houses in hot–humid climate of Malaysia

The main objectives of this study were to investigate vernacular passive cooling techniques and their potential application for improving indoor thermal comfort of naturally ventilated, modern brick terraced houses in Malaysia. Field measurement was conducted in two traditional timber Malay houses and two traditional masonry Chinese shophouses to examine their indoor thermal environments. The results of the former showed that the indoor air temperatures were higher than the outdoor air temperatures by 1°C during daytime under open window conditions and 2°C at night under closed window conditions on average. The emphasis was on reducing the temperature of the outdoor air before entering the lightweight house for bodily cooling by cross ventilation. The outdoor air temperature at the Malay house sites was lower than that of the terraced house site by 1.7°C on average. The results of the latter revealed that indoor air temperatures in rooms that were adjacent to small internal courtyards were lower than the immediate outdoors by about 5°C on average at the peak period. At night, the indoor air temperatures maintained values that were similar to the outdoors. The small courtyards were effective to cool the high thermal mass structures through nocturnal ventilative and radiative cooling. When assessed using an adaptive thermal comfort equation for hot–humid climates, the periods of indoor operative temperatures exceeding the 80% comfortable upper limit in the Malay houses, Chinese shophouses, daytime ventilated and night ventilated terraced houses were 47%, 7–8%, 91% and 42%, respectively, on fair weather days. Potential passive cooling techniques for the existing terraced houses including night ventilation, roof or ceiling insulation, window and wall shading, small courtyard concept, and microclimate modification and/or urban heat island mitigation were discussed.

高温多湿気候下のマレーシアの都市住宅を対象としたパッシブクーリングによる省エネルギー改修効果の検討

The main objective of this study was to examine the effectiveness of energy-saving renovation techniques through passive cooling for urban houses in hot-humid climate of Malaysia. Effects of two strategies, i.e. complete natural ventilation (NV) strategy and partial air conditioning (AC) strategy, were simulated using TRNSYS. The results revealed that indoor thermal comfort was achieved in the complete NV strategy by applying multiple passive cooling techniques that prevented external heat on the outer building envelope and night ventilation, even under heated urban climatic conditions. In the partial AC strategy, reductions of about 45% in the sensible cooling load and about 30% in the latent cooling load compared to the current condition were obtained by insulating inner surfaces of the master bedroom while applying several passive cooling techniques to the other spaces.

Numerical Investigation of Ground Cooling Potential for Malaysian Climate

In equatorial countries like Malaysia, the cooling of buildings is almost entirely dependent on air-conditioning, with electricity as the main source of the energy required. As the country develops, with more buildings being built, and as the population grows, with more people demanding thermal comfort in the buildings they work and live in, the rate of electricity consumption for cooling purposes will continue to increase dramatically from year to year. This phenomenon requires the application of alternative energy options and thermal storage. Ground thermal storage is an example of thermal storage which can supply cooling and heating effects resulting in a significant reduction of electricity consumption. This paper discusses the potential of the implementation of ground thermal storage by using a ground heat exchanger (GHE) to supply passive cooling for any application. An analysis has been conducted based on an empirical equation from conduction heat transfer for depths of up to 30 m and thermal diffusivities from 0.04 to 0.1 m2/day. The main input parameters were obtained from a local weather station for three consecutive years. The result showed that a significant reduction occurs at a depth of 2.0 m and below, meaning that cooling can be supplied constantly throughout the year. The temperature amplitude is also attenuated relatively with depth, whereby amplitudes of less than 1 °C occur at a depth of more than 4 m with a thermal diffusivity of 0.04 m2/day. In addition, thermal diffusivity gives a significant increment in temperature amplitude and it is suggested to be maintained at a value of less than 0.06 m2/day. This result provides useful information to researchers and engineers in the field of underground installation of materials or systems such as gas pipelines, water supply and for underground cable transmittance.

Effects of Fiscal Regime Changes on Investment Climate of Malaysia's Marginal Oil Fields: Proposed Model

The paper proposes a model to examine the effect of the 2010 fiscal regime changes on investment climate of Malaysia's marginal oil fields. It proposes the use of investment appraisal tools, such as Net Present Value, Internal Rate of Return, Profitability Index, Saving Index and Access to Gross Revenue, for the study. Two scenarios would be considered using the fiscal terms of Production Sharing Contract (PSC) and Risk Service Contract (RSC), respectively. Each scenario would be of a fifteen-year simulation. Sensitivity analysis will also be conducted for both the scenarios under different prices and reserves levels. The study, when undertaken, will be beneficial to both industry and the government.

The reliability of Predicted Mean Vote model predictions in an air-conditioned mosque during daily prayer times in Malaysia

A field study was conducted to investigate the relationship between the estimated Predicted Mean Vote (PMV) for comfort and the actual measured climate data and occupant comfort sensations recorded in an air-conditioned mosque building in Malaysia. The study was conducted between November 2012 and April 2013 during the five daily periods of prayer. PMV was calculated using the Fanger equations while the Actual Mean Vote (AMV) was gathered from the survey data of 330 randomly selected worshippers. The results show that the thermal responses from worshippers during the five daily prayer periods largely recorded in the neutral zone. PMV model calculations underestimated the temperatures at which people could be comfortable (25.9°C) in the mosque when compared to the AMV of respondents at 30.4°C. The difference of 4.6 K between PMV and AMV indicates that ASHRAE Standard-55 is considerable and obviously has serious energy implications for this organization if temperatures were to be kept at the PMV-required temperatures. It was concluded that worshippers in this air-conditioned mosque located in the hot and humid climate of Malaysia found the indoor thermal conditions to be thermally acceptable at the temperatures they experienced.

Comparative Evaluation of Reflective and Refractive Optical Concentration Systems in Tropical Climate

Convergence of global economic inequalities and greenhouse emissions makes it imperative that fossil- fuel dependence be replaced by renewable energy revolution. Sunlight is the only truly free and abundant global energy resource capable of replacing fossil fuels. Historically, thermal and electrical forms of energy have been generated through Concentrated Solar Power (CSP) systems. A major disadvantage of existing CSP systems lies in their long lead times, large start-up costs and integration with an advanced electricity transmission grid. Research work reported here is focused on evaluation of reflective and refractive optical concentration systems in tropical climate with the aim of developing small scale distributed electricity generation systems linked to micro grids. Evaluation of seven optical concentrators in reflection and refraction modes in tropical Malaysian climate has been carried out. The experimental methodology was based on measurement of temperature at the focal point of the optical systems as a function of time and solar irradiance. Highest temperatures achieved with reflective systems were in 200-300°C range, in contrast, Fresnel-lens based refractive systems approached temperatures in excess of ~1300°C. For the Fresnel lenses investigated, an approximate logarithmic temperature dependence on lens diameter was determined. For the Malaysian climate, sunlight to thermal energy conversion of refractive systems was determined to be significantly superior to reflective systems.