Performance of Low Cost Alternative Radiant Cooling Panel in Malaysia

Radiant panel cooling is still considered uncommon in Malaysia due to unavailability of local manufacturers with limited architects or engineers who are familiar in the system. The initial construction cost for radiant cooling system may be higher than air system and not forgetting the need for a smaller supplementary air system to dehumidify the air to avoid condensation which is an inherited problem of the system in hot and humid region. Promotion and public awareness is lacking in the country and very much dependable on government demonstration program of green technology application where only a few governments owned building having such system. With the aim of long term energy and cost saving this study looks into the development of custom design and locally assembled low cost radiant cooling panel and how its performance in comparison to its overseas and more expensive counterpart could help in provide alternative cheaper building cooling system. Custom build cooling panels with selected materials were constructed and tested to find out its cooling capacity. Finite Element Method (FEM) software was used to establish a design chart to assist in the design and sizing of the alternative radiant panel for Malaysian residential house. The experiment shows that cooling performance in term of mean surface temperature and its cooling capacity is almost identical to its overseas counterpart. Use of cooling radiant panel with free night cooling of water as its chill water supply shows a significant energy saving potential while at the same time provide an acceptable room thermal comfort. Given the local made product having similar performance and suits local condition the technology could grow and be applied with confidence.       Â

Microextraction of Xenobiotics and Biomolecules from Different Matrices on Nano Structures

Sample preparation is the backbone of any analytical procedure; it involves extraction and pre-concentration of the desired analytes; often at trace levels. The present article describes the applications of nanomaterials (carbon based inorganic and polymeric materials) in miniaturized extraction such as solid phase micro-extraction, stir-bar sorptive extraction, liquid phase micro-extraction, and dispersive liquid phase micro-extraction in the analyses of aqueous samples. The nanoparticles used for micro-extractions are discussed on the basis of their chemical natures. The synthetic route and the preparation of nanomaterials are described along with the optimization strategies for micro-extraction. A comparison between the conventional materials and nanomaterials for micro-extraction is proposed. The key roles of the nanomaterials for the micro-extraction of different analytes such as drugs, pesticides, polycyclic aromatic hydrocarbons, proteins and peptides from aqueous samples are reported. The use of nanomaterials, combined with miniaturized micro-extraction techniques, proved to be highly promising for sample preparation of various matrices with analytes at trace levels

Investigation of earth tube system application in low income building in Kuching, Sarawak

Modern residential building in Malaysia particularly in Sarawak rarely consider the ground as a source of heat sink to cool down the building. This is probably due to the lack of information on surveyed ground temperature and energy modelling of such building. A typical low income residential building in Sarawak with earth tube was modelled in Energy Plus to determine the effect of earth tube to passively cool the building in Sarawak. From the simulation result, the indoor air temperature of the east facing zone of the building could be lowered from 33°C to 29.5°C. A further drop of about 0.6°C could be achieved if the room volume served by the earth tube is reduced. The PMV of the building were greatly reduced from 3 to 1.5 on a thermal sensation scale. The operative temperature is within 80% acceptability limits of 30.3°C operative temperature as per ASHRAE Standard 55 for naturally conditioned spaces. © School of Engineering, Taylor’s University

Night Cooled Radiant Cooling Panel for Sustainable Building Cooling Mode in Malaysia

Night air temperature in Malaysia is generally about 23°C and is a potential source of heat sink to dissipate heat gain from a building. A thermal storage tank was used to store a certain quantity of water and was passively cooled during the night using the pitched roof as a heat exchanger to chill the water to as low as 22°C. The free cooling of water was then used as a cooling medium to cool the modular radiant cooling panel during the day time when the outdoor temperature exceeds 30°C. The experiment shows that the system was able to maintain an indoor temperature of less than 28°C when the outdoor temperature peaked to nearly 34°C while providing acceptable thermal comfort with certain controlled air movement. The use of the hydronic radiant cooling panel with free night cooled water as its coolant is proven to have signifcant energy saving potential of up to 85% while at the same time provide an acceptable room thermal comfort which meets the international standard criteria such as the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 55

Nocturnal Cooling of Water as Free Cooling Source for Building Indoor Radiant Cooling in Malaysian Climate

Normally mechanical chiller supplies chill water temperature at a higher operating temperature to charge a radiant cooling system in building. Other source of cooling is possible since the operating temperature for radiant cooling is limited by the air dew point temperature. This study investigates cooling of water through long wave radiation to the night sky in Kuching Sarawak, Malaysia and utilise this water for radiant cooling purpose. Mathematical model were developed to predict the cooling power of the nocturnal cooling over typical metal roof and was compared to an experimental data. The measurement from the test model verified the predicted data and a yearly potential from nocturnal cooling in this region was established. The amount of cooled water generated from this night cooling system was also calculated. Results showed that an average of 73 W/m2 nocturnal cooling power is possible in this region

Investigation of thermal characteristics of CNF-based nanofluids for electronic cooling applications

A major problem being faced by existing coolants is the limited amount of heat that can be absorbed by the fluids. An innovative way to overcome this limitation is by utilizing a nano-coolant as a heat transfer medium in a cooling application. This paper was aimed at formulating an efficient nanofluid from Pyrograf III HHT24 carbon nanofibers (CNF) in a base fluid consisting of deionized water (DI) and ethylene glycol (EG) with polyvinylpyrrolidone (PVP) as the dispersant. The experiment was conducted by setting the variable weight percentage of CNF from 0.1 wt% to 1.0 wt%, with the base fluid ratio of 90:10 (DI:EG) weight percent. Then, the thermal properties of the formulated nanofluids were investigated. The test on the thermal conductivity of the nanofluids showed that the highest thermal conductivity of 0.642 W/m.K in this experiment was produced when the concentration of nanofluid is 0.5 wt% at a temperature of 40°C. Experimental investigations into the forced convective heat transfer performance of the CNF-based nanofluid in a laminar flow through a mini heat transfer test rig showed that the presence of nanoparticles enhanced the heat transfer coefficient as opposed to the original base fluid. The highest heat transfer coefficient was reported using nanofluid with a concentration of 0.6 wt% at 40°C. The enhancement of the heat transfer coefficient was due to the higher thermal conductivity value. The Nusselt number was also calculated and presented in this paper. This study showed that the CNF-based nanofluids have a huge potential to replace existing coolants in electronic cooling applications. Thus, in order to commercialize nanofluids in practice, more fundamental studies are needed to understand the crucial parameters that affect their thermal characteristics. Keywords: carbon nanofibers; nanofluid; thermal conductivity; heat transfe

Thermal conductivity and viscosity of deionised water and ethylene glycol-based nanofluids

This paper focused on thermal conductivity and viscosity of deionised water and ethylene glycol-based nanofluids at three different temperatures (6C, 25C and 40C). For the preparation of nanofluids, a two-step method, comprised of homogenisation and sonication, was used on a mixture of MWCNT-OH, PVP and the base fluid. The results revealed that thermal conductivity was enhanced by about 8.86% for 0.8 wt% deionised water-based MWCNT-OH nanofluid, and by 5.37% for 0.2 wt% ethylene glycol-based MWCNT-OH nanofluid. Meanwhile, in viscosity test, the highest temperature of 40C exhibited lowest viscosity. This phenomenon happened only with ethylene glycol-based nanofluid, whilst the data on the viscosity of deionised water-based nanofluid was inconsistent at certain nanofluid concentrations . In conclusion, addition of MWCNT-OH into base fluid enhanced base fluid performance , giving it the potential to be used in cooling system applications. Keywords: Nanofluids; thermal conductivity; viscosity

Recent advances of wearable antennas in materials, fabrication methods, designs, and their applications: state-of-the-art

The demand for wearable technologies has grown tremendously in recent years. Wearable antennas are used for various applications, in many cases within the context of wireless body area networks (WBAN). In WBAN, the presence of the human body poses a significant challenge to the wearable antennas. Specifically, such requirements are required to be considered on a priority basis in the wearable antennas, such as structural deformation, precision, and accuracy in fabrication methods and their size. Various researchers are active in this field and, accordingly, some significant progress has been achieved recently. This article attempts to critically review the wearable antennas especially in light of new materials and fabrication methods, and novel designs, such as miniaturized button antennas and miniaturized single and multi-band antennas, and their unique smart applications in WBAN. Finally, the conclusion has been drawn with respect to some future directions

A randomized controlled trial on the effect of VCO in reducing glucose and body weight in post-acute coronary syndrome patients : a pilot study

The aims of this paper were to determine the effect of virgin coconut oil (VCO) on bodyweight and serum glucose level among acute coronary syndrome (ACS) patients. Various clinical trials on animal studies have found that the VCO has many beneficial effects on health. However, there have been limited published human studies on the pharmacological properties of VCO. Investigation on human subjects is extremely required in order to provide more empirical evidence to show the effect of VCO for ACS patients. Randomised single blind study conducted between March 2018 and April 2018. RCT was conducted among 70 ACS patients for 30 days. Participants in group A received their bottles containing 100 pieces of virgin coconut oil soft gels and were required to ingest 10 capsules per day (5 mL/5 gm) and continue routine treatment (diabetic diet and diabetic medication). Group B participants continued receiving routine treatment. Changes in serum fating blood sugar and body weight were identified using a paired t-test and independent t-test. A total of 70 patients participated with ages of 51 years old and older and were mostly male. The serum FBS and body weight of the intervention group that received VCO were reduced about 13.6% on day 30, from the baseline on day 1. They also had body weight reduction of about 2% with p value of less than 0.05. In contrast, the control group that only received routine treatment showed an increment of 12.1% in their serum FBS and had no changes in body weight. These reductions were noted within 30 days of consuming a daily dose of VCO (5 g every day). The properties of lauric acid and antioxidants present in the VCO composition were key players in the reduction of serum glucose levels and body weight. VCO can reduce serum glucose levels and body weight with 5 mL (5 g) of VCO per day for 30 days. Also, VCO may have a positive effect towards the glucose level and other cardiovascular risk factors