Radiant Times Series (RTS) For Equatorial Climates

Air conditioning units are the most significant energy user in a building. Therefore, an accurate cooling load calculation is important to optimize the design of these air conditioning units for a better system for the building energy load. American Society of Heating, Refrigerating and Air Conditioning (ASHRAE) has developed a method called Radiant Times Series (RTS) to improve the accuracy of cooling load calculation. There are several traditional cooling load calculation methods commonly practiced by designers in Malaysia especially Rules of Thumbs, CLTD (Cooling Load Temperature Difference) and TFM (Transfer Function Method). Designer may considered higher safety factor for conventional method because of constraint in initial parameter consideration, thus this will promote higher loading and over designed air conditioning system. This study will discuss the various types of cooling load methods in equatorial climates (hot and humid), where buildings in Malaysia is used as a subject in this paper. The results would be useful for Mechanical, Ventilation and Air Conditioning (MVAC) designer to consider and design a better and optimum system for the building. The finding shows that the huge convocation hall with estimated occupant of 5000 tenants shall be design between the ranges of Cooling Load per Square Feet, of 70 Btu/Hr.ft2 to 125 Btu/Hr.ft2 based on RTS method and CLTD method respectively. Meanwhile, for office building the design shall be between the ranges of Cooling Load per Square Feet, of 33.81 Btu/Hr.ft2 to 46.79 Btu/Hr.ft2 based on RTS method and CLTD method respectively. These values are to be achieved comfort cooling for the respective building. The results also showed that the accuracy of cooling load will be determined by the considered parameter of the cooling load methods. It's important to use this method in Malaysian perspectives because of the accuracy and recommended for other hot and humid countries

Macro-surface Modification through Exploitation of Rivets and Dimples –Numerical and Experimental

Research related to rivets and dimples has been conducted as early as the 1930s. The irregularities of surfaces have believed to be a factor to fuel consumption increase of airplanes. NASA reported that it is vital to eliminate the surface irregularities or other protuberances from the surface that is exposed to the airflow [1]. This is believed to due to the extreme increase of the drag coefficient

Macro-Surface Modifications of Subsonic Flow on Airplane Winglets

Airplane winglets are used to improve the efficiency and noise or vibrations of fixed-wing aircraft. In this paper, the surface modification involves alteration on surface’s features to improve the performance of a product is being conducted. The surface modification was implemented on winglet surface in order to investigate whether the modified winglets provide better performance or not compared to the conventional wing designs. Two types of models were used which is a rectangular plane and airplane winglet, each with different types of surface modifications. For rectangular plane, four surfaces were introduced which is smooth plane, dimpled plane, riveted plane and extruded rivet plane. As for winglets, three surfaces were used which is the smooth winglet, dimpled winglet and riveted winglet. The parameters used for the simulations were based on the actual cruising flight and zero degree angle of attack. From the results, both show that the surface with rivets is better. The flow trajectories show that the flow velocity across riveted surface modified winglet is 5% higher than the smooth conventional winglet

Effects of Hematocrit of the Sealed Blood on the Leakage Characteristics of Blood Cell Component and Plasma Component in a Mechanical Seal

The purpose of this study is to find out the effects of hematocrit of the sealed blood on the leakage characteristics of blood cell components and plasma components in a mechanical seal, which separates blood from cooling water. The hematocrit was controlled to 0, 10, 20, 30 and 40%. Each component leakage was obtained by measuring the increase in the potassium ion concentration and the sodium ion concentration in the cooling water. It was revealed that each component leakage became larger with the increase of the hematocrit in the three-hour measurement. When changing the hematocrit from 20% to 30%, the volume percentage of the blood cell component leakage remarkably increased by 7.7 times. The friction characteristics of the mechanical seal under blood sealing and the hemolytic properties of the sealed blood were also studied. There is a typical trend under the mixed lubrication condition where the friction torque decreased with each of the sealed blood as the rotational speed increased. The hemolytic index of the sealed blood after the measurement experiments of the blood leakage increased with the increase of the hematocrit