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The purpose of this paper is to investigate a wall-integrated solar chimney for passive ventilation of a building cavity. Ventilation is required to improve the circulation of air in the built environment. This can be achieved through natural or forced convection. Natural circulation can be driven by renewable energy, and so it promotes sustainable exploitation of energy resources. Solar energy is one of the promising renewable energy resources.

The chimney was designed to face the Equator on the wall of a room which required ventilation. Mean monthly daily heating and cooling loads of the room were computed with and without a solar chimney by using hourly meteorological data from nine different weather sites at low, medium and high latitudes. The chimney was implemented with and without airflow control, and simulated by using the ESP-r software.

Results show that the solar chimney with airflow control marginally reduced the heating load in the building envelope, with a similar effect being exhibited by the chimney with uncontrolled airflow. The cooling load was reduced by the controlled airflow at all the nine sites. In contrast, the uncontrolled airflow increased the cooling load at some sites. In addition, the chimney with airflow control reduced the annual total thermal load at all the sites, while the chimney with uncontrolled airflow raised the total thermal load at some locations.

The performance of solar chimneys designed with and without airflow control systems has been investigated under the same prevailing meteorological conditions at a given site. Findings show that controlling airflow in a solar chimney reduces the total thermal load in the built environment. This information can be applied in different parts of the world.

The purpose of this paper is to develop an efficient termination control strategy of air-vented dryer in term of energy saving, improving smoothness and reducing microscopic damage of fiber.

A simple, low cost termination control strategy is developed by testing the instantaneous humidity of exhaust air and then deducing the drying degree of fabric in process. The practicability evaluation of this novel strategy was investigated by using both experimental and mathematical approaches. The effect of termination control strategy on drying efficiency and fabric apparent properties were also discussed.

Termination control strategy significantly affects drying time, energy consumption, smoothness and microscopic of fiber. Specially, a novel termination control strategy that the combination of equilibrium moisture content of fabric in ambient environment and relative humidity of exhaust air in exhaust duct is workable and can save 25.2 percent of energy consumption, 26.7 percent of the drying time and improve 0.7 grade of the appearance smoothness, as well as significantly reduce the microscopic damage of fiber compare to the original control strategy of dryer. This indicates possible ways to minimize drying energy consumption and dryer damage by reducing unnecessary migrate out of the water from the clothes.

The paper is helpful in not only the development of new drying product but also the optimization of appearance smoothness of fabric after drying and reduce the microscopic damage of fiber.

A novel termination control strategy of dryer is applied to improve drying efficiency of dryer and reduce fabric damage.

This paper presents some of the problems associated with the design and operation of airborne vapour cycle refrigeration equipment, created by the extreme environmental conditions, and indicates where applicable the manner in which the difficulties can be overcome. The design philosophy behind a small high‐speed oil‐free reciprocating compressor is described, by certain fundamental requirements which the designer of airborne cooling equipment must consider. The particular difficulties, associated with effects due to rapid variation of ambient air temperature and pressure, which are peculiar to design and operation of such equipment are then explained. Rapid changes in heat load necessitate careful selection of the type of compressor drive and capacity control, and since extremes of temperature occur during a comparatively short operating cycle, particular attention must be paid to control of condensing pressure, and to prevention of migration of the refrigerant liquid into the low side of the system. The effects of vibration and of high acceleration make it necessary to design the components in such a manner that they can withstand these extreme effects, both while operating and during off‐cycle periods. In conclusion, the author contends that a new field of application for refrigeration equipment is emerging as a result of the more stringent aircraft and missile requirements; considerable theoretical and experimental effort is being devoted to the many problems, and the hope is expressed that continued co‐operation between the Refrigeration and Aircraft Industries may contribute to the more conventional as well as to the more specialized applications of refrigeration.

This work aims to study the hydrothermal behavior of mortar cement toward certain environmental factors (ambient air temperature and air velocity) based on its drying kinetics data. The objective is to provide a better understanding and controlling the stability of mortar structures, which integrate the sorption phenomenon, drying process, air pressure and intrinsic characteristics. This leads to predict the comportment of mortar structures in relation with main environmental factors and minimize the risk of cracking mortar structures at an early age.

Thermokinetic study was carried out in natural and forced convection solar drying at three temperatures 20, 30 and 40°C and three air velocities (1, 3 and 5 m.s-¹). The empirical and semiempirical models tested successfully describe the drying kinetics of mortar. These models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures.

The models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures. The average activation energy obtained expressed the temperature effect on the mortar diffusivity. The drying constant and the diffusion coefficient can be used to predict the influence of these environmental factors on the drying behavior of various building materials and therefore on their durability.

Evaluation of the effect of several environmental factors and intrinsic characteristics of mortar structures on their durability.

THE COMPLEXITY of modern pressurisation and air conditioning systems for jet aircraft have led increasingly to the practice of selecting a single contractor to design and integrate all of the components into a compatible system tailored to the mission requirements of the aircraft.

Potato (Solanum tuberosum L. cv. Kara) was grown in Open‐Top Chambers (OTCs) in Northern Egypt at ambient (ca 350 ppm) or doubled CO₂ (ca 690 ppm) either in charcoal‐filtered air (15 nl l‐1) or in non‐filtered ambient air (78 nll‐1 O₃) to investigate the changes in physiology and yield under long‐term elevated CO₂ and/or O₃ throughout 100 days. Ambient O₃ level reduced net photosynthetic rates, number and weight of tubers by 18 per cent, 41 per cent and 21 per cent, respectively, whereas elevated CO₂ caused the opposite effect where it increased the same parameters by 44 per cent, 37 per cent and 20 per cent, respectively. Significant O₃ x CO₂ interactions were detected. However, O₃ caused an increase in GR and POD by 18 per cent and 35 per cent, respectively, while CO₂ caused an increase in POD only by 46 per cent, and there was no effect of O₃ and/or CO₂ on other enzymes. The results of this study are discussed in relation to predicted atmospheric changes.

The rate and volume of air exchanged between the bed microclimate and the ambient environment determines in part how much heat is lost from the human body. This study investigated the ventilatory characteristics of infant over‐bedding to determine whether different combinations of bedding items (i.e. sheets, blankets, duvets) and types of tucking (i.e. loosely, firmly and swaddled/firmly tucked) affected microclimate ventilation. Microclimate volumes and air exchange rates were determined and used to calculate the ventilation indices. The presence of a duvet in the bedding combination resulted in lower ventilation indices than when bedding did not include a duvet. The type and combination of blankets did not significantly affect ventilation indices. The type of tucking had a significant effect on ventilation indices only when the assembly did not include a duvet.

Thermal behavior of light-emitting diode (LED) device under different operating conditions must be known to enhance its reliability and efficiency in various applications. The purpose of this study is to report the influence of input current and ambient temperature on thermal resistance of InGaAlP low-power surface-mount device (SMD) LED.

Thermal parameters of the LED were measured using thermal transient measurement via Thermal Transient Tester (T3Ster). The experimental results were validated using computational fluid dynamics (CFD) software.

As input current increases from 50 to 90 mA at 25°C, the relative increase in LED package (ΔR_thJS) and total thermal resistance (ΔR_thJA) is about 10 and 4 per cent, respectively. In addition, at 50 mA and ambient temperature from 25 to 65°C, the ΔR_thJS and ΔR_thJA are roughly 28 and 22 per cent, respectively. A good agreement between simulation and experiment results of junction temperature.

Most of previous studies have focused on thermal management of high-power LEDs. There were no studies on thermal analysis of low-power SMD LED so far. This work will help in predicting the thermal performance of low-power LEDs in solid-state lighting applications.

The paper aims to apply Buckingham Pi dimensional analysis method for assessing direct evaporative cooler performance with a cooling pad made of banana midrib and ramie fiber. The saturation efficiency acted as the indicator performance of the evaporative cooler.

The paper describes an experimental study of the direct evaporative cooler with a cooling pad made of banana midrib and rami fiber. There were six parameters in the experiment: absorbed water as a dependent variable was affected by independent parameters such as air velocity and temperature, cooling pad cross-section area and thickness. Based on these variables, we arranged three dimensionless numbers and their correlation.

The paper provides three calculated dimensionless numbers plotted on a curve with a specific correlation. The curve trends for 30 mm and 50 mm pad thickness were almost similar. The range of Reynolds number for 10 mm pad was narrower than other pad thicknesses. The thicker the cooling pad, the more extensive was the calculated Reynolds number range. A new curve exhibited the relationship between the evaporation rate with the μA/t number. The broader cooling pad cross-section, the thinner pad thickness, and the lower pad temperature were factors that increased the evaporation rate, even though the increase was less significant.

A new material in cooling pad from banana midrib fiber was tested and compared to ramie fiber and conventional cooling pad.

The ventilation and air-conditioning systems consume the highest energy in the building sector. The proper ventilation in residential buildings through the passive solar systems can substantially reduce the energy consumption in building sector. The paper aims to identify the application of wind shaft as a solar chimney, a passive ventilation system and evaluated the performance of the system.

The paper investigated the performance of the solar chimney with size, absorber area 9.76 m2 and height 4.57 m, based on experimental data recorded in the city, Kota (25°10N, 75°52E), India. Solar data were recorded using the state of the art weather station situated very closer to the residence. The air velocity and temperatures in the chimney and in the building are recorded in data logger. A simple mathematical model was used for the evaluation of the air change per hour (ACH) in the residential building.

From the analysis of weather data, it was found that the ambient temperature varies linearly with the solar irradiance. Air change rate of 5.7-7.7 can be achieved from this solar chimney, in peak summer season which is appropriate and meets the ventilation requirement as per BIS (Handbook of Functional Requirements of Buildings – 1987).

The air temperature increases from bottom to top in the solar chimney. The solar irradiance dictates the chimney air temperature, and both are in step with each other. It shows that the solar chimney is working in tune with the solar radiation availability. In peak summer, it provides sufficient ACH to the tune of 3-6. Resulting wind shaft can act effectively as a solar chimney. It is a feasible solution for the ventilation needs and it improves the looks of any residential building.