Solar Fan Research Articles

CFD simulation of solar grain dryer

Open sun drying has been used for many years for grain drying. Unfortunately, in open sun drying, solar energy is improperly utilized, and it takes a longer time to dry, leading to a compromise in product quality. Also, it requires larger floor space, continuous observation for drying, and suffers from quality impairments. In this work, a compact solar grain dryer design is being proposed and optimized for higher energy efficiency. Different designs were tested using CFD simulations for their performance. To make this grain dryer energy efficient, part of the hot air was recirculated, and simulations were performed to optimize the sizing and location of the solar fan. Several other parameters that determine the overall performance was considered, such as air flow rate, temperature, and pressure. An orifice was introduced at the inlet of the pipe to increase the quantity of recycled air. The effect of the diameter of the orifice was studied, and its optimum was determined. Finally, two dryer designs were proposed, one without fins and the other with fins.

The design and application of the solar energy fan

This article introduces a solar fan device, which can alleviate the overheating phenomenon of solar water heating system, and can be installed on the building as a component of the building, which can ventilate the building and improve the air quality of the building. introduced its design principle and structure. Taking the actual project as an example, the application and test results of the solar scalp were explained, which provided certain practical experience for the promotion and application of the solar scalp.

Attraction of stink bugs to rocket traps with different combinations of wing and landing board color

Abstract The stink bugs, Halyomorpha halys and Riptortus pedestris, are two of the most economically important pests of leguminous crops and fruits in Korea. Here we present the results from a field monitoring test that evaluated the effect of variation in rocket trap type and color on stink bugs captures. We tested various types of rocket traps, along with wing combinations and landing boards of various colors. The test was run in soybean fields in Miryang, Korea. We developed a modified rocket trap intended to enhance the capture efficacy of stink bugs. We evaluated traps including (1) yellow rocket trap with a solar fan and blue LED lamp, (2) a yellow trap with solar fan but no light, (3) rocket traps with black, green, yellow, white, red, brown, and blue color stimuli, (4) different color combinations of trap wings, and (5) traps with a landing board were evaluated. Our results showed that yellow winged rocket traps with solar fans and blue LED lamps attracted significantly more stink bug species than other traps, in both soybean fields. Use of these improved traps such as a yellow trap with a solar fan and blue LED lamp, and a yellow trap with a solar fan would therefore enhance the monitoring and capture of stink bugs in diversified agro-ecological landscapes. The potential use of traps with a specific hue, combination of features, and modifications to monitor stink bugs accurately is discussed. Continuing improvements to traps to meet the demands of a changing pest landscape and agricultural mechanization are needed.

Comparative Study between Solar Dryer and Open Sun dried Tomato under North Plateau Climatic Zone

The solar dryer consists of transparent glass window, tray, solar photovoltaic fans and solar panel. The solar radiation passes through the transparent glass window, located on the top of the cabinet. The cabinet is made of anti-corrosive material and of modular nature to meet the varying sizes and loading capacities of food products, ranging from 7 to 8 kg. The ambient air enters from the bottom of the cabinet and gets heated up with solar radiation incident from the top window. The heat energy is trapped in the cabinet and heats up the air. The hot air passed through the trays, carries the moisture from the product to the space below the glass. Then it is exhausted by Solar Photovoltaic Fans. The forced circulation of air in the cabinet is achieved through this solar fan. Assessment of the dryer showed a raised temperature of about 470c attainable in the drying chamber. The dryer temperature and drying rate was found to be higher than the natural open sun drying method. The dryer was able to reduce moisture content of tomato from initial moisture content of 93 per cent wet basis to 4 per cent in three days with effective drying time of 24hr and drying rate of 0.03833 kg/hr, whereas the traditional sun drying was able to reduce moisture content of tomato from initial moisture content of 93 per cent wet basis to 4 per cent in five days with drying time of 34hr and drying rate of 0.0272 kg/hr. The results showed a considerable advantage of solar dryer over the traditional open sun drying method in term of drying rate and less risk for spoilage.

Thermal performance of three improved biomass-fired cookstoves using fuel wood, wood pellets and coconut shell

India produces 500 million metric tones of renewable agricultural biomass every year, primarily used as a cooking fuel. Inefficient combustion of biomass is one of the major hindrances for the effective utilization of this vast reserve of energy. Inefficient combustion may occur due to several factors such as lack of proper air circulation, improper packing of fuel and excess moisture content in the fuel. This paper describes the performance evaluation of three improved stoves; natural draft TLUD stove and forced draft Purti and Mpurti stove using three kinds of biomass fuel as wood chips, wood pellets and coconut shell. It was found that the thermal efficiency of the natural draft TLUD stove was 26–27%, electric fan operated Purti stove was 44–45%, and solar fan operated Mpurti stove was 46–48%. This performance was assessed by the standard laboratory-based water boiling test method (WBT) to get thermal efficiency, burning rate, boiling point, specific fuel consumption and firepower. The economic analysis study was carried out to get an idea about the approximate cost that would be incurred per month on the fuel. All these desirable parameters are maximized for the efficient combustion of fuel. The gaseous components like CO and CO2 obtained over the fuel bed are analyzed using gas chromatography. Particulate matter (PM2.5) was measured by the fine particulate sampler. PM2.5 concentration for traditional cookstoves was much higher than studied forced draft Mpurti (510 ± 45 μg/m3) and Purti stove (677 ± 40 μg/m3). The reduction in the indoor concentration of PM2.5 for Mpurti is about 60–63% as compared to traditional stove. Mean CO emissions on a volumetric basis during the cold start and hot start phase were lowest for Mpurti forced draft stove (2.41%). The study reveals that clean cooking can be achieved using the forced draft Mpurti stove.

Evaluation of an improved rocket traps, and baits combination for its attractiveness to hemipteran bugs in grass and soybean fields

Alydids and pentatomids are economic pests of leguminous crops and fruits in Korea. Direct impacts given by these phytophagous adult and nymphal by sucking on the pods, seeds and fruits can reduce germination potential of leguminous seeds, and yield poor nutritional quality. For monitoring of these bugs, various types of traps housing species-specific baiting with pheromones are widely practiced. However, a trap developed for one species has not been found to capture other species. Here, we developed a multi-species trapping device with some modification for enhancing capture efficacy of sympatric hemipteran bugs, called ‘rocket trap with solar fan’ pertaining to its shape. The trap with and without solar fan, and yellow, black, and white color stimuli were examined for the attractiveness of sympatric hemipteran bugs against conventional traps such as pyramid and fish-net traps. In addition, the attractiveness of single or mixed baits combination to sympatric hemipteran was also tested. Among the tested traps, yellow rocket trap with solar fan was found to attract significantly higher number of stink bug species. Major stink bugs, Riptortus pedestris, Halyomorpha halys, and Piezodorus hybneri were attracted to yellow rocket trap with solar fan baited with aggregation pheromone of H. halys in the fields. The yellow rocket trap baited with aggregation pheromones along with food and synergist was found more attractive to stink bugs. Results designate that yellow rocket trap with solar fan, and yellow rocket trap baited with mixed form of baits would have enhanced the monitoring and capturing sympatric hemipteran bugs in diversified agricultural landscapes.

THERMAL COMFORT ANALYSIS INSIDE A CAR

Owing to the hot harsh weather conditions in Kuwait during the summer months, the ambient temperature inside a car parked in the sun may reach 50°C and the temperature may reach 75°C. As a result, people are seriously concerned about how to keep their cars cool. This paper addresses the behaviour of the air temperature inside a car parked in the sun. Different covering arrangements were tested, including covering the front windshield, covering the front windshield and four side windows, and covering both windshields and four side windows. In addition, the novel idea was also tested of installing a solar powered ventilating fan. Such a technique was found to be very effective in reducing the inside air temperature of a car parked in the sun. The effects of the covering arrangements of the car and the solar fan on the initial cooling rate of an air-conditioning system during normal driving conditions were also analysed. Different physical parameters, namely air velocity, mean radiant temperature and humidity, were combined with air temperature to determine the comfort level of a person inside a car. © 1997 by John Wiley & Sons, Ltd.

DEVELOPMENT OF A NATURAL DRAFT SOLAR FAN FOR VENTILATION OF GREENHOUSES IN HOT CLIMATES

This paper presents the description and the performance curves of a natural draft solar fan that suits the ventilation requirements of greenhouses in hot climates. The developed solar fan utilizes the abundant sun energy (fan heating load) to induce upward air flow due to buoyancy forces and chimney thermal effect. The ventilated air is extracted into the greenhouse from outside through a wet pad, thus producing air cooling by means of evaporation. A back-up passive system is used for overnight and cloudy days. Different greenhouses - fan configurations and fan performance theoretical analysis are presented. The greenhouse ventilation air flow rate was found to depend upon the fan heating load, chimney height, greenhouse set temperature and ambient temperature. Computation results for a typical 3 m greenhouse height, 2000 m greenhouse ground area and 5 m chimney height indicated that the ventilation rate is 29 air volume change per hour AVCH (m = 11 kg/s), when the greenhouse is maintained at 25°C and the...