http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Imtiaz Hussain, M.,Lee, G.H. Association for Applied Solar Energy ; Elsevier Sc 2016 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.133 No.-
The purpose of this study was to analyze and compare the thermal performances of a line-focus and a point-focus solar concentrators (LFSC and PFSC, respectively) under similar operating and weather conditions in South Korea. Both concentrator systems had Fresnel lenses of the same surface area. To reduce heat loss, absorber pipes of the LFSC and PFSC systems were covered with borosilicate glass tube and foamed polyethylene insulation, respectively. Collector temperature (inlet and outlet temperature differential), collected energy, and thermal efficiency over experimental test time were calculated while the solar radiation, volumetric flow rate, and inlet temperature of the thermal fluid were varied. Good harmony was observed between the experimental and predicted results. Calibration of the both models reduced the deviation between the experimental and predicted temperature results compared to the uncalibrated models. Although both solar collectors showed similar trends in the variations of the average efficiency and total collected energy, these parameters were about 7% and 8% higher, respectively, in the PFSC compared to the LFSC. Overall, the results indicate that the PFSC performs slightly better than the LFSC in terms of the thermal efficiency, total collected energy, and heat loss.
Imtiaz Hussain, M.,Ali, Asma,Lee, Gwi Hyun Elsevier 2015 ENERGY Vol.90 No.2
<P><B>Abstract</B></P> <P>This paper compares the thermal performance characteristics of LFL and SFL (linear and spot Fresnel lens, respectively) solar collectors for heating identical greenhouses in Chuncheon, South Korea. LFL and SFL collectors with similar storage capacities and Fresnel lens surface areas were tested under the same weather and operating conditions. Both systems were equipped with a dual-axis solar tracker for tracking the sun position and a circulating pump for forced convective heat transfer. Economic analyses of the solar collectors were performed by considering the current interest rate, inflation rate, and electricity prices in South Korea. The available energy per unit area and thermal efficiency were higher for the SFL than for the LFL collector. The discounted payback period decreased and electricity savings increased when the storage capacity was increased with either collector. All results indicate that SFL collector performance was about 7–12% higher than that of LFL collector. It is also noticed that changing the inlet flow rate of the greenhouse heat exchanger may be a good solution for obtaining the seed germination temperatures needed for different crops.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SFL collector has more available energy per unit area compared to LFL collector. </LI> <LI> Useful energy gain for both collectors varied with varying storage capacities. </LI> <LI> The fraction of heat supplied by SFL for greenhouse heating was higher than LFL. </LI> <LI> SFL collector has lower discounted payback period compared to LFL collector. </LI> </UL> </P>
Utilization of Solar Energy in Agricultural Machinery Engineering: A Review
Hussain, M. Imtiaz,Lee, Gwi Hyun Korean Society for Agricultural Machinery 2015 바이오시스템공학 Vol.40 No.3
Background: Various solar energy collecting systems have been developed and analyzed for agricultural applications. They include solar thermal and electric devices such as solar crop dryers, solar water pumps, solar greenhouse heating, ventilation for livestock, solar aeration pumps, solar electricity, and many more. Purpose: This review provides the current status of research and development in the field as well as the solar energy systems that are currently in use in the agriculture sector across the globe. Review: Solar energy is the largest and cheapest energy resource on earth; one hour of solar radiation exceeds the complete global energy consumption in one year. The potential annual total solar radiation in South Korea is $3.58-5.4 kWh/m^2/day$. The available solar energy is sufficient for agricultural applications across the entire country. Conclusion: The scope of solar energy utilization in agricultural machinery engineering in South Korea and in other countries is promising.
Imtiaz Hussain, M.,Lee, G.H. Pergamon ; Elsevier Science Ltd 2014 Energy conversion and management Vol.87 No.-
In the present research, a conical solar water heater (CSWH) with an attached thermal storage tank, with or without a vacuum glass absorber, was analyzed under different operating conditions. For maximum solar radiation of the system, the collector was equipped with a dual-axis tracking system and sun sensor, which kept the system oriented towards the sun at every instant during its operation. A forced cooling system circulated fluid to remove the solar heat from the absorber surface. Performance analyses with and without the vacuum glass absorber were conducted at different mass flow rates, inlet temperatures, and solar irradiation values. The influence of the vacuum glass cover and all operational parameters on the collector efficiency, outlet temperature, and thermal stratification were investigated. The efficiency increased with increasing inlet flow rate, and the maximum efficiency was obtained at a critical flow rate of 6L/min. When the flow rate was increased beyond this critical value, the efficiency began to decrease. The temperature rise of the working fluid with vacuum glass at a high rate of insolation was considerably higher than without a vacuum glass for all flow rates. Use of a high flow rate deteriorated the thermal stratification process in the storage tank, while it increased the efficiency of the conical solar water-heating system. It can be concluded that the CSWH operates more efficiently if the fluid is heated slightly at a critical flow rate.
High Solar Flux Dryer for Various Agricultural Products
( M. Imtiaz Hussain ),( Gwi Hyun Lee ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.2
The main purpose of this paper is to develop a solar dryer capable of drying various agricultural products. The solar agricultural products dryer consists of a conical concentrators, heat storage tank and dryer. The inside temperature of the dryer is controlled by the control box, which consisted controller (FOX-2001, Daesung ENG, KOREA), magnetic switch, earth leakage breaker, operation lamp, temperature relay, timer relay and digital temperature compensated crystal oscillator (DTXCO). Pumpkin and carrots were used as agricultural products. For the performance evaluation, the time required to reach the set temperature and the humidity were measured. It was observed that the inside chamber temperature was kept at the set temperature for 10 hours. Experimental results showed that the drying times which take to reach the set drying temperature of 40℃, 50℃, and 60℃ were 20 minutes, 45 minutes, and 60minutes, and the temperature inside the dryer was maintained well at the set temperature for 10 hours. The experimental results were considered to be suitable for drying various crops. For future study, simulations will be used to analyze the temperature distribution inside the dryer and to modify the system for a smoother drying. Economic analysis will also be carried out to demonstrate that the proposed solar agricultural product dryer is economic energy-saving devices for farmers.
High Solar Flux Dryer for Various Agricultural Products
( M. Imtiaz Hussain ),( Gwi Hyun Lee ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.2
The main purpose of this paper is to develop a solar dryer capable of drying various agricultural products. The solar agricultural products dryer consists of a conical concentrators, heat storage tank and dryer. The inside temperature of the dryer is controlled by the control box, which consisted controller (FOX-2001, Daesung ENG, KOREA), magnetic switch, earth leakage breaker, operation lamp, temperature relay, timer relay and digital temperature compensated crystal oscillator (DTXCO). Pumpkin and carrots were used as agricultural products. For the performance evaluation, the time required to reach the set temperature and the humidity were measured. It was observed that the inside chamber temperature was kept at the set temperature for 10 hours. Experimental results showed that the drying times which take to reach the set drying temperature of 40℃, 50℃, and 60℃ were 20 minutes, 45 minutes, and 60minutes, and the temperature inside the dryer was maintained well at the set temperature for 10 hours. The experimental results were considered to be suitable for drying various crops. For future study, simulations will be used to analyze the temperature distribution inside the dryer and to modify the system for a smoother drying. Economic analysis will also be carried out to demonstrate that the proposed solar agricultural product dryer is economic energy-saving devices for farmers.