A Study for the Use of Solar Energy for Agricultural Industry - Solar Drying System Using Evacuated Tubular Solar Collector and Auxiliary Heater -

이귀현 한국농업기계학회 2013 바이오시스템공학 Vol.38 No.1

Purpose: The objectives of this study were to construct the solar drying system with evacuated tubular solar collector and to investigate its performance in comparison with indoor and outdoor dryings. Methods: Solar drying system was constructed with using CPC (compound parabolic concentrator) evacuated tubular solar collector. Solar drying system is mainly composed of evacuated tubular solar collector with CPC reflector, storage tank, water-to-air heat exchanger, auxiliary heater, and drying chamber. Performance test of solar drying system was conducted with drying of agricultural products such as sliced radish, potato, carrot, and oyster mushroom. Drying characteristics of agricultural products in solar drying system were compared with those of indoor and outdoor ones. Results: Solar drying system showed considerable effect on reducing the half drying time for all drying samples. However, outdoor drying was more effective than indoor drying on shortening the half drying time for all of drying samples. Solar drying system and outdoor drying for oyster mushroom showed the same half drying time. Conclusions: Oyster mushroom could be dried easily under outdoor drying until MR (Moisture Ratio) was reached to about 0.2. However, solar drying system showed great effect on drying for most samples compared with indoor and outdoor dryings, when MR was less than 0.5.

Drying methods for municipal solid waste quality improvement in the developed and developing countries: A review

Maw Maw Tun,Dagmar Juchelkova 대한환경공학회 2019 Environmental Engineering Research Vol.24 No.4

Nowadays, drying methods for municipal solid waste quality improvement have been adopted in the developed and developing countries to valorize wastes for a renewable energy source, reduce dependency on fossil fuel and keep safer disposal at landfills. Among them, biodrying, biostabilization, thermal drying and solar drying are the most common. Drying of municipal solid waste could offer several environmental and economic benefits. Therefore, this review highlighted the drying methods for municipal solid waste quality improvement around the world and compared them based on the reduction of moisture, weight and volume of municipal solid wastes against drying temperature and time by using statistical analysis. It was observed that the drying temperature of different drying methods accounted for 115 ± 40℃ for thermal drying, 59 ± 37℃ for solar drying, 55 ± 15℃ for biodrying and 58 ± 11℃ for biostabilization. Among the drying methods, thermal drying provided the shortest drying time. The moisture reduction, weight reduction, volume reduction and heating value increase of municipal solid waste could vary with drying temperature and time. Finally, the benefits and drawbacks of different drying methods were specified, and recommendations were made for the future efficient drying.

건조방법에 따른 건고추의 품질특성과 생산효율 비교

조명희(Myeoung Hee Jo),신종화(Jong Hwa Shin) (사)한국생물환경조절학회 2018 생물환경조절학회지 Vol.27 No.4

고추는 조미채소의 한 종류로 우리나라 채소시장에서 큰 비중을 차지하는 품목이다. 대부분 고추의 이용은 건고추의 분말형태인 고춧가루로 가공하여 이용되고 있으므로, 고추건조에 대한 품질과 생산성 향상이 중요한 부분이다. 따라서 본 연구에서는 고추의 건조방법에 따라 고춧가루의 품질을 좌우할 수 있는 성분의 변화에 대하여 비교하고, 생산비를 고려하여 적정 건조방법을 제시하고자 실험을 수행하였다. 건조방법으로는 관행으로 많이 이용되는 양건과 화건을 이용하였으며, 제습기를 이용한 제습건조방식을 추가 적용하여 건고추 생산성과 품질을 비교하였다. 고추의 건조방식에 따른 건조율은 화건이 85.1%로 제일 높았고, 이에 따라 고춧가루의 수분함량도 13.5%로 가장 낮게 나타났다. 고추의 색택을 좌우하는 ASTA(American Spice Trade Association) 색도는 양건처리에 비해 화건과 제습건조처리가 높은 결과를 보였다. 고춧가루의 신미성분인 capsaicinoid 함량은 양건처리에 비하여 화건과 제습건조처리에서 모두 낮게 나타나 이에 대한 추가적인 적정 건조조건에 대한 연구가 추가되어야 된다. 당함량은 건조시간이 비교적 짧았던 화건과 제습건조처리에서 양건에 비해 높게 나타났으나 두 처리간에는 유의한 차이를 보이지 않았다. 건고추 생산비용은 제습건조처리가 화건처리에 비해 9.9% 효율이 높은 것으로 나타났다. 본 연구를 통해 화건과 제습건조가 당함량의 증진과 건고추의 색 발현 측면에서는 효과적이었음을 알 수 있었다. 고추의 신미성분인 capsaicinoid 함량 증진을 위해서는 화건과 제습건조처리에서 적정한 건조온도와 건조시간에 대한 연구가 추가되어야 될 것으로 판단되었다. Hot pepper is a kind of seasoning vegetables, which is a major item in the Korean vegetable market. Since the use of hot pepper is processed into pepper powder, which is a powder form of dried hot pepper, improvement of quality and productivity of dried hot pepper is important. Therefore, this experiment was conducted to suggest proper drying method by comparing the changes of hot pepper powder ingredients considering production cost according to the drying method. As a drying method, we used sun drying and heat drying which are widely used in practice. We also compared the productivity and quality of dried hot pepper by applying a dehumidifying drying method using a dehumidifier. Drying rate of hot pepper was highest of 85.1% at heat drying. Accordingly moisture content of hot pepper powder was lowest of 13.5% at heat drying. The American Spice Trade Association (ASTA) color value, which influenced the coloring of red pepper, showed higher in heat drying and dehumidified drying treatment than the sun drying treatment. The content of capsaicinoids was higher at sun drying treatment than that of at both heat drying and dehumidified drying treatments. The content of sugar was higher at heat drying and dehumidified drying treatment where drying time was relatively short than that of sun drying treatment. Also, there was no significant difference in sugar content between the two treatments. The production cost of dried hot pepper with dehumidified drying was 9.9% more efficient than heat drying. Through this study, it was found that heat and dehumidified drying method were effective in increasing sugar content and coloring of hot pepper powder. In order to improve the capsaicinoid content of red pepper, it is considered that appropriate drying temperature and drying time should be added in the process of heat drying and dehumidified drying.

Drying characteristics and quality of red ginseng using far-infrared rays

Ning, Xiaofeng,Lee, Junsoo,Han, Chungsu The Korean Society of Ginseng 2015 Journal of Ginseng Research Vol.39 No.4

Background: The current typical drying methods for red ginseng are sun drying and hot-air drying. The purpose of this study was to investigate drying characteristics of red ginseng by using far-infrared drying. Methods: The far-infrared drying tests on red ginseng were conducted at two drying stages: (1) high temperature for 24 h drying and (2) low temperature drying until the final moisture content was $13{\pm}0.5%$ (wet basis). The high temperature drying stage included three drying chamber temperature conditions of $60^{\circ}C$, $65^{\circ}C$, and $70^{\circ}C$. The low temperature drying stage was conducted at temperatures of $45^{\circ}C$ and $50^{\circ}C$. Drying characteristics were analyzed based on factors such as drying rate, color changes, energy consumption, and saponin content. The results were compared with those of the hot-air and sun drying methods. Results: The results revealed that increases in drying temperature caused a decrease in drying time and energy consumption for far-infrared drying. The saponin content decreased under all drying conditions after drying, the highest value (11.34 mg/g) was observed at drying conditions of $60{\sim}50^{\circ}C$. The sun drying condition showed the lowest color difference value when compared with far-infrared and hot-air drying. Conclusion: The far-infrared drying showed a faster drying rate, higher saponin content, lower color difference value, and a decrease in energy consumption than seen in hot-air drying.

Drying Characteristics and Models of Red Ginseng Slice Using Far-Infrared Rays

Ning Xiao Feng,Xu Ji Tong,장문기 한국농업기계학회 2021 바이오시스템공학 Vol.46 No.4

Purpose The aim of this study was to improve the drying quality and find the suitable drying model for the far-infrared drying of red ginseng slice. Methods The far-infrared drying tests on ginseng slice were conducted at two slice thickness of 2 and 4 mm and three drying temperatures of 50, 60, and 70 °C. The results were compared with the hot air drying method. The drying characteristics were analyzed based on factors such as drying rate, color changes, and elastic modulus. The Page, modified Wang and Singh, and logarithmic models were used to select the best model for far-infrared drying of red ginseng slices. Results The results revealed that increasing drying temperature and decreasing ginseng thickness caused a decrease in drying time. The color differences (ΔE) at 70 °C values were higher than 50 and 60 °C values. The highest elastic modulus (32.42 MPa) was observed at drying temperatures of 60 °C ginseng slice of 4mm. The drying quality of far-infrared dryingwas better than that of hot air drying under the same drying condition. The Page model showed the highest R2 values and lowest RMSE values than the other models. Conclusion The quality of red ginseng slice can be improved by far-infrared drying. The Page model was the best model to fit adequately most of the drying conditions for the far-infrared drying of red ginseng slice.

건조 방법에 따른 건조 문어의 품질특성

배태진 전남대학교 수산과학연구소 2015 수산과학연구소논문집 Vol.23 No.-

This study was performed to investigate the method improving the quality of dried octopus, this study compared artificial drying methods i.e. hot air drying and cold air drying with natural drying method. The drying rates of octopus were in the order of hot air, cold air and natural drying. However, cold-air drying was slower than natural drying at 7℃. As the drying temperature increases the drying rate is accelerated. At cold air drying at 7℃, the force of dehumidification was lower than other drying conditions, which resulted in a lower drying rate. There were little color differences between the drying methods and temperature. Octopus dried by cold air-drying had better mechanical texture and sensory qualities than with other drying methods.

Drying characteristics and quality of red ginseng using far-infrared rays

Xiaofeng Ning,Junsoo Lee,한충수 고려인삼학회 2015 Journal of Ginseng Research Vol.39 No.4

Background: The current typical drying methods for red ginseng are sun drying and hot-air drying. The purpose of this study was to investigate drying characteristics of red ginseng by using far-infrared drying. Methods: The far-infrared drying tests on red ginseng were conducted at two drying stages: (1) high temperature for 24 h drying and (2) low temperature drying until the final moisture content was 13 0.5% (wet basis). The high temperature drying stage included three drying chamber temperature conditions of 60C, 65C, and 70C. The low temperature drying stage was conducted at temperatures of 45C and 50C. Drying characteristics were analyzed based on factors such as drying rate, color changes, energy consumption, and saponin content. The results were compared with those of the hot-air and sun drying methods. Results: The results revealed that increases in drying temperature caused a decrease in drying time and energy consumption for far-infrared drying. The saponin content decreased under all drying conditions after drying, the highest value (11.34 mg/g) was observed at drying conditions of 60w50C. The sun drying condition showed the lowest color difference value when compared with far-infrared and hot-air drying. Conclusion: The far-infrared drying showed a faster drying rate, higher saponin content, lower color difference value, and a decrease in energy consumption than seen in hot-air drying. Copy

Agricultural Process and Food Engineering ; A Study for the Use of Solar Energy for Agricultural Industry -Solar Drying System Using Evacuated Tubular Solar Collector and Auxiliary Heater-

( Gwi Hyun Lee ) 한국농업기계학회 2013 바이오시스템공학 Vol.38 No.1

Purpose: The objectives of this study were to construct the solar drying system with evacuated tubular solar collector and to investigate its performance in comparison with indoor and outdoor dryings. Methods: Solar drying system was constructed with using Cl`C (compound parabolic concentrator) evacuated tubular solar collector. Solar drying system is mainly composed of evacuated tubular solar collector with Cl`C reflector, storage tank, water-to-air heat exchanger, auxiliary heater, and drying chamber. Performance test of solar drying system was conducted with drying of agricultural products such as sliced radish, potato, carrot, and oyster mushroom. Drying characteristics of agricultural products in solar drying system were compared with those of indoor and outdoor ones. Results: Solar drying system showed considerable effect on reducing the half drying time for all drying samples. However, outdoor drying was more effective than indoor drying on shortening the half drying time for all of drying samples. Solar drying system and outdoor drying for oyster mushroom showed the same half drying time. Conclusions: Oyster mushroom could be dried easily under outdoor drying until MR (Moisture Ratio) was reached to about 0.2. However, solar drying system showed great effect on drying for most samples compared with indoor and outdoor dryings, when MR was less than 0.5.

전처리 조건 및 건조방법에 따른 건조대추의 품질특성 및 항산화 활성

김재원(Jae-Won Kim),이신호(Shin-Ho Lee),노홍균(Hong-Kyoon No),홍주헌(Joo-Heon Hong),박창수(Chang-Su Park),윤광섭(Kwang-Sup Youn) 한국식품영양과학회 2013 한국식품영양과학회지 Vol.42 No.8

건조 전처리와 건조방법에 따른 대추의 건조특성과 품질의 변화를 비교분석 하였다. 수분함량은 glyceol 전처리에서 유의적으로 낮았고 열풍건조가 천일 및 냉풍건조에 비해 건조효율이 높은 것으로 나타났다. 가밀도는 NaCl boiling 처리에서 가장 높았고, 가용성 고형분의 함량의 경우 열풍건조, 냉풍건조, 천일건조 순으로 높은 함량을 나타내었으며 전반적으로 glycerol 침지에서 높은 함량을 보였다. 적정도는 열풍건조가 타 건조 방법에 비해 높은 값을 나타내었으며, 전처리에 따라서는 무처리 및 glycerol 침지에서 높은 경향을 나타내었다. 반면 boiling 처리 시 대추 고유의 산도는 저하되는 것으로 나타났다. 당산비의 경우 천일건조에서 가장 높았으며 다음으로 냉풍건조 열풍건조 순으로 나타났고, 전처리에 따라서는 NaCl boiling> glycerol> 무처리 순으로 높은 함량을 나타내었다. 갈변도는 열풍건조, 냉풍건조, 천일건조 순으로, 전처리 방법에 따라서는 NaCl boiling, 무처리, glycerol 침지 순으로 높은 값을 나타내었다. 적색도의 경우 무처리가 NaCl boiling 및 glycerol 침지에 비해 유의적으로 높은 경향을 나타내었으며, boiling 처리한 건조대추의 경우 적색도는 감소하고 황색도는 증가하는 것으로 나타나 기호성이 다소 저하되는 것으로 관찰되었다. 건조방법에 따른 폴리페놀 함량은 열풍건조> 냉풍건조> 천일건조순으로 높은 함량이 검출되었으며, 전처리 방법 간에는 무처리 및 glycerol 침지가 NaCl boiling 처리에 비해 유의적으로 높았다. 반면 플라보노이드 함량에서는 boiling 전처리를 행한 모든 건조방법에서 높은 함량이 검출되었다. DPPH, ABTS 라디칼 소거활성은 유용성분의 함량과 항산화 활성간의 비례적인 상관관계를 나타내었으며, 열풍건조에서 유의적으로 높은 라디칼 소거활성을 나타내었다. 관능검사 결과 NaCl boiling 처리는 외관과 함께 품질이 가장 떨어지는 것으로 나타났으며, 종합적 기호도는 glycerol 침지가 가장 기호성이 높은 것으로 조사되었고 다음으로 무처리, boiling 순이었다. 이상의 결과 종합적 기호도 및 이화학적, 기능적 품질특성을 고려해 보았을 때 glycerol 전처리와 열풍건조방법을 효과적으로 이용하는 것이 건조효율 증대 및 품질손상을 억제할 수 있는 방안이 될 것으로 사료된다. This study was performed to determine the effects of pretreatment (NT: non-treatment, BTS: boiling treatment with 3% sodium chloride, DTG: dipping treatment in glycerol) and drying methods (sun drying, hot air drying, and cold air drying) on the physicochemical properties and antioxidant activities of dried jujube (Zizyphus jujuba Mill.) fruits. Our results show that moisture content is lower (P<0.05) with DTG, and that moisture content is lower with hot air drying compared to other drying methods. The bulk density was highest with BTS. The soluble solids content was highest with DTG. Additionally, the soluble solids content were highest in the following order: hot air drying> cold air drying> sun drying. The titratable acidity of hot air drying was highest of all the drying methods. The titratable acidity was higher with NT and DTG, and the brix and acid ratio of sun drying was higher than other drying methods. Among the drying methods, BTS showed the best browning-retarding effect, whereas boiling treatment affected quality and color. The total polyphenol content from hot air drying and NT or DTG treatment was relatively higher than the content from BTS. The flavonoid content was highest with BTS, and all dried jujube showed relatively high antioxidant activities. The sensory evaluation results indicated that the organoleptic scores for overall preference were higher in the NT and DTG treatment groups. These results suggest that pretreatment and drying methods affect the quality of dried jujube fruit, and show that glycerol treatment with hot air drying can be applied to the production of high quality dried jujube.

Drying Characteristics and Energy Analysis of Food Waste Dryer using Steam from Incineration Plant

Dae-Bin Song,Ki-Hyeon Lim,Dae-Hong Jung,Jong-Hyun Yoon 경상대학교 농업생명과학연구원 2020 농업생명과학연구 Vol.54 No.3

This study was conducted to develop a high-moisture food waste dryer that uses steam as a direct heat source to improve the drying speed. Another objective was to verify its performance through experiments. A dryer with a drying capacity of 10,000 kg/hr, which uses steam from an incineration plant as a drying heat source, was fabricated. The performance and applicability of the dryer were verified through drying experiments, in which the food waste collected from large restaurants near the incineration plant was used as the experimental material. The drying experiment results showed that the input steam temperature increased by 21℃ from approximately 145℃ to 166℃ compared to the case in which drying was performed by converting steam into heated air. The drying speed increased by 1.5 times from approximately 0.63 to 0.94 %/hr, and drying up to approximately 20%(wb) moisture content was possible. The drying energy rate, which represents the ratio of the energy consumed for drying to the input energy, increased by approximately ten times from 7.17% to 70.87%. The total drying time still remained approximately 100 hr due to the re-condensation of moisture. When steam was directly used as a drying heat source to improve the drying speed of food waste containing high moisture, the drying speed, water content after drying, and drying energy rate were clearly improved compared to the case in which steam was converted into heated air for use. Therefore, it was deemed necessary to develop a dryer that directly uses steam from an incineration plant for drying. To shorten the total drying time, it is necessary to develop a device that solves the problem of moisture condensation in the dryer.