scholarly journals Design and Thermal Analysis of an Air Source Heat Pump Dryer for Food Drying

2018 ◽  
Vol 10 (9) ◽  
pp. 3216 ◽  
Author(s):  
Haolu Liu ◽  
Khurram Yousaf ◽  
Kunjie Chen ◽  
Rui Fan ◽  
Jiaxin Liu ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Heat Pump ◽  
Initial Moisture Content ◽  
Extraction Rate ◽  
Experimental Heat ◽  
Moisture Extraction ◽  
Temperature And Humidity ◽  
Heat Pump Drying

In this study, an experimental heat pump dryer was designed. The specific moisture extraction rate and moisture extraction rate were used as performance indicators to explore the influence of environmental factors and the style of the hot air cycle on heat pump drying. The average temperature and humidity in Nanjing’s summer, winter, and throughout the whole year were taken as the experimental ambient temperature and humidity. Garlic slices 3 mm thick, with an initial moisture content of 66.714% w.b., were dried until the end moisture content was 10% w.b. Experimental results and thermal analysis showed that the open and semi-open heat pump dryers were greatly affected by ambient temperature and humidity. The closed heat pump drying system was greatly affected by the bypass air rate.

California Almond Shelf Life: Changes in Moisture Content and Textural Quality During Storage

2019 ◽  
Vol 62 (3) ◽  
pp. 661-671 ◽  
Author(s):  
Jia Wu ◽  
Xiangyang Lin ◽  
Shengnan Lin ◽  
Paul Chen ◽  
Guangwei Huang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Storage Temperature ◽  
Initial Moisture Content ◽  
Textural Properties ◽  
Storage Conditions ◽  
Temperature And Humidity ◽  
Lower Temperature ◽  
And Storage ◽  
Over Time

Abstract. The effects of packaging and storage conditions on the moisture content and instrumental and sensory textural properties of raw and salty light roasted (SLR) California almonds were studied under different storage conditions. The controlled combinations included low, medium, and high temperatures and low and high relative humidity (RH). Almond samples were packaged in cartons or polyethylene (PE) bags with and without vacuum. Both absorption and desorption of moisture by almonds were observed during storage and were dependent on the packaging and storage conditions. In general, gradual changes were observed for samples with PE and vacuum PE packaging in most of the storage conditions, while the samples packed in cartons showed more dramatic changes because these unprotected samples were more vulnerable to seasonal changes in humidity. The SLR almonds showed consistent moisture gains, while the raw almonds tended to lose moisture content in most of the storage conditions. This may be attributed to the low initial moisture content of the SLR samples. All raw samples packed in cartons became softer over time. The softening tended to be enhanced by high storage humidity and temperature. The raw almonds packaged in PE bags were firmer than those packed in cartons but also became softer over time. The firmness of the SLR samples was generally lower than that of raw samples, probably because roasting reduced the density and mechanical strength of the kernels. The firmness of PE packaged SLR samples increased in uncontrolled storage conditions and in higher storage temperature and humidity conditions but decreased slightly in lower temperature and humidity conditions. Vacuum packaging did not affect the firmness much. Using PE packaging and maintaining the RH below 50% and the temperature below 25°C are effective in stabilizing both raw and processed almonds. Keywords: Almond, Firmness, Nonpareil, Packaging, Relative humidity, Sensory, Storage, Temperature, Texture.

scholarly journals Comparative investigation of performance of gas dryer and two other types of domestic clothes dryers

2020 ◽  
Author(s):  
Xiao-Mei Huang ◽  
Lian-Sen Xiong ◽  
Yan-Wen Zheng ◽  
Hui-Qing Liu ◽  
Yi-Zhen Xu ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Ambient Temperature ◽  
Heat Pump ◽  
Thermal Energy ◽  
Dry Mass ◽  
Primary Energy ◽  
Comparative Investigation ◽  
Ambient Temperatures ◽  
Moisture Extraction

Abstract The moisture extraction rate (MER) and energy efficiency of domestic gas clothes dryers, heat-pump clothes dryers and electric clothes dryers were assessed. The assessment was performed with regard to five indices: the MER, specific MER, specific thermal energy consumption for dehumidification (mSPC), energy efficiency (ηt) and primary energy efficiency (η1). The effects of the dry mass of clothes (mBD) and the ambient temperature on the performance of the clothes dryers were evaluated. The experiments were divided into two parts. In the first part, the ambient temperature was 20°C, and mBD was set as 1.5, 2.5, 3.5, 4.5 and 6 kg. In the second part, mBD was 3.5 kg, and the performance of the dryers was tested at ambient temperatures of 5, 7.5, 10, 12.5, 15 and 20°C. The experimental results indicated that the gas dryer had the highest MER the heat-pump dryer had the best performance with regard to energy conservation and all three types of dryers had a higher MER and energy efficiency when the ambient temperature increased. The performance of the gas dryer was lower than that of heat-pump dryer when the temperature was 20°C. But when the temperature was < 9.5°C, the primary energy efficiency of the gas dryer was higher than that of the heat-pump dryer.

HIGH-TEMPERATURE MICRONIZATION OF FLAX SEEDS

2018 ◽  
Author(s):  
С.В. ЗВЕРЕВ ◽  
В.А. ЗУБЦОВ
Keyword(s):  
Heat Treatment ◽  
Moisture Content ◽  
Initial Moisture Content ◽  
Raw Material ◽  
Moisture Loss ◽  
Oxidative Enzymes ◽  
Heating Process ◽  
Ir Radiation ◽  
Temperature And Humidity ◽  
Flax Seeds

Проведены исследования процесса термообработки семян льна для снижения их влажности. Эксперименты проводили на лабораторной установке путем нагрева сырья в потоке инфракрасного (ИК) излучения – микронизации. Получена зависимость текущего влагосодержания от температуры зерна и исходной влажности. Установлена ее инвариантность к режимам нагрева. Предложена математическая модель изменения влагосодержания от температуры семян и исходной влажности. Для разработки модели влагопотери использованы зависимости, описывающие изменение температуры и влажности от времени в процессе нагрева, полученные А.В. Лыковым и его учениками. Обоснованы рациональные технологические режимы получения стабилизированных семян льна с минимальной активностью окислительных ферментов, улучшенными органолептическими свойствами и повышенным объемом. Разработанный способ включает очистку семян льна от примесей, пропаривание водяным паром, термическую обработку методом ИК-облучения и охлаждение до комнатной температуры. Researches of process of heat treatment of seeds of flax for decrease in their humidity are carried out. Experiments were carried out at the laboratory facility by heating the raw material in the flow of infrared (IR) radiation – micronization. The experimental dependences of seed temperature and humidity on the heating time under different modes of infrared heat treatment are obtained. The dependence of the current moisture content on the grain temperature and initial humidity is obtained and its invariance to the heating regimes is established. The proposed mathematical model the change of moisture content from the temperature of the seeds and initial moisture content. To develop the model of moisture loss used dependences describing the change in temperature and humidity from time to time in the heating process, obtained A.V. Lykov and his students. Rational technological regimes of obtaining stabilized flax seeds with minimal activity of oxidative enzymes improved organoleptic properties and increased volume are explain. The developed method consists of cleaning flax seed from impurities, steaming by water vapor, heat treatment by IR irradiation, and cooling to room temperature.

Study on Condensation of the Moisture in Current Transformers with Current Flow Considering Sharp Temperature Decrease

2012 ◽  
Vol 241-244 ◽  
pp. 322-327 ◽  
Author(s):  
Zhen Hua Yan ◽  
Xiang Ren ◽  
Hang Ren ◽  
Wei Dong Ding
Keyword(s):  
Moisture Content ◽  
Ambient Temperature ◽  
Current Flow ◽  
Initial Moisture Content ◽  
National Standard ◽  
Temperature Decrease ◽  
Current Transformers ◽  
Duration Of Operation ◽  
Relationship Of ◽  
The Relationship

On-site experience suggests the possibility of condensation of the moisture in Current transformers (CTs) with initial moisture content lower than the Chinese National Standard. In order to verify such possibility, the relationship between moisture content and ambient temperature in a typical 110 kV CT is studied. The positive correlation of ambient temperature and moisture content without current flow is clarified, and the relationship of moisture content and current RMS value is studied. Increase in current results in increase of moisture content, and the longer the duration of operation, the larger the moisture content. The possibility of frost condensation of the moisture with sharp ambient temperature decrease has been confirmed with initial moisture content lower than the Chinese National Standard.

scholarly journals Heat pump drying of industrial wastewater sludge

2020 ◽  
Vol 15 (2) ◽  
pp. 404-415
Author(s):  
Gang Yuan ◽  
Khim Hoong Chu
Keyword(s):  
Heat Pump ◽  
Industrial Wastewater ◽  
Closed Loop ◽  
Energy Savings ◽  
Specific Energy Consumption ◽  
Extraction Rate ◽  
Wastewater Sludge ◽  
Loop Layout ◽  
Moisture Extraction ◽  
Exhaust Treatment

Abstract The popularity of heat drying of wastewater sludge has increased over the past several years because it can reduce sludge mass and volume, and hence disposal costs. However, drying sludge using conventional combustion-heated dryers is energy-intensive. Heat pump dryers can be efficient and offer significant energy savings by recycling the drying heat. This paper describes a heat pump dryer designed for continuous drying of industrial wastewater sludge. The dryer constructed was essentially a closed-loop air system. The air used for drying is dehumidified to recover the latent heat of vaporization, re-heated using the recovered heat, and recirculated in a closed environment. The closed-loop layout eliminates emissions of dust, malodorous gases, and volatile compounds, obviating the need for exhaust treatment otherwise required to meet environmental regulations. Data on the moisture extraction rate, specific moisture extraction rate, and specific energy consumption are presented and discussed.

Experimentation and performance analysis of solar-assisted heat pump dryer for intermittent drying of food chips

2021 ◽  
pp. 1-35
Author(s):  
A Singh ◽  
Jahar Sarkar ◽  
Rashmi Sahoo
Keyword(s):  
Energy Efficiency ◽  
Economic Analysis ◽  
Heat Pump ◽  
Payback Period ◽  
Extraction Rate ◽  
Maximum Enhancement ◽  
Drying Time ◽  
Moisture Extraction ◽  
And Performance ◽  
Drying Efficiency

Abstract A solar-assisted heat pump dryer is fabricated for intermittent drying. The experiment is performed for different intermittency ratios for radish drying using future refrigerant R1234yf. The effects of total drying time (on-period + off-period) on various energetic, exergetic, and economic performances are investigated. Radish chips were dried to extract moisture from 92.4% to 11.9%. Energy efficiency and drying efficiency are estimated higher for a lower intermittency ratio. The moisture extraction rate and specific moisture extraction rate are higher for intermittent drying as compared to continuous drying and increase with a decrease in intermittency ratio. The economic analysis concludes that the payback period is lower for a lower intermittency ratio. The payback period for intermittency ratio of 1, 0.66, 0.33 and 0.2 are estimated as 1.617 years, 1.459 years, 1.384 years, and 1.347 years, respectively. Present experimental thermo-economic analysis reveals that intermittent drying is much better (maximum enhancement of specific moisture extraction rate is 60.6%, that of energy efficiency is 56.4% and maximum reduction of drying cost is 37.9% with studied conditions) than continuous drying.

Solar-Assisted Heat Pump Drying of Coriander: An Experimental Investigation

2018 ◽  
Vol 26 (04) ◽  
pp. 1850037 ◽  
Author(s):  
Abbas Alishah ◽  
Mohammad Valizadeh Kiamahalleh ◽  
Fereshteh Yousefi ◽  
Anita Emami ◽  
Meisam Valizadeh Kiamahalleh
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Solar Collector ◽  
Coefficient Of Performance ◽  
Air Flow Rate ◽  
Drying Time ◽  
Air Temperatures ◽  
Moisture Extraction ◽  
Heat Pump Drying ◽  
Time And Energy

In this study, the solar-assisted heat pump dryer was designed, manufactured, tested and optimized for drying operations of coriander for its preservation. The heat of drying was mainly provided by a solar collector and a heat pump with two experimental modes of turned on and off. The air temperatures and velocity were identified as the critical drying variables. The responses of the experiments were evaluated in terms of coefficient of performance (COP), energy consumption and the specific moisture extraction rate (SMER). Dehumidification of coriander from the moisture contents of 0.9 to 0.1 kg/kg was considerable. The results demonstrated that utilizing heat pump noticeably decreases the drying time (down to [Formula: see text]25%), energy consumption (down to [Formula: see text]12%) and increases SMER (up to [Formula: see text]20%). The increasing of air flow rate and air temperature significantly led to decreasing the drying time and energy consumption, however, increasing the COP and SMER.

scholarly journals DESIGN AND FABRICATION OF SOLAR TUNNEL DRYER FOR COPRA APPLICATION

2021 ◽  
Vol 9 (2) ◽  
pp. 267-273
Author(s):  
P.M. Venkatesh, Et. al.
Keyword(s):  
Moisture Content ◽  
Ambient Temperature ◽  
Flat Plate ◽  
Initial Moisture Content ◽  
Load Condition ◽  
Full Load ◽  
Heating Mechanism ◽  
Tunnel Dryer ◽  
Heated Air ◽  
Load Conditions

 A semi-cylindrical forced convection type solar tunnel dryer (STD) was designed and commissioned at M/s Miraj Products Pvt. Ltd., Nathdwara for drying processed tobacco. Essentially it is based on the mixed mode with direct and indirect type of heating mechanism i.e. the heated air from different solar flat plate collectors is passed through drying cabinet. At the same time, the drying cabinet absorbs solar energy directly through the transparent walls and roofs. It consists of 16×3.75 m2 area, tunnel equipped with 12 solar flat plate collectors of 2 m2 each propelled with 2 exhaust fans of 1 kW capacity placed on both ends of the tunnel. The dryer was tested at no-load and full-load conditions.  During no-load, without flat plate collectors, temperatures inside the dryer were about18-20℃ higher than the ambient temperature during summer day-light, where as in no-load with flat plate collectors, it was about 30℃ higher than the ambient temperature.  A batch of processed tobacco of 500 kg with an initial moisture content 138% d.b. were successfully dried in full load condition to have final moisture content of about 8.7% d.b. in 8 h. It has been observed that STD has many other advantages i.e. getting rid of toxicant gas to labours during opening drying due to lime presence in material, avoidance of product expose to fly contamination and dust concentrations etc.

scholarly journals Experimental Assessment of the Thermal Performance of a Heat Pump Dryer System Based on the Variations in Compressor Discharge Pressure on Oregano Drying

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6333
Author(s):  
Arley Salazar-Hincapié ◽  
Alvaro Delgado-Mejía ◽  
Andrés Felipe Romero-Maya ◽  
Eduardo Duque-Grisales
Keyword(s):  
Heat Pump ◽  
Coefficient Of Performance ◽  
Drying Time ◽  
Drying Temperature ◽  
Baseline Case ◽  
Moisture Extraction ◽  
Drying System ◽  
Heat Pump Drying ◽  
Discharge Pressure ◽  
Time And Energy

The current study shows an empirical analysis to establish the effects of the variations in compressor discharge pressure on the drying performance of aromatic herbs, in terms of the coefficient of performance (CoP), moisture content (MC), specific moisture extraction rate (SMER), drying temperature, drying time and energy consumption. In conducting the research, a heat pump drying system was utilized as a mechanism for dehydrating herbs, seeds, and fruits. It was used thanks to its benefits like higher efficiency and its low power consumption. Three levels of discharge pressure were considered, 1380 kPa, 1100 kPa, and 827 kPa, using 1,1,1,2-tetrafluoroethane (R134a) as a refrigerant and oregano leaves as the main product. The findings show that, concerning the same oregano moisture sample, the lower the compressor discharge pressure, the lower drying temperature, also, the higher drying time was obtained. Despite the fact that the CoP decreased with the compressor discharge pressure, in comparison with the baseline case, it remained essentially the same for the other two cases.

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