Experimental investigation of the drying characteristics of a mixed mode natural convection solar crop dryer with back up heater

Sekyere, Charles Kofi Kafui; Forson, F.K.; Adam, Fuseini

doi:10.1016/j.renene.2016.02.020

Cited by 61 publications

(20 citation statements)

References 12 publications

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“…Many autonomous solar dryers have no auxiliary heating as thermal mass provides shortterm heat storage to enable drying to continue in intermittently, cloudy or inclement weather (Condori et al, 2017 Ayua et al, in press). Crops that dry rapidly are suited to such dryers as thermal mass is rarely sufficient to sustain drying nocturnally (Sekyere et al, 2016).…”

Section: Indirect Passive Solar Dryersmentioning

confidence: 99%

Solar dryers for tropical food preservation: Thermophysics of crops, systems and components

Tomar

Tiwari

Norton³

2017

Solar Energy

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Drying reduces the moisture content of harvested crops thus slowing decay processes to enable longerterm storage. Solar dryers contain the crop being dried, to enhance solar energy collection incurring lower crop losses than are associated with open-sun drying and recurrent costs than are inherent to uses of fossil-fuels for drying. The influences of key environmental, operational and design parameters for solar dryers are discussed including: (i) psychrometry of drying processes and ambient conditions, (ii) how initial crop properties are converted to final desired product attributes, (iii) feasibility of using powered components such as fans and (iv) air-heating solar collector selection.

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Section: Indirect Passive Solar Dryersmentioning

confidence: 99%

Solar dryers for tropical food preservation: Thermophysics of crops, systems and components

Tomar

Tiwari

Norton³

2017

Solar Energy

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“…Conventional solar dryers may be a solution to these challenges but due to the high weather dependency, usage is limited during rainy periods, cloudy weather conditions and at night. Due to this, the commercialization of solar dryers has generally not been successful leading to limited or non-adoption of such systems by farmers in Ghana [11]. To overcome the restrictions of the conventional type solar dryers, a hybrid solar dryer with heat energy from solar radiations and fossil fuel or biomass is required for drying agricultural products [12].…”

Section: Introductionmentioning

confidence: 99%

Drying Temperature Effect on Kernel Damage and Viability of Maize Dried in a Solar Biomass Hybrid Dryer

Akowuah¹,

Maier²,

Opit³

et al. 2018

OJAppS

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Though several maize varieties have been developed and introduced over the years in Ghana, farmers still face challenges of access to quality seed maize. Among the major constraint is lack of proper drying systems to guarantee quality of seed produced. As in most parts of Africa, drying of maize in the open, on bare ground along shoulders of roads is still a common practice in Ghana. In this study, a 5-tonne capacity hybrid solar biomass dryer was developed for drying maize for seed and food/feed in Ghana. Effect of air temperature in the dryer on the physiological quality and germination of maize kernels was investigated. Maize grains were dried in the open sun simulating farmers practice and using the dryer at 4 varying levels (L1, L2, L3 and L4) with corresponding heights (0.6 m, 1.2 m, 1.8 m and 2.4 m, respectively) from the ground. Harvested maize at 22.8% moisture content was dried at the varying levels until reaching the final desired moisture content of 12.8% ± 0.2% (wb). Results showed that, air temperatures in the dryer increased in accordance with height with lowest mean temperature of 44.4˚C ± 4.6˚C recorded at L1 and mean maximum of 52.8˚C ± 5.4˚C at L4. Drying temperatures recorded at L1-L3 and ambient had no significant effect (p < 0.05) on kernel damage and viability. Drying conditions at L1-L3 were considered optimum (<50˚C) for kernel drying compared to the topmost tray, L4. Kernel stress crack index (multiple and checked) was therefore reduced on average by 14%

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“…The dried chili peppers are then stored in containers (Hage, Herez, Ramadan, & Bazzi, ). There are various drying methods used including mechanical (Daghigh, Ruslan, Sulaiman, & Sopian, ; Fatouh, Metwally, Helali, & Shedid, ; Qiu et al, ; Zlatanović, Komatina, & Antonijević, ), electrical (Nimrothama, Songprakorpa, Thepaa, & Monyakul, ), infrared (Aktas, Sevik, Amini, & Khanlari, ), dielectric (Jiang, Zhang, Fang, Mujumdar, & Xu, ) and solar (Janjai, Intawee, Kaewkiew, Sritus, & Khamvongsa, ; Kouchakzadeh, ; Prakash & Kumar, ; Sekyere, Forson, & Adam, ; Zarezade & Mostafaeipour, ). Solar energy remains the most popular drying method because of the free energy source (Janjai & Bala, ).…”

Section: Introductionmentioning

confidence: 99%

“…They are mainly utilized in agriculture and industries to reduce bacteria and preserve certain agricultural products (Aghbashlo, Mobli, Rafiee, & Madadlou, 2013). Solar dryers are mainly categorized into four modes: direct solar dryer (Zarezade & Mostafaeipour, 2016), indirect solar dryer (Prakash, Laguri, Pandey, Kumar, & Kumar, 2016), mixed solar dryer (Sekyere et al, 2016) and hybrid solar dryer (Kouchakzadeh, 2016).…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of solar‐assisted heat pump dryer with heat recovery for the drying of chili peppers

Naemsai

Jareanjit

Thongkaew

2019

J Food Process Engineering

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This research investigated the performance of a solar‐assisted heat pump dryer (SAHPD) with heat recovery to reduce the amount of thermal energy needed for drying chili peppers. The dryer selected for the experimental study consisted of a heat pump, a greenhouse cover and multi trays. It was found that the SAHPD with recovery gave better drying performance than a traditional dying method. The dryer system can offer drying time, drying efficiency, coefficient of performance and specific energy consumption of approximately 24 hr, 33.2%, 3.17, and 2.21 kWh/kg, respectively. Furthermore, the SAHPD with heat recovery provided a higher drying performance than without the heat recovery although the ambient condition changed. Base on the economic analysis, the payback period and net present value of the SAHPD with heat recovery were approximately 1.9 years and 915.60 USD. The SAHPD with two drying rooms also yielded better drying performance than the SAHPD with one room. Practical applications Drying is the process of moisture reduction to a safe limit of moisture content, which allows agriculture to extend the shelf life of the crops by restraining the growth of microorganism. In chili peppers drying process, a solar assisted heat pump drying as one of hybrid solar dryers is preferred because heat and mass transfer rate are rather high and it offers the ability to operate both daytime and nighttime. However, the exhausted air to the ambient still has considerable thermal energy. Thus, the heat recovery system has been employed to design and fabricate inside the dryer. Findings of this research contribute to the evaluation of heat recovery in a typical solar assisted heat pump dryer in terms of drying efficiency and economic feasibility in order to be a guideline for small and medium‐sized enterprises.

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Experimental investigation of the drying characteristics of a mixed mode natural convection solar crop dryer with back up heater

Cited by 61 publications

References 12 publications

Solar dryers for tropical food preservation: Thermophysics of crops, systems and components

Solar dryers for tropical food preservation: Thermophysics of crops, systems and components

Drying Temperature Effect on Kernel Damage and Viability of Maize Dried in a Solar Biomass Hybrid Dryer

Experimental investigation of solar‐assisted heat pump dryer with heat recovery for the drying of chili peppers

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