Comparative Analysis of Energy Performance in Infrared Drying Process

This report presents a comparative analysis of energy performance in infrared drying processes, contrasting them with traditional methods like hot air drying and exploring the use of drying software such as Simprosys, dryPAK, and DrySel. The study highlights the importance of energy efficiency in food preservation and post-harvest activities. It delves into the operational conditions, including drying time, speed, and temperature, and assesses the advantages and disadvantages of each method. The report emphasizes the benefits of infrared drying, like direct radiation and shorter drying times, while also acknowledging its limitations, such as quick heat diminishing. Furthermore, it discusses the role of software in optimizing drying processes, including kinetics simulation, drying time determination, and process design. The conclusion underscores the significance of user-friendly interfaces, affordability, and replicability in successful drying software, ultimately aiming to improve the quality of dried products while minimizing energy consumption.

COMPARATIVE ANALYSIS OF ENERGY PERFORMANCE IN INFRARED DRYING
PROCESS
INTRODUCTION
In olden days, people used to dry eatables through the usage of direct sunlight and other storage
methods. But, there occurs the loss of fruit properties and it ranges from 10% to 30%. One of the
traditional methods of food preservation is the technique of dehydration practised by humans.
Extension of the shelf life and moisture reduction are the main aims of drying of foods along
with exportation. The reduced usage of energy consumption and maintenance of water content of
food to a certain level (without much loss of taste, presence, taste, flavour and colour) are the
major challenges faced used dehydration of food. (Antal and Kerekes, 2015)
Postharvest activities include harvesting, handling, storage, processing, packaging, transportation
and marketing. Post harvested food material’s shelf life extension gets limited through a process
called deterioration. In addition to post-harvest, other challenges faced by the post harvested
foodstuff are, the nutrition value, appearance of the product, weight consideration during
shipping and finally the packaging cost
The combination of various drying methods is somewhat cost-effective, efficient and can be
considered as the fastest process. The combination of dehydration methods like microwave, hot
air, infrared radiation, microwave vacuum with freeze-drying, in recent years found successful.
(Agronomy.emu.ee, 2019) The present work aims at performing an assessment of drying
methods and comparing the energy aspects like energy requirement and energy efficiency along
with conditions of operation such as drying time, speed of drying and the temperature.
Fig 1: Thermodynamic model of solar thermal power plant (Lingayat, Chandramohan and Raju,
2017)

To improve the effectiveness of dehydration, hybrid drying like hot air freeze-drying and
infrared freeze-drying has been successfully employed. (Wang et al., 2014)
One of the most commonly employed commercial methods for dehydration of fruits and
vegetables is the (HAD) Hot air drying method. In this method, the hot air produces heat for the
product by convection, as well as the convection method is used to transport the evaporated
water to the air. Hot air dehydrating method is not that fast, as it requires more drying time even
at high temperatures, and this longer time results in the degraded quality of material, which is
one of the major disadvantages. (Lingayat, Chandramohan and Raju, 2017)
Fig 2: hot air drying process on apple slices (Source: sciencedirect.com)
In the case of infrared drying, the heating element is used to transfer the infrared radiation
directly to the surface of the product, without causing any temperature change to the surrounding
air. The product to be dried is the target of radiation, the radiation penetrates through the product,
and subsequently being converted into sensitive heat. (Rudobashta and Zueva, 2015)
The decrease in absorbance ability of the product takes place due to a decrease in water content
during the drying process (Pawar and Pratape, 2015). However, the major disadvantage
associated with infrared dehydrating is the limited warming and quick heat diminishing takes
place as soon as the device is turned off. 11-12% shrinkage, 18-23% density, 30-34% volume
decrease is being shown by infrared drying in case of apple slice drying.

Fig 3: Infrared drying of apple slices (Source: sciencedirect.com)
Other methods except for infrared drying and hot air drying are software for drying purpose. In
the early 1980s, with the introduction of modern electronic computers, knowledge in science and
engineering has developed, which led an effective way for the application of computers in
industrial practices. (Qadri and Srivastava, 2015)
The solutions to a high level and complex problems were made readily available with the help of
software inbuilt in the computers. Computer software is being used by engineers for the
calculation purposes and even to perform design tasks in almost all industrial sectors instead of
using a countless number of books to look up the needed engineering data. Significant increase
in efficiency and productivity has increased with the usage of properly designed computer inbuilt
software.
Drying software like Simprosys, dryPAK and DrySel is used for dehydration. A drying suite
consisting of a collective combination of inter-related parts sharing the same equipment, material
drying gas models and material database, moreover this drying suite should be the drying
software. (Gong and Mujumdar 2014)
Such available software is much cost-effective compared to traditional methods of dehydration,
involving design, analysis, troubleshooting and even control and optimization of the drying
systems.
This software will be useful in many aspects ( Gong and Mujumdar 2014 ) like, (i) drying
kinetics simulation used to predict the mass diffusion and transient coupled heat, (ii) drying time
determination, (iii) drying design involving calculations with variables like heat and mass
diffusion, (iv) optimized design and operation with control over drying process, and (v)
simulation of process.
METHODOLOGY

Even though the software like Simprosys, dryPAK and DrySel mentioned below were designed
for dehydration purposes, they were also used for troubleshooting the problems related to
designing of dryers. A drying software is officially said to be ideal if it includes the parts like
material database and models of drying gas, equipment being used and materials. An ideal drying
software is a collective combination of the above parts mentioned.
Simprotek Corporation developed a windows based process simulator called Simprosys, used for
design and simulation of drying, flowsheet and evaporation systems. Along with product
material stream, the Symprosys software can also simulate the recycled exhaust gas stream.
Users of Simprosys can construct any kind of evaporation and drying related process as there are
19 unit operations are available for Simprosys 1.01. (PRAVEEN KUMAR et al., 2005)
When it comes to interface, Simprosys has a user-friendly and intuitive interface. Simprosys
provides protection when it comes to its user, and helps it’s user not to commit mistakes.
Minimal effort and self-training are required to use this software. Not only the companies but
also the university instructors, undergraduate and postgraduate students find the Simprosys
software to be an efficient tool.
dryPAK – a Technical University of Lodz developed software based on DOS dryer design.
Alike Simprosys, this software includes drying kinetics, heat balance and mass balance
calculations (combining equilibrium and drying curve characteristic methods). Fick’s diffusion
equation is based on two types of boundary conditions for an isothermal or adiabatic case and
three basic geometries. Drying kinetics is based on Fick’s diffusion equation. (Gong and
Mujumdar 2014).
DrySel a proprietary software package comprising of almost 50 dryer performance that too of
different types. This software helps the user while choosing what factors should be considered
and even it offers advice. Graphical as well as numerical displays are provided while dryers are
being ranked. The DrySel software tool helps process engineers to make good decisions related
to design. (Hamiruce Marhaban & Azura Che Soh (2015))
Drying software other than mentioned above has been developed, mainly CFD-based models of
dryers. Most common are the fluid bed, flash, spray, impinging jet, etc. These are not available
openly as these are designed as parts of research and development projects and are often not
user-friendly. There is a limitation over parameter ranges in this software. Although some free
online software packages are available for humidity calculations as well as psychrometric
calculations. (Ranjbaran, Emadi and Zare, 2014)
CONCLUSION
Key to the success of drying software involves many factors such as, (i) easy to use interface
which makes the user to self-train for operating the software, (ii) affordable software is another

key to success, and even (iii) replicability and easy modelling of liquid. (Gong and Mujumdar
2014)
The idea of this article was first to study the drying of food using many software like
Simprosys, dryPAK and DrySel and then to compare the results of these taking into
consideration the factor energy efficiency. (Hamiruce Marhaban & Azura Che Soh (2015))
Indeed, even if the use other drying methods, Simprosys has several advantages over this
dehydration software. The motivation for using Simprosys becomes more obvious when we
compare it with other drying software.
Time is one of the most basic factors in all the industrial applications, especially in industrial
food drying, Simprosys is being used as ideal for improving the drying time to least value as
much as possible. (Lingayat, Chandramohan and Raju, 2019) The amount of energy being
consumed and the final quality of the dried product are also important factors along with the
drying time, which should be considered during designing such drying software. Key to the
success of Simprosys drying software involved many factors such as, easy to use interface which
makes the user to self-train for operating the software, affordable software is another key to
success, and even replicability and easy modelling of liquid. (Gong and Mujumdar 2014) The
results of using Simprosys for dehydration of the food were almost ideal, like, better quality and
less energy consumption, as stated by several researchers. By noting the positive factors of
Simprosys software in drying processes, exponential growth in the food material processing
sector will likely be carried out by using Simprosys. (Hamiruce Marhaban & Azura Che Soh
(2015))
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