Natural energy & natural heat are the most important thing for a healthy lifestyle, even if you want to preserve something for a long time, then you must have to keep it in sunlight from time to time. Solar drying is an ancient technique that is using to store food items for a long time.

During primitive times, the sun was solely used for its heat and light for all day-to-day activities, when there was no electricity. But in modern times it has been replaced by fossil fuels and thermal electricity. Therefore, the increasing use of these fuels has also increased the risk of global warming. These increasing pollution problems have encouraged people to adopt the old methods in a developed manner. The solar dryer is the evolved & efficient way of the traditional food dehydrating process.

In this blog, we will know about the solar dryers & many more other things related to them:

• Types of Solar Dryer
• Uses of solar dryer
• Limitations
• Cost

A solar dryer is another application run by solar energy, which is used immensely in the food and agriculture industry. Although the sunlight is used as yet natural heat for drying food and garments in the world. The solar dryer is also an indirect source of solar energy which can be used for this purpose. But drying directly under the sun has many drawbacks like dirt, animals, insects, etc. Besides, there is a dread of unexpected changes in weather conditions like wind or rain. While using the solar dryer, there is no need to worry about all this, as the things are covered and dried.

Now we talked about the types of solar dryers. Currently, there are various types of solar dryers available in the market. Here we will discuss 6 types of solar dryers:

• Cabinet Type Dryer
• Tunnel Dryer
• Foldable Dryers
• Table Top Tank Dryer
• Chimney Type Dryer
• Plastic Foldable Dryers

This type of solar dryer is based on the greenhouse effect and convection. In a cabinet type of solar dryer, when solar heat enters the glass cabinet, it gets trapped in it which further heats the air inside it. The inside hot air rises and passes through the food product through the ventilator, out of the cabinet. In the process, it also carries the moisture of the food item with it.

A tunnel dryer is mostly used in commercial work which utilizes the exhaust system to forge air. Because of their bigger size & loading capacity, they are neither efficient nor implemented for general convection systems. If these solar dryers are used for commercial or industrial purposes, then external exhaust fans are used to make the airflow.

Foldable solar dryers are developed by Bhabha Atomic Research Centre. its design makes it more efficient to work on the natural airflow process & which makes it a better solar dryer as compared to other ones. The negative part of this product is that it is not very user-friendly for unlocking. There are so many nuts and boults available to unlock the device.

Tabletop tank solar dryer is designed in a very basic way, making it the most common solar dryer. This solar dryer is the 1st choice of many small farmers, new solar dryer entrepreneurs, etc to start their business.

The chimney-type dryer dries fresh foods with the help of solar heat and rapid air collection. The chimney helps to make a continuous airflow around the product, thus increasing the speed of drying compared to other designs. The large heat-collection area of the device, also known as the drying table, provides high temperatures and rapid water removal. Besides, the design of the chimney dryer is flexible and allows users to modify tray depth and size to fit local demands.

This solar dryer is the most basic dryer that can be easily manufactured or developed. The good thing about it is easy to carry. These dryers are made with foldable plastic, so users can just fold them into a bag. These solar dryers are mostly used in mountain areas.

After knowing the types of solar dryers, we will know about the uses of these dryers. Solar dryers can be utilized for various domestic or commercial purposes. Industries like fruit, food processing, textiles, wood, paper, pharmaceutical, and agro-industries, etc are used these dryers for various uses.

• The solar drying process is the most hygienic and efficient.
• Compare to other dryers that run on conventional fuel/electricity, solar dryers are more cost-effective.
• Solar drying systems have low operation and maintenance costs. A typical dryer can last 15-20 years with minimum maintenance.

The solar dryer has a very user-friendly efficient way to store the thing still it has some limitations. The solar dryer can be performed only during sunny days unless the system is integrated with a conventional energy-based system. the solar drying process is very efficient and better than other ways but this is slow in the process as compared with dryers that use conventional fuels. These dryers can be utilized only for drying at 40-50 C temperature.

The cost factor will depend on the local market & other factors also. But for an idea, a solar dryer of 50 kg capacity ranges from about Rs 30 000 to Rs 50 000 approx. On a larger industrial scale, the system may cost between Rs 4 lakhs and Rs 10 lakhs. The consumer can use the facility of interest subsidies in the form of soft loans that provides MNRE as per their guidelines.