USE OF SOLAR DRYER INSTALLATION IN PROCESSING AGRICULTURAL PRODUCTS

ABSTRACT

The article notes that the most appropriate direction for using solar energy in agriculture is the production of heat, since the potential energy of this source is more fully used and complex and expensive converting devices are not required.

АННОТАЦИЯ

В статье отмечается, что наиболее целесообразным направлением использования солнечной энергии в сельском хозяйстве является получение тепла, поскольку полнее используется потенциальная энергия этого источника и не требуются сложные и дорогие преобразующие устройства.

Keywords: solar technology, agriculture, solar energy, solar collectors, photovoltaic installation, power plant

Ключевые слова: гелиотехника, сельское хозяйство, солнечная энергия, солнечные коллекторы, фотоэлектрическая установка, электростанция.

Information is provided to assess the influence of the main parameters and operating conditions of solar installations on the efficiency of using solar energy to produce heat. It's the 21st century. And no one doubts that the energy crisis that has gripped humanity threatens its very existence on earth. The development of civilization involves the search for more and more new sources of energy. By actively consuming, and more often thoughtlessly wasting natural energy reserves such as coal, gas, oil, we upset the ecological balance on our planet. In addition, it must be taken into account that the energy content of the Earth is depleted. The growing needs of agriculture for energy resources and rising prices for fossil fuels, combined with the emergency condition of electrical networks and equipment, as well as the negative impact of traditional energy facilities on the environment, necessitate the search for alternative energy sources. One way to solve this problem is to use solar energy in the power supply system for agricultural consumers. In agriculture, solar collectors are used for heating and hot water supply to residential and livestock buildings; for drying fruits, grains, and other products; heat treatment of roughage. The solar energy potential in Uzbekistan, according to experts from the Asian Development Bank, is about 51 billion tons of oil equivalent. The number of sunny days per year exceeds 300, the number of sunny hours in the south reaches 3000. It should be noted that the state is taking concrete steps to develop solar energy - for example, the country's first solar power plant with a capacity of 100 MW is being built near Samarkand. Once operational, this station will provide electricity to several areas. By 2020, it is planned to build 3 solar power plants with a capacity of 100 MW each in Uzbekistan. These are large stations. Medium-sized stations are also being built; in 2015, a test solar photovoltaic station (SPPS) with a capacity of 130 kW was put into operation in the Namangan region. In the Bukhara region in April 2016, a mobile solar power plant with a capacity of 1.2 MW (1200 kW) was launched to supply energy to the facilities of the Russian company Lukoil. The use of solar energy in agriculture has become easier and more affordable due to rapid advancements in technology and increased awareness of renewable energy sources. Although it is difficult for many farms to rely solely on solar energy, natural methods of harnessing the sun's energy and installed solar panels are the basic methods that can be adopted by almost all farm owners. At the same time, savings on traditional energy resources can reach 30-90%. Modern advances in chemistry and physics, the use of cheap materials with high technical characteristics (engineering plastics, transparent and aluminized synthetic films, selective coatings of receiving surfaces, etc.) help to increase the productivity of solar installations and reduce their cost, which significantly expands the boundaries of the practical use of solar energy .

International demand for organic dried fruits is growing. High-quality dried fruits are an excellent and healthy alternative to various sweets.

The main source of energy for drying fruit is fossil fuels (mainly gas), and with rising prices for gas fuels, interest in renewable energy sources is obvious. While in industrialized countries high-quality dried fruit is produced using high-tech and often patented methods such as vacuum and microwave drying, small agricultural cooperatives in rural areas of developing countries have great difficulty supplying the required quality and quantity to the international market using acceptable energy-efficient methods, technologies.

The operating principle of a solar dryer (Fig. 1, Fig. 2) is that hot air is lighter than cold air and rises to the upper zone of the chamber. Moving upward, warm air comes into contact with the product, which dries and takes away some moisture. An electric heater is installed in the chamber to ensure that the drying process continues in the absence of solar radiation. Air circulation inside the dryer is carried out by two axial fans. Warm air contains a lot of moisture and exits the dryer through the exhaust fan.

Figure 1. Solar dryer

Figure 2. Internal structure of the dryer

The solar dryer is manufactured in such a way that maximum absorption of solar radiation is available throughout the day. This is made possible by the fact that every part of the dryer (east side of the dryer, west side of the dryer, main copper absorber and door) is absorbent. Each of these parts is colored with a selective dye that has 85% absorption and 15% emission of solar radiation.

The entire dryer is a polycarbonate shell, which prevents direct contact of the product being dried. The protective coating prevents heat from escaping from the dryer and protects the products from any external harmful influences. Let's look at the operating principle of the ECO120 solar dehumidifiers. Depending on the division of solar dehumidifiers, ECO120 belongs to the group of direct forced air dehumidifiers. The electronics in the dryer control the drying process according to the crop for which the drying process is intended. The dryer is primarily designed to use solar energy, and the heating must be electric. The automatic multifunction controller operates using a microprocessor, which is programmed depending on the product being dried. Dehydration, i.e. drying process, used for longer storage of agricultural crops (fruits). Essentially, the main purpose of the process is to remove enough water from the product to allow it to be stored longer without rotting due to bacteria or fungi. The moisture content of most fruits is between 80% and 95%. Drying reduces the weight and volume of food products. Dried foods can be consumed as is or rehydrated.

Dried fruits and vegetables are convenient to store and transport. During the fruit harvest season, drying allows you to store and use them throughout the year. Processing of food products with their dehydration (drying) is becoming increasingly important due to increased shelf life, reduced weight, easier handling during transportation and delivery to consumers. Reducing weight (from 1/4 to 1/9 of fresh product) and volume, reducing the required storage space, as well as transport costs.

The advantage of drying is that it reduces the activity of the water contained in it, which prevents the growth of microorganisms, mold and fungi. This way, food can be stored longer without spoiling. Drying offers a highly effective and practical way to preserve agricultural products, so you can wait for a favorable price and adjust the market supply according to demand.

We are talking about the use of solar energy for drying agricultural products for small farms and our own household needs, we are definitely talking about an economical solution. The techno-economic advantage of solar dryers appears to be more related to the reduction of post-harvest losses than to conventional energy savings. This is obviously an additional value that dried products receive in solar dryers, such as: uniform and increased quality, compliance with phytosanitary requirements, the possibility of placement at reasonable prices (independent of market conditions), the possibility of higher earnings with a higher class of products, etc. .d.

Different products (fruits, herbs) have different maximum permissible drying temperatures. The air temperature for drying should not exceed the maximum permissible value, and this is achieved by adjusting the length of the solar collector (for a tunnel dryer) or the air flow through the number of operating fans.

Various concepts for using the sun for drying purposes make it possible to develop a feasible, technologically simple and reliable system that could be replicated by artisans on small farms, using mainly local materials, to obtain the greatest effect from the production of dried fruits. In addition to the installations discussed, you can also use greenhouse dryers, which can be used for large-scale production of dried fruits and fruit lozenges. A solar dryer-greenhouse is a structure - a room with transparent walls (except for the north) and ceiling. Such premises are used as greenhouses in winter and work as dryers in summer. To switch from the drying mode to the greenhouse mode and vice versa in such installations, it is necessary to carry out the necessary actions that change the operating mode of the room. To ensure that fruits do not lose their presentation and taste, such dryers use filters to protect products from ultraviolet radiation. Thus, the drying devices considered help improve the process of drying dried fruits and lead to the production of high efficient technologies for drying agricultural products.

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