Himin Solar energy dryer
The solar dryer is developing very quickly, especially for most developing countries need more. When the electricity and other conventional energy shortage, solar energy drying agricultural products comparative economic.
Solar drying is divided into two stages: the first stage is the on air heating; the second stage is the hot air control of dryness in the water in the material.
Heating the air in two ways: one is the direct heating of air, which control the drying on the drying room, directly under the radiation of the sun; Z is indirectly heated air, the air heater air temperature increase, and reduced relative humidity for drying materials for the wet material from the water, must provide the enough quantity of heat the evaporation of moisture in materials. For example, in 20 ℃, heat of vaporization of bath water was 2454kJ / k8g when the air temperature rise 11Y, relative humidity decreased by about half of the materials to be dried. In the dryer, the wet material absorption strokes shoot after the heat of the sun, the temperature rises to the corresponding water vapor partial pressure than in the surrounding air pressure, moisture from the wet material surface evaporation. So, not only to meet the requirements of the dryer temperature, but also consider the ventilation, to reduce the pressure of air dryer. For the different needs of drying materials, the temperature of the dryer should be different. Temperature is too high will cause changes in physical or chemical change of materials, the impact of material quality. Some of the permeable, breathable material bad skin in low drying rate, drying of the surface of the material, otherwise easy to form a hard shell.
The solar dryer according to the structure can be divided into high and low temperature type two categories. High temperature type solar dryer for focus, often using parabolic concentrator, automatic tracking of the sun. The dry material is the amount of particulate, such as food etc.. A screw conveyor for the material to the linear focusing surface, the side of the road side drying, high efficiency. The drying device for more complex system, also the high cost. Low temperature type solar dryer, general requirements for temperature 40 - 65 ℃, commonly used air collector or tunnel greenhouse as the dryer body, it is especially suitable for fruit drying and processing agricultural and sideline products need. Applied at home and abroad Xiang belongs to low temperature type dryer. Low temperature type solar dryer can be divided into the following; 1) collector type dryer
Use of solar air heater to heat air, and give the drying chamber. Structure of drying room, with a box type kiln, flow bed and fixed bed. Kiln type and fixed bed type more, it also can be used in combination with dryer and conventional energy, to reduce energy consumption. As shown in figure 2.5.
2) warm air drier
Greenhouse type dryer with solar greenhouse is similar to general, only with a wet mouth, easy to dry the water in the material discharge. This dryer is suitable for drying intensity object dark material and requirements. Because the absorption of light by different shades of color, material is easy to reflect sunlight.
3) the whole dryer
The collector and the greenhouse are combined into a whole, porcelain and structure, good drying effect, cost is relatively low. The dryer for drying fruit, except Chinese herbal medicine etc, also suitable for the preparation of soy sauce, vinegar and other industries, a wide range of uses. Figure 2.6 shows an integral type dryer, the greenhouse at the top of the glass cover plate, tray items to be dried in a greenhouse in, it not only directly
Heating by solar radiation, but also on the hot air heating from solar air heater. |
Company News
