Solar energy source is endless, never runs out-energy .In remote past, people have the most kinds of energy for this production and activities such as heating and for the animals, using glass effects to the trees on cold weather (green house) and dried seafood farm … However, do not have the technology and equipment of the reasonable performance should use this energy is too low, the product after drying does not guarantee quality desired, especially export.
Today, the need to use clean energy (solar, wind the heat ..) within the world increasing, especially in developed countries has been enhanced to exploit the type this amount for benefits for people. Fossil energy (oil, coal) increasingly exhausted, a source of environmental pollution, Ozon layer destroy and cause consequences for humanity. Solar energy is one of the clean energy source has (gradually replacing the fossil energy and contribute actively reduce harm bad for the environment. And people are using solar energy to purposes such as:
- solar battery (photovoltage)• The glass trees (green house).• Make hot water for living (cooking, heating)
- How hot air for drying agricultural seafood.
Vietnam is located in tropical areas should strength solar radiation (W /m2) is quite large at high points in summer can be up to 1200W/mand sunshine hours in many years also, especially in from the provinces to the Central, this is the favorable conditions for farmers in the dry product. Our country is an agricultural country with many kinds of seafood farmers need drying. According to traditional practice, farmers often exposed to agricultural products on the course, on the national highway here is a simple drying, but there are many weaknesses , loss product quality is not guaranteed ..
Therefore, in addition to the drying equipment used to create heat energy than is oil, buffalo .. we need to research equipment drying energy to the surface performance of high temperature and overcome the disadvantage points compared with exposure natural sunlight. Drying equipment using solar energy consists of three basic parts such as the Ministry of cluster (connector), drying and ventilation fans, the body temperature of the role is very important. Ministry of temperature can make all kinds of different materials, useful drugs and a different shape, but the specific parameters of the nature of the collection is performance (TL). Performance of the heat of the sun is calculated by formula:
Here:
c – heat content of air, Jun / kg,
p – in particular by air, Kg / M3,
q – Traffic passing through the air to the heat, M3 / s
T1, T2 – temperature at the input and output of the earnings,
I – Strength of solar radiation, W / m2
S area of the plate absorbs, m2
Materials to manufacturing equipment drying with solar energy is mainly used roofing leaves, angle iron, glass or where hair during and Thermal (including macro). These materials are currently available in the provinces. When the technical design and instructions on creating the technology for the local mechanic can make the size of the type drying equipment Drying scale different for households in the Dry farming seafood.
In 1996, the Institute of Agriculture has power research and common production equipment drying with solar energy. SD drying cabinet – 25 is dried using solar energy have forced ventilation or natural through the humid outdoor air pollution, small-scale drying should be suitable for economic of farmer family
In 2000, the needs of dried seafood products in the large island district Cô Tô Quang Ninh province, Institute of Agriculture has power research, design and installation of drying room solar energy scale drying per tons , with the capacity to 50 m2 .To increase drying process and improve product quality after drying, drying room has equipped more ozone generators air (), the device automatically controls the islands fans, fans and outdoor gas pipe system to save a part of gas drying equipment solar energy for use during the day. committees and on rainy nights, this is a weaknesses of the devices using solar energy in general.
After building and installing drying room solar energy at two locations District COTO island, the seafood after drying has a higher quality beauty salon and drying than with wood. Also, when drying room has attracted a workforce idle people in resolving employment to increase income, contribute to a stable population, this is the social effect is practical for people on islands and remote mountain region.
However, equipment using solar energy in general and in particular for drying is not much interested, there are still at the level of exploration and research and testing manufactured price is too high compared to income people. If the support of expenditure of the State as the extension, extension or other organizations within and outside the country, hopes the equipment used solar energy will gradually close to us .
Nguyễn Trọng Thư & Trần Xuân Hưng
Institute of Electrical agriculture
