Study And Design Of Solar Energy-Heat Pump Combined Drying Wheat System

China is a large agricultural country. It is the world’s largest grain producer and consumer, but it is also one of the highest rates of national food loss. According to statistics, China’s annual grain in post-harvest losses up to 15%, in which the waste food due to drying not timely accounted for 5%. Because of China’s grain planting more dispersed, and traditional sun drying influenced by the weather, so finding an effective way of drying is the starting point of this article.The traditional drying operation is a technological process of high energy consumption. Our drying energy consumed each year accounted for about 12% of the total energy consumption of the national economy. Solar energy is a clean, renewable energy, people gradually began to research and promotion of solar energy in the drying operation. Heat pump dryers has the advantages of energy saving, safety and environmental protection. Solar drying and heat drying by common drying the organic combination of not only energy saving, but also to overcome the shortcomings of both overcome improve drying quality.In this paper, we design a set of solar assisted heat pump combined drying food system which powered by Photovoltaic power generation systems, based on the theoretical basis for the previous solar heating pumps drying. The system has two heat source, a solar radiation from the heating of the air; another heat pump heating energy consumption of air. Wherein the generating capacity of the power required to pump all from photovoltaic systems. Under sunny condition to meet the entire electricity consumption of the drying operation.Even in the face rainy weather, the system can complete the drying process by consuming grid electricity and reduce polluting emissions on the environment.Based on the first law of thermodynamics and photovoltaic design standards, we completed the drying apparatus and photovoltaic module design and selection. To facilitate real-time monitoring of the progress of drying, we installed the temperature and humidity transmitter. It completed collection of drying date via programming and connecting PC. In sunny and overcast skies, we use wheat as test materials to getting on heat pump drying performance test with sun and without sun. Through five hours of drying results show t the solar has obvious effect for drying system, also can speed up the drying rate, shorten the drying time and save a lot of energy. The experimental data show that in sunny light condition better weather conditions, the heating system COP coefficient can reach 2.3. When the COP of the system is greater than 2,it will be able to exceed the steam boiler heating efficiency, the data show that under certain circumstances this system can replace the boiler as a heat source of the drying operation. Solar photovoltaic systems can generate electricity continuously In the drying operation is not performed, the battery can be directly incorporated into the national grid to ease the supply pressure, and also get economic returns. According to China’s PV industry support policies, we can recover costs in 5-6 years. It has a high economic value to popularize.