Study Of Heat Transfer Performance Of Solar Heat Collector By Nanometer Fluid Heat Pipe

Energy as an essential material basis for human survival and social development, reasonable exploitation and utilization of energy has the vital significance. Due to fossil energy is increasingly exhausted, New Energy and Renewable Energy instead of fossil energy is inevitable trend of the current social development. New Energy and Renewable Energy mainly include solar, wind,biomass,ocean,geothermal and hydrogen, etc.The most ideal renewable energy is solar energy. Solar energy is root of all kinds of renewable energy on earth, wide coverage and inexhaustible, without any pollution on the environment. Photovoltaic power generation and thermal utilization are the main development direction of solar energy, whether solve the collection, storage, conversion of solar collection effectively, it is the key to large scale application of solar energy.The paper presents a novel method to improve the heat exchange performance of solar collectors, introduces a glass evacuated solar collector tube with an inserted heat pipe, which combines glass vacuum technology and heat pipe technology, it is confirmed by experiment that the average heat loss coefficient of the glass evacuated solar collector tube with an inserted heat pipe is lower than in all-glass vacuum collector tube , find the optimum parameters, its Structure has superiority. The working fluids of the glass evacuated solar collector tube with an inserted heat pipe, take the nano fluid (Fe3O4) instead of the water, enhanced heat transfer from heat transfer working fluids Point of View, improve the the heat transfer performance of heat pipe heat and enhance thermal performance of solar devices, create a new way of heat transfer enhancement.In order to study the thermal properties of the glass evacuated solar collector tube with an inserted heat pipe, nano fluid as working media of heat pipe, experiment is describesd with a self-designed heat transfer system Test-bed. Experiment system include four parts: vacuum heat pipe heat exchanging system; cooling system; measurement systems and data acquisition system. In experiment, take the nano fluid and water as working fluid of heat pipe, through the experimental comparative study found that working fluids of heat pipe directly affect the thermal properties of the glass evacuated solar collector tube with an inserted heat pipe. When working fluids of heat pipe is the nano fluid (Fe3O4), the thermal properties of collector is better than the water-based collector, for the two working fluids in the glass vacuum solar collector tube with an inserted heat pipe, daily average efficiency and instantaneous efficiency, analysis on the magnetic nano fluid solar collector tube are higher than than of the water-based solar collector tube, both of them have the same trend of daily average efficiency curve, the best tilt angle is aroud 45°; and instantaneous efficiency of magnetic nano fluid solar collector tube is higher than the water-based solar collector tube's, their instantaneous efficiency have the same trend, first decreases then gradually increases and then reduced.All-glass evacuated solar collector tube with an inserted heat pipe, and the working fluids of heat pipe use the magnetic nano fluid (Fe3O4), for the solar collector safe ,has a stable and highly efficient operation, further enhance heat transfer performance of solar collector provides a new idea.