Study On The Effect Of Organic Matter Adsorption On Surface Characteristics And The Ability To Inhibit The Condensation Of Cold Radiation Plate

The application of cold radiation air conditioning system is subject to the influence of condensation on its surface,but cold radiation air conditioning system has the advantages of reducing building energy consumption,good thermal comfort and excellent indoor air quality.For this reason,most of the traditional researches focus on the water supply terminal control of the cold radiation air conditioning system,such as water supply temperature control and water supply flow control,so as to avoid condensation on the surface of the cold radiation panel.However,these methods need to maintain a higher surface temperature of the cold radiation panels,which weakens the cooling capacity of the cold radiation air conditioning system In this paper,superhydrophobic surface is prepared by laser etching combine with heat treatment to make organic matter adsorb on micro-nanostructure,and the dew suppression characteristics of the superhydrophobic surface and its application in cold radiation air conditioning are studied.The cylindrical micro-nanostructure is etched on the surface of alnminum alloy by laser,and then the organic matters in the air are adsorbed on the surface of the etched aluminum alloy by heat treatment to reduce the free energy of the etched aluminum alloy surface.The contact Angle of the samples are measured.The results show that after heat treatment,the surface contact Angle of the aluminum alloy with micro-nanostructure is greater than 160°,and the surface contact Angle of the aluminum alloy is changed from super hydrophilic before heat treatment to super hydrophobic after heat treatment.The organic groups and its crystal structures on the surface of the saumples are analyzed by means of infrared spectroscopy,XPS and XRD,and it is confirmed that the organic matters play a key role in the wettability transformation of the samples.The surface of laser etched aluminum alloy is heat-treated with 4-methyloctanoic acid and butyl acetate in vacuum.The contact angle of the sample is measured by changing the concentration of organic matter and heating temperature.The results show that changing the concentration of organic matter(3.6 g/m~3～118.9 g/m~3)has little effect on the wettability,but the higher the heating temperature(50℃～90℃),the better the hydrophobicity of the sample.The characteristics of the two organic compounds are compared from the aspects of cost and wettability(contact angle:etched aluminum alloy surface<smooth aluminum alloy surface<4-methyloctanoic acid treatment<butyl acetate treatment).Finally,the adsorption of 4-methyloctanoic acid and butyl acetate on the sample surface are confirmed by IR and XPS,and the adsorption mechanism is analyzed.Duction experiment chamber is used to change the relative humidity of the air in the chamber under the condition of constant temperature and humidity,observe the formation and growth of droplets on the sample surface,and analyze the characteristics of different sample surfaces(dew-inhibiting and dew-delaying).The results show that the degree of droplet coverage:the etched surface>smooth surface>4-methyloctanoic acid>butyl acetate treatment,the better the hydrophobic surface is,the better the dew-inhibiting effect is.Finally,the nucleation principle and condensation behavior of droplet are analyzed.