Study On Optical And Thermal Properties Of Phase Change Composite Glass

Solid-liquid phase change material?PCM?has been widely used in building energy conservation.An important aspect of building application is to passively use it in building envelope,such as wall,window,floor,roof,concrete and brick components,etc.Its role is to enhance the heat capacity of building envelope and improve the thermal inertia of building.For example,for buildings located in hot regions,summer can transfer the heat and humidity load to the low period of electricity consumption and reduce the equipment capacity;For buildings located in cold areas,winter can increase solar heat gain,reduce the heat dissipation to the environment through the enclosure,and reduce the heating load of the building.Therefore,the application of PCM in building maintenance structure can make the cold/heat load become gentle and the indoor temperature fluctuate less with the ambient temperature,thus reducing the energy consumption of building refrigeration or heating,which is conducive to improving the thermal comfort of the building indoor environment and realizing the zero energy consumption of the building.With PCM is widely used in the field of construction,utilizing heat carrier of the PCM as a glass enclosure structure,in order to improve this kind of light summer heat insulation and winter heat preservation of structure is becoming an important direction of research and development,its mechanism is:when the PCM filled between the glass in the solid state through the PCM can make the solar radiation in the visible part of the,still can achieve the function of glass daylighting;The invisible part is absorbed by the PCM and converted into heat stored away from the interior.In hot summer,the heat stored in the PCM can not enter the room,so as to reduce the solar heat gain through the glass envelope and reduce the building's air-conditioning energy consumption.In cold winter,the heat stored in PCM can reduce indoor heat dissipation to the environment through solidification and heat release,thus reducing heating energy consumption.At present,the research on the application of PCM in glass window system is not enough.First,the existing research only for a few PCM to carry out the study,such as paraffin wax,CaCl₂·6H₂O,LiNO₃·3H₂O,Na₂SO₄·10H₂O,etc.For the three salt hydrate,the common chemical properties is not stable.It is not suitable for application in the construction.In general,organic phase change materials are more suitable for passive applications in architecture,such as fatty acids.The application of PCM in glass window system has not been carried out,and the data of radiation characteristics and thermal performance are still blank.Second,how to solve the problem of excessive heat absorption after complete melting of PCM from the material itself has not been proposed yet.This article,from the above two questions as a starting point,start with ten acid and polyethylene glycol?peg?as the double glass Windows system of phase change material,to investigate the radiative?optical?properties of a double glazed composite window system in the wavelength range of 220²600nm solar radiation:including fatty acid in the solid phase,liquid phase state transmittance,reflectance.Second step study in selected phase change material adding titanium dioxide,hollow glass beads and nickel titanate yellow infrared reflective materials on the influence of the radiation characteristics of double deck glass composite Windows system,especially the study of adding titanium dioxide,hollow glass beads and nickel titanate yellow after ten acid and polyethylene glycol transmissivity,absorptivity and solid phase and liquid phase change of infrared light transmittance.The third step is to establish a small-size model of composite glass window system with ten acid and polyethylene glycol box variable materials,conduct outdoor testing of thermal performance,and study the thermal environment parameters of the experimental model under different solar radiation intensity.