| Building energy consumption plays an important role in China's total energy consumption. In a broad sense, building energy consumption means the process of building material manufacturing, construction and building energy use. In a narrow sense, building energy consumption means people's daily use, namely heating, air conditioning, lightning, cooking, laundry and other energy consumption, they are the dominant part of building energy consumption. The proportion of air conditioning energy consumption is about 2\3. Thus reducing air conditioning energy consumption is the main element of energy saving. Researching and applying a new energy saving building material that can both reduce building consumption and improve indoor environment thermal comfort is an imperative line.In phase-transition period, PCM energy is absorbed or released without extra increase energy. It has a widely applied theoretical foundation. Phase-change material is applied in building, the intelligent room thermostat can be achieved to improve living comfort.and energy efficiency,to help provide a new way to save building energy consumption.The phase-change material of the subject is liquid paraffin and solid paraffin. The adsorptive absorption is light-weight clay ceramsite and expanded perlite. It investigates the selection of phase-transition temperature and enthalpy. It investigates the absorption situations about light-weight clay ceramsite and expanded perlite in different absorption condition. It makes paraffin/ceramsite (expanded perlite) phase change materials. It investigates package effect about package material to fixed phase-change material. According to technical specification for lightweight aggregate concrete, Standard for test method of basic properties of construction mortar, it makes phase-change concrete,phase-change mortar, there's blank sample. After maintaining 28days,the specimen's mechanics and thermal stability is tested. It investigates the applying effect and applying value about roofing phase-change material.The experiment result shows:By DSC and temperature-time curve we can make sure that there're two types of compound paraffin fit village and towns building roofing. One:3# paraffin:solid paraffin=4:6, the phase-transition temperature and phase-transition enthalpy are 23.51? and71.47J/g. The other is n-tetradecane:solid paraffin=4:6, the phase-transition temperature and phase-transition enthalpy are 24.79?? 71.59J/g.Vacuum and nature adsorption methods are used and the quality of paraffin which is absorbed in vacuum condition for 2 hours is 95.5%. By nature adsorption paraffin quality is only 11.3%. The quality of paraffin is 223.1% when expanded perlite is absorbed in vacuum condition. By nature adsorption paraffin quality is 169.5%. So vacuum absorption method is selected.Paraffin/ceramsite was encapsulated by the mixture of epoxy resin and triethylenetetramine. The proportion of which is 1:0.098.The minimum leakage quality is 3.3% which is half the unencapsulated after 30 thermal cyclings.Five serieses of Phase-transition concrete (J,W3#,F3#,W14,F14,superscript indicates the type of wax used, J is the reference concrete,W is ceramsite unencapsulated,F is ceramsite encapsulated) in maintaining period retained well. No drawing off, no cracking after 30 thermal cyclings, concrete quality loss is 0.89%, which can be neglected. The maximum of F14 series phase-transition intensity is 7.1MPa. The loss is 7.8%. Paraffin/expanded perlite was encapsulated by EVA and five series of Phase-transition mortar (J,W3#,F3#,W14,F14) are prepared, after 30 times of heat cycling, the minimum of F14 series phase-transition mortar leakage is 1.1%. The maximum intensity is 2.3Mpa,the loss is 20.7%. Thus package material can effectively stop the phase-transition material in ceramsite and expanded perlite leakage, decreasing intensity loss.The subject investigates that J?W?F series thermal conductivity is around 0.17W/m·K. For further research on phase-transition storing energy roofing material to indoor thermostat effect, an experiment box which can keep heat and insulation is made for the experiment. F14Concrete which is used as roof frame is put on top of the box.Phase-transition concrete is acted as roof, the temperature drops from 24? to 18?, which takes 450 minutes,47.5% longer than normal concrete acts as roof. It shows that phase-transition concrete can effectively reduce indoor temperature range, defer indoor temperature fluctuation time. It functions well as a thermostat and improves living comfort. |
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