Currently,people pay more and more attention to the transitional resettlement of victims after various natural disasters.There is an urgent need for a large number of temporary houses to resettle the victims after nat...Currently,people pay more and more attention to the transitional resettlement of victims after various natural disasters.There is an urgent need for a large number of temporary houses to resettle the victims after natural disasters.Disaster-relief temporary houses(DTHs)played an important role in the post-disaster resettlement in the past,which can not only be produced on a large scale,but also can be quickly and conveniently erected,which were the main means to solve the problem of transitional resettlement.However,due to their temporary nature,there was no extra energy consuming system installed in the DTHs generally.Hence the indoor thermal environment inside the DTHs was severe in summer.In this study,combined with the field experimental tests of the DTHs in Wenchuan Earthquake and Lushan Earthquake and the experimental study of the full-size DTH,it found that the thermal environment inside the DTH was intolerably high in summer.It had negative impact on victims.In order to improve the thermal environment inside DTHs during post-disaster period which lacked of extra energy resources,this study used the method of combining phase change materials(PCMs)with walls of the DTH to explore its feasibility and effectiveness.The results showed that PCMs could effectively improve the thermal environment inside the DTH in summer.Furthermore,the difference of the composite positions between PCMs and the wall affected the improvement effect.The energy release rate of the PCMs assembly system(PAS)varied according to the positions of the PCMs.展开更多
Energy is essential for every human activity for more comfortable life, but it also consumes more natural resources. Fossil fuel is the major energy source for energy consumption, and it also emits a lot of air pollut...Energy is essential for every human activity for more comfortable life, but it also consumes more natural resources. Fossil fuel is the major energy source for energy consumption, and it also emits a lot of air pollution during usage to atmosphere and not reproductively. Electrical energy is the secondary energy sources from fossil fuel which is used to operate air conditioning system. In order to control human comfort temperature, it is usually required when the temperature differences swing between indoor and outdoor temperatures. PCMs （phase change materials） are the high latent heat materials which can be used in building materials for energy conservation purpose. PCMs can store thermal energy and prevent heat to pass through temperature control areas. Paraffin has been used as PCMs which is absorbed into the pore of fly ash as paraffin/fly-ash composite and mixed into the buildings materials. Paraffin is an organic material with high melting point （-59 ~C） and nonflammable material, therefore, it can be used as the building materials for the function of PCMs for energy saving purposes. Composite PCMs can be prepared by vacuum impregnation process. Paraffin in liquid form will be impregnated into the pore of fly ash by vacuum capillary force to form paraffin/fly ash composite PCMs. Vacuum impregnation pressures, vacuum times, impregnation times of liquid paraffin in fly ash pores and temperatures for melting the solid paraffin into the liquid form are all affect on the thermal properties of paraffin/fly ash composite PCMs. Composite PCMs will be selected by the optimum thermal properties with optimum of the production conditions for replace the cement powder in the mortar plate compositions. Cement mortar plate with and without composite PCMs will be tested for the thermal insulation properties by comparison as the real day and night time for 8 h period from spot light turn on and off. Temperature detection on the surface and inside the model building under mortar plate with and without composite PCMs is detected every 1 min. Temperature differences between surface of mortar plate over the model building and inside temperature of model building under mortar plates increase with more composite PCMs contents in mortar plates. Thermal insulation efficiency in the building can be enhanced by the composite PCMs utilization as the composition of the building materials.展开更多
An experimental investigation was conducted to study the efficiency of thermal insulation of composite PCMs(phase change materials)produced by vacuum impregnation process between paraffin(PCMs)and fly ash particles.DS...An experimental investigation was conducted to study the efficiency of thermal insulation of composite PCMs(phase change materials)produced by vacuum impregnation process between paraffin(PCMs)and fly ash particles.DSC(differential scanning calorimeter)has been used to determine the thermal properties of latent heat of melting and heat capacity for composite PCMs.Vacuum impregnation pressure of 40 in.Hg,paraffin melting temperature of 90℃,vacuum time and impregnation time of paraffin of 30 min are the optimum condition of composite PCMs productions.The values of latent heat of melting and heat capacity are 74.00 J/g and 15.726 J/g.℃for composite PCMs that produces by the optimum condition in vacuum impregnation process.Increasing the amount of composite PCMs replacing for cement in mortars causes the compressive strength,flexural strength and tensile strength reduction.Compressive strength,flexural strength and tensile strength of mortar with and without composite PCMs can be increased by the longer time of water curing for mortar specimens.Thermal conductivity(k)of mortar cement is reduced by increasing the amount of composite PCMs which replaced for cement in mortar plate compositions.Composite PCMs have the efficiency for thermal energy insulation when incorporated into the buildings.Therefore,this property of paraffin/fly ash composites PCMs can reduce the energy consumption for temperature control in the buildings.展开更多
Energy is essential for every human activity for more comfortable life but also consumes more natural resources. In order to control human comfort, temperature usually required when the differences in temperature swin...Energy is essential for every human activity for more comfortable life but also consumes more natural resources. In order to control human comfort, temperature usually required when the differences in temperature swing between indoor and outdoor temperatures. PCMs （phase change materials） are the high latent heat materials which can be used in building materials for energy conservation purpose. PCMs can store thermal energy and also can prevent heat to pass through temperature control areas. Paraffin has been used as PCMs are absorbed into the pore of fly ash as paraffin/fly-ash composite and mixed into the buildings materials. Paraffin is an organic material with high melting point （-59℃）, and nonflammable materials therefore paraffin can be used as the building materials for the function of PCMs for energy saving purposes. Composite PCMs can be prepared by vacuum impregnation process. Paraffin in liquid form will be impregnated into the pore of fly ash by vacuum capillary force to form paraffin/fly ash composite PCMs. Vacuum impregnation pressures, vacuum times, impregnation times of liquid paraffin in fly ash pores and temperatures for melting the solid paraffin into the liquid form are all affect on the thermal properties of paraffin/fly ash composite PCMs. Paraffin or PCMs impregnation are also relate to the physical property including the fractal dimensions of the pores of the fly ash particles and paraffin/fly ash composite PCMs. The fractal dimensions of the pore of fly ash and paraffin/fiy ash composites PCMs are between the values of 1.0 and 2.0. Fractal dimensions of paraffin/fly-ash composite PCMs have the same trend as the thermal properties for heat capacity and latent heat of melting. These fractal dimensions technique is a novel method to measure physical property of building material related to latent heat and heat capacity.展开更多
The reduction of gained heat,heat peak shifting,and the mitigation of air temperature fluctuations are some desirable properties that are sought after in any thermal insulation system.It cannot be overstated that thes...The reduction of gained heat,heat peak shifting,and the mitigation of air temperature fluctuations are some desirable properties that are sought after in any thermal insulation system.It cannot be overstated that these fac-tors,in addition to others,govern the performance of such systems thus their effect on indoor ambient conditions.The effect of such systems extends also to Heating,Ventilation and Air-conditioning(HVAC)systems that are set up to operate optimally in certain conditions.Where literature shows that PCMs and natural materials such as wood-shavings can provide efficient passive insulation for buildings,it is evident that such approaches utilise methods that are of a degree of intricacy which require specialist knowledge and complex techniques,such as micro-encapsulation for instance.With technical and economic aspects in mind,an amalgam of PCM and wood-shavings has been created to be utilised as a feasible thermal insulation.The amalgamation was performed in the simplest of methods,through submerging the wood shavings in PCM.An experimental procedure was devised to test the thermal performance of the amalgam and compare this to the performance of the same un-amalgamated materials.Comparative analysis revealed that no significant thermal gains would be expected from such amal-gamation.However,a significant reduction in the total weight of the insulation system would be achieved that,in this case,shown to be up to 20.94%.Thus,further reducing possible strains on structural elements due to the application of insulation on buildings.This can be especially beneficial in vernacular architectural approaches where considerably large amounts and thicknesses of insulations are used.In addition,cost reduction could be attained as wood shavings are significantly cheaper compared to the cost of PCMs.展开更多
文摘Currently,people pay more and more attention to the transitional resettlement of victims after various natural disasters.There is an urgent need for a large number of temporary houses to resettle the victims after natural disasters.Disaster-relief temporary houses(DTHs)played an important role in the post-disaster resettlement in the past,which can not only be produced on a large scale,but also can be quickly and conveniently erected,which were the main means to solve the problem of transitional resettlement.However,due to their temporary nature,there was no extra energy consuming system installed in the DTHs generally.Hence the indoor thermal environment inside the DTHs was severe in summer.In this study,combined with the field experimental tests of the DTHs in Wenchuan Earthquake and Lushan Earthquake and the experimental study of the full-size DTH,it found that the thermal environment inside the DTH was intolerably high in summer.It had negative impact on victims.In order to improve the thermal environment inside DTHs during post-disaster period which lacked of extra energy resources,this study used the method of combining phase change materials(PCMs)with walls of the DTH to explore its feasibility and effectiveness.The results showed that PCMs could effectively improve the thermal environment inside the DTH in summer.Furthermore,the difference of the composite positions between PCMs and the wall affected the improvement effect.The energy release rate of the PCMs assembly system(PAS)varied according to the positions of the PCMs.
文摘Energy is essential for every human activity for more comfortable life, but it also consumes more natural resources. Fossil fuel is the major energy source for energy consumption, and it also emits a lot of air pollution during usage to atmosphere and not reproductively. Electrical energy is the secondary energy sources from fossil fuel which is used to operate air conditioning system. In order to control human comfort temperature, it is usually required when the temperature differences swing between indoor and outdoor temperatures. PCMs （phase change materials） are the high latent heat materials which can be used in building materials for energy conservation purpose. PCMs can store thermal energy and prevent heat to pass through temperature control areas. Paraffin has been used as PCMs which is absorbed into the pore of fly ash as paraffin/fly-ash composite and mixed into the buildings materials. Paraffin is an organic material with high melting point （-59 ~C） and nonflammable material, therefore, it can be used as the building materials for the function of PCMs for energy saving purposes. Composite PCMs can be prepared by vacuum impregnation process. Paraffin in liquid form will be impregnated into the pore of fly ash by vacuum capillary force to form paraffin/fly ash composite PCMs. Vacuum impregnation pressures, vacuum times, impregnation times of liquid paraffin in fly ash pores and temperatures for melting the solid paraffin into the liquid form are all affect on the thermal properties of paraffin/fly ash composite PCMs. Composite PCMs will be selected by the optimum thermal properties with optimum of the production conditions for replace the cement powder in the mortar plate compositions. Cement mortar plate with and without composite PCMs will be tested for the thermal insulation properties by comparison as the real day and night time for 8 h period from spot light turn on and off. Temperature detection on the surface and inside the model building under mortar plate with and without composite PCMs is detected every 1 min. Temperature differences between surface of mortar plate over the model building and inside temperature of model building under mortar plates increase with more composite PCMs contents in mortar plates. Thermal insulation efficiency in the building can be enhanced by the composite PCMs utilization as the composition of the building materials.
文摘An experimental investigation was conducted to study the efficiency of thermal insulation of composite PCMs(phase change materials)produced by vacuum impregnation process between paraffin(PCMs)and fly ash particles.DSC(differential scanning calorimeter)has been used to determine the thermal properties of latent heat of melting and heat capacity for composite PCMs.Vacuum impregnation pressure of 40 in.Hg,paraffin melting temperature of 90℃,vacuum time and impregnation time of paraffin of 30 min are the optimum condition of composite PCMs productions.The values of latent heat of melting and heat capacity are 74.00 J/g and 15.726 J/g.℃for composite PCMs that produces by the optimum condition in vacuum impregnation process.Increasing the amount of composite PCMs replacing for cement in mortars causes the compressive strength,flexural strength and tensile strength reduction.Compressive strength,flexural strength and tensile strength of mortar with and without composite PCMs can be increased by the longer time of water curing for mortar specimens.Thermal conductivity(k)of mortar cement is reduced by increasing the amount of composite PCMs which replaced for cement in mortar plate compositions.Composite PCMs have the efficiency for thermal energy insulation when incorporated into the buildings.Therefore,this property of paraffin/fly ash composites PCMs can reduce the energy consumption for temperature control in the buildings.
文摘Energy is essential for every human activity for more comfortable life but also consumes more natural resources. In order to control human comfort, temperature usually required when the differences in temperature swing between indoor and outdoor temperatures. PCMs （phase change materials） are the high latent heat materials which can be used in building materials for energy conservation purpose. PCMs can store thermal energy and also can prevent heat to pass through temperature control areas. Paraffin has been used as PCMs are absorbed into the pore of fly ash as paraffin/fly-ash composite and mixed into the buildings materials. Paraffin is an organic material with high melting point （-59℃）, and nonflammable materials therefore paraffin can be used as the building materials for the function of PCMs for energy saving purposes. Composite PCMs can be prepared by vacuum impregnation process. Paraffin in liquid form will be impregnated into the pore of fly ash by vacuum capillary force to form paraffin/fly ash composite PCMs. Vacuum impregnation pressures, vacuum times, impregnation times of liquid paraffin in fly ash pores and temperatures for melting the solid paraffin into the liquid form are all affect on the thermal properties of paraffin/fly ash composite PCMs. Paraffin or PCMs impregnation are also relate to the physical property including the fractal dimensions of the pores of the fly ash particles and paraffin/fly ash composite PCMs. The fractal dimensions of the pore of fly ash and paraffin/fiy ash composites PCMs are between the values of 1.0 and 2.0. Fractal dimensions of paraffin/fly-ash composite PCMs have the same trend as the thermal properties for heat capacity and latent heat of melting. These fractal dimensions technique is a novel method to measure physical property of building material related to latent heat and heat capacity.
文摘The reduction of gained heat,heat peak shifting,and the mitigation of air temperature fluctuations are some desirable properties that are sought after in any thermal insulation system.It cannot be overstated that these fac-tors,in addition to others,govern the performance of such systems thus their effect on indoor ambient conditions.The effect of such systems extends also to Heating,Ventilation and Air-conditioning(HVAC)systems that are set up to operate optimally in certain conditions.Where literature shows that PCMs and natural materials such as wood-shavings can provide efficient passive insulation for buildings,it is evident that such approaches utilise methods that are of a degree of intricacy which require specialist knowledge and complex techniques,such as micro-encapsulation for instance.With technical and economic aspects in mind,an amalgam of PCM and wood-shavings has been created to be utilised as a feasible thermal insulation.The amalgamation was performed in the simplest of methods,through submerging the wood shavings in PCM.An experimental procedure was devised to test the thermal performance of the amalgam and compare this to the performance of the same un-amalgamated materials.Comparative analysis revealed that no significant thermal gains would be expected from such amal-gamation.However,a significant reduction in the total weight of the insulation system would be achieved that,in this case,shown to be up to 20.94%.Thus,further reducing possible strains on structural elements due to the application of insulation on buildings.This can be especially beneficial in vernacular architectural approaches where considerably large amounts and thicknesses of insulations are used.In addition,cost reduction could be attained as wood shavings are significantly cheaper compared to the cost of PCMs.
