Regulating the indoor temperature of public transport on hot sunny days is a prime concern,as both the external and internal heat sources play an active role in heat gain.Experimental studies have been carried out on ...Regulating the indoor temperature of public transport on hot sunny days is a prime concern,as both the external and internal heat sources play an active role in heat gain.Experimental studies have been carried out on a bus model using sodium sulphate decahydrate as a phase-change material(PCM)that is placed in between the ceiling and the roof.Studies are conducted on a sunny day and also for different cases of external(300-W surface heater)and internal(25-W light bulb)heat sources.The results show that PCM,in the presence of an external heat source,can help to keep the indoor temperature lower and delay the time period for increasing the temperature by absorbing heat during the phase change.On the other hand,the presence of the internal heat source contributes to a detrimental effect on the indoor temperature,which gradually increases with the elapse of time.With the combination of the external and internal heat sources,it is found that the internal heat source plays a dominating factor to raise the indoor temperature.It is revealed from the experimental results that a 12.7-mm single layer and a single PCM are not enough to counter the internal heat of 25 W unless the thickness of the PCM layer is increased to delay the increase in the indoor temperature.An additional PCM layer with a lower melting temperature could be placed at the inner portion of the ceiling to have effective thermal-energy storage by absorbing the substantial heat gain from the internal heat sources.展开更多
In view of the continuous increase in the proportion of renewable energy connected to the grid in China and the increasing peak-to-valley difference in electricity demand on the power grid,this paper proposes a high-t...In view of the continuous increase in the proportion of renewable energy connected to the grid in China and the increasing peak-to-valley difference in electricity demand on the power grid,this paper proposes a high-temperature thermal-storage combined-cycle power-generation system.Using Thermoflex thermal simulation analysis software,a high-temperature thermal-storage combined-cycle simulation analysis system model was established,and the influence of different initial temperatures and pressure ratios on the combined-cycle system was analysed.Sensitivity analysis of factors such as electricity cost,annual operating hours,initial equipment investment,unit efficiency and other factors that affect the net income of the system was carried out.According to the current power-peak-shaving auxiliary service market in China,it is pointed out that high-temperature thermal-storage combined-cycle projects must be profitable and obtain good economic benefits.The results obtained,on the one hand,provide suggestions for the flexibility and transformation of current gas-fired steam generators for peak shaving and,on the other hand,provide references for the subsequent development of high-temperature thermal-storage combined-cycle demonstration projects.展开更多
基金supported by the Mechanical and Production Engineering Department(MPE)of Ahsanullah University of Science and Technology(AUST).
文摘Regulating the indoor temperature of public transport on hot sunny days is a prime concern,as both the external and internal heat sources play an active role in heat gain.Experimental studies have been carried out on a bus model using sodium sulphate decahydrate as a phase-change material(PCM)that is placed in between the ceiling and the roof.Studies are conducted on a sunny day and also for different cases of external(300-W surface heater)and internal(25-W light bulb)heat sources.The results show that PCM,in the presence of an external heat source,can help to keep the indoor temperature lower and delay the time period for increasing the temperature by absorbing heat during the phase change.On the other hand,the presence of the internal heat source contributes to a detrimental effect on the indoor temperature,which gradually increases with the elapse of time.With the combination of the external and internal heat sources,it is found that the internal heat source plays a dominating factor to raise the indoor temperature.It is revealed from the experimental results that a 12.7-mm single layer and a single PCM are not enough to counter the internal heat of 25 W unless the thickness of the PCM layer is increased to delay the increase in the indoor temperature.An additional PCM layer with a lower melting temperature could be placed at the inner portion of the ceiling to have effective thermal-energy storage by absorbing the substantial heat gain from the internal heat sources.
文摘In view of the continuous increase in the proportion of renewable energy connected to the grid in China and the increasing peak-to-valley difference in electricity demand on the power grid,this paper proposes a high-temperature thermal-storage combined-cycle power-generation system.Using Thermoflex thermal simulation analysis software,a high-temperature thermal-storage combined-cycle simulation analysis system model was established,and the influence of different initial temperatures and pressure ratios on the combined-cycle system was analysed.Sensitivity analysis of factors such as electricity cost,annual operating hours,initial equipment investment,unit efficiency and other factors that affect the net income of the system was carried out.According to the current power-peak-shaving auxiliary service market in China,it is pointed out that high-temperature thermal-storage combined-cycle projects must be profitable and obtain good economic benefits.The results obtained,on the one hand,provide suggestions for the flexibility and transformation of current gas-fired steam generators for peak shaving and,on the other hand,provide references for the subsequent development of high-temperature thermal-storage combined-cycle demonstration projects.
