The performance of a direct-expansion ground-source heat pump（DX GSHP）system is theoretically analyzed.Compared with the conventional ground-source heat pump（GSHP）,the DX GSHP has a lower condensing temperature in...The performance of a direct-expansion ground-source heat pump（DX GSHP）system is theoretically analyzed.Compared with the conventional ground-source heat pump（GSHP）,the DX GSHP has a lower condensing temperature in the cooling mode and a higher evaporating temperature in the heating mode,and the ground heat exchanger（GHE）in the DX GSHP has a low thermal resistance.Therefore,the coefficient of performance（COP）of the DX GSHP is higher than that of the GSHP.In addition,the system performance of the DX GSHP system is higher than that of the conventional GSHP system because there are no secondary solution loops and water circulating pumps in the DX GSHP system.The experimental energy performance of the DX GSHP system is also investigated based on the actual operational data.The tested DX GSHP system is installed in Xiangtan,China.The U-vertical GHE of the DX GSHP is buried in a water well.The length and the outside nominal diameter of the GHE are 42 m and 12.7 mm,respectively.The experimental results show that the maximum（COP）and the average COP of the DX GSHP system in the heating mode are 5.95 and 4.72,respectively.展开更多
In order to effectively improve the properties of anion exchange membrane(AEM)materials,a series of novel poly(aryl ether nitrile)s with flexible side-chain-type quaternary phosphonium cations(PAEN-TPP-x)were designed...In order to effectively improve the properties of anion exchange membrane(AEM)materials,a series of novel poly(aryl ether nitrile)s with flexible side-chain-type quaternary phosphonium cations(PAEN-TPP-x)were designed and prepared on the basis of considering the influences of polymer backbone,cationic group species and the connection way between the cations and polymer chains.The synthetic method,structure and ion-exchange capacity,water absorption,swelling,hydroxide conductivity and alkaline stability of the obtained AEMs were studied.A comparative study with other reported AEMs was also performed for further exploration of the relationship between the structure and properties.These AEMs with flexible side-chain-type quaternary phosphonium cations displayed good comprehensive properties.Their water uptakes and swelling ratios were in the range of 11.6%–22.7%and 4.4%–7.8%at 60℃,respectively.They had hydroxide conductivity in the range of 28.6–45.8 mS cm^-1 at 60℃.Moreover,these AEMs also exhibited improved alkaline stability,and the hydroxide conductivity for PAEN-TPP-0.35 could remain 82.1%and 80.6%of its initial value at 60 and 90℃in 2 mol L^-1 NaOH solution for480 h,respectively.展开更多
基金The National Key Technologies R&D Program of Chinaduring the 11th Five-Year Plan Period(No.2006BAJ04B04,2006BAJ04A05,2006BAJ04A13)
文摘The performance of a direct-expansion ground-source heat pump（DX GSHP）system is theoretically analyzed.Compared with the conventional ground-source heat pump（GSHP）,the DX GSHP has a lower condensing temperature in the cooling mode and a higher evaporating temperature in the heating mode,and the ground heat exchanger（GHE）in the DX GSHP has a low thermal resistance.Therefore,the coefficient of performance（COP）of the DX GSHP is higher than that of the GSHP.In addition,the system performance of the DX GSHP system is higher than that of the conventional GSHP system because there are no secondary solution loops and water circulating pumps in the DX GSHP system.The experimental energy performance of the DX GSHP system is also investigated based on the actual operational data.The tested DX GSHP system is installed in Xiangtan,China.The U-vertical GHE of the DX GSHP is buried in a water well.The length and the outside nominal diameter of the GHE are 42 m and 12.7 mm,respectively.The experimental results show that the maximum（COP）and the average COP of the DX GSHP system in the heating mode are 5.95 and 4.72,respectively.
基金supported by the National Natural Science Foundation of China (21404016)the Key Research Program of Jiangsu Province (BE2017645)+1 种基金the Six Talent Peaks Project of Jiangsu Province (XCL-078)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions of China
文摘In order to effectively improve the properties of anion exchange membrane(AEM)materials,a series of novel poly(aryl ether nitrile)s with flexible side-chain-type quaternary phosphonium cations(PAEN-TPP-x)were designed and prepared on the basis of considering the influences of polymer backbone,cationic group species and the connection way between the cations and polymer chains.The synthetic method,structure and ion-exchange capacity,water absorption,swelling,hydroxide conductivity and alkaline stability of the obtained AEMs were studied.A comparative study with other reported AEMs was also performed for further exploration of the relationship between the structure and properties.These AEMs with flexible side-chain-type quaternary phosphonium cations displayed good comprehensive properties.Their water uptakes and swelling ratios were in the range of 11.6%–22.7%and 4.4%–7.8%at 60℃,respectively.They had hydroxide conductivity in the range of 28.6–45.8 mS cm^-1 at 60℃.Moreover,these AEMs also exhibited improved alkaline stability,and the hydroxide conductivity for PAEN-TPP-0.35 could remain 82.1%and 80.6%of its initial value at 60 and 90℃in 2 mol L^-1 NaOH solution for480 h,respectively.
