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
We do a new Li-ion battery evaluation research on the effects of cell resistance and polariza- tion on the energy loss in batteries based on thermal property and heat generation behavior of battery. Series of 18650 ce...We do a new Li-ion battery evaluation research on the effects of cell resistance and polariza- tion on the energy loss in batteries based on thermal property and heat generation behavior of battery. Series of 18650 cells with different capacities and electrode materials are evalu- ated by measuring input and output energy which change with charge-discharge time and current. Based on the results of these tests, we build a model of energy loss in cells' charge- discharge process, which include Joule heat and polarization heat impact factors. It was reported that Joule heat was caused by cell resistance, which included De-resistance and reaction resistance, and reaction resistance could not be easily obtained through routine test method. Using this new method, we can get the total resistance R and the polarization parameter U. The relationship between R, η, and temperature is also investigated in order to build a general model for series of different Li-ion batteries, and the research can be used in the performance evaluation, state of charge prediction and the measuring of consistency of the batteries.展开更多
In China, REC (residential energy consumption) is the second largest energy use category (10%) following the industry. To fulfill the Chinese government's commitment that Chinese CO2 emissions would peak in 2030,...In China, REC (residential energy consumption) is the second largest energy use category (10%) following the industry. To fulfill the Chinese government's commitment that Chinese CO2 emissions would peak in 2030, as a result, improving the energy efficiency and reducing the emissions from the building sector is significantly important. A survey, in the form of a questionnaire, of energy consumption and thermal situation in different residential building types (detached house, multi-story building, high-rise building), was undertaken in three cities (Shanghai, Hangzhou, and Changzhou) in hot-summer and cold-winter regions, these three cities were selected to represent the most flourishing economic provinces. This region in China was selected for the evaluation of EETP (energy and thermal performance analysis), because of its special weather conditions, huge energy consumption (as both heating in winter and cooling in summer are necessary), and other regional characteristics. 183 households were sampled and experiments were separately done in typical examples of three different building types. Systematic evaluation on EETP for three different residential building types, were put forward to assess the energy efficiency and thermal performance of three different building types.展开更多
Good learning outputs in schools require an acceptable physical environment inside schools. Whatever the climatic context that surrounds any school buildings, energy flows of different types should be provided. Concer...Good learning outputs in schools require an acceptable physical environment inside schools. Whatever the climatic context that surrounds any school buildings, energy flows of different types should be provided. Concerns may include thermal environment, luminous environment and acoustics environment. Types of energy used are an important variable that contributes to thermal comfort. Physical structure of the school building is another factor to be taken into consideration. This article established a relationship between thermal comfort inside schools and types of energy flows which have been consumed to maintain the level of comfort required, controlled by the building fabric and consequent economic factors that affect energy consumption of school buildings. Different approaches were applied in order to achieve the research objectives. Field surveys, field measurements and analyzing historical data were the most approaches followed to implement this study. The final outputs of this work have a national value nationwide: establishing a relationship among thermal comfort, energy flows and building fabric is of importance. Furthermore, it is of great importance to the decision maker for educational facilities. Research will also establish a wide platform based on scientific investigations for developing climate responsive school architecture in Jordan.展开更多
Energy saving and CO2 emissions reduction are critical tasks currently,and great effort has been made by Chinese government. Renewable energy consumption and CO2 emissions and reduction plan in China are introduced in...Energy saving and CO2 emissions reduction are critical tasks currently,and great effort has been made by Chinese government. Renewable energy consumption and CO2 emissions and reduction plan in China are introduced in this paper. Analysis is also made on present status and prospect of geothermal power generation and direct use in China respectively. Now,there is a new understanding of geothermal resources,and hot dry rock,considered as the future of geothermal resources,is likely used to generate electricity.展开更多
The building sector has a significant weight in the global energy consumption in almost of the countries. So, there is a high potential for increasing its energy efficiency. With the enforcement of the energetic certi...The building sector has a significant weight in the global energy consumption in almost of the countries. So, there is a high potential for increasing its energy efficiency. With the enforcement of the energetic certification, it was tried to select different solutions that presents less energy consumption and waste, as well as an effective reduction of CO2 emissions. This work fits in this perspective, since the main goal is to evaluate the contribution of passive and active solutions that can be used in buildings for the improvement of its energetic efficiency, as well as to evaluate the contribution of renewable energy sources. Contribution of solar systems for hot water heating and electric energy production has been studied, as well as cogeneration, Combined Heat and Power (CHP). The case studied is a hotel. To improve the building performance, there were proposed several changes, with the goal of evaluating the contribution of the different solutions proposed. It was concluded that they contribute to a reduction of thermal needs of 25.2% and avoided emissions of CO2 is 30.4%. The analysis of the implementation of trigeneration, Combined Heat, Cooling and Power (CHCP) turns it executable. The payback period is less than 8 years.展开更多
Under the RHO (renewable heat obligation), public buildings in the Republic of Korea must achieve an 11% overall reduction to thermal energy consumption in buildings more than 10,0O0 m^2. RETScreen Plus is a freely ...Under the RHO (renewable heat obligation), public buildings in the Republic of Korea must achieve an 11% overall reduction to thermal energy consumption in buildings more than 10,0O0 m^2. RETScreen Plus is a freely available software tool developed by the Canadian Government which can be used to develop energy baselines of clean energy technologies. Using curve-fitting and statistical methods like CUSUM, the software can combine actual energy performance with near real time weather information from NASA. We developed a method to simulate the performance of a GSHP (ground source heat pump). The three distinct energy zones involve heating, no-energy, and cooling. RETScreen Plus methodology is used to develop curve fits for each distinct zone as it builds a correlation with NASA satellite data. The model then factors the impact of ICT (information and control technologies) as a means to improve and lower the building's energy consumption. Two values of COP (coefficient of performance) are used--the first is a standard ICT COP, while the second is an improved ICT COP with a smart controller. This methodology can then be expanded to incorporate current and future smart meter technologies, time of use rates, energy price signals, demand response and electricity storage options. In summary, this methodology enables a building owner or energy conservation official to quickly and accurately determine the baseline energy for a building and the potential impacts of smart ICT technologies, especially for buildings equipped with GSHP technologies.展开更多
An effective thermodynamic transformation analysis method was proposed in this study. According to the phenomenon of ex- ergy consumption always coupling with heat transfer process, the effective thermodynamic tempera...An effective thermodynamic transformation analysis method was proposed in this study. According to the phenomenon of ex- ergy consumption always coupling with heat transfer process, the effective thermodynamic temperatures were defined, then the actual power cycle or refrigeration/heat pump cycle was transformed into the equivalent reversible Carnot or reverse Carnot cycles for thermodynamic analysis. The derived effective thermodynamic temperature of the hot reservoir of the equivalent reverse Camot cycle is the basis of the proposed method. The combined diagram of TR-h and TR-q was adopted for the analy- sis of the system performance and the exergy consumption, which takes advantage of the visual expression of the heat/work exchange and the enthalpy change, and is convenient for the calculation of the coefficient of performance and exergy con- sumptions. Take a heat pump water heater with refrigerant of R22 for example, the proposed method was systematically intro- duced, and the fitting formulas of the effective thermodynamic temperatures were given as demonstration. The results show that the proposed method has advantage and well application foreground in the performance simulation and estimation under the variable working conditions.展开更多
The three-dimensional global magnetohydrodynamic model(PPM-LR MHD)is employed to investigate the energy budget in the solar wind-magnetosphere system during the super magnetic storm on November 20,2003,one of the bigg...The three-dimensional global magnetohydrodynamic model(PPM-LR MHD)is employed to investigate the energy budget in the solar wind-magnetosphere system during the super magnetic storm on November 20,2003,one of the biggest storms during the last decade with Dst^-500 n T.During this event,about 23%solar wind kinetic energy is transferred into the magnetosphere.The total energy input is estimated to be about 9.50×1017 J,about 14 times of a moderate storm.The energy dissipation via the inner magnetosphere is less than the energy input with the coupling efficiency of^63.3%.The energy dissipated via ring current injection is less than that via high-latitude ionosphere at the initial stage of the super storm.Furthermore,both the simulation results and the empirical results indicate that the ratio of ring current injection to the total energy output increases with the enhancement of the magnetospheric activity level.These are consistent with the statistical results we have got before.The empirical equations underestimate the solar wind kinetic energy,the energy input,and the energy dissipation via high-latitude ionosphere compared with the simulation results;however,the coupling efficiency of the high-latitude ionosphere(23.4%)is close to the simulation result(23.1%)during the entire storm time period.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.
文摘We do a new Li-ion battery evaluation research on the effects of cell resistance and polariza- tion on the energy loss in batteries based on thermal property and heat generation behavior of battery. Series of 18650 cells with different capacities and electrode materials are evalu- ated by measuring input and output energy which change with charge-discharge time and current. Based on the results of these tests, we build a model of energy loss in cells' charge- discharge process, which include Joule heat and polarization heat impact factors. It was reported that Joule heat was caused by cell resistance, which included De-resistance and reaction resistance, and reaction resistance could not be easily obtained through routine test method. Using this new method, we can get the total resistance R and the polarization parameter U. The relationship between R, η, and temperature is also investigated in order to build a general model for series of different Li-ion batteries, and the research can be used in the performance evaluation, state of charge prediction and the measuring of consistency of the batteries.
文摘In China, REC (residential energy consumption) is the second largest energy use category (10%) following the industry. To fulfill the Chinese government's commitment that Chinese CO2 emissions would peak in 2030, as a result, improving the energy efficiency and reducing the emissions from the building sector is significantly important. A survey, in the form of a questionnaire, of energy consumption and thermal situation in different residential building types (detached house, multi-story building, high-rise building), was undertaken in three cities (Shanghai, Hangzhou, and Changzhou) in hot-summer and cold-winter regions, these three cities were selected to represent the most flourishing economic provinces. This region in China was selected for the evaluation of EETP (energy and thermal performance analysis), because of its special weather conditions, huge energy consumption (as both heating in winter and cooling in summer are necessary), and other regional characteristics. 183 households were sampled and experiments were separately done in typical examples of three different building types. Systematic evaluation on EETP for three different residential building types, were put forward to assess the energy efficiency and thermal performance of three different building types.
文摘Good learning outputs in schools require an acceptable physical environment inside schools. Whatever the climatic context that surrounds any school buildings, energy flows of different types should be provided. Concerns may include thermal environment, luminous environment and acoustics environment. Types of energy used are an important variable that contributes to thermal comfort. Physical structure of the school building is another factor to be taken into consideration. This article established a relationship between thermal comfort inside schools and types of energy flows which have been consumed to maintain the level of comfort required, controlled by the building fabric and consequent economic factors that affect energy consumption of school buildings. Different approaches were applied in order to achieve the research objectives. Field surveys, field measurements and analyzing historical data were the most approaches followed to implement this study. The final outputs of this work have a national value nationwide: establishing a relationship among thermal comfort, energy flows and building fabric is of importance. Furthermore, it is of great importance to the decision maker for educational facilities. Research will also establish a wide platform based on scientific investigations for developing climate responsive school architecture in Jordan.
文摘Energy saving and CO2 emissions reduction are critical tasks currently,and great effort has been made by Chinese government. Renewable energy consumption and CO2 emissions and reduction plan in China are introduced in this paper. Analysis is also made on present status and prospect of geothermal power generation and direct use in China respectively. Now,there is a new understanding of geothermal resources,and hot dry rock,considered as the future of geothermal resources,is likely used to generate electricity.
文摘The building sector has a significant weight in the global energy consumption in almost of the countries. So, there is a high potential for increasing its energy efficiency. With the enforcement of the energetic certification, it was tried to select different solutions that presents less energy consumption and waste, as well as an effective reduction of CO2 emissions. This work fits in this perspective, since the main goal is to evaluate the contribution of passive and active solutions that can be used in buildings for the improvement of its energetic efficiency, as well as to evaluate the contribution of renewable energy sources. Contribution of solar systems for hot water heating and electric energy production has been studied, as well as cogeneration, Combined Heat and Power (CHP). The case studied is a hotel. To improve the building performance, there were proposed several changes, with the goal of evaluating the contribution of the different solutions proposed. It was concluded that they contribute to a reduction of thermal needs of 25.2% and avoided emissions of CO2 is 30.4%. The analysis of the implementation of trigeneration, Combined Heat, Cooling and Power (CHCP) turns it executable. The payback period is less than 8 years.
文摘Under the RHO (renewable heat obligation), public buildings in the Republic of Korea must achieve an 11% overall reduction to thermal energy consumption in buildings more than 10,0O0 m^2. RETScreen Plus is a freely available software tool developed by the Canadian Government which can be used to develop energy baselines of clean energy technologies. Using curve-fitting and statistical methods like CUSUM, the software can combine actual energy performance with near real time weather information from NASA. We developed a method to simulate the performance of a GSHP (ground source heat pump). The three distinct energy zones involve heating, no-energy, and cooling. RETScreen Plus methodology is used to develop curve fits for each distinct zone as it builds a correlation with NASA satellite data. The model then factors the impact of ICT (information and control technologies) as a means to improve and lower the building's energy consumption. Two values of COP (coefficient of performance) are used--the first is a standard ICT COP, while the second is an improved ICT COP with a smart controller. This methodology can then be expanded to incorporate current and future smart meter technologies, time of use rates, energy price signals, demand response and electricity storage options. In summary, this methodology enables a building owner or energy conservation official to quickly and accurately determine the baseline energy for a building and the potential impacts of smart ICT technologies, especially for buildings equipped with GSHP technologies.
基金supported by the National Natural Science Foundation of China (Grant No. 51076147)
文摘An effective thermodynamic transformation analysis method was proposed in this study. According to the phenomenon of ex- ergy consumption always coupling with heat transfer process, the effective thermodynamic temperatures were defined, then the actual power cycle or refrigeration/heat pump cycle was transformed into the equivalent reversible Carnot or reverse Carnot cycles for thermodynamic analysis. The derived effective thermodynamic temperature of the hot reservoir of the equivalent reverse Camot cycle is the basis of the proposed method. The combined diagram of TR-h and TR-q was adopted for the analy- sis of the system performance and the exergy consumption, which takes advantage of the visual expression of the heat/work exchange and the enthalpy change, and is convenient for the calculation of the coefficient of performance and exergy con- sumptions. Take a heat pump water heater with refrigerant of R22 for example, the proposed method was systematically intro- duced, and the fitting formulas of the effective thermodynamic temperatures were given as demonstration. The results show that the proposed method has advantage and well application foreground in the performance simulation and estimation under the variable working conditions.
基金supported by the National Basic Research Program of China(Grant No.2012CB825602)the National Natural Science Founda-tion of China(Grant Nos.41204118,41231067)the Specialized Research Fund for State Key Laboratories of China
文摘The three-dimensional global magnetohydrodynamic model(PPM-LR MHD)is employed to investigate the energy budget in the solar wind-magnetosphere system during the super magnetic storm on November 20,2003,one of the biggest storms during the last decade with Dst^-500 n T.During this event,about 23%solar wind kinetic energy is transferred into the magnetosphere.The total energy input is estimated to be about 9.50×1017 J,about 14 times of a moderate storm.The energy dissipation via the inner magnetosphere is less than the energy input with the coupling efficiency of^63.3%.The energy dissipated via ring current injection is less than that via high-latitude ionosphere at the initial stage of the super storm.Furthermore,both the simulation results and the empirical results indicate that the ratio of ring current injection to the total energy output increases with the enhancement of the magnetospheric activity level.These are consistent with the statistical results we have got before.The empirical equations underestimate the solar wind kinetic energy,the energy input,and the energy dissipation via high-latitude ionosphere compared with the simulation results;however,the coupling efficiency of the high-latitude ionosphere(23.4%)is close to the simulation result(23.1%)during the entire storm time period.