A hybrid heat pump(compression/absorption)with an integrated thermal photovoltaic unit is studied.The considered working fluids are organic mixtures:R245fa/DMAC and R236fa/DMAC,chosen for their low Global Warming Pote...A hybrid heat pump(compression/absorption)with an integrated thermal photovoltaic unit is studied.The considered working fluids are organic mixtures:R245fa/DMAC and R236fa/DMAC,chosen for their low Global Warming Potential.The main objective is the optimization of energy efficiency in order to minimize the environmental impact through the implementation of a sustainable strategy.It is shown that Exergy Analysis itself is a valuable tool in energy integration.Within the imposed framework of minimizing total annual costs,entropy analysis can be instrumental in determining the optimal plant concept,optimizing energy conversion and use,and improving profitability.The present results are discussed under the optimistic hope that they may help to define new energy and environmental policies.展开更多
A hybrid ground-coupled heat pump（HGCHP）project in Nanjing,China is chosen to analyze the building energy-consumption properties in terms of different control strategies,building envelope and the terminal air-condit...A hybrid ground-coupled heat pump（HGCHP）project in Nanjing,China is chosen to analyze the building energy-consumption properties in terms of different control strategies,building envelope and the terminal air-conditioning system.The HGCHP uses a supplemental heat rejecter to dissipate extra thermal energy to guarantee underground soil heat balance.The software EnergyPlus is employed to simulate the project and design the heat flow of the cooling tower and the borehole heat exchanger（BHE）.Then two feasible control strategies for the cooling tower and the borehole heat exchanger are proposed.The energy-saving potential of the building envelope is analyzed in terms of the surface color of the wall/roof.With the same terminal system,it is found that in the cooling season the heat flow of the insulated building with black wall/roof is 1.2 times more than that with white wall/roof.With the same insulated building and gray wall/roof,it is concluded that the heat pump units for a primary air fan-coil system show an annual energy consumption increase of 44.7 GJ compared with a radiant floor system.展开更多
Recovering waste heat from industrial processes is bene ficial in order to reduce the primary energy demands and heat pumps can be used to this purpose.Absorption heat pumps are energy-saving and environment-friendly ...Recovering waste heat from industrial processes is bene ficial in order to reduce the primary energy demands and heat pumps can be used to this purpose.Absorption heat pumps are energy-saving and environment-friendly because use working fluids that do not cause ozone depletion and can reduce the global warming emissions.The hybrid heat pump processes combine the conventional vapor-compression and the absorption heat pump cycles.Studies about the simulations and modeling of hybrid heat pumps are few in literature.In this research a mathematical model for single effect absorption and hybrid heat pump is carried out with Chem Cad? 6.0.1.LiBr–H_2O is used as working fluid while electrolytic NRTL and electrolytes latent heat are used as thermodynamic model due to the better results.Binary parameters of activity coef ficients are regressed from experimental vapor pressure data while default constants are used for the solubility expressions.A design of heat pumps is developed and a new modeling of generator is analyzed.The coef ficient of performance of absorption heat pump and hybrid heat pump is equal to 0.7 and 0.83 respectively.For absorption heat pump a sensitivity analysis is carried out to evaluate the effect of temperature and pressure generator,the concentration of Li–Br solution on coef ficient of performance,cooling capacity and working fluid temperature.For hybrid heat pump,the different coef ficients of performance,the primary energy ratio,the generator heat,and the compressor power are analyzed for different values of compressor proportion.Results show that comparing the two systems the hybrid pump allows to save more primary energy,costs and carbon dioxide emissions with respect to absorption heat pump with the increasing of compressor proportion parameter.Future researches should focus on the construction of this heat pumps integrated in chemical processes as a biogas plant or trigeneration systems.展开更多
Preliminary investigation shows that air sourced type heat pumps by energy efficiency are competitive with gas boilers having 93% of coefficient of performance （COP） if heat pumps are used in climatic zones, having ...Preliminary investigation shows that air sourced type heat pumps by energy efficiency are competitive with gas boilers having 93% of coefficient of performance （COP） if heat pumps are used in climatic zones, having outside air temperature higher than （-3 ℃ to -5 ℃）. But, in such conditions the heat pump＇s evaporator is covered by ice crust, which cuts off the flow of outside air-heat source through the evaporator of heat pump. For avoiding stating problems it is recommended to use as heat source a mixture of waste warm gases. In this article a high efficiency heating-cooling system is developed, consisting of warm gases mixture sourced heat pump, heating boiler operating simultaneously with heat pump and solar air heater. The heating demand of the served house is shared between boiler and heat pump. Instead of outside air the warm gases mixture enters into evaporator of heat pump. A new construction of heat exchanger was developed. The article presents the structure and principle of operation, as well as the method for optimization and design of suggested system. Analysis proved high energy efficiency and cost effectiveness of the new system.展开更多
The increase in the population of Tunisia and the industrial development posed with acuity during the end of the major problems. Without contribution of additional resources, water will then be likely to be done incre...The increase in the population of Tunisia and the industrial development posed with acuity during the end of the major problems. Without contribution of additional resources, water will then be likely to be done increasingly rare. The solar still is a small production system, yielding on average 2-5 L/day. In this study we propose a solar distiller assisted by a heat pump. The design of this distiller uses for the evaporation of water and its condensation two phenomena are studied Simple Solar Distiller （SSD） and Simple Solar Still Distiller Hybrid with heat Pump （SSDHP）. The performance is less than 2 L/mVday and a performance of 30% for the SSD. But the SSDHP is 12 L/m2/day, the energetic efficiency reaches 90%.展开更多
Seafood,especially sea cucumbers and oysters are an expensive delicacy in several Asian countries.Traditional sun-drying of these products takes 3 to 4 days and fetches a lower market price.Modern industrial drying ma...Seafood,especially sea cucumbers and oysters are an expensive delicacy in several Asian countries.Traditional sun-drying of these products takes 3 to 4 days and fetches a lower market price.Modern industrial drying machines used for seafood drying are unable to dry sea cucumbers and oysters without texture and color degradation as they are delicate,temperature-sensitive and have longer drying time.An economical drying system that does not cause texture or color degradation is the heat pump drying system and is commonly applied for agriculture and fabric drying.In this study,the heat pump technology is applied to develop two hybrid dryer models(bottom discharge and front discharge)to dry shellfish and sea cucumbers in large scale for storage and transportation.Each model is tested in a laboratory-scale with wet sponges as input material for its dehumidification capacity and the power consumed to attain the target dryness.The front discharge model is found to have rapid drying capability and economy.Computational fluid dynamic tools are used to study the hot air flow behavior and flow uniformity inside the drying chamber.The front discharge model showed smooth uniform flow over the trays with fewer losses in the flow velocity.The front discharge model with higher drying rate,lower power consumption and uniform airflow distribution over the trays is chosen for the industrial-scale design.展开更多
文摘A hybrid heat pump(compression/absorption)with an integrated thermal photovoltaic unit is studied.The considered working fluids are organic mixtures:R245fa/DMAC and R236fa/DMAC,chosen for their low Global Warming Potential.The main objective is the optimization of energy efficiency in order to minimize the environmental impact through the implementation of a sustainable strategy.It is shown that Exergy Analysis itself is a valuable tool in energy integration.Within the imposed framework of minimizing total annual costs,entropy analysis can be instrumental in determining the optimal plant concept,optimizing energy conversion and use,and improving profitability.The present results are discussed under the optimistic hope that they may help to define new energy and environmental policies.
文摘A hybrid ground-coupled heat pump（HGCHP）project in Nanjing,China is chosen to analyze the building energy-consumption properties in terms of different control strategies,building envelope and the terminal air-conditioning system.The HGCHP uses a supplemental heat rejecter to dissipate extra thermal energy to guarantee underground soil heat balance.The software EnergyPlus is employed to simulate the project and design the heat flow of the cooling tower and the borehole heat exchanger（BHE）.Then two feasible control strategies for the cooling tower and the borehole heat exchanger are proposed.The energy-saving potential of the building envelope is analyzed in terms of the surface color of the wall/roof.With the same terminal system,it is found that in the cooling season the heat flow of the insulated building with black wall/roof is 1.2 times more than that with white wall/roof.With the same insulated building and gray wall/roof,it is concluded that the heat pump units for a primary air fan-coil system show an annual energy consumption increase of 44.7 GJ compared with a radiant floor system.
文摘Recovering waste heat from industrial processes is bene ficial in order to reduce the primary energy demands and heat pumps can be used to this purpose.Absorption heat pumps are energy-saving and environment-friendly because use working fluids that do not cause ozone depletion and can reduce the global warming emissions.The hybrid heat pump processes combine the conventional vapor-compression and the absorption heat pump cycles.Studies about the simulations and modeling of hybrid heat pumps are few in literature.In this research a mathematical model for single effect absorption and hybrid heat pump is carried out with Chem Cad? 6.0.1.LiBr–H_2O is used as working fluid while electrolytic NRTL and electrolytes latent heat are used as thermodynamic model due to the better results.Binary parameters of activity coef ficients are regressed from experimental vapor pressure data while default constants are used for the solubility expressions.A design of heat pumps is developed and a new modeling of generator is analyzed.The coef ficient of performance of absorption heat pump and hybrid heat pump is equal to 0.7 and 0.83 respectively.For absorption heat pump a sensitivity analysis is carried out to evaluate the effect of temperature and pressure generator,the concentration of Li–Br solution on coef ficient of performance,cooling capacity and working fluid temperature.For hybrid heat pump,the different coef ficients of performance,the primary energy ratio,the generator heat,and the compressor power are analyzed for different values of compressor proportion.Results show that comparing the two systems the hybrid pump allows to save more primary energy,costs and carbon dioxide emissions with respect to absorption heat pump with the increasing of compressor proportion parameter.Future researches should focus on the construction of this heat pumps integrated in chemical processes as a biogas plant or trigeneration systems.
文摘Preliminary investigation shows that air sourced type heat pumps by energy efficiency are competitive with gas boilers having 93% of coefficient of performance （COP） if heat pumps are used in climatic zones, having outside air temperature higher than （-3 ℃ to -5 ℃）. But, in such conditions the heat pump＇s evaporator is covered by ice crust, which cuts off the flow of outside air-heat source through the evaporator of heat pump. For avoiding stating problems it is recommended to use as heat source a mixture of waste warm gases. In this article a high efficiency heating-cooling system is developed, consisting of warm gases mixture sourced heat pump, heating boiler operating simultaneously with heat pump and solar air heater. The heating demand of the served house is shared between boiler and heat pump. Instead of outside air the warm gases mixture enters into evaporator of heat pump. A new construction of heat exchanger was developed. The article presents the structure and principle of operation, as well as the method for optimization and design of suggested system. Analysis proved high energy efficiency and cost effectiveness of the new system.
文摘The increase in the population of Tunisia and the industrial development posed with acuity during the end of the major problems. Without contribution of additional resources, water will then be likely to be done increasingly rare. The solar still is a small production system, yielding on average 2-5 L/day. In this study we propose a solar distiller assisted by a heat pump. The design of this distiller uses for the evaporation of water and its condensation two phenomena are studied Simple Solar Distiller （SSD） and Simple Solar Still Distiller Hybrid with heat Pump （SSDHP）. The performance is less than 2 L/mVday and a performance of 30% for the SSD. But the SSDHP is 12 L/m2/day, the energetic efficiency reaches 90%.
基金supported by a grant(No.10067058)from the Korea Institute of Energy Technology Evaluation and Planning(KETEP)that was funded by the Ministry of Trade,Industry and Energy(MOTIE)。
文摘Seafood,especially sea cucumbers and oysters are an expensive delicacy in several Asian countries.Traditional sun-drying of these products takes 3 to 4 days and fetches a lower market price.Modern industrial drying machines used for seafood drying are unable to dry sea cucumbers and oysters without texture and color degradation as they are delicate,temperature-sensitive and have longer drying time.An economical drying system that does not cause texture or color degradation is the heat pump drying system and is commonly applied for agriculture and fabric drying.In this study,the heat pump technology is applied to develop two hybrid dryer models(bottom discharge and front discharge)to dry shellfish and sea cucumbers in large scale for storage and transportation.Each model is tested in a laboratory-scale with wet sponges as input material for its dehumidification capacity and the power consumed to attain the target dryness.The front discharge model is found to have rapid drying capability and economy.Computational fluid dynamic tools are used to study the hot air flow behavior and flow uniformity inside the drying chamber.The front discharge model showed smooth uniform flow over the trays with fewer losses in the flow velocity.The front discharge model with higher drying rate,lower power consumption and uniform airflow distribution over the trays is chosen for the industrial-scale design.
