Study On New Types Of Absorption Heat Transformer Based On Low Grade Waste Heat Recovery

Absorption heat transformer used for low grade waste heat recycling,on the one hand,can improve energy efficiency and economic benefits,also indirect reduce combustion of fossil energy and the global greenhouse effect;On the other hand,can clean the thermal pollution because of the discharge of high temperature waste heat,and reduce the urban heat island effect.Therefore,the heat transformer technology is one of the important technology,which on the mission of cleaner production and saving energy and reducing consumption.Under the background of the study,this paper puts forward new types of absorption heat transformer based on low-grade waste heat recovery.Firstly,in this paper,a steady state simulation model about recovering low-grade waste heat by using LiBr-H20 absorption heat transformer has been developed,which is based on detailed mass and energy balances and thermodynamic relationships of the system and its components.Using orthogonal experimental methods,a comprehensive parameter F is put forward after taking total heat exchange area,circulation flow,COP(coefficient of performance)into consideration.The sensitivity of all system parameters affected by temperature difference of each component and their couple effect is illustrated,and the impact of each temperature difference on the total area,circulating flow,COP and index of F was analyzed.Secondly,A new ejection-absorption heat transformer with two generators is proposed in this paper.Compared with the traditional heat transforper,a low pressure generator and ejector is introduced in the new system:high pressure refrigerant vapor from the evaporator drive ejector,whose entraining keep the low pressure generator in lower pressure,which results in the extreme decrease of pressure in the whole system and the increase of system’s concentration difference and temperature rise in heat transformer.After the analysis of thermal dynamics of the system,the results shows that the temperature rise has become 25℃ rather than the 17.6℃ of traditional counterparts and the new system improve the heat quality.Thirdly,To solve the problem of heating and cooling source where both heat and cool are needed with one device,a new ejection-absorption heat transformer combined with refrigeration that can both cooling and heating is put forward in this paper.The thermal simulation of this new system is conducted,based on theory of mass and energy balances and ejector theory.The effects of various parameters on the performance of the system are also analyzed.And by recovering low-grade waste heat,it can provide services.The results show that the performance of the heat flows through the evaporator first tandem process is superior to the other processes;Low pressure evaporator in chilled water outlet temperature is higher,the condenser cooling water outlet temperature is lower,the better the performance of the system.And water supply temperature in absorber is higher,the greater the efficiency of heating exergy,the lower the coefficient of performance.Finally,in this paper,economic analysis and evaluation of the new ejection-absorption heat transformer with two generators and the new ejection-absorption heat transformer combined with refrigeration,which show they have good environmental and economic benefits.