Research On Performance Of Waste Heat Recovery Solar Jet-compression Composite Refrigeration System In Printing And Dyeing Factory

While China’s national economy is developing rapidly,it is also facing serious energy crisis and environmental problems.Therefore,people gradually shift their attention to the utilization of clean energy.The textile industry is a high-energy-consuming,high-consumption,high-pollution industry.It consumes a large amount of heat during its production process.The large amount of waste heat generated is lost to the atmosphere with waste hot water and waste flue gas,causing serious energy losses.As a big textile country,it is necessary to recycle the waste heat resources of textile printing and dyeing plants.On the other hand,China’s solar energy resources are extremely rich and can be used free of charge without restriction.Therefore,the introduction of solar collectors into textile printing and dyeing enterprises will surely reduce energy consumption even more.Since the solar injection refrigeration system can use low-grade heat sources such as solar energy and residual heat,it has the characteristics of reliable operation and simple structure,and the research is of great significance.However,solar energy has strong dependence on the season and weather,and its performance is also affected.Based on this,a heat recovery solar injection-compression combined refrigeration system is proposed,which not only recovers waste heat and waste heat of the textile printing and dyeing plant,but also reduces energy consumption.At the same time,it also improves the performance coefficient of the solar injection-compression combined refrigeration system.The system also provides an auxiliary heat source,which enhancesthestabilityandapplicabilityofthesystem.Based on the preliminary research of the research group,this paper designs a waste heat recovery solar injection-compression composite refrigeration system for the specific situation of waste heat discharged from a certain textile printing and dyeing plant.The EES software is used under the premise of its thermodynamic analysis.The calculation model of the system was established,and the energy-saving effect of the waste heat recovery system was compared and analyzed.Finally,the influence of the change of temperature and flow rate of the wastewater waste heat recovery unit waste water on the performance of the system was studied and the enery-saving of the system was analyzed.Themainworkis as follows:（1）A specific heat-relevant data study was conducted using a knitted printing and dyeing plant in Jinjiang City,Fujian Province as an example.The heat collection area of the solar heat collection system was determined based on the amount of waste heat generated by the company and the required cooling load,combined with the actual conditions of the plant.Situation,a specific waste heat recovery plan was designed,and finally economic benefits were analyzed.The results showed that the annual amount of waste heat that the enterprise can recycle is 5.01×10¹⁰kJ,and the annual cost after recycling can be about15,247,680 yuan.The annual cumulative reduction of pollutant emissions is 217.8 tons of dust,363.0tons ofcarbon dioxide,and127.1tonsofnitrogenoxides.（2）Based on the thermodynamic analysis of the waste heat recovery injection-compression composite refrigeration system,the thermodynamic calculation model of the system was established.The thermodynamic calculation program was programmed with EES software.The changes of the system COP,generator heat load,and heat collection area after preheating by the waste heat recovery unit were studied.Finally,different working fluids were selected to compare the energy saving and application value of the waste heat recovery system with respect to the conventional spray-compression refrigeration system.The results show that the higher the outlet temperature of the waste heat recovery system,the lower the heat load of the generator required for the three working fluids and the higher the COP value of the system.The COP values of the three are descending from the order:R1234ze（E）>R1234yf>R134a,the heat load of the generator is R134a>R1234yf>R1234ze（E）in order;Compared with the traditional spray-compression type composite refrigeration system,the heat load of the generator required for the waste heat recovery type system is lower and the COP value is larger.The greater the preheating temperature difference,the more obvious the energy-saving effect.When the temperature difference is 30°C,the heat load of the generator can be saved about 28.42%,and the COP valuecanbeincreasedby36.51%.（3）For the main influencing factors of the waste heat recovery injection-compression composite refrigeration system,the effects of different temperature,evaporation temperature and condensing temperature on the COP and generator heat load are studied.The results show that the COP value of the system is proportional to the change of evaporation temperature and is inversely proportional to the change of condensing temperature under the same working conditions.It will increase first and then decrease with the increase of temperature.The higher the temperature,The larger the change,the higher the COP value of the system when the temperature is 75°C.When the other conditions are the same,the heat load required by the generator is inversely proportional to the change of evaporation temperature,which is proportional to the change of the condensing temperature.The heat load required by the generator appears to decrease first and then increase with increasing temperature.The higher the temperature is,the larger the change is,and the minimum heat load required by the generator is 75°C;in other conditions When constant,the greater the flow rate of waste water,the higher the temperature,the greater the COP value of the system,and the smaller the heat load required by the generator;the higher the temperature,the higher the condensing temperature,the more impact the change in flow rate has on system performance.small.（4）After adding the waste heat recovery device,the collector only needs to provide a heat collection area of 21m².Recovered waste heat is responsible for 93.6%of the generator heat load,which can reducethe heat-collecting areabyabout 291m²,andhasgoodenergy-saving effect.