Scheme Design And Analysis Of Measurement And Control Operation Of Ammonia Water Absorption Refrigeration Test Bench

In the new period of the energy revolution,developing the new clean energy is one way to ease the energy crisis,but improving utilization efficiency of primary energy is also a way which we need to pay attention.Ammonia absorption refrigeration system(AARS)occupies an important position in the field of refrigeration by the virtue of the environmental friendliness of the circulatory working fluid and the advantage of utilizing the low grade or waste heat.However,the investigations of promoting the miniaturization of AARS mainly focused on the ammonia solution circulation of nanoparticles is mostly concentrated in a certain part of the solution cycle,such as the strengthening of the generation process,or the strengthening of the absorption process,yet the literature in the experimental research on the impact on the whole solution circulation caused by added nanoparticles has not been reported.Therefore,the paper presents a stable and reliable ammonia absorption refrigeration test bench used for studying the effect of nanoparticles on the entire system under the new situation of energy shortage.The design conditions of the test bench are: generation temperature is 160°C,evaporation temperature is-15°C,inlet cooling water temperature is 32°C,and cooling capacity is 3kW of the test bench.Firstly,the thermal load of each experimental device is calculated by theoretical thermal calculation,and the compact and suitable equipment is selected and used to assemble the test bench that is convenient for experimental operation;the three-dimensional graphics software is used to provide instructions for on-site assembly work,and the control circuit scheme for safe operation of experimental equipment is customized.Secondly,using the theoretical model to simulate the change trend of the performance coefficient of the experimental system under the different external environment,simulate the changing of the generator thermal load under the same cooling capacity,and analyze the relationship between the load change and the performance coefficient.In addition,the relationship between refrigerant purity and temperature and pressure is calculated.On the basis of analyzing the impact on system of refrigerant purity,a purification scheme is proposed.In addition to the theoretical research,the complete process flow and control circuit of the test bench are designed in combination with the actual design,and the necessity of the process flow is analyzed.What’s more,a set of data acquisition and processing system is established to monitor the operating parameters of the test bench at all time and to process the experimental result data for each set of working conditions to improve the experimental work efficiency.Finally,finding and repairing the loop leakage points and equipment insulation defects by completing the debugging work of the test bench.A complete first-time liquid-filled and startup plan is designed with the accordance of the process flow,and the feasibility is verified through the practical operation.The experimental result of the coefficient of performance under a certain working condition is compared with the theoretical simulation,and the energy loss of the test bench is calculated and analyzed.By varying the working condition of experiments,the coincidence of the coefficient of performance curves between the experimental results and the theoretical simulation is compared.The results show that the curves change of the coefficient of performance under the variable generation temperature and the variable evaporation temperature are consistent with the simulation results;however,the test bench performance coefficient deviates more from the simulation results when the inlet cooling water temperature is lower.Taking into account the flow rate of the cooling water of reflux condenser is so large that the refrigerant condenses and flows back to the generator,it’s causing the extra heat loss;as the inlet cooling water temperature rises,the experimental results curve is getting closer to the simulation curve.Also,the experimental results demonstrate the possibility of practical application in improving the energy utilization.In addition,the refrigerant concentration in the evaporator is calculated for each group of operating condition.According to the change trend of the refrigerant concentration,the purification scheme of the refrigerant enters the evaporator is also proposed.The most critical process of the experimental research work lies in the control and adjustment of the test bench.Taking the test bench as the object,the control schemes of the ammonia-water absorption refrigeration system are discussed in conjunction with the practical operation,and the closed control and regulation schemes that are composed of several adjustment methods are proposed in the form of flow charts.