Design Of Low Temperature Power Generation Experimental Platform And Research On Temperature Control Algorithm Of Cold Source Output

Organic Rangkine Cycle(ORC)power generation is a new low temperature waste heat utilization technology,which has the advantages of high efficiency,low investment and environmental friendly,and plays an important role in the utilization of middle and low grade waste heat resources.The research on ORC power generation technology mainly focuses on the application and power generation performance optimization of geothermal power generation,industrial waste heat recovery power generation,solar thermal power generation,biomass energy combustion power generation and other fields.In order to provide simulation experiment conditions for the application of ORC power generation technology in engineering field and scientific experiment research,a new low temperature power generation experiment platform with variable output temperature of cold and heat source is designed in this paper,which can be used to simulate the operation state of ORC power generation system under different temperature conditions.This paper is mainly studied from the following four aspects:(1)Based on the 3 k W ORC generator set,the system design of the low-temperature power generation experimental platform is completed,the thermodynamic mathematical model of the working principle of the experimental platform is established,and the components design of the low-temperature power generation experimental platform is completed,including the design of the cold and heat source module and the design of the system monitoring module.The main performance indicators of the experimental platform are as follows: The cold source module can output a cold source whose temperature ranges from-20 ° C to 30 ° C;the heat source module can output a heat source whose temperature ranges from 50 ° C to 120 ° C;the system monitoring module can control the heat source module to output a stable heat source temperature and collect and monitor system data.(2)In order to achieve the stable output temperature of-20℃～30℃ of the cold source module,it is necessary to establish an accurate control algorithm of the cold source output temperature.Therefore,experimental research is conducted on the influencing factors of the cold source output temperature,and the variation rule between the heat source output temperature,outdoor temperature,frequency converter and the cold source output temperature is explored.The experimental results show that the output temperature of the cold source increases linearly with the increase of outdoor temperature when the output temperature of the heat source and the frequency of the converter remain unchanged.When the output temperature of the heat source remains unchanged and the frequency of the frequency converter is changed,it is found that the change rate between the output temperature of the cold source and the outdoor temperature at different frequencies is very small,and its average value can be directly taken.At the same time,it is found that when the outdoor temperature and the heat source output temperature remain unchanged,the cold source output temperature decreases with the increase of frequency converter.(3)By regression analysis of the experimental data of the factors affecting the output temperature of the cold source,the variation rule of the output temperature of the cold source and frequency converter is obtained under the condition of changing outdoor temperature and heat source temperature,and the control algorithm of the output temperature of the cold source is established.In this paper,the accuracy of the above control algorithm is analyzed by random working condition experiment.Experimental results show that the maximum absolute error between the predicted value of the output temperature of the cold source and the experimental value is 0.4℃,within the experimental error of ±0.5℃.The results show that the accuracy of the control algorithm can meet the experimental requirements of the experimental platform.(4)Using the cold source output temperature control algorithm,the development of the cold source output temperature control system is completed,so that the cold source module can output the cold source with stable temperature according to the experimental demand.The control system is mainly composed of man-machine interaction module,PLC controller,driver module and fault detection module.The experimental results show that the control system can maintain the stability of the output temperature of the cold source by automatically adjusting the frequency of the frequency converter.Within the error range of±0.5℃,the actual output temperature of the cold source accords with the temperature set before the experiment,indicating the stability and reliability of the control system.In this paper,through the theoretical and experimental research of the low temperature power generation experimental platform and its output temperature of cold source,a high accuracy control algorithm of cold source output temperature is established,and the stability of cold source output temperature is realized,and then the cold and heat source with variable temperature can be stably output by the experimental platform is realized.The research of the control algorithm and the design method of the experimental platform can provide an important reference scheme for the experimental system development and standardization of ORC power generation technology,and provide an important theoretical basis for the experimental system development.