The Experimental Research And Development Of Rock-soil Thermal Response Test Equipment

As the 21st century comes, the Chinese economy developed rapidly, industry and cities construction stepped up, the demand and supply contradiction of energy is more and more apparent. At the same time, the environment is becoming more and more serious, especially the increasing emissions of greenhouse gas lead the global climate becoming worse, and sustainable development of our society is seriously threat.Shallow geothermal as a renewable energy had gradually attracted people attention, the ground source heat pump has been widely used not only for its high energy efficient but also as a clean and green heat source. But there is some deviation in the design of ground heat exchanger, which enlarges the initial investment of ground source heat pump. This restricts the promotion and development of the Ground Source Heat Pump system. The key to solve this question is gaining the accurate thermal properties parameters of underground rock-soil. But the test equipment of thermal properties parameters about rock-soil is scarce, and the test method is limit, too. This paper study the test method and made the rock thermal properties response test equipment on the ground of "Ground Source Heat Pump Systems engineering technology manual ".This paper designed the rock-soil thermal properties response test equipment based on the average heat transfer coefficient of the line heat source model. According to the testing needs, we compiled the data collection system based on the MCGS software.The thermal response test apparatus used electric heaters to simulate the heat pump's condenser in summer conditions. The import and export temperatures of the ground heat exchanger are measured, as well as the initial temperature of rock-soil and the volume of circulating water. All of them will be deal with by the MCGS software and the average heat transfer coefficient of the rock-soil will be calculated. The values of electric current are obtained by the current transformer, current transducer and data collecting module; the values of voltage come from the voltage transducer and data collecting module; the flow measurement by the electromagnetic flow meter and data acquisition module; at the same time, the temperature is achieved by using PT100 platinum resistance temperature sensor and temperature data collected module. Finally, these signals will be converted from the RS-485 to RS-232 by ADAM-4520 communication module, and then the RS-232 signal communicated with computer equipped by MCGS system.The MCGS system of thermal response properties response test equipment can handle a variety of test parameters. The sampling parameters, calculated parameters and these curves are dynamic displayed on the screen. At the same time, the system has the functions that automatically justify the system stable, record data, automated calculations. It can also analysis the historical graphical curve and output data.The thermal properties response test apparatus was made successfully. We design the corresponding experiment. The experiment was completed in the ground source heat pump laboratory and the average heat transfer coefficient of rock-soil had been obtained.