CN102062745A - Tester for rock-soil heat transfer property - Google Patents

Abstract

The invention discloses a rock and soil heat transfer performance tester, which is characterized in that the tester includes a box body, a heat source part, a cold source part and a user part; The controller outside the water tank is connected; the cold source part includes an evaporator installed inside the constant temperature water tank, and the two ends of the evaporator are respectively connected with one end of the compressor outside the constant temperature water tank and one end of the expansion valve; the other end of the compressor and the other end of the expansion valve are respectively connected to the two ends of the condenser; the compressor is also connected to the controller through the signal line; the user part includes the interface valve of the buried pipe heat exchanger, and the two ends of the interface valve are respectively passed The circulating water pump and the heat meter are connected to the constant temperature water tank, the heat meter is also connected to the data recorder, and the circulating water pump is also connected to the controller through the signal line; except that the interface valve is set outside the box, the rest of the components are installed inside the box.

Description

A rock and soil heat transfer performance tester

technical field

The invention relates to a thermal performance tester, in particular to a rock-soil heat transfer performance tester for measuring the heat transfer and heat storage performance of rock-soil bodies on site.

Background technique

In recent years, the development and application technology of shallow geothermal energy resources based on buried pipe drilling has been favored in the field of building energy conservation. Method to realize. Mastering the heat transfer performance of rock and soil has important guiding significance for the implementation of the above technologies. The heat transfer performance index of rock and soil mainly includes the average thermal conductivity of rock and soil and the heat transfer per unit depth.

The rock-soil thermal response testers currently on the market only use adiabatic electric heaters to provide test heat sources, and use constant heat flow to obtain the average thermal conductivity of rocks and soils, and use this parameter to guide the design of ground-source heat pump systems . The tester has poor working condition adjustment (suitable for summer working conditions), and the heating heat flow is seriously affected by field voltage fluctuations, which often leads to large post-data processing errors, and the instrument can only perform single-working condition testing, and the temperature measurement range Small (only from room temperature to 40°C), unable to obtain heat transfer data under heat extraction conditions, and its use is greatly limited.

Contents of the invention

Aiming at the deficiencies of the existing technology, the technical problem to be solved by the present invention is to provide a rock-soil heat transfer performance tester, which can obtain the heat transfer per unit depth of rock-soil mass through heat discharge and heat extraction conditions tests. And the average thermal conductivity, which can provide the actual parameter basis for the design of shallow geothermal energy storage system, has the characteristics of simple structure, wide temperature measurement range, and is suitable for actual use on site.

The technical solution of the present invention to solve the technical problem is to design a geotechnical heat transfer performance tester, which is characterized in that the tester includes a box, a heat source part, a cold source part and a user part; the heat source part includes an internal setting The constant temperature water tank of the heater, the heater is connected with the controller outside the constant temperature water tank; the cold source part includes an evaporator arranged inside the constant temperature water tank, and the two ends of the evaporator are respectively connected to one end of the compressor outside the constant temperature water tank and the expansion valve The other end of the compressor and the other end of the expansion valve are respectively connected to the two ends of the condenser; the compressor is also connected to the controller through the signal line; the user part includes the buried tube heat exchanger Interface valve, the two ends of the interface valve are respectively connected to the constant temperature water tank through the circulating water pump and the heat meter, the heat meter is also connected to the data recorder, and the circulating water pump is also connected to the controller through the signal line; except that the interface valve is set in the tank Except for the outside of the body, the rest of the parts are installed in the box.

Compared with the prior art, the tester of the present invention adopts cold and heat compensation technology, realizes constant water tank temperature through high-precision PID control technology, has good adjustability, and stability can reach ±0.5°C, thereby ensuring stable heat exchange conditions , to reduce the test error; the tester of the present invention is compact in structure, flexible in installation, easy in operation and suitable for mass production.

Description of drawings

Fig. 1 is a schematic diagram of the composition and structure of an embodiment of the geotechnical heat transfer performance tester of the present invention.

Detailed ways

Further describe the present invention below in conjunction with embodiment and accompanying drawing thereof:

The geotechnical heat transfer performance tester (abbreviation tester, referring to Fig. 1) of the present invention design is characterized in that the tester includes a box body 13, a heat source part, a cold source part and a user part; The constant temperature water tank 1 of the device 5, the heater 5 is connected with the controller 6 (PID) outside the constant temperature water tank 1; One end of the compressor 7 outside the water tank 1 is connected with one end of the expansion valve 8; the other end of the compressor 7 and the other end of the expansion valve 8 are respectively connected on the two ends of the condenser 9; the compressor 7 is also connected with the The controller 6 is connected to each other; the cooling fan 10 is installed above the condenser 9; the user part includes the interface valve 2 of the buried pipe heat exchanger, and the two ends of the interface valve 2 are connected with the circulating water pump 3 and the heat meter 11 respectively. The constant temperature water tank 1 is connected, the heat meter 11 is also connected with the data recorder 12, and the circulating water pump 3 is also connected with the controller 6 through the signal line; except that the interface valve 2 is arranged outside the box body 13, other components All are installed in the casing 13.

The prior art tester uses an adiabatic electric heater to provide the heat source, which can only test the heat storage performance of rock and soil in summer, and the temperature measurement range is only normal temperature -40°C. The tester of the present invention has a new design, adopts the PID cold and heat compensation technology based on the refrigeration cycle and the adjustable heater, to maintain stable heat exchange conditions, and can obtain the heat storage performance of the rock and soil in summer and the heat extraction performance in winter, and the temperature measurement The range is extended to 5-80°C, thus making the application field of this technology more extensive.

The tester of the present invention includes two circulation loops: one is a refrigeration circulation loop formed by an evaporator 4, a compressor 7, an expansion valve 8, and a condenser 9; the other constant temperature water tank 1 is formed by a circulating water pump 3 and a buried pipe heat exchanger Heat exchange loop.

The working or testing temperature range of the constant temperature water tank 1 of the tester of the present invention is 5-80°C, which is higher than the normal temperature of -40°C in the prior art.

A further feature of the testing instrument of the present invention is that the evaporator 4 is installed above the heater 5 ; the cooling fan 10 is installed above the condenser 9 . The advantage of installing the evaporator 4 above the heater 5 is that it is more conducive to cold and heat compensation, and maintains a stable temperature in the constant temperature water tank 1 . The benefit of the cooling fan 10 being installed above the condenser 9 is that it is more convenient to fully exchange heat with the outdoor air.

A further feature of the tester of the present invention is that the evaporator 4 adopts a multi-layer casing structure. This structure is conducive to improving the refrigeration efficiency per unit volume and realizing a compact structure design; the condenser 9 adopts a finned tube structure. This structure is conducive to increasing the heat exchange area with the outdoor air and improving the cooling efficiency.

The testing instrument of the invention is suitable for testing the heat transfer performance of rock and soil within a depth of 150m. The matching forms of the buried tube heat exchanger include single U-shape, double U-shape, sleeve-pipe heat exchanger, and the like.

The working principle and process of the tester of the present invention are as follows: First, connect the single U-shaped or double U-shaped buried pipe heat exchanger with the interface valve 2 of the tester, and then fill the constant temperature water tank 1 with water or antifreeze Liquid, and confirm that the airtightness is good, and then start the test work.

The tester of the present invention includes two test working modes: heat discharge mode and heat acquisition mode. The heat removal mode is suitable for testing the heat storage performance of rock and soil mass in summer, while the heat extraction mode is suitable for testing the heat acquisition performance of rock and soil mass in winter. This design expands the range of working conditions of the tester and is more suitable for practical applications.

For the heat removal mode, first set the temperature of the constant temperature water tank 1 through the controller 6 (PID), and the temperature range is from normal temperature to 80°C; then turn on the circulating water pump 3 to discharge heat from the rock and soil mass. Under the intervention of the controller 6, the fluid temperature in the constant temperature water tank 1 will maintain a relatively stable value. When the stable heat exchange state is reached, turn off the circulating water pump 3; then reset the temperature of the constant temperature water tank 1, and enter another working condition test.

For the heat extraction mode, the temperature of the constant temperature water tank 1 is first set by the controller 6, and the temperature range is from 5°C to normal temperature; then the circulating water pump 3 and the compressor 7 are turned on, and the expansion valve 8, the condenser 9 and the cooling fan 10 are simultaneously Also in working condition. Under the temperature compensation of the heater 5 and the intervention of the controller 6, the temperature of the fluid in the constant temperature water tank 1 will maintain a relatively stable value. When reaching a stable heat exchange state, turn off the circulating water pump 3 and the compressor 7; then reset the temperature of the constant temperature water tank 1, and enter another working condition test.

During the above testing process, the heat meter 11 can record the temperature and circulation flow at the interface valve 2 of the buried pipe heat exchanger in real time, and print it out through the data recorder 12 for use in subsequent data processing.

The tester of the present invention designs a constant temperature water tank 1, and constitutes a circulation loop through the circulating water pump 3 and the buried pipe heat exchanger, and the heat transfer performance of the rock and soil mass can be obtained by changing the temperature of the inlet and outlet under a certain flow rate; A heater 5 is installed in the water tank 1, and is connected with the controller 6, which can realize a constant temperature of the exhaust heat fluid in the range of room temperature to 80°C; an evaporator 4 is also installed in the constant temperature water tank 1, and the compressor 7, expansion The valve 8, the condenser 9 and the cooling fan 10 together form a cooling cycle, and through the coordinated action of the controller 6 and the heater 5, a constant heat-taking fluid temperature test within the range of 5°C to room temperature can be realized. The tester designed by the present invention breaks through the limited temperature measurement range of the traditional technology, and can only test the limitation of summer working conditions, and extends the application range to the high temperature heat storage field of rock and soil, and the temperature measurement range is extended to 5-80°C. The performance parameters of rock and soil heat storage in summer and heat extraction in winter can be obtained, which has a practical guiding role in realizing the efficient utilization of shallow geothermal energy and the cross-season utilization of solar energy and industrial waste heat.

Claims (4)

1. a ground heat transfer property tester is characterized in that this tester comprises casing, thermal source part, low-temperature receiver part and User Part; Described thermal source comprises that partly inside is provided with the constant temperature water tank of well heater, and well heater is connected with constant temperature water tank controller outward; Described low-temperature receiver partly comprises the inner evaporator that is provided with of constant temperature water tank, and the two ends of evaporator are connected with an end of constant temperature water tank compressor outward and an end of expansion valve respectively; The other end of compressor and the other end of expansion valve are connected on the two ends of condenser; Compressor also is connected with controller by signal wire; Described User Part comprises the interface valve of ground heat exchanger, and the two ends of interface valve are connected with constant temperature water tank with calorimeter by water circulating pump respectively, and calorimeter also is connected with datalogger, and water circulating pump also is connected with controller by signal wire; Except that described interface valve is arranged on the outside of casing, all the other parts are installed within the casing.

2. ground heat transfer property tester according to claim 1 is characterized in that described evaporator is installed in the top position of well heater; Described cooling blower is installed in the top position of condenser.

3. ground heat transfer property tester according to claim 1 is characterized in that described evaporator adopts multilayer sleeve formula structure; Described condenser adopts the fin tube type structure.

4. according to claim 1,2 or 3 described ground heat transfer property testers, the temperature-measuring range that it is characterized in that described tester is 5-80 ℃.

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