KR100818769B1 - Device of evaluating ground thermal conductivity - Google Patents

Abstract

A measuring device of underground thermal conductivity is provided to measure accurate underground thermal conductivity in real time by including an HPE tube, a supplementary water tank, a supplementary water circulating pump, measuring equipment, a measuring instrument and a control unit. A measuring device of underground thermal conductivity comprises an HPE tube, a supplementary water tank, a supplementary water circulating pump(12), measuring equipment, a measuring instrument and a control unit. The HPE tube transfers heat of circulating water heated by an electric heater(8) to underground and allows the circulating water to flow into the measuring device. The supplementary water tank stores supplementary water for supplementing the circulating water lost during air purging inside the HPE tube and operation of the measuring device. The supplementary water circulating pump circulates the supplementary water to a Tee pipe(14). The measuring equipment heats the circulating water in the HPE tube, measures the temperature of the circulating water at underground inlet and outlet and measures the flow rate of the circulating water in the HPE tube. The measuring instrument is connected to an output terminal of each measuring device in the measuring equipment and measures a value for evaluating thermal conductivity. The control unit calculates underground thermal conductivity based on the processed data by using an underground thermal conductivity measuring program.

Description

Device for evaluating ground thermal conductivity

1 is an installation state diagram of the underground thermal conductivity measuring apparatus according to the present invention.

Figure 2 is a detailed view showing the installation state of the underground thermal conductivity measuring apparatus according to the present invention.

3 is a detailed structural diagram of a sensor and a flow meter provided in the terminal box of FIG.

Figure 4 is a photograph showing the detailed structure of the terminal box of Figure 1;

<Explanation of symbols for the main parts of the drawings>

One… Make-up tank

4… Terminal box

6... HPE Tube

8… Electric heater

9... RTD sensor pocket

11... Flow meter

12... In-line circulation pump

14... Tee Piping for Air Purging and Filling

The present invention relates to underground thermal conductivity measurement, and more particularly, to an underground thermal conductivity measurement apparatus that can be easily installed and can accurately measure thermal thermal conductivity in real time in the field.

Most commonly used energy sources are fossil fuels such as coal, petroleum, natural gas, or nuclear fuels. However, fossil fuels pollute the environment due to various pollutants generated during the combustion process, and nuclear fuel generates harmful substances such as water pollution and radioactivity, and these energy sources have a limited amount of reserves.

Therefore, in recent years, the development of alternative energy to replace this has been actively progressed.

Among these alternative energy, researches on natural energy such as wind, solar, geothermal, etc. have been conducted for a long time and practically installed and used air-conditioning and heating system. These natural energies have almost no influence on environmental pollution and climate change. While there is an advantage in obtaining energy, it is a key point in the development of natural energy technology to increase the density and convert it into a usable form due to the drawback of very low energy density.

One of such natural energy technologies is known as a heat pump system that performs cooling and heating using geothermal heat as a heat source. Heat pump system using geothermal heat is a technology that uses heat exchanger to install heat exchanger to recover heat in the ground of 10 ~ 20 ℃ or discharge heat into the ground.

In general, as a heat source of a heat pump, an air heat source method of obtaining or discharging heat in the air, such as an air conditioner, a water heat source method of discharging heat through a cooling tower, and the like are used. The use of geothermal sources has the advantage that the energy efficiency is very high compared to air heat sources.

In particular, the year-round air temperature in the areas where the four seasons are obviously changed greatly varies from -20 to 40 ℃, while the underground temperature is almost constant at 10-20 ℃ during the year below 5m underground.

Therefore, when cooling in summer, the air heat source temperature is consumed a lot of power to discharge the cooling heat to 30 ℃ or more, while the geothermal heat source is smoothly discharged to 10 ~ 20 ℃ shows a high efficiency. On the contrary, in the case of heating in winter, the air heat source is difficult to supply the heat required for heating at the lowest temperature of -20 ° C, while the underground heat source is 10 to 20 ° C, which can stably supply the heating heat to the heat pump.

The geothermal heat pump system is known to have the highest energy efficiency among all air-conditioning technologies. Therefore, it is an essential technology in a situation where energy resources are scarce and energy costs are high.

Another advantage of geothermal heat pump systems is the ability to store cooling or heating heat underground. In other words, the soil or rock in the ground has a low thermal conductivity, so the heat is not easily diffused and stored. Therefore, when heat is exchanged to the ground by cooling in summer, the heat is stored in the ground without disappearing. In addition, because the heat stored in the ground can be absorbed and used in winter, when heating and cooling are performed simultaneously, it has higher energy efficiency. Such heating and cooling can be easily switched between cooling and heating modes through a switch operation installed on the heat pump. have.

The general geothermal heat pump system is composed of a heat pump unit and an underground heat exchanger, which is a device that absorbs or releases heat from the ground while the heat medium circulates in the underground heat exchanger.

The underground heat exchanger extracts heat from the rock to the heat source of the heat pump and drills a deep vertical borehole with high thermal conductivity in the rock for continuous heat supply, that is, using the form of a vertical underground heat exchanger. Is common.

Vertical underground heat exchangers include open type, closed type U-loop type, and concentric double tube type depending on the type of circulating fluid used and the type of energy exchange. Most have been equipped with sealed borehole heat exchangers. Enclosed geothermal heat exchanger is installed by inserting U-shaped pipe into bore hole of 100 ~ 200m depth, inserting into pipe and bore hole, grouting between pipe and bore hole.

The construction of a vertical underground heat exchanger costs rock drilling, pipe piping, and geothermal heat exchanger construction, which can affect the overall cost of installing a geothermal heat pump system. There is a need to economically construct a geothermal exchanger to prevent this.

In particular, the performance of underground heat exchangers is affected by the thermal resistance of perforated boreholes and the thermal conductivity of soil and rock. When designing a vertical underground heat exchanger, the thermal properties (thermal conductivity, thermal diffusivity and heat capacity) of the ground vary with depth, and it is most effective to obtain the average thermal properties according to the depth.

Underground thermal conductivity can be calculated by performing on-site thermal conductivity test, drilling underground holes (boring holes) under the same conditions as in the field, laying underground heat exchangers (pipes through which fluid flows), and conducting thermal conductivity tests The measured data is applied to a line source model and calculated.

Conventionally, such a thermal conductivity measuring apparatus has been provided, but the heat insulation performance of the pipes in charge of the heat exchange function buried in the ground is not properly processed, which affects the heat exchange performance, and furthermore, a measurement means for informing the thermal conductivity measurement in real time in the field is provided. There was always the hassle of having to store data on a computer provided in an office or the like and then calculate it through a predetermined program.

As a result, various variables for underground thermal conductivity measurement are difficult to install and measure reliably, so even when the thermal conductivity value is found, there is a problem in that it is difficult to utilize because it is less accurate when applied to the actual geothermal heat pump system through this value.

Therefore, the present invention is proposed to solve the general problems occurring in the conventional underground thermal conductivity measuring apparatus as described above,

SUMMARY OF THE INVENTION An object of the present invention is to provide an underground thermal conductivity measuring apparatus that can be easily installed and can accurately measure thermal thermal conductivity in real time in the field.

The present invention for achieving the above object,

Connect underground heat exchanger piping to valve socket type connections of thermal conductivity measurement equipment, install RTD sensors and electric heaters, and connect flow meters, RTD sensors, and wattmeter outputs to designated channels in the terminal box. The output terminal is connected to a measuring instrument and connected to a computer with a built-in underground heat conductivity measurement program using an RS-232C communication cable, and after purging the air in the underground heat exchanger pipe, the electric heater is operated to heat the circulating water. After providing a, the ground heat conductivity is accurately measured in real time through the process of calculating the ground heat conductivity value by measuring the circulating water temperature of the inlet and outlet of the underground heat exchanger, the flow rate of the circulating water and the power consumption of the electric heater. will be.

"Underground thermal conductivity measuring apparatus" according to the present invention for achieving the present invention,

An HPE tube embedded in the perforation of the ground to transfer heat of the circulating water heated by the electric heater to the ground, and introducing the circulated water circulated in the ground to the measurement equipment;

A replenishment tank in which replenishment water is stored for replenishing circulating water missed during operation of the air air purging and measuring device in the HPE tube;

A replenishment water circulating pump for circulating the replenishment water in the replenishment water tank to an air purging and refilling water tee pipe;

A measurement device embedded in a terminal box for heating the circulating water in the HPE tube, measuring the temperature of the underground inlet and underground outlet circulating water, and measuring the volume flow rate of the circulating water flowing in the HPE tube;

A measuring device connected to an output terminal of each measuring device of the measuring device and measuring a measured value for thermal conductivity evaluation;

And a control means connected to the measuring device and a communication cable to process the data measured by the measuring device, and calculate ground thermal conductivity based on the processed data using a built-in underground thermal conductivity measuring program.

The measuring equipment,

A valve socket for maintaining ease of attachment and detachment of the HPE tube;

A first check valve for opening and closing the circulating water flow to the HPE tube connected to the valve socket;

An air purging and refilling water tee pipe for supplying air purging and replenishing water in the HPE tube and the circulating water pipe before operation of the underground thermal conductivity measuring device;

A second check valve connected to the air purging and refilling water tee pipe to open and close the flow of replenishing water of the air purging and refilling water tee pipe;

A third check valve for controlling the flow rate of the circulating water in the circulating water pipe;

An air vent for discharging bubbles in the circulation water pipe and the HPE tube to the outside;

A fourth check valve connected to the air vent and used to remove air;

A sensor pocket for installing an RTD sensor, which is a resistance thermometer for measuring the temperature of underground inlet and underground outlet circulation water, at a predetermined depth in the circulation water pipe;

An inline circulation pump to compensate for the kinetic energy loss caused by the friction of the pipes of the head and the pipe and to maintain a constant flow rate;

A volume flow meter for measuring a volume flow rate of the circulating water flowing in the circulating water pipe;

A flange for connecting the flowmeter pipe and the circulation water pipe;

It includes an electric heater for heating the circulating water by applying a heat amount to the circulating water.

The terminal box,

A pulley-type wheel installed at a plurality of lower parts to secure ease of movement in the field;

A handle installed at a predetermined position of a side surface to ensure ease of movement at the site;

Includes a cover installed to protect the device against external rainwater ingress.

Hereinafter, described in detail with reference to the accompanying drawings a preferred embodiment of the present invention. If it is determined that the detailed description of the known function or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 and 2 is an installation state diagram of the underground thermal conductivity measuring apparatus according to the present invention, Figure 3 is a detailed structural diagram of the sensor and flow meter, etc. provided in the terminal box of Figure 1, Figure 4 is a photograph showing the detailed structure of the terminal box of Figure 1 to be.

As shown, a replenishment water tank 1 is provided which stores replenishment water for purging air air in the underground heat exchanger pipe (HPE tube) 6 and for replenishment of circulating water that is lost during operation of the measuring device. It is connected with (1), the replenishment water circulation pump (2) is provided in order to flow the replenishment water of the replenishment water tank (1) through the air purging and the tee pipe (14) for replenishment water.

In addition, a perforation (3) is formed to a certain depth (150-200m) and a certain diameter (30mm) by an underground perforator, which is used to fix the HPE heat exchanger tube (6) and HPE to fix the bentonite and lime. Finished with grouting mixture.

In addition, a terminal box (4) is provided for the built-in measurement equipment, this terminal box (4) is made of 1000mm in width, 700mm in length, 700mm in height. It is obvious here that the size of the terminal box 4 is not uniform, and the size of the terminal box 4 can be changed as necessary. Compared to the existing trailer-loaded thermal conductivity measuring equipment, the size is greatly reduced, thereby ensuring the ease of field mobility.

In FIG. 2, reference numeral 5 denotes an electric heater power line for power supply of the electric heater.

In addition, the heat of the circulating water at the inlet side of the underground heat exchange part heated by the electric heater is transferred to the ground, and the temperature of the circulating water at the outlet side of the underground heat exchange part is flowed out at a reduced temperature compared to the temperature of the inlet side circulating water. An HPE tube (6) is provided, and a flexball tube (7), which is a piping that allows the replenishment water from the replenishment tank (1) to flow replenishment water to the air purging and refilling water tee piping (14). do.

Next, looking at the internal configuration of the terminal box (4), an electric heater (8) for heating the circulating water by applying heat to the operating circulating water using a 5 kW electric heater is provided, wherein the electric heater (8) is in operation In case of failure of the heater, it is preferable to install one at each of the upper and lower sides.

In addition, in order to measure the temperature of the underground inlet and underground outlet circulating water, RTD sensor, which is a resistance thermometer, is installed at a predetermined depth in the circulating water pipe by the RTD sensor pocket 9, and is contained in the circulating water pipe and the HPE tube 6. An air vent 10 for discharging the bubble to the outside is installed, and a fourth check valve 160 is installed for use when removing air by being connected to the air vent 10.

Next, in order to measure the volume flow rate of the circulating water flowing in the circulating water pipe, a volumetric flow meter 11 is installed at a predetermined position of the circulating water pipe, and such a flow meter 11 corresponds to the measured flow rate of 0-10V. To generate the output voltage.

An inline circulation pump 12 is installed to compensate for the kinetic energy loss caused by the friction of the pipes of the head and the pipe and to maintain a constant flow rate. The in-line circulation pump 12 is installed and detached from the circulating water pipe and the geothermal heat exchanger pipe of the underground thermal conductivity measuring device. In order to maintain the ease of installation, the valve socket 13 is installed, and an air purging and refilling tee pipe 14 for air purging in the circulation water pipe and the underground heat pipe before the operation of the equipment for measuring the thermal conductivity is installed. The air purging and refilling water tee pipe 14 is provided with a second check valve 17 for controlling the flow of replenishing water in the air purging and refilling water tee pipe 14.

In addition, a third check valve 150 for controlling the flow rate of the circulating water is installed at a predetermined position in the circulating water pipe, and a flange 19 for connecting the flowmeter pipe and the circulating water pipe is installed.

Next, the terminal box 4 is provided with a plurality of pulley-type wheels 20 (for example, four) in the lower part in order to ensure the ease of movement in the field, preferably each angle to grasp the center of gravity It is installed close to the corner. In addition, the handle 21 is installed on the side of the terminal box (4) in order to ensure the ease of movement in the field, the cover 22 is provided to prevent damage to the device by rainwater inflow or other foreign matter to the outside. Is installed.

Looking at the underground thermal conductivity measurement process of the underground thermal conductivity measurement apparatus according to the present invention configured as described above are as follows.

First, the underground heat exchanger and the thermal conductivity measuring equipment are combined in the field. That is, the HPE tube 6, which is an underground heat exchanger pipe, is connected to the valve socket type connection part 13 of the thermal conductivity measuring device.

Next, the RTD sensor is installed in the pocket 9 for RTD sensor, and the electric heater 8 is installed in the electric heater installation piping. Connect the electric heater wire to the watt meter to measure the power required of the electric heater. The meter, RTD sensor and wattmeter outputs are then connected to a designated channel (not shown) attached to the side of the terminal box (4).

Although not shown in the drawing, output terminals such as a flow meter 11, an RTD thermometer, a watt meter, and the like of the terminal box 4 installed in the thermal conductivity measurement equipment are connected to the measuring instrument (Agilent 34901A MUX). And using the RS-232C communication cable to the built-in measuring instrument and underground heat conduction program and connected to the control means (not shown in the figure) to calculate the underground heat conduction. Here, the connection with the control means is connected using a serial port, it is preferable that the control means using a general personal computer (PC) or notebook computer. In particular, it is preferable to use a notebook computer for convenience of movement, but it will be obvious to those skilled in the art that a terminal capable of performing a function similar to a separate computer may be used.

When the connection between the measurement equipment and each pipe is completed, the replenishment water is connected to the refill water Tee pipe 14 of the heat conductivity measurement device and then operate the circulation pump 12 to purge the air in the circulation water pipe and the heat exchanger pipe.

When the air purging is completed, the electric heater 8 is operated to provide heat quantity to the circulating water to raise the circulating water to a desired temperature, and when the temperature of the circulating water is completed, the underground thermal conductivity measurement program is operated to calculate the ground thermal conductivity value. do. Here, the ground heat conductivity value is calculated internally by measuring the ground heat conductivity value inside the program by measuring the ground heat exchanger inlet, the outlet circulating water temperature, the flow rate of the circulating water, and the power consumption of the electric heater.

In particular, in order to calculate underground thermal conductivity values, physical signals such as circulating water flow rate, circulating water temperature, and compressor power consumption are converted into electrical signals through sensors such as flow meters, resistance thermometers, and watt meters, and the Agilent 34970A module and 34901A MUX instruments To convert analogue electrical signals into digital electrical signals. In addition, the RS-232C communication cable establishes an interface with the application program installed in the computer (control means) and uses the Labview Development Studio-based performance evaluation application to establish the physical interface. The raw raw data on the computer monitor is converted into a signal and shown through the indicator.

In this case, it is desirable to remotely monitor the status of the performance evaluation application being executed on the Internet web and to remotely control the status of the program on the Internet web.

According to the present invention described above, there is an advantage that can accurately measure the ground thermal conductivity in real time in the field. In addition, since the ground thermal conductivity measuring apparatus can be manufactured in a small size, there is an advantage to provide convenience in movement.

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Claims (4)

delete correction In underground thermal conductivity measuring apparatus, An HPE tube embedded in the perforation of the ground to transfer heat of the circulating water heated by the electric heater to the ground, and to introduce the circulated water circulated in the ground to the measurement equipment; A replenishment tank in which replenishment water is stored for replenishing circulating water missed during operation of the air air purging and measuring device in the HPE tube; A replenishment water circulating pump for circulating the replenishment water in the replenishment water tank to an air purging and refilling water tee pipe; A measurement equipment embedded in a terminal box for heating circulating water in the HPE tube, measuring temperature of underground inlet and underground outlet circulating water, and measuring volume flow rate of circulating water flowing in the HPE tube; A measuring device connected to an output terminal of each measuring device in the measuring device and measuring a measured value for thermal conductivity evaluation; It is connected to the measuring instrument and a communication cable, and comprises a control means for processing the data measured by the measuring instrument, the ground heat conductivity based on the processed data using the built-in underground thermal conductivity measurement program, The measuring equipment, A valve socket for maintaining ease of attachment and detachment of the HPE tube; A first check valve for opening and closing the circulating water flow to the HPE tube connected to the valve socket; An air purging and refilling water tee pipe for supplying air purging and replenishing water in the HPE tube and the circulating water pipe before operation of the underground thermal conductivity measuring device; A second check valve connected to the air purging and refilling water tee pipe to open and close the flow of replenishing water of the air purging and refilling water tee pipe; A third check valve for controlling the flow rate of the circulating water in the circulating water pipe; An air vent for discharging bubbles in the circulation water pipe and the HPE tube to the outside; A fourth check valve connected to the air vent and used to remove air; A sensor pocket for installing an RTD sensor, which is a resistance thermometer for measuring the temperature of underground inlet and underground outlet circulation water, at a predetermined depth in the circulation water pipe; An inline circulation pump to compensate for the kinetic energy loss caused by the friction of the pipes of the head and the pipe and to maintain a constant flow rate; A volume flow meter for measuring a volume flow rate of the circulating water flowing in the circulating water pipe; A flange for connecting the flowmeter pipe and the circulation water pipe; Underground thermal conductivity measuring apparatus comprising an electric heater for heating the circulating water by applying heat to the circulating water. delete delete

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