CN110715564A - Assembled buried pipe ground source heat pump system - Google Patents

Abstract

The invention discloses an assembled underground pipe ground source heat pump system, comprising a buried pipe system, a heat pump unit and an air-conditioning terminal system. The buried pipe system is composed of several heat exchange modules connected in series, and each heat exchange module includes a ground Buried pipe and heat storage and release unit, the heat storage and release unit is a rectangular box placed horizontally, and the box is filled with phase change material; the buried pipe is set in the box and wrapped by the phase change material, and the two The ends pass through the corresponding two sides of the box to form the inlet and outlet of the buried pipe; the inlet and outlet of the buried pipe of the heat exchange module located in the middle are respectively connected with the outlet and the inlet of the buried pipes of the adjacent two heat exchange modules, The inlet and outlet of the buried pipes of the heat exchange modules at both ends are respectively connected with the liquid outlet of the liquid outlet pipeline and the liquid inlet of the liquid inlet pipeline of the heat pump unit. The system has high heat exchange efficiency, large heat exchange area of buried pipes, and simple and fast assembly.

Description

A prefabricated buried pipe ground source heat pump system

technical field

The invention belongs to the technical field of utilization of renewable energy and intensified heat exchange of a buried pipe system, in particular to a ground source heat pump system of a prefabricated buried pipe.

Background technique

Modern buildings are the bulk of energy consumption, and the energy consumption of the construction industry accounts for about 40% of the country's total energy consumption. About 50% of building energy consumption goes to HVAC systems.

From a global perspective, energy saving and environmental protection have become the two major themes of the modern construction industry. With the continuous reduction of the earth's fossil energy, the development and utilization of new energy has become the focus of the world's attention. Shallow geothermal energy is a new renewable and environmentally friendly energy source, which is mainly derived from solar radiation and the earth's gradient warming. The underground rock and soil has good heat storage performance. Through the buried pipe heat exchanger, the cold energy stored in winter is used for cooling in summer, and heat is stored underground at the same time; in winter, the heat stored in summer is used for heating, and the heat is stored underground at the same time Store cold energy. Therefore, it is necessary to design a system (ie, ground source heat pump system) that uses shallow geothermal energy to control the indoor heat and humidity environment of buildings, so as to achieve the mutual supply of cold and heat in winter and summer.

The ground source heat pump system is a ground source heat pump system that utilizes the closed-circuit circulation of heat in the underground rock and soil. It flows in the closed underground buried pipe through the circulating fluid (water or antifreeze with water as the main component) to realize the heat transfer between the system and the earth.

At present, the actual heat exchange efficiency of the existing buried pipe ground source heat pump system is low and the heat exchange area of the buried pipe is small. Large-scale popularization and application of ground source heat pump system.

SUMMARY OF THE INVENTION

In view of the above deficiencies in the prior art, the purpose of the present invention is to provide a ground source heat pump system with high heat exchange efficiency, large heat exchange area of the buried pipe, and simple and quick assembly.

The technical scheme of the present invention is realized as follows:

An assembled buried pipe ground source heat pump system, comprising a buried pipe system, a heat pump unit and an air-conditioning terminal system; the buried pipe system is composed of several heat exchange modules connected in series, and each heat exchange module includes a buried pipe and a storage The heat release unit, the heat storage and release unit is a rectangular box placed horizontally, and the box is filled with phase change material; the buried pipe is set in the box and wrapped by the phase change material, and the two ends of the buried pipe pass through the box The two sides corresponding to the body are connected to form the inlet and outlet of the buried pipe; the inlet and outlet of the buried pipe of the heat exchange module located in the middle are respectively connected with the outlet and inlet of the buried pipes of the adjacent two heat exchange modules, and the exchanges located at both ends are connected. The inlet and outlet of the buried pipe of the thermal module are respectively connected with the liquid outlet of the liquid outlet pipeline and the liquid inlet of the liquid inlet pipeline of the heat pump unit.

Further, the fluid circulating in the buried pipe is a nanofluid.

Further, the buried pipes inside the heat storage and release unit are alternately arranged and connected in series with spiral pipes and straight pipes.

Further, each heat storage and release unit is provided with a plurality of buried pipes, and the buried pipes are metal pipes, which is convenient to enhance the heat exchange efficiency between the heat storage and release unit and the buried pipes.

Further, the inlet and outlet of the buried pipe are provided with matching socket joints to facilitate the connection between the heat exchange modules; at the same time, the liquid inlet and outlet of the heat pump unit are respectively provided with the outlet and the inlet of the buried pipe. The connected socket joint is convenient for connecting the buried pipe with the heat pump unit.

Further, the phase change material is paraffin.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention uses nanofluids to replace traditional heat transfer fluids. Compared with pure liquids, nanoparticles suspended in nanofluids do random motion under the action of Brownian force, gravity, and friction between fluids and particles (Brown Diffusion, thermal diffusion, sedimentation and dispersion, etc.), the laminar bottom layer of the fluid flow is destroyed, the fluid disturbance is strengthened, and the flow turbulence intensity is also enhanced, which reduces the heat transfer resistance and strengthens the heat transfer. At the same time, the micro-movement of nanoparticles produces micro-convection between the particles and the liquid, which enhances the energy transfer process between the particles and the liquid. Since the interface area between nanoparticles and liquid is much larger than that of millimeter or micron-sized particles under the same particle volume content, adding nanoparticles to liquid can significantly increase the thermal conductivity of liquid. Therefore, the use of nanofluids can significantly enhance the heat exchange performance, which can increase the effective heat exchange area and improve the heat exchange efficiency of the system.

2. In the present invention, the effect of nanofluids and the structural characteristics of heat exchange modules to enhance heat exchange are taken into consideration. The buried pipe is composed of a spiral pipe and a straight pipe in series. The material is uniform and fully heat exchanged, and the straight pipe reduces the flow resistance of the nanofluid in the buried pipe. In this way, the spiral pipe and the straight pipe are alternately connected in series to improve the comprehensive heat exchange efficiency.

3. The present invention uses paraffin wax with a melting point of about 22°C as a phase change material, and paraffin wax is a low temperature phase change material. The low temperature phase change material has high latent heat of phase change, no supercooling and precipitation, and phase change after repeated heat absorption and release. The temperature and latent heat of phase transition change little, and it has the advantages of non-toxicity and low price.

4. The heat exchange module of the present invention adopts a rectangular box structure, and the contact area between its outer surface and the soil is much larger than that of the traditional horizontal buried pipe, which increases the equivalent heat exchange area of its cross-section, thereby improving the heat exchange efficiency. At the same time, the phase change material is sealed in the box, which reduces the safety risk in traditional horizontal buried pipe laying and backfilling.

5. The heat exchange modules of the present invention are connected by socket joints. At the same time, the heat exchange modules can be standardized in the factory workshop, and then when assembled on site, the assembled installation and application scale of the horizontal buried pipe can be realized through the socket joints. expansion, and the assembly is simple and fast, thereby improving the assembly efficiency.

Description of drawings

Figure 1 - a schematic diagram of the structure of the heat exchange module of the present invention.

Figure 2 - a schematic cross-sectional view of the heat exchange module of the present invention.

Among them: 1-buried pipe; 2-spiral pipe; 3-straight pipe; 4-phase change material; 5-box body; 6-socket joint.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to Figures 1 and 2, an assembled underground pipe ground source heat pump system includes a buried pipe system, a heat pump unit and an air-conditioning terminal system. The buried pipe system is composed of several heat exchange modules connected in series, each heat exchange The module includes a buried pipe 1 and a heat storage and release unit. The heat storage and release unit is a rectangular box 5 placed horizontally, and the box 5 is filled with a phase change material 4; the buried pipe 1 is set in the box 5 and is The phase change material 4 is wrapped, and the two ends of the buried pipe 1 pass through the corresponding two sides of the box 5, thereby forming the inlet and outlet of the buried pipe; the inlet and outlet of the buried pipe of the heat exchange module located in the middle are adjacent to The outlets and inlets of the buried pipes of the two heat exchange modules are connected, and the inlets and outlets of the buried pipes of the heat exchange modules at both ends are respectively connected to the liquid outlet of the liquid outlet pipeline of the heat pump unit and the liquid inlet of the liquid inlet pipeline. .

Here, the heat storage and release unit adopts a rectangular box structure, and the contact area between the outer surface and the soil is much larger than that of the traditional horizontal buried pipe, which increases the equivalent heat exchange area of its cross-section, thereby improving the heat exchange efficiency. At the same time, sealing components, such as sealing rings, sealing tapes, etc., are provided on the two corresponding surfaces of the box body corresponding to the buried pipe, so as to seal the box body, prevent the phase change material from leaking out, and improve safety.

In specific implementation, the fluid circulating in the buried pipe 1 is a nanofluid.

Here, nanofluids are used as heat transfer fluids, and the nanoparticles suspended in the nanofluids do random motions (Brownian diffusion, thermal diffusion, sedimentation and dispersion, etc.) under the action of Brownian force, gravity, and friction between fluid and particles. ), the bottom layer of the laminar flow of the fluid flow is damaged, the fluid disturbance is strengthened, and the flow turbulence intensity is also enhanced, which reduces the heat transfer resistance and strengthens the heat transfer. At the same time, the micro-movement of nanoparticles produces micro-convection between the particles and the liquid, which enhances the energy transfer process between the particles and the liquid. Since the interface area between nanoparticles and liquid is much larger than that of millimeter or micron-sized particles under the same particle volume content, adding nanoparticles to liquid can significantly increase the thermal conductivity of liquid. Therefore, the use of nanofluids can significantly enhance the heat exchange performance, which can increase the effective heat exchange area and improve the heat exchange efficiency of the system.

In specific implementation, the buried pipe 1 located inside the heat storage and release unit is composed of spiral pipes 2 and straight pipes 3 alternately arranged and connected in series.

Here, the spiral tube can effectively increase the heat exchange area between the nanofluid and the phase change material in the buried tube, but it also increases the flow resistance of the nanofluid in the buried tube. Alternately connected in series, while increasing the heat exchange area between the nanofluid and the phase change material, it can also effectively ensure the disturbance of the nanofluid and enhance heat transfer, thereby improving the heat exchange efficiency of the system.

In specific implementation, each heat storage and release unit is provided with a plurality of buried pipes 1, and the buried pipes are metal pipes, which is convenient to enhance the heat exchange efficiency between the heat storage and release unit and the buried pipes.

In this way, each buried pipe in each heat exchange module can be respectively connected to the buried pipe corresponding to the adjacent heat exchange module, or the inlet and outlet of all buried pipes of each heat exchange module can be integrated into a total of The inlet and the total outlet are then connected with the total inlet and outlet of the buried pipe corresponding to the adjacent heat exchange modules.

In the specific implementation, the inlet and outlet of the buried pipe are provided with socket joints 6 that are connected with each other, so as to facilitate the connection between the heat exchange modules; at the same time, the inlet and outlet of the heat pump unit are respectively provided with the outlet of the buried pipe and the outlet of the buried pipe. The inlet and socket joints are matched with the connection, which is convenient for the connection between the buried pipe and the heat pump unit.

In this way, the heat exchange module is processed in the factory workshop, and socket joints are set at the inlet and outlet of the buried pipe at the same time, so that when assembled on site, only the socket joint corresponding to the matching connection needs to be connected to complete the assembly. Operation Simple and fast, it is beneficial to improve the assembly efficiency of the buried pipe ground source heat pump system.

In a specific implementation, the phase change material is paraffin.

Here, paraffin wax with a melting point of about 22°C is used as the phase change material, and paraffin wax is a low temperature phase change material. The low temperature phase change material has high latent heat of phase change, no supercooling and precipitation, and the phase change temperature and The latent heat change is small, and it has the advantages of non-toxicity and low price.

The working mode of the present invention is divided into summer mode and winter mode, and its work flow is as follows:

Summer mode: In summer, the high-temperature nanofluid from the liquid outlet end of the heat pump unit enters the buried pipe for heat exchange with paraffin, and the paraffin absorbs the heat of the high-temperature nanofluid and melts into liquid. Due to the effect of latent heat, the heat absorption increases, which can speed up The paraffin absorbs the heat in the buried pipe to achieve better heat transfer, and then the heat is stored in the paraffin, and the temperature of the nanofluid is reduced to a low-temperature nanofluid and flows back to the heat pump unit. The whole process is repeated until all the paraffin has melted. When the buried pipe stops running in summer, the temperature of the buried pipe decreases, and the paraffin transfers from the liquid phase to the solid phase, releasing heat. The higher temperature gradient between the heat exchange module and the soil is beneficial to improve the thermal diffusivity. Phase change materials reduce soil temperature fluctuations and improve system performance.

Winter mode: In winter, the low temperature nanofluid from the liquid outlet end of the heat pump unit absorbs heat from the paraffin and the temperature rises to a high temperature nanofluid and flows back to the heat pump unit. The buried pipe absorbs heat from the soil, and the phase change process increases the heat accumulation in the heat exchange module, which is beneficial to the heat absorption process of the buried pipe, thereby improving the performance of the system.

The device of the invention utilizes nano-fluid to strengthen the heat exchange inside the buried pipe and phase change material to strengthen the external energy storage of the buried pipe, so as to enhance the heat exchange and improve the heat exchange efficiency of the horizontal buried pipe system. The prefabricated system has simple structure, convenient installation, stable work, energy saving, environmental protection and high efficiency, strong applicability, and has significant economic and social benefits.

Finally, it should be noted that the above-mentioned embodiments of the present invention are only examples for illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, changes and modifications in other different forms can also be made on the basis of the above description. Not all implementations can be exhaustive here. Any obvious changes or changes derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (6)

1. An assembled buried pipe ground source heat pump system comprises a buried pipe system, a heat pump unit and an air conditioner tail end system; the underground pipe system is characterized in that the underground pipe system is formed by connecting a plurality of heat exchange modules in series, each heat exchange module comprises an underground pipe and a heat storage and release unit, the heat storage and release unit is a rectangular box body which is horizontally placed, and phase change materials are filled in the box body; the buried pipe is arranged in the box body and is wrapped by the phase-change material, and two ends of the buried pipe penetrate through two corresponding surfaces of the box body, so that an inlet and an outlet of the buried pipe are formed; the inlet and the outlet of the buried pipe of the heat exchange module positioned in the middle are respectively connected with the outlet and the inlet of the buried pipe of the two adjacent heat exchange modules, and the inlet and the outlet of the buried pipe of the heat exchange module positioned at the two ends are respectively connected with the liquid outlet of the liquid outlet pipeline and the liquid inlet of the liquid inlet pipeline of the heat pump unit.

2. The assembled buried pipe ground source heat pump system of claim 1, wherein the fluid circulating in the buried pipe is a nano fluid.

3. The assembled buried pipe ground source heat pump system of claim 1, wherein the buried pipe inside the thermal storage and release unit is composed of spiral pipes and straight pipes which are alternately arranged and connected in series.

4. The assembled buried pipe ground source heat pump system of claim 1 or 3, wherein a plurality of buried pipes are arranged in each heat storage and release unit, and the buried pipes are metal pipes, so as to enhance the heat exchange efficiency between the heat storage and release unit and the buried pipes.

5. The assembled buried pipe ground source heat pump system of claim 1, wherein the inlet and the outlet of the buried pipe are provided with socket joints for connection in a matching manner, so as to facilitate connection between the heat exchange modules; meanwhile, socket joints which are matched and connected with the outlet and the inlet of the buried pipe are respectively arranged at the liquid inlet and the liquid outlet of the heat pump unit, so that the buried pipe is conveniently connected with the heat pump unit.

6. The assembled buried pipe ground source heat pump system of claim 1, wherein the phase change material is paraffin.

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