Thesis opening report on ground source heat pump technology

First, the basis and significance of the topic:

1. in accordance with:

After entering the 1990s, China's living environment and industrial production environment have widely applied hot water supply devices, and hot water supply devices have become a must for modern schools. In the mid-1990s, due to the tight power supply in large and medium-sized cities, the power supply department began to pay attention to demand management and peak-filling, and heat pump heating technology was mentioned on the agenda. In recent years, due to changes in energy structure, the rapid development of ground source heat pump heating units has been promoted.

With the continuous development of production and technology, humans have also made a series of improvements to ground source heat pump heating technology. At the same time, they are also actively researching environmentally friendly and energy-saving ground source heat pump heating products and technologies. Now they are using mature electronic technology. Comprehensive control and integration with solar energy pay more attention to the comprehensive utilization of energy, energy conservation, environmental protection and a comfortable environment that is naturally inevitable.

2. significance:

Ground-source heat pump technology uses the characteristics of underground soil, surface water and groundwater temperature to be relatively stable. By consuming electric energy, the heat in the low-level heat source is transferred to the place where heat or heating is needed in winter. The residual heat in the room is transferred to the low heat source to achieve the purpose of cooling or cooling. The ground source heat pump does not require an artificial cold and heat source and can replace traditional heating methods such as boilers or municipal pipe networks and central air conditioning systems. In winter, it replaces boilers to extract heat from soil, groundwater or surface water to heat buildings. In summer, it can replace ordinary air conditioners to release heat from soil, groundwater or surface water to buildings. At the same time, it can also supply domestic water, which is a three-pronged way, is a way to effectively use energy. Usually divided into three categories according to the heat source and heat sink of the heat pump:

Air source heat pump system ashp

Water source heat pump system wshp

Ground source heat pump system gshp

There are still people who call the heat pump system differently according to the primary and secondary media:

Air---water heat pump system

Water --- air heat pump system

Water --- water heat pump system

Air---air heat pump system

These are all formed by including heat sources, heat sinks, and delivery media for air conditioning systems.

In order to be in line with international standards, we should still be named according to international practice. In 1997, the standard terminology was unified by the American ashara. Both wshp and gshp are called gshp-ground source heat pump systems.

In addition, in order to make it easier for us to learn and discuss, introduce some concepts of ground source heat pump outdoor energy exchange system:

Soil tube system----soil heat exchanger

Groundwater system

Surface water system

These are the heat sources or heat sinks of ground source heat pumps.

Fig.1.1 Soil heat exchanger diagram

Fig.1.2 Soil heat exchanger diagram

Fig. 1.3 Surface water system diagram

Fig. 1.4 Groundwater system diagram

Second, research status and development trends at home and abroad

1. Development history of ground source heat pump

Ground source heat pump is an advanced technology, which is efficient, energy-saving and environmentally friendly, and is conducive to sustainable development. This technology first began in 1912, and Swiss Zoelly proposed the concept of “geothermal source heat pump”. In 1946, the United States began a systematic study of ground source heat pumps, and the first ground source heat pump system was built in Oregon. The operation was very successful, which led to the commercial climax of ground source heat pump systems in the United States. In 1985, 14,000 ground source heat pumps were installed in the United States, and 45,000 units were installed in 1997. At present, more than 400,000 ground source heat pumps have been installed, and they are delivered at a rate of 10% per year. In 1998, ground source heat pump air conditioning systems for commercial buildings in the United States accounted for more than 19% of air conditioning, of which 30% were in new buildings. In European countries, it is more to use shallow geothermal resources for heating or heating. Since the 1970s, with the gradual becoming serious problems of energy and environment, energy conservation has been considered more in all aspects. The ground source heat pump with renewable geothermal energy as energy has attracted people's attention. Especially in recent years, with the increasingly prominent energy and environmental issues, the research and application of ground source heat pumps have developed rapidly. Many universities and research institutions at home and abroad have carried out research on theoretical and practical applications. With the deepening of research, our ground source heat pump researchers held various exchange seminars nationwide. The Second Professional Committee of China Refrigeration Society hosted the “National Conference on Waste Heat Refrigeration and Heat Pump Technology”; in 1988, the Guangzhou Energy Research Institute of the Chinese Academy of Sciences hosted the “Expert Seminar on Heat Pumps in China's Application and Development”; the China Energy Research Association Geothermal Professional Committee The 4th National Geothermal Energy Development and Utilization Seminar was held in Beijing from September 6 to 8, 1994. Since the 1990s, each session of the National HVAC Academic Annual Conference has the topic of “heat pump application”; From June 19th to 23rd, the Sino-US ground source heat pump technology exchange meeting was held in Beijing. The meeting introduced ground source heat pump technology, foreign application status and promotion in China; Shandong Institute of Architecture and Engineering, Ground Source Heat Pump Research Institute and Shandong Architecture The Society of Thermal Power Professionals jointly sponsored and hosted the “International Geothermal Heat Pump New Technology Reporting Conference” held on March 17th, XX in Shandong Institute of Architecture and Engineering, and strengthened the exchange of advanced technologies for ground source heat pumps at home and abroad.

2. Development status and prospects of ground source heat pumps in China:

At present, groundwater heat pump systems have been widely used in China, and the soil source heat pump system is still in the engineering exploration and research stage of research institutions.

From the survey, the groundwater heat pump project has not really succeeded. The reason is that it is not easy to achieve 100% recharge and recharge to the same aquifer, not pollute the groundwater, and can run stably for a long time. At the same time, there have been a large number of heat pump projects that do not perform recharge. What is more, there is a direct use of groundwater into the fan coil for air conditioning. In doing so, one pollutes the water and the other wastes water.

The development of soil source heat pumps is mainly from 1998. Several domestic universities have established soil source heat pump test benches, and most of them have carried out long-term joint operation of underground heat exchangers and ground heat pump equipment. In 1998, Chongqing Jianzhu University built a heat pump system including shallow buried vertical tube heat exchanger and horizontal buried tube heat exchanger; in 1998, Qingdao Institute of Construction completed a polyethylene vertical soil source heat pump system; Hunan University, 1998 A horizontal buried soil source heat pump system was constructed; in 1999, Tongji University built a vertical soil source heat pump system. These systems have laid the foundation for the promotion of soil source heat pumps in China. Since XX, a series of demonstration projects of soil source heat pump systems have been established in Changchun, Jinan, Wenzhou, Chongqing and Miquan. More and more soil source heat pump systems have been paid attention to and adopted by real estate developers.

In view of the domestic conditions and the characteristics of the ground source heat pump system, we analyze their respective prospects. With the improvement and standardization of groundwater heat pump engineering technology, there is still a huge potential market due to its outstanding energy conservation and protection of the atmospheric environment. Horizontal buried soil source heat pump, although it occupies a large area, it can naturally restore the ground temperature by surface heat transfer, and it has advantages in areas where the annual heat output and heat absorption are not balanced. Vertically buried soil source heat pump, with the development of professional installation team, the improvement of drilling equipment, will inevitably reduce the cost significantly, will undoubtedly become the most competitive air conditioning method in the future.

Third, the research project of this topic:

This topic belongs to the design and renovation of the existing hot water system, the hot water supply system of the school dormitory. In the transformation should be fully considered:

1. The student's regular heating, required power and system reverberation time.

2. It belongs to the transformation system and should be combined with the existing system.

3. Considering the cost issue, is the cost reasonable?

4. Whether the cost of maintenance and technical requirements during the use process are reasonable.

5. Operational safety and noise handling issues.

6. Waste disposal and environmental protection issues.

Fourth, the content of this research:

The hot water supply modification of the 5# in the North District of Guangxi University of Technology.

1. The air conditioning project of the building includes:

1-6 floors of hot water supply, all dorms.

2, design parameters:

There are 14 rooms on each floor, each with 8 people and a total of 6 floors.

3. Basic meteorological parameters in Liuzhou area:

According to the phenological report, between May 1 and October 1, there is very little hot water in the high temperature zone, and no hot water during the winter vacation.

4. The specific research content of this topic:

, calculation of circulating water heat exchanger

Soil heat exchanger design for soil heat pump system

Underground buried heat exchanger is a key component of ground source heat pump system. It is the core content of soil source heat pump system design. Whether the form of selection is reasonable and whether the design is correct is related to whether the whole ground source heat pump system can meet the requirements and Normal use.

The design of underground buried heat exchanger mainly includes the form of underground heat exchanger and pipe selection, pipe diameter, pipe length and number of shafts, spacing determination, pipe resistance calculation and pump selection.

Arrangement type

At present, there are mainly two types of ground source heat pump underground heat exchangers, namely horizontal buried pipes and vertical buried pipes. The choice depends on the size of the site, the type of soil in the area, and the cost of excavation. If the site is large enough and has no hard rock, the horizontal is more economical; if the site is limited, it is vertically arranged, which is the only option in many occasions.

Although the horizontal arrangement is usually a shallow buried pipe, the initial investment is generally cheaper, but its heat exchange performance is much smaller than that of the vertical buried pipe, and is often limited by the available land area, so the vertical buried pipe arrangement is generally adopted.

3.1 Horizontal buried pipe

The horizontal buried pipe mainly has the form of single groove single pipe, single groove double pipe, single groove two layer double pipe, single groove two layer four pipe, single groove two layer six pipe, etc., because the lower pipe of the multilayer buried pipe is in a relatively stable state. The temperature field, the heat exchange efficiency is better than the single layer, and the floor space is small, so more multi-layer tubes are applied.

In recent years, two horizontal buried pipes have been newly developed in foreign countries, one is a flat curved tube and the other is a spiral tube. They have the advantage of shortening the length of the trench and increasing the length of the tube that can be buried.

3.2 Vertical buried pipe

Depending on the type of buried pipe, there are generally single u-shaped tubes, double u-shaped tubes, sleeve-type tubes, small-diameter spiral coils and large-diameter spiral coils, vertical cylindrical tubes, spider tubes, and the like; According to different embedding depths, it is divided into shallow buried, medium buried and deep buried.

1) U-shaped pipe type: U-shaped pipe is installed in the pipe well of the borehole. The general pipe diameter is 100-150mm, the well depth is 10~200m, and the u-shaped pipe diameter is generally below φ50mm. The diameter is generally 100 to 200 mm, and the inner tube is φ15 to φ25 mm. Its heat transfer efficiency is 16.7% higher than that of the u-tube. Disadvantages: (1) The lower tube is more difficult, and the initial investment is higher than the u-shaped tube. (2) in the casing