On the environment protection and energy of ground source heat pump technology

Paper Keywords: ground source heat pump energy-saving Sustainable Development
Abstract: This paper describes a ground source heat pump technology works, classification and application of significance analysis of the characteristics of ground-source heat pump and Economic benefits, introduces the historical Development of ground source heat pump as well as domestic Research on the status of ground source heat pump is proposed to source heat pump in our energy, environmental protection, sustainable Development has broad prospects.

1 Introduction
Today's society due to rapid Economic Development and rapid population growth, global ecological destruction, environmental pollution and resource scarcity has reached the natural environment could bear; energy, resources, environmental constraints, has become an obstacle to future Economic Development of countries bottleneck. to alleviate the pressure of huge energy and the environment, energy saving in recent years has become the new theme of social development. People take all kinds of positive response, renewable energy out of people's priority areas of national energy development, the energy structure system from fossil fuels as the main energy era transition to sustainable energy era. ground-source heat pump technology development and applications, is that people should choose one of the measures. ground source heat pump technology is the use of underground shallow geothermal resources to achieve the building to provide heating, cooling and domestic hot water energy efficient environmentally friendly air conditioning technologies. Ground source energy is a clean renewable energy, it has a heat flux density, easy to collect and transport, and stability parameters (flow, temperature, ), easy to use, without geographical restrictions and so on. the theoretical basis of heat from the Carnot cycle, the same with the refrigerator, in accordance with the reverse cycle, namely by entering the small number of high-grade energy (eg electricity) to serve as a ground source source heat pump for cooling in summer cooling and winter heating heating the low temperature heat source. In the winter, the geothermal energy in the heat "take out" to raise the temperature, the supply of indoor heating, and cold storage to prepare for summer use; summer through the heat pump on the indoor temperature, while the indoor heat released into the underground, for energy storage, to prepare for winter use, the entire cycle of the earth play a role in the accumulator. ground-source heat pump system 70% of the energy is obtained from the earth renewable energy sources. in its capacity as the main energy supply, which saves a lot of energy, but also effective in reducing,: and dust emissions. this technology compared with traditional air conditioning system, advantage is that it achieved the unity of energy saving and environmental protection.

2 ground-source heat pump system and the principle of the working environment
2.1 Ground Source Heat Pump work environment
30 ~ 300 m away from the underground formation between a constant temperature zone, the temperature of the Earth's surface from solar heat radiation and heat conduction of the combined effects of the Earth's core, known as the overall balance, also known as shallow underground layer. Temperature throughout the year relative stability, high temperature than the ambient air in winter and summer than the ambient air temperature is low. ground source heat pump system is to use the constant temperature zone of the soil, pebbles, rocks deep underground aquifers and surface water sources and sinks for the heat pump to building in winter heating, summer cooling.

2.2 The structure and ground source heat pump works
2.2.1 Structure
Ground source heat pump system consists of outdoor ground-source heat exchange system, and indoor air-conditioning heat pump unit 3, the end of the system components. Heat pump part of the main driving force, by the refrigeration compressor, evaporator, condenser, expansion valve and other component circuits. Which compression machine is a heat pump system in the heart, through the power-driven compressor, continue to compress and transfer refrigerant from the low temperature and pressure cycle to the high temperature and pressure at the place, and again and again to the cycle; cold evaporator is the output device, it is the role of through the throttle valve inflow of liquid refrigerant evaporates to absorb heat from the object to be cooled to achieve the purpose of cooling; condenser is the heat output of the device, from the evaporator to absorb heat and power consumption of the compressor into the heat , the cooling medium in the condenser was removed to achieve the purpose of heating; said expansion valve or throttle on the throttle cycle play the role of the working fluid, and adjust the cycle of the evaporator into the refrigerant flow.

2.2.2 Principles of heating
Figure 1 shows the principle of ground source heat pump heating system. How it works: First, the charge in the refrigeration circuit refrigerant. Compressors pass into the three-phase AC high-speed rotation, the low-temperature low-pressure suction refrigerant gas compressors. Change after compression into a high-pressure high-temperature gas, the gas is cooled by the condenser water cooling, but also into the pressure of liquid refrigerant in the temperature of the liquid through the expansion valve, evaporator throttle given away after decompression. evaporator connected to the compressor suction air intake, the compressor continuously inhaled gas refrigerant evaporator, making a large number into the evaporator refrigerant pressure reduced refrigerant further substantial evaporation. because the other side of the evaporator and outdoor ground-source heat exchange system of underground water pump connections, so when a large number of groundwater flow through the evaporator, the refrigerant is evaporated away a lot of heat in groundwater. These low-temperature heat evaporates the refrigerant through the absorption of refrigerant into the heat, and be inhaled continuously compressor. compressed by the compressor into the 80 ~ 90 �� high temperature gas, the high temperature gas cooled through the condenser, while a large amount of heat to the condenser, the other side, that is the end of the indoor air conditioning system, but also said heating system. refrigerant gas is cooled in the process, it can be seen as the high temperature heat transfer process to the cooling system, or heating the heating system, heating system water temperature is generally 50 ~ 60 �� by the end of the indoor air-conditioning system The fan coil or radiator heating the room.


From the perspective of energy conversion, heat pump compressor mechanical energy into electrical energy and then mechanical energy into heat energy. Compressors for compressing the output of the total energy absorption of mechanical and electrical power and the compressor and heat energy from the ground, and underground thermal energy away electrical power than the compressor. general heat extracted from the ground is compressed Electrical power generated heat 4 to 5 times, so the energy efficiency heat pump is about 4.5, and 0.9 EER electric boilers 0.98.

2.2.3 Principles of Refrigeration
Figure 2 is a ground-source heat pump refrigeration system works. Refrigerant heat pump works the same as shown in Figure 1, the refrigerant circuit remain unchanged. But by converting the end of the valve to the indoor air conditioning system (ie refrigeration circuit) connected to the evaporator suction hot end; outdoor ground-source heat exchange system connected to the condenser end of heat release. heat pump refrigerant, the compressor will be low-temperature heat-absorbing low-pressure suction side refrigerant gas by the high temperature and high pressure compressed refrigerant gas into a line of people condensation converters were connected to the condenser side of the cooling water system to become suppressed in the temperature of the liquid refrigerant. refrigerant fluid through the throttling expansion valve after decompression, further expansion into the evaporator, evaporation, heat, the refrigerant from liquid endothermic gas was again turned into the compressor suction side. and then compressed by the compressor, and high temperature high pressure refrigerant gas into a row of people condenser, evaporator side and will also end the indoor air conditioning system (ie air-conditioned room) steady flow of heat by the side of the condenser heat water in the line of people. absorbed in the water heat of vaporization of refrigerant after the compressor from liquid into gas by inhalation, compression, heat. again and again, the cycle completed the entire refrigeration process.



Cooling ground source heat pump system will be generated when the waste heat recovery can be made of 50 - 55 �� domestic hot water, saving of fuel consumption for water heating or coal, air pollution, water does not meet the system energy consumption the energy saving effect; the same time as the system out of the chilled water can be added to the return system, to reduce the backwater system return water temperature, resulting in improved cooling efficiency and reduce the power consumption of the refrigeration system.

3 Classification of Ground Source Heat Pump
According to the different cold and heat source, ground source heat pump system can be divided into the use of soil as a source of ground source heat pump hot and cold, hot and cold to the use of groundwater as the groundwater source heat pump system and the use of surface water for the cold surface water source heat pump systems Category 3 .

3.1 Ground Source Heat Pump
Ground source heat pump uses heat from underground aquifers in the closed loop heat pump system. Heat pump heat exchanger buried in the ground, hot and cold and the earth were exchanged. It does this by circulating fluid (water or with water as the main ingredient of antifreeze) in the underground pipe in confined flows, heat transfer between the system and the earth. winter heating, the fluid collected from underground heat, and then brought through the system to heat the room. summer cooling system reverse run when, from the interior with take the heat, and then send the heat through the system in the underground rock layers.

The arrangement of the underground heat exchanger is divided into vertical pipe, horizontal pipe, and hunting buried in Class 3.

Vertical heat exchanger is commonly used U-way, according to the depth of pipe can be divided into shallow (less than 30 m), middle (30 ~ 100 m) and deep (greater than 100 m) 3 species. Vertical heat exchanger heat pump system, small footprint, need less pipe, pump, low energy consumption for per unit length than the level of the heat pipe, but the cost is relatively high. the level of heat exchanger with a single tube and multi- tube 2 forms, the general level of buried depth of 1.5-3.0 m. heat exchanger cost is relatively low, now widely used. but need more space, performance, instability, high pump energy, the system less efficient. snake Comparison of heat exchanger for the case of limited space. Although the level of mining is only one-tube heat exchanger for 20% to 30%, but significantly increased with the amount of control. In this way change the characteristics of a similar level of pipe heat.

3.2 Ground Water Heat Pump
Ground source heat pump system heat source is from wells or abandoned mines in the extraction of groundwater. The most common form of system is connected with the side of the groundwater heat pump connection side (heat exchanger). The early use of single well system, groundwater system about to groundwater through the plate heat exchanger directly after discharge. The downside is that a waste of groundwater resources, and likely to cause ground subsidence, or even cause geological disasters. Shuangjing system was created, pumping a well, a recharge well. groundwater heat pump is used most within 50 m deep shallow wells, the advantage is lower cost than ground source heat pumps, wells and between wells is compact, small footprint, technology is relatively mature. drawback is the limited availability of groundwater, water treatment demanding all the recharge of groundwater extraction and can not be contaminated. now more drawn by the 2 back 1 or 2 3 to 4 back to the pumping technology, this technology is currently used more Shenyang and other cities.

3.3 Surface Water Heat Pump
Surface water source heat pump system is ponds, lakes or rivers in the surface water. Surface water source heat pump system consists of closed and open systems. In cold areas, open system does not apply, but to use closed-circuit system. Surface water source heat pump with cost is relatively low, the pump energy is low, easy maintenance and low operating cost advantages. but the surface water source heat pump system is also affected by natural conditions. in the common rivers, the water pipes or other equipment susceptible to damage. If the river and lakes is too small or too shallow, the water temperature with the larger changes of climate, prone to reduced efficiency, reduced cooling or heating capacity of the consequences. The technology used was more coastal cities. Links to Research Papers Download Center http://www.hi138.com 4 advantages of ground source heat pump system and Economic benefits
4.1 The full realization of energy efficient use of natural resources
Solar energy is inexhaustible and renewable green energy, shallow surface equivalent to a huge solar collector, which collects 47% of the solar energy, use of energy each year than humans more than 500 times. Ground source heat pump is in the winter Using this stored in the shallow ground as a heat source of infinite energy; in the summer Zeyi surface temperature of shallow geothermal energy as a constant cold source, the compressor can only achieve low-power energy conversion air-conditioning system. Survey results show that , the use of ground source heat pump air heat pump energy-saving technologies than 40%, 70% of electric heating energy than the 48% efficiency gas furnace, air conditioning than the required refrigerant reduced by 50%, is truly energy efficient.

4.2 has great environmental benefits
Conventional heating, air conditioning heating in winter and summer respectively, cooling. Their system investment, covers an area of ​​more, and very serious impact on the environment. The atmosphere is the most basic human survival environment for one of the elements. However, as the winter use of coal, fuel oil and natural gas as fuel, burning large amounts of pollutants, including a large number of, , Gases such as air pollution caused serious damage to the atmospheric environment, reduce people's quality of life. Summer use of air-conditioning system also exists: emissions of greenhouse gases as an important Is caused by global climate change one of the main factors.


Row of a large number of people heat the atmosphere, resulting in a heat island effect, while also generating an intolerable noise, making the external space environment conditions even worse. The use of ground source heat pump is the heat storage capacity, the excess heat in summer row of people the earth reserved for winter access to the extra cold winter, summer can be reserved for access, air conditioning system to eradicate the source of the urban heat island effect. ground-source heat pump is very low pollutant emissions, the system used by the injection of refrigerant in the factory who was completely sealed, no leakage during use, users do not have to fill any refrigerant at all times, thus reducing the damage to the ozone layer. heat pump system can be built in a residential area, while eliminating the need for heating in winter, the boiler and boiler room, there is no combustion, no smoke; there is no waste, no pile of fuel, waste sites, not long-distance transport of heat, which greatly improved the limits of air conditioning and other pollutants such as particulate matter emissions; cooling time eliminating the need for cooling towers, cooling towers to avoid the noise and fungal contamination. ground-source heat pump can be used by all of the groundwater recharge, water quality will not cause pollution; ground source heat pump system is not direct consumption of coal or fuel oil, natural gas and other fossil fuels, so as to achieve the environmental protection requirements.

4.3 stable and reliable operation and long service life
Whether the traditional water-cooled air conditioning system or air-cooled, heat the environment are the atmosphere, because of its exposure to the heat exchanger must be placed in the air, it is inevitably affected by changes in environmental conditions, reduce the heat transfer efficiency and service life, and the appearance of the building; and ground source heat pump to heat the soil as the soil temperature is the main advantage of the relative stability of the basic from the outside environment; pipe heat exchanger does not require defrosting, reducing the frosting and defrosting energy; heat pump system designed to be simple, less moving parts than conventional systems, and installed in the interior, a high degree of automation can be unattended; system security without combustion equipment, there is no explosion, burning hidden; the system is not exposed to storm, so maintenance is simple, useful life were 20 a unit above ground heat exchanger life of up to 40 ~ 50a; ground source heat pump system cooling, heating smooth, reducing the stop, the frequency and air power the peak heat and cold; to ground source heat pump heat exchanger buried in the ground, it will not damage the building's appearance.

4.4 Economic Benefit Analysis
Ground source heat pump system economics is determined by the many. Different regions, different geological conditions, structure and prices of different energy and so on will directly affect their economy. A ground-source heat pump system and other forms of energy to compare the investment (in the North Building, comprehensive functions for example), results in Table 1.


100 families in Beijing, for example, the total heat consumption of winter heating 125d as: 100x 125dx24 hx3 600x0.05 kW = 5 400 �� kJ, is getting so much heat, use different heating methods, consumption of fuel, combustion efficiency, energy costs are different.

Statistics shows that coal-fired heating most economical, but due to coal burning in Beijing has limited use, comprehensive comparison, ground-source heat pump system is the best choice.

Only oil-fired boilers and ground source heat pump to provide the same for example, ground source heat pump compare the environmental characteristics, assuming the electricity comes from geothermal heat pump fuel power plants. Calorie 5 400 GJ for the case of the fuel power plants the fuel needed to heat the boiler for the 4 050 GJ; and if the direct use of oil-fired boiler, the thermal efficiency of 80%, you need to heat the fuel for the 6 750 GJ. Emissions from the two heating conditions shown in Table 2.


Be seen from Table 2, the use of ground source heat pump, , And : Emissions were reduced by 69%, 93% and 73%, so its environmental advantages are clear.

1 set of the system can replace the original boiler plus air-conditioning plus 3 sets of domestic hot water systems; Although the initial investment than conventional coal-fired boiler heating system 1 to 3 times higher than the higher cogeneration heating system 34% to 50%. But the experience at home and abroad, as ground source heat pump operating costs low, increase the initial investment can be recovered within 3 ~ 7 a, ground source heat pump system in the entire service period will be lower than the average cost of traditional air-conditioning system. upfront connection fees than in traditional systems with a higher number of, mainly laying the ground heat exchanger, the cost of your design and installation, and annual savings in energy costs, the system would quickly offset the higher installation costs, over time, from the energy consumption savings can quickly recover the investment. Meanwhile, the system nearly maintenance-free and maintenance, can save a lot of expenses. as a clean energy source, ground source heat pump has also been subject to state policy support. Beijing's policy, Beijing's various projects within the construction, heating and cooling system uses heat pump system, fixed assets investment in Beijing will be arranged in a one-time grants, subsidies of 50 yuan /.

Shenyang aquifer permeability strong after 20 m below the surface of the basic constant temperature 12 ��. The natural geographical and hydrological conditions for ground-source heat pump technology application. As much as gravel aquifer structure, permeability, and can be guaranteed does not affect and damage the aquifer recharge under the premise of full atmospheric pressure. According to Statistics, Shenyang, there are 180 million each winter The heating area, so the vast space for the development of heat pump. So far, Shenyang has ground source heat pump area of ​​more than 3 000 million. According to the General Office of Liaoning Provincial Government requirements: Any application of ground source heat pumps with renewable energy technologies such as new condition , reconstruction, expansion of construction projects, the future must be a "geothermal" heating and cooling. authority offices, hotels, shopping malls, office buildings and other energy-hungry, should be preferred ground source heat pump. estimated that by 2010, can be achieved in Shenyang City source heat pump technology area of ​​6500 Million, accounting for 30% of the total heating area is about. Then, save standard coal per heating period to reach 1,265,500 t, to reduce emissions 25 000 t, smoke 19,000 t.

5 Conclusion
In our building resource-saving and environment-friendly society in the process of the set of ground source heat pump energy-saving and environmental protection as one of the new technology, more and more people's attention and favor. I believe in the near future, after domestic engineering technology to the untiring efforts and the successful experience from abroad, China's ground-source heat pump will be further promotion and development of China's sustainable development it will bring new opportunities. reposted elsewhere in the Research Papers Download http : / / www.hi138.com