0 Overview As a clean energy, geothermal energy has both the value of "heat" and the value of "water". The advantages of heating and domestic hot water are obvious and have been rapidly developed in northern China. Domestic geothermal heating applications mainly in Tianjin, Beijing, Hebei, Xi'an and other places. Tianjin geothermal heating applications are more common. At present, the geothermal heating area in Tianjin has reached 5 million m2. According to the calculation of alternative coal-fired boiler heating, more than 110,000 tons of coal are replaced in each heating season, and good environmental protection benefits have been achieved. Geothermal heating in a prominent issue is that after the heat of geothermal discharge water temperature is relatively high, generally above 45 ℃, and some even up to 60 ℃, resulting in a waste of resources and environmental heat pollution. In addition, a few geothermal fields have low temperatures (below 55 ° C). Such low-temperature heat source to be used for heating, to be further heated, such as the use of traditional boiler heating, heating the discharge water temperature will be above 40 ℃. Such as the use of heat pump technology can not only recover the geothermal discharge of water heat, heating temperature heating water temperature, while increasing the heating capacity of geothermal, can make a well equivalent to one and a half to two wells to use, in addition to reduce the geothermal discharge water temperature, to environmental protection Claim. 1 geothermal heat pump heating program previous analysis [1,2]: geothermal heat pump heating system, geothermal heat pump peak heating mode of heating costs and investment is lower than the heat pump alone as a heat source of heating. This paper selects the geothermal heat pump peak heating as the basic system for three kinds of geothermal heat pump heating program of technical and economic analysis. Option 1: Geothermal heat pump peak heating system design Geothermal heat pump peak heating system schematic scheme shown in Figure 1. Geothermal heating for the basic heat source to meet the basic heating load requirements of the heating system, to the heating period, geothermal calories can not meet the heating load requirements, enable heat pump peak shaving to increase heating cycle water temperature, peak heating to achieve the requirements. In this system, the tailrace water after geothermal heating acts as the heat source of the heat pump evaporator, so the geothermal drainage temperature will be further reduced. Option 2: Geothermal heat pump peak heating and living hot water supply to meet the program 1 heating requirements, but also take into account the supply of domestic hot water, that is, the use of geothermal heating of tail water as domestic hot water supply. Compared with a single geothermal heating, geothermal heating and domestic hot water supply not only use the geothermal "heat", but also the use of geothermal "water." Since the temperature of the tail water after geothermal heating is lower than 45 ° C, a system of heating the tail water is needed. Here, a certain amount of geothermal water is designed to be mixed with a certain amount of geothermal tail water to reach 45 ℃ for domestic hot water. As shown in Figure 1, this solution involves reducing the supply of geothermal heat, ie reducing the supply of geothermal heat Therefore, correspondingly, it is necessary to increase the amount of heat regulation of the heat pump. Option 3: Geothermal heat pump peak heating supply of domestic hot water and taking into account the summer air conditioning to meet the above program 2 geothermal heat pump based on the heat pump to consider the use of summer air conditioning. The working principle of a heat pump is the same as that of a refrigerator, and both have the same main components except for the operating temperature and pressure range. Heat pump unit with dual-use, improve the utilization of equipment, a corresponding reduction in heating, air-conditioning system, the initial investment of equipment, while the initial installation fee only one-time charge, the investment economy can be improved. Heat pump air conditioner dual-use, and the unit running time in summer air conditioning heating peak winter than the long running hours, so the initial investment of the heat pump can be 50% or even more than 60% of the air-conditioning system. Technical and Economic Analysis of Geothermal Heat Pump Heating System According to the above mentioned three kinds of geothermal heat pump heating programs and two types of geothermal resources: geothermal utilization of tail water or new drilling geothermal wells for heating the basic heat source heat pump peak heating for heating . Calculation and analysis of technical and economic parameters of the program are based on the actual parameters of a project in Beijing: geothermal water supply temperature is 55 ℃, flow rate is 80t / h; heating and return water temperature is calculated at 35 ℃; heating area is 50,000m2, according to the building energy saving requirements, heating The thermal index can be 50w / m2. The local energy price is 0.36 Yuan / kWh, the geothermal water fee is 0.3 yuan / ton, the tap water water fee is 0.7 yuan / ton, the coal price is 220 yuan / ton and the natural gas price is 1.8 yuan / m3. As the heating supply and return water temperature is low, the choice of the terminal radiator will be considered. Calculation found that the low temperature 55 ℃ below heating, such as the use of conventional radiator heating, radiator area required by at least 50% increase, the corresponding investment will increase by 50%. At present, a new PP-C pipe floor radiant radiator is emerging and put into use, because it is buried under the floor of the room, the cooling mode is radiated from the bottom up, suitable for human body and life needs. This feature, even if it is to reduce the temperature of its supply and return, such as the use of 50 ℃ / 35 ℃, its cooling effect is not much effect. This makes radiant floor radiator radiator in the low temperature heating in a very competitive. Therefore, the combination of building the actual situation, the terminal can be used radiator, radiator or radiant floor. According to the conditions and parameters mentioned above, the specific calculation of the three kinds of geothermal heat pump heating programs is carried out. The results are shown in Table 1 and Table 2 below. Analysis and comparison of calculation results: 1, Table 1 calculates the investment and unit operating costs of different heating terminals and new drilling geothermal wells system. From the three geothermal heating programs, the low investment in program 1, heating costs are low, but there is no domestic hot water supply. Comprehensive comparison, Option 3 has both heating, domestic hot water supply, but also take into account the summer air-conditioning, from the investment and operating costs, the program 3 in between programs 1 and 2 can be used as the preferred solution. 2, Table 2 calculates the economic parameters when calculating and excluding geothermal wells. Excluding geothermal wells, the system has only heat pumps, pipelines and heating terminals. There is no geothermal well investment and running costs, and its heating costs are only accounted for about 55% of geothermal well systems. Table 1 Calculation of Economic Parameters of Geothermal Heat Pump under Different Schemes Terminal Geothermal Heating Scheme Geothermal Well Network Terminal Investment (10,000 Yuan) Initial Investment of Heat Pump (10,000 Yuan) Electricity of Heat Pump Unit (Yuan / m2) Heating Unit Cost (Yuan / m2 ) Domestic Hot Water Investment (10,000 yuan) Water Supply Unit Cost (yuan / m2) Initial Investment Total (10,000 yuan) Heating Radiator Program.7018.02 // 724.0 Program.2219.55461.35815.0 Program.60461.35713.0 Floor Radiator Program.7019. 24 // 1014.0 Plan.2220.78461.351105.0 Plan.82461.351003.0 Heating Increase Investment Plan.7015.83 // 584.0 Plan.2217.37461.35675.0 Plan.41461.35573.0 Table 2 Comparison of heating of geothermal heat pump and boiler heating (according to heating increase Investment calculation) Heating scheme Investment in heating system (10,000 yuan) Heating unit cost (yuan / m2) Domestic hot water system investment (10,000 yuan) Water supply unit cost (yuan / m2) Initial investment (10,000 yuan) Geothermal heat pump heating scheme 158415.83 // 584 Geothermal heat pump heating scheme 262917.37461.35675 Geothermal heat pump heating scheme 352715.4 1461.35573 Excluding geothermal well cost Geothermal heat pump heating scheme 13348.28 // 334 Geothermal heat pump heating scheme 23799.66461.35425 Geothermal heat pump heating scheme 32777.70461.35323 Boiler coal-fired boiler heating 21513.65704.50285 Gas boiler heating 24026.7610511.32345 3 Geothermal heat pump for Comparison of heat and boiler heating Users are more concerned about the general is, whether the geothermal heat pump heating with the traditional boiler heating competition, to calculate the coal, gas boiler heating and domestic hot water supply of the initial investment and unit costs, see Table 2 compares the cost and investment of both geothermal heat pump heating schemes (with or without geothermal well costs) and boiler heating. From Table 2, the heating unit cost of a coal-fired boiler is 13.65 yuan / m2. The heating unit cost of the heat pump peaking heating scheme 3 is 15.41 yuan / m2, 13% higher than that of the boiler. The heating cost excluding the geothermal well is 7.70 yuan / m2, about 56% of the boiler. However, the heating costs of gas-fired boilers have exceeded the heating standard of 20 yuan / m2. Compared to the cost of living hot water supply, the cost of supplying hot water for geothermal life is only 1.35 yuan / ton, lower than the cost of coal-fired boilers 4.50 yuan / ton, much lower than the cost of gas-fired boilers of 11.32 yuan / ton. Based on the above calculated geothermal heating system investment and cost, as well as the investment and cost of boiler heating, the annual gross profit (heating revenue and domestic hot water revenue) of geothermal heating and boiler heating and the investment recovery period can be calculated respectively. See Table 3. Geothermal heat pump heating scheme 3, the highest annual heating and domestic hot water revenue, consider maximizing the geothermal heat for the domestic market, make full use of the geothermal heat and water. Investment recovery period, the coal-fired boiler about 7 years, geothermal heat pump system, when included in geothermal wells, the investment recovery period of about 9 years, excluding geothermal wells about 4 years, lower than the boiler system. It should be explained that when comparing the local heat with the boiler heating scheme, the difference in economic benefits caused by the land occupation can not be ignored. The boiler room should include coal, ash and transportation channels. Usually, the hot well plan covers only about 1/5 of the boiler room plan. As in the downtown area, its land value is quite high. 4 geothermal heat pump heating energy-saving environmental benefits Compared with the traditional boiler heating, the use of geothermal heat pump heating can achieve water-saving and coal-saving benefits. If according to the living hot water supply 40t / h calculation, the annual water supply is 87,600 tons, the use of geothermal heat water supply instead of boiler heating tap water, the annual water saving is 87,600 tons, which not only saves about 60,000 yuan of water, More importantly, clean water is saved, which is very meaningful for water-scarce regions. According to the construction heating of 50,000 m2, the annual unit consumption of coal is 21.53 kg / m2, and the geothermal heat pump is used to replace the boiler heating. Each heating season can save 1077 tons of coal. In addition, the domestic hot water supply is 87,600 tons / year. If the boiler is heated, the annual coal consumption will be 980 tons / year. This can calculate the use of geothermal heating instead of boiler heating, saving 2057 tons per year, according to the coal price of 220 yuan / ton, equivalent to save 453,000 yuan. Table 3 geothermal heating and boiler heating investment recovery (according to increase heating investment calculation) unit program 1 program 2 program 3 boiler gas boiler heating area million m25 heating fee yuan / m220 unit heating costs yuan / m228.289.667.7013.6526. 76 Heating Maori million / year 58.6051.7061.5031.75-33.80 Domestic hot water supply tons / year 87600 Hot water charges standard yuan / ton 6 Hot water supply cost yuan / ton /1.351.354.5011.32 Hot water supply Maori million / Year 0.0040.7340.7313.14-46.60 Gross profit Total RMB10,000 / year 58.6092.43102.2344.89-80.40 Geothermal well cost Gross profit RMB10,000 / year 20.8553.8863.6844.89-80.40 System investment RMB10, Investment recovery period Year 28.012. 59.06.3 No unit area investment fee / m2116.8135.0114.657.069.0 Excluding geothermal wells costs Gross profit RMB10,000 / year 58.6092.43102.2344.89-80.40 System investment RMB10,34425323285345 Investment recovery years 5.74.63.26.3 No unit Area investment fee / m266.885.064.657.069.0 Alternative coal-fired boiler heating, coal saving 2057 tons of air pollution reduction can be calculated accordingly The costs of processing the amount of pollution 12.4 million. According to the above calculated calculated by the coal-fired boiler heating to achieve water-saving, coal-saving and environmental benefits, you can draw a total value of benefits: 60,000 yuan (water) + 453,000 yuan (coal) + 124,000 yuan (environmental protection) = 637,000 yuan This is an indirect benefit of geothermal heat pump heating instead of coal-fired boiler heating, which can be calculated geothermal heat pump heating program 3 direct benefits and indirect benefits of 636800 yuan +63.7 million = 12.738 million yuan, if calculated according to this income heat recovery plan for geothermal heat pump 3 investment recovery period of 4.5 years. 5 Conclusion 1, according to the results of technical and economic evaluation, that heat geothermal heat pump program 3 (heating, domestic hot water, air conditioning) as the preferred program. 2, Geothermal heat pump heating system, when included geothermal wells heating unit cost of 15.41 yuan / m2, and coal-fired boilers, excluding geothermal wells when only 7.70 yuan / m2, about only 60% of the boiler, indicating that the recovery of geothermal Tailrace geothermal heat pump peak heating costs are very low. 3, geothermal heat pump heating system, geothermal wells included in the system when the investment recovery time of about 9 years, excluding geothermal wells when only about 4 years, lower than the boiler system for 7 years. 4, Geothermal heat pump peak heating to improve the utilization of geothermal energy, while reducing the geothermal drainage temperature to meet environmental standards. 5, geothermal heat pump heating alternative coal-fired boiler heating to achieve water-saving, coal saving and environmental benefits totaled 637,000 yuan, which can be calculated geothermal heat pump heating program 3 direct and indirect benefits and the sum of 12.738 million yuan . References: 1. Li Xinguo, low temperature geothermal heat pump heating technology and economic analysis, "Journal of Tianjin University", No3,1996. Li Xinguo, geothermal heat pump heating peak heating system and economic analysis, "Journal of solar energy", No2,1997.
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