| Under the international environment of promoting renewable energy alternative for traditional energy sources structure and the context of the discipline developing requirement, geothermal energy is promoted as a clean energy. The paper promoted adaptability evaluation on the base of investigation and evaluation studies of shallow heat energy resource in Changchun area, and came up with reasonable pumping and reinjection models on the base of numerical simulations, which provides scientific programs and necessary support for the geothermal energy development and utilization in Changchun.First of all, the paper analyzed the shallow heat energy in Changchun by the geotechnical distribution characteristics in the urban area. The utilization of the shallow heat energy is forbidden by the water yield property, water temperature, water quality and other aspects of the pore water under Yitong River Valley and bedrock groundwater. There are water of good quality but little quantity in Jia Jiawazi and Si Jianfang area. Therefore, it is suggested to increase the proportion of surface water exploitation, while groundwater for heating in order to maximize utilization of energy. There are more remaining resources in Yitong River Valley under good recharge conditions, which should be developed under the requirements of the water quality.Next, the paper tested actual thermal parameters of three different lithological types for the calculation and evaluation of the shallow heat energy. In the temperature distribution analysis, the relationship of the ground temperature and the depth is clear and specific by different changes in different drilling depth. For the whole area of Changchun, the ground temperature is periphery low but relatively high interior, which provide necessary direction for the use of shallow geothermal energy selection.Then, the paper evaluated the suitability partition of the research area, on the basis of the hydrogeological conditions, water yield property, water temperature, water quality analysis. The conclusion is: Changchun City ground source heat pumps are suitable for exploitation; ?area(Jia Jia Va sub- Bali Bao- Xinglonggou west of the fractured rock band) is the unsuitable area for extraction of groundwater source heat pump, ?area(JIA Jiawa sub- Bali Bao- Xinglonggou bedrock fissure water with the West Bank and east to the Yitong River mesa scarp zone) is the relatively suitable area for the development and utilization of groundwater source heat pump, ?area(Yitong River Valley area) is the suitable area for groundwater source heat pump.And on the basis of the urban area of geotechnical conditions and shallow geothermal reservoir temperature field distribution, the thermal coupling simulation model of Changchun City shallow heat energy was established by TOUGH2, and the model identification and verification were carried out by observing temperature and pressure data, and the 5 year forecasting was calculated from the current year 2011 on the temperature field, the overall impact on the system operation temperature field have an overall downward trend.With the hydrothermal coupling model, the study of groundwater source heat pump system pumping wells and recharge wells production patterns are discussed. Single pumping reinjection single case, only the case of the connection between recharge wells and pumping wells parallel to the natural hydraulic gradient was concerned, the hydraulic gradient along the direction of the pumping wells recharge wells pointing mode, the pumping capacity of 500 m3 / d, 800 m3 / d and 1500 m3 / d, respectively, in the 30 m, 50 m, 80 m, 100 m and 150 m pumping reinjection wells spacing is obtained for thermal breakthrough time spent, as well as different pumping thermal breakthrough time and reasonable well spacing fitting relations; in pumping capacity <800 m3/d when, ?area, ?area are suitable for the establishment of water source heat pump system; pumping> 800m3 /d when, ?area at the same pumping and well spacing, the thermal breakthrough time for a ?area than delayed, so when a single pumping reinjection single time,??area compared to the area to be more suitable for the operation of groundwater source heat pump system.In order to improve the utilization efficiency water source heat pump, in the double pump-single reinjection mode, five kinds of wells set plan are concered, considering the scope of the thermal break and temperature field, linear wells set program a(two recharge wells pumping wells located on the same side parallelly, and pumping wells located upstream) and line wells set program d(two recharge wells located on the same side of the pumping wells vertically, pumping wells located upstream) are optimal well spacing program. the reasonable well pattern spacing corresponding to the study area pumping 500 m3 / d, 800 m3 / d and 1500 m3/d is 75 m, 90 m and 150 m in ?area, 70 m, 90 m and 150 m in ?area, under the corresponding wells set program, after the 10 years operation of water source heat pump system, the impact on the temperature field is the temperature is less than the initial temperature of the pumping wells 0.5? in the range of 400m* 200 m.According to the use of the characteristics of shallow geothermal energy, the Changchun City shallow geothermal energy capacity was calculated by the establishment of research depth shallow heat energy concepts and mathematical models to calculate, concluded ? district heat capacity of 3.9 × 1013 k J, ?district heat capacity of 8.1 × 1013 k J, focus on the area of Changchun City, the total heat capacity of 1.2 × 1014 k J, from the numerical display, in the absence of the aquifer hilly areas, as only the heat capacity of the soil and rock layers, the stored energy is low, in groundwater areas, relatively high thermal capacity. Ground water source heat pump, ground source heat pump systems heat power calculation, the optimum well spacing settings from the introduction of groundwater conversion method to calculate the area of heat transfer rate, the conclusion is: the total area of groundwater source heat pump system suitable area in the loose gravel under Changchun Yitong River Valley and Qingshankou weathered bedrock aquifers total heat transfer rate are 33.4 × 104 k W(winter), 66.8 × 104 k W(summer),which can supply heat for buildings of 668×104m2 and cool down buildings of 835×104m2. |
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