I. Overview of the project. Supervision basis 1, Technical Specification for Ground Source Heat Pump System Engineering (GB 50366-2005) II. Code for Construction Engineering Supervision (GB503 19-20003), Design and construction drawings and disclosure of ground source heat pump, and minutes of blue prints.the design. Construction organization design of ground source heat pump. Difficulties and key analysis The control technology of 65438 ground source heat pump is relatively complicated, and the initial investment cost is high, and the system needs to control and adjust two water systems and heat pump units at the same time, otherwise it will lead to unstable operation of the system, so this item is also one of the key points in the installation of ground source heat pump. 2. The core of ground source heat pump system is soil coupled underground heat exchanger. Pipe, pipe diameter, pipe length, number and spacing of vertical shafts, pipeline laying, pump selection and pipeline pressure-bearing capacity check are all key and difficult processes in the installation of ground source heat pump system. 3. Installation and debugging of underground system and water collector in air conditioning room. Because the valves on the water distributor and the water collector can control the heat exchange of each group of underground pipes, and it is convenient to find the accident site in case of failure, the flow balance between branch pipes needs to be adjusted through this system. 4. Installation and debugging of heat pump unit. In order to improve the energy efficiency ratio of heat pump unit under heating conditions, it is required to increase the evaporation temperature of the unit as much as possible. The operating cost of the system is the first concern of users. The inlet and outlet temperatures of the underground heat exchanger under heating conditions have been determined, that is, the inlet and outlet temperatures of the evaporator of the unit have been determined. The only way to improve the evaporation temperature is to reduce the temperature difference at the evaporator outlet, so the correct installation and normal operation of the heat pump is particularly important. Four. Control target value and method (1) Control of riser construction 1. Pay-off shall be carried out with reference to the positioning axis of the field project, and the position of the heat exchange hole shall be calibrated according to the construction drawings to ensure the accurate position. 2. The vertical drilling rig (1) should use the drilling point to locate the tower chassis, and level the chassis horizontally and vertically, with the levelness ≤ 0.5 mm/m..(2) After the chassis is positioned, install the vertical pole of the tower, and measure the verticality of the tower with a plumb hammer and a ruler to ensure the verticality of the tower vertical pole. (3) Install power head of drilling rig, lifting device of drilling rig, water filling (mud) of drill bit and other auxiliary devices. (4) The concrete floor in the site shall be broken in time, and the sedimentation tank and mud ditch shall be dug and kept unblocked as required. (5) Connect the electricity and water pipes to the drilling rig and its accessories, and test each equipment to determine the steering. 3. Before drilling (1), make sure that the steering is correct, and recheck the levelness and verticality of the tower underframe and upright post. (2) When drilling, the drilling speed should be uniform, and the operation of the drilling rig and auxiliary equipment should be paid close attention to. If any abnormality is found, it should be handled in time to prevent the thread of drill pipe and joint from being pulled off and the bit from falling off. At the same time, we should always pay attention to and record the geological changes of the stratum. (3) During drilling, the platform manager and operators should regularly check the platform and ancillary equipment, and do a good job of maintenance in time to improve work efficiency. (4) When the hole is drilled to the required depth, it should be drilled repeatedly to create smooth conditions for the lower heat exchange tube. 4. Before the pressure test of the heat exchange tube, the water pressure test shall be conducted according to the design requirements. The test pressure is 25MPa, and the pressure is stabilized for at least 30 minutes. After the pressure is stabilized, the pressure drop should not be greater than 3%, and there is no leakage. Hot-melt seal its nozzle and prepare to run the pipeline. 5. Downward heat exchange tube (1) In order to ensure the heat exchange effect and prevent the phenomenon of heat backflow between branches, the distance between the two heat exchange branches should be kept, and the two heat exchange tubes should be separated and positioned with a separation positioning pipe clamp before descending the tube, and the distance between the separation positioning pipe clamps is 3 meters. (2) According to the actual situation of the well, use the pipe running machine to run the pipe at a uniform speed to prevent the pipeline from being damaged in the process of running the pipe. If there are obstacles and obstacles, the reasons should be found out in time, and the pipe can be run again after being properly handled. (3) When lowering the pipe device, the HDPE pipe head should be connected and fixed with the pipe device, and the pipe head should be tied with a plastic rope. (4) Insert the lower pipe device together with the HDPE pipe into the borehole, and manually lift the HDPE pipe to one side to lower the pipe. (5) When the pipe head sinks into the borehole, it should be measured according to the drill pipe, and the pipe should be stopped after reaching the effective depth, and it should be pulled by nylon rope to prevent sinking. (6) If a pipe-lowering machine is used to lower the pipe, the pipe-lowering drill pipe should be lifted after the heat exchange pipe is in place. In order to prevent the heat exchanger from floating, a little grouting or yellow sand should be injected before lifting the pipe. 6. Backfilling (1) Backfilling method: backfill with underground mud. Using special backfill pump, the filler is injected from the bottom of the hole and backfilled upward, so that the air is gradually removed, ensuring no backfill gap and ensuring heat transfer effect. (2) Backfill: The thermal conductivity of backfill material has an important influence on the heat exchange capacity of underground pipelines. Backfill materials are in closest contact with underground heat exchangers after construction. The proportion and selection of backfill materials determine its heat transfer performance, which directly affects the heat transfer effect. In addition to heat transfer, its solidification strength grade should also be considered. Due to different geological structures, different expansion capacities and different extrusion pressures. Choosing suitable backfill can also prevent the underground heat exchange tube from being damaged by extrusion. Therefore, according to the geological report, the selection of backfill is also an important part to ensure the successful application of ground source heat pump. (3) Backfilling equipment: When backfilling materials, high-pressure backfilling is required. If manual backfilling is used, the pressure is not enough and there are many gaps, which seriously affects the heat transfer effect, fails to reach the design parameters and cannot realize the cooling and heating of the system. The backfill equipment used has high backfill pressure, and the backfill material is injected from the bottom of the hole to ensure that there is no backfill gap, and the backfill material has good thermal conductivity after solidification. (4) Full-hole backfilling to the elevation of the working face. After completion, it shall be marked with colored flags or other marks. (2) Cross-pipe construction control 1, material inspection and storage The internal and external walls of pipe fittings and pipelines shall be smooth, free of bubbles, cracks, peeling and obvious marks and depressions; The colors of pipe fittings and pipes shall be consistent, and there shall be no uneven colors. 2. Handle with care when loading, unloading, transporting and handling. Don't be hit by violent collisions and sharp objects. Don't throw, drop, roll or drag to avoid contact with oil. During storage and construction, prevent dirt and sundries from entering the pipeline, and avoid direct sunlight in the storage place. 3. Connection mode According to the design requirements, all polyethylene pipes should be connected by butt welding. The hot-melt connection of pipelines must be carried out in accordance with the manufacturer's construction technical specifications and standards. 4. In this project, most buried heat exchanger pipes are laid under the floor of the building. In order to ensure that the buried heat exchanger pipeline will not have problems due to pressure, the following two measures are taken: (1) First, the pressure bearing capacity of the buried heat exchanger pipeline should be 1.6MPa, and the pipeline made of HDPE 100 and bearing pressure 1.6 MPa should be used to ensure its circumferential stiffness. (2) The laying and backfilling of horizontal pipelines must be carried out in strict accordance with the following construction schemes:
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