Introduced ground-source heat pump system buried in the ground heat exchanger system, deepen the construction program, equipment procurement and supply, installation, training, commissioning and final acceptance, the quality of the warranty period, repair, distribution, exchange service. Has some reference to similar projects.
Project Overview: Haian County Administration Center is located in the East China, the MSC central urban area, with a total construction area of 73,000 m², the project building height of 75 m, divided into three zones. The one area archives, air-conditioned area of 141.5 m²; Second District Conference catering building, air-conditioned area of 139.9 m²; three districts, the main floor, air-conditioned area of 48,590.4 m². This project uses the heat exchanger system, selection of ground source heat pump exchange fluids and soil heat exchange, the summer heat pump machine chilled water supply and return water temperature 7/12 °C; winter air conditioning water supply and return water temperature of 50/45 ℃. Ground source water temperature in summer is 25 ~ 30 °C, the maximum does not exceed 35 °C; winter water temperature of 10 ~ 15 °C, the minimum of not less than 7.5 ℃. The design life of hot water, domestic hot water units, water temperature is 50 ℃.
Construction deployment program design this project to pipe heat pump system, the thermal properties of the aquifers with the structure of rock and soil, rock and soil temperature, groundwater static water level water temperature, water quality and distribution, groundwater flow direction, speed, and permafrost thickness of the major technical indicators for analysis and ground heat exchanger systems safety review simulation to determine the ground source system of this project the highest summer water temperature of 35 °C and The winter minimum water temperature is 7.5 °C. Engineering survey results to assess the feasibility of implementation and economic pipe thermal systems to determine the construction program are as follows: outdoor ground source heat exchanger for a total of 900 holes, setting 15 partitions, each partition is responsible for the 60 source Kong; each hole depth of 90 m, the well location was a rectangular array, two adjacent wells spacing of 4 m, the total drilling depth of approximately 81,000 m; the level of PE pipe length of about 20,000 m buried depth of 2 m. Each partition set points, water catchment, ground source hole and partitions, the catchment PE valve connection. The buried part of the ground source system does not have any metal structure, parts. Each partition by land-derived stem tube connected to the total, the catchment, flow balancing valve settings for each partition repair wells in the total score, the catchment.
According to construction progress, the project’s outdoor ground lotus pipe construction and the floor indoor host system, air conditioning end of the system construction at the same time. The entire ground lotus root system is designed to partition the same way system, all the hot melt connection.
Ground the construction 3.1 buried the construction the principle (1) the principles from the outside; (2) by the vertical to the level principle; the (3) by the branch to the charge of the principle.
3.2 Pipe materials the to prepare (1) construction budget, construction plans and construction schedule, the reasonable preparation of materials, equipment, approach and use plan, to avoid the scene materials, equipment stacked more; (2) the erection of temporary materials stacking, storage warehouse, erection of piping prefabrication shed; (3) professional supplier manufacturers of hot melt connectivity tools, equipment, in strict accordance with manual operation; (4) high-density ground lotus root system of this project polyethylene HDPE3408 pipe, the pressure rating of the product of 1.2 MPa, thermal conductivity was 0.46-0.57 W/(m·K).
The (5) projects in the main aquifers with medium dense silt layer, its thermal conductivity is 2.1 to 2.3 W/(m·K). To ensure that the backfill dense, low temperature cracking and thermal conductivity of the backfill material shall be greater than the thermal conductivity of the soil strata, so backfill selection of 5% bentonite and 95% fine sand concrete concrete mixture, the thermal conductivity of 2.4~2.8 W/(m·K); (6) the heat transfer medium of the project using tap water, to meet the heat transfer medium must be security, heat transfer, the lower the frictional resistance and affordable technology requirements.
Material testing and storage 3.3 pipe and fittings shall meet the design requirements, product certification and related testing of the application of pipes, fittings and accessories should be enterprise quality inspection department the department of quality inspection reports. Pipe should be the stability of the chemical properties, corrosion resistance, thermal conductivity, the flow resistance of small plastic pipes and fittings should be used polyethylene pipe (PE) or polybutylene (PB) should not be used polyvinyl chloride (PVC) pipe. Pipes, fittings and accessories should be of the same material. Buried quality should be consistent with the provisions in the current national standards. The pipe shall be marked with the specifications, trademark, or manufacturer name, nominal pressure, and date of manufacture, packaging should meet the requirements, shall be marked with the length. Nominal pressure and temperature should be of the the pipe to meet the design requirements, and the pipe’s nominal pressure of not less than 1.0 MPa, to pipe outside diameter and wall thickness according to the water supply polyethylene (PE) pipe GB/T and the hot and cold water piping systems use polybutylene (PB) pipes and the appearance of quality to meet the following requirements: the pipe should be complete, no defects, no distortion, mold seam intersection should be smooth, no cracking. Pipe, the pipe transport and storage should meet the following requirements: (1) pipe, fittings transportation, storage should not be damaged packaging, not exposure, rain. Bundles, boxes of discoid pipes and fittings should be neatly stacked, the other should be not greater than 2 m. The fulcrum of material should be wood, width ≥ 0.2 m, the spacing should be justin bieber spiderman beats, and will not cause the flushing fluid to circulate the drilling process is interrupted. Formation leakage case, the flushing fluid continuous supply can continue drilling; (7) in the drilling process, arrangements for quality inspector at any time to check the location of the drill, to ensure the correctness of the position of the hole, and do good inspection records, such as the deviation exceeds the standard requirements, should be promptly corrected to re-locate; (8) drilling completed to check the quality of the drilling depth and drilling and make the hidden works records reported construction units (Supervision) acceptance; drilling process in the (9) of earth and earth excavation, the soil should be focused on stacked, and color of the cloth cover; (10) in the drilling the process in order to avoid drilling landslides poured mud in the drilling process, drilling borehole wall mud solidification Wall to prevent the collapse hole.
Buried site 3.5 and pre-assembly construction technology (1) buried in the U-tube should be pre-assembled at the scene, before the tubes pre-assembled stacked in a flat on the ground levels should not be partial pressure to the pipe deformation stacking height should not exceed 2 m; fittings should be stored into the storage box on the shelf or the code heap on a flat plane, the code heap on the ground height of not more than 2 m. HDPE pipe delivered to the site using the color of the cloth covering the long time sun exposure is strictly prohibited; (2) HDPE pipe connection should pay attention to the hot melt tube head cleaning, pipe cutting diameter ≤ de50 rotating cutter; diameter＞ de50, handmade woodworking saws; (3) of HDPE pipe in the ground connection is completed, pressure test, after passing the pipe; pressure test again after the backfilling of the wells, qualified the rear can be connected to levels of dry pipe; level of Explorer you have finished connecting the pressure test, after passing the backfill. Explorer connection after system pressure test; (4) HDPE pipe connection can be used hot melt socket connection connection (hot melt, hot melt welded connections), should be connected with the metal pipe flange connection; (5) hot-melt socket connection: hot melt socket connection should be reliable quality hot melt equipment, portable welding tool for final connection of Φ ≤ 63 mm piping and systems, desktop welding equipment applicable in of Φ ≥ 63 mm pipe pre-equipment connection. Heating tool heated to welding temperature of 260 ± 10 °C, the socket end of the tube should be cut flat and perpendicular to the axis. Use a pen to make the appropriate tags, in order to facilitate connection to the positioning of sockets and spigots. The die of the heating tool to melt the outer surface of the socket pipe end punch to melt the inner surface of the socket. After heating, quickly remove the heated mold, the jack-side straight into the socket side, to achieve the fixed connector in the connection strength, natural cooling to ambient temperature; (6) Butt: pipe diameter Φ ≥ 63 mm HDPE pipe can be butt connected, the method is economical and reliable, and their joints for tensile and pressure than the pipe itself has a higher strength. The hot melt bonding temperature: 200~210 ℃. When using this method, the device only hot melt docking machine, the steps are as follows: ① The pipe to be connected and clamped in the welder fixture; ② clean pipe connector and milling connection surface; ③ The school straight two docking, so face dislocation amount of not more than 10% of the pipe wall thickness; ④ into the hot plate and heat; The ⑤ heating is completed, remove the heating plate; ⑥ The rapid bonding of two heating surface, the boost to the welding pressure and holding pressure cooling.
HDPE Pipe connections Note (7): response to pipes, fittings and ancillary equipment before ① The pipe connections, valves, meters to be checked according to design requirements, and at the construction site. Visual inspection, to meet the requirements shall be allowed to use. The connection should be used for pipes and fittings of the same manufacturer, if it proves necessary to different manufacturers (brands) pipe and tube connections should be tested to prove its reliable behind the prospective use of the. Each connection is completed, the appearance quality inspection does not meet the requirements must rework; the (2) construction personnel should conduct induction training; ③ each construction, the nozzle should be temporary seal block; ④ When the outdoor temperature dr dre headphones ferrari, we head to go down construction method of precast concrete guide. Pre-guidance head diameter slightly smaller than the hole diameter, occupied the position of the diameter of greater than 4 HDPE circulation pipe (pre-test pressure test) should be guided first production. Rely on the weight of the guide head and the weight of the HDPE pipe water to go down, both to ensure the speed but also to ensure that the source of HDPE pipe can effectively reach bottom of the well pipe under the same time, but also to protect the HDPE pipe to go down process from sidewall tip stone scratches and damage. Commonly used artificial down tube, down tube must be multiplayer co, not mention the pipe in the ground dragging should not form a natural bending, but not allowed to produce point of view. To avoid the loss of thermal bridges, U-shaped pipe spacing should be strictly in accordance with design requirements, to maintain concentricity under the pipe to make pipe and tube, do not touch too tight, the construction of every U-tube separated from 2 to 4 m to set a fixed support card unchanged to ensure the relative position of the vertical ground source heat exchange tubes, the vertical heat exchange tubes will not stick together. HDPE Pipe to go down after the completion shall be U-shaped tube two ports sealed.
3.7 to backfill construction technology To ensure the quality of the grout backfill, this project go down in the precast concrete guide head at the same time, the grouting pipe at the same time with the guide head go down. Go down the project, staff were pulled grouting tubes and four HDPE pipe when the PE pipe to the bottom of the well, the grout pipe to release the grouting pipe and artificially poke down, the connection charge of the tray and The guide head retractor separated from, and then should be put to immediate use grout pipe mixed slurry poured into the borehole the backfill sealing isolation aquifer. Perfusion construction should ensure the continuity of the grout, grouting tube to enhance the speed determined according to the speed of the mechanical filling, to ensure that the slurry from the bottom in my full cavity. When the density of the mud on the back with perfusion material is equal to the grouting work has been completed. Confirm the U-shaped tube leakage bentonite backfill, available screening had ≤ 15 mm × 15 mm backfill backfill backfill mesh ≤ 15 mm × 15 mm drain sieve to sift, to ensure that no gravel and sharp stones, broken concrete backfill. Vertical ground backfilling should be in the pipeline on both sides of synchronization backfill, double or multiple row pipeline buried horizontally in the same trench, the pipe between the backfill compaction between the pipes and tank wall backfill compaction symmetry. The compacted surface height should not exceed 30 cm. Provided to ensure that the gap between the to be the tube and the hole well, the first time the form is completed should be multiple inspections, multiple backfill. More difficult to backfill for pipe axillary and other parts, using artificial backfill to ensure that the backfill compacting. Backfill should focus on doing the backfill on each pipe above the 15 to 20 cm. Piping the top and sides of 50 cm should be used lightly compacted wooden rammer prohibited the use of compaction equipment directly acting on the pipe. Upon the completion of each district under the tube connected to the set, divider, the first artificial trench excavation, will be divided into the catchment at the inspection wells and connection with the U-shaped tube, to form a complete closed loop. Points, the catchment is set exhaust and sewage installations. When the backfill of the pipe region as a whole should be layered with a wooden rammer compaction. The overall backfill should be mixed in one of the sharp stones, broken concrete are taken out.
4. Ground heat exchanger system washing Reliable operation of the heat exchange system to ensure that ground must be flushing system, system flushing, mainly in the following construction phase: ① The ground heat exchanger before installation; ② The ground heat exchanger loop header assembly complete; ③ The heat exchanger system fully installed is completed.
Ground heat exchanger system pressure test Test pressure: when the working pressure ≤ 1.0 MPa working pressure of 1.5 times the working pressure and should not be 1.0 MPa, the work pressure of 0.5 MPa. Water pressure test procedure in : (1) vertical pipe before the heat exchanger into the drilling should be done the first hydraulic pressure test. The test pressure after the regulator for at least 15 min, the regulator pressure should not be> 3%, and no leakage; drilling in the state of pressure sealed insert, after the completion of grouting pressure for 1 h. (2) the level of ground heat exchanger into the trench before the first hydraulic pressure test should be done. The test pressure after the regulator for at least 15 min, the regulator pressure drop should not be> 3%, and no leakage. (3) vertical or horizontal underground pipe heat exchanger and the loop header assembly is completed, the second hydrostatic test should be conducted before backfilling. Under the test pressure, the regulator at least 30 min, the regulator pressure drop should not be> 3%, and no leakage; (4) loop set of tubes with the engine room manifold connection is completed, backfill The third hydrostatic test should be conducted before. Test pressure, voltage regulators, at least for 2 h, and no leakage; all (5) heat exchanger system is installed, and flushing, venting, backfilling is completed, the fourth hydrostatic test. Test pressure, the regulator at least 12 h, the regulator pressure drop should not be> 3%. System pressure test shall not be replaced by pneumatic pressure test; hydrostatic test should be used for the slow hand pump pressure, the pressing process should arrange to be observed at any time and check the lines, there is no leakage.
This project uses the method of construction of the partition design, each partition set points catchment, ground source Kong and Zoning, the catchment PE valve connection. The buried part of the ground source system does not have any metal structure, parts. Each partition through to source dry tube with the total score, the catchment connections, flow balancing valve settings for each partition in the score, the catchment repair wells. Once the local source in the operation unexpected failure can be the inverse method can immediately identify faulty ground source wells. Failure, the first score, the catchment at the pressure gauge readings to detect the failure of ground source partition; to find the trouble source partition, enter the repair wells, and similarly, by opening and closing the PE valve, to measure the pressure immediately able to detect a faulty ground source wells, and its corresponding PE valve is closed. Inspection of the entire system, repair with no system downtime.
6 test and the identification In consciously take the initiative to accept the owners, and supervision units to the construction site supervision and test in accordance with the following report: (1) location of the shaft and The depth and length of the heat exchanger meets the design requirements; (2) inspection of the backfill process is carried out simultaneously with the installation of soil heat exchanger; (3) supervision of the circulation line, the cycle set tube and pipe pressure test whether the above requirements, to ensure that no leakage. Hidden works records in pay the owner, supervision and inspection, and after passing under a process. Test and evaluation results of the above to submit a report to the owners, and to ensure that the actual completion of records in the design plan.
Ground source heat pump installed in 7 centralized the host of this project ground source heat pump, chilled water for the whole project is the harmonization of output from the engine room, with host size, to ensure in all cases the best ratio, but also to ensure the different units and pumps running under different loads, the unit is always kept at full load operating conditions, in the best conditions, the COP value was maintained at the optimum value to achieve the long-running the best energy-saving effect.
8 Ground source heat pump system operation The debugging and acceptance , ground source heat pump system as a whole operation, commissioning and acceptance must comply with the GB-2005 ground source heat pump systems engineering technical specifications, GB, and air conditioning construction quality acceptance standard, GB, refrigeration equipment, air separation equipment installation construction and acceptance the source heat pump systems delivered, should the overall operation, commissioning and acceptance. The overall operation and debugging programs reported that professional supervising engineer review and approval before implementation. Source heat pump system overall acceptance of the need for a relatively long time to debug the system overall acceptance should be divided into winter and summer, carried out acceptance of the whole system to make the evaluation of the measured performance of ground source heat pump system, commissioning finished debugging the report should be prepared and run operating procedures, and submitted to the archive after the confirmation of the unit owners.
Ground source heat pump system operation, commissioning and acceptance include the following: (1) the system pressure, temperature, flow, and other technical data should be consistent with the provisions of the relevant technical documents; continuous operation (2) The system should meet the normal smooth; the pump pressure and pump electric current should not be substantial fluctuations; (3) all kinds of electric measuring and testing components and implementing agencies should be normal; meet the building automation system to the determination of parameters for detection and control requirements; (4) control and testing equipment should be able to normal and the detection of the system components and implementing agencies to communicate the status of the system parameters should be able to display correctly, chain equipment, automatic adjustment, automatic protection should be able to correct operation; (5) debug report should be ready to record before commissioning, hydraulic balance, unit and system commissioning test data; (6) ground source heat pump system in the winter and summer run tests, including indoor air parameters and operation energy consumption for the determination of operation energy consumption includes the energy consumption of all water source heat pump units, water pumps and terminal equipment.
The warranty source heat pump central air-conditioning system, through scientific design in accordance with stringent quality standards of construction to protect the underground part of the maintenance-free warranty for 50 years, the aerial parts warranty with 20 years. In accordance with Article 7 of the Ministry of Construction Decree 80 system warranty period of 10 years, the system warranty period from the project completion and acceptance began to 10 years free maintenance of the system have any questions. Each product according to the manufacturer’s warranty period.
Conclusion: Precisely because of the inherent characteristics of ground source heat pump systems use shallow geothermal resources for heating and air conditioning, has a good energy saving, environmental protection, aesthetics, does not consume minerals in the country in recent years an increasingly wide range of support and promote the use of, but not using a ground source heat pump system, the magnitude of its energy-saving will be able to achieve the desired state. Similarly, the traditional air-conditioning system, the end host, the water pump part load maximum operating energy in the system design must be considered, the project design multi-head host, large and small with the end of the electric two-way valve control pump configuration of a variable frequency pump, the entire system uses the number of units and frequency to meet during the operation of the load changes, to ensure the system to maximize the energy saving. This project is located in the East China coastal areas