A residential district temperature and humidity independent control air conditioning system design

According to the Geotechnical Thermal Response Test Report for Ground Source Heat Pump of the site, the initial average temperature of geotechnical soil is 19.09 ℃, and the integrated thermal conductivity of geotechnical soil is 1.85 W/(m-K). The diameter of the heat exchanger borehole is 150 mm, the effective depth is 120 m, double U-shaped buried pipe is used, the heat discharge of a single well is 7.20 kW, and the heat extraction of a single well is 5.64 kW. The buried pipe heat exchanger of this project is selected according to the winter condition, the spacing of boreholes is 4.5 m, the supply/return temperature of the side of the buried pipe is 10 ℃ / 5 ℃, and the design condition COP is 5.119, the winter load is 3,522 kW, and soil Heat extraction is 2,834 kW, taking into account the safety factor of 1.2, heat exchanger group additional correction factor of 0.8, the number of calculated wells is 754, the project is designed to use 760 wells, of which 6 are used as ground source temperature monitoring wells, and another 3 are arranged as soil temperature monitoring wells.

Underground heat exchanger system heat exchanger unit for each well individually 1 circuit, summarized into a number of groups of primary manifold. One level of manifold is set up in the inspection well near the basement wall, and one level of manifold is summarized and connected to the ground source heat pump room, and flexible waterproof casing should be set up at the pipe line through the wall. Vertical buried pipe and horizontal contact pipe are made of high density polyethylene (HDPE) pipe, vertical buried pipe specification is De25×2.3 mm (SDR11 series, bearing pressure 1.6 MPa), horizontal collector specification is De32×3.0 mm (SDR13.6 series, bearing pressure 1.25 MPa), and the buried pipe adopts hot melt connection.

In order to balance the heat release and heat extraction, it is necessary to turn on the cooling tower and the magnetic levitation unit to assist the operation, the calculation and the operation control mode are suggested as follows: according to the annual energy consumption calculation results, the project's residential part of the annual cumulative heat consumption of 4,470,000 kW-h, the annual cumulative consumption of cold is 6,120,000 kW-h. When the water temperature of the heat pump unit on the ground source side in the summer is more than 32 ℃ or the cumulative heat release is greater than the heat extraction, the cooling tower and the magnetic levitation unit will be turned on. Cooling tower and magnetic levitation unit. According to the annual load calculation, the cooling load peaks in mid-August, so it is recommended to set the cooling tower and the buried tube heat exchanger to run simultaneously from June 15th to September 1st. The difference between the annual cumulative heat gain and heat release of the soil under this operation strategy is not significant, which satisfies the soil heat balance requirements.
 

The air conditioning system adopts centralized cold and heat source, household heat exchange transmission and distribution system, which saves the pipe network investment and reduces the transmission energy consumption; the user-side fixed-pressure water replenishment adopts vertical partitioning to reduce the pressure of water replenishment, control the working pressure of user-side capillary tube system, and improve the reliability and service life of capillary tube radial end; the replacement of new wind adopts local micro-drop plate buried processing, which saves the space in the household; the new wind system is vertically partitioned, and the area of the indoor well is reduced, which increases the use area, which is optimized by double cooling source deep heat recovery new wind unit to centrally recover the exhaust air energy. Increase the use of area, by the dual cooling source depth heat recovery fresh air unit centralized recovery of exhaust air energy, optimize the unit configuration, to avoid the heat pump outdoor condenser takeover, the heat pump recovery of low-temperature exhaust air energy, to improve the efficiency of the built-in heat pump; optimize the basement fresh air unit functional section configuration, reduce the size of the unit, saving installation space.