Waste heat recovery integrated construction method for refrigerating system of large refrigeration house

Abstract

The invention discloses a waste heat recovery integrated construction method for a refrigerating system of a large refrigeration house, which can perform multi-scene utilization on waste heat generated by the large refrigeration house, simplify the construction process, improve the integration level and the energy utilization efficiency of a heat recovery system and reduce the operation cost of the refrigerating system. Scientific and normative guidance is provided for energy-saving and emission-reducing transformation and new projects of the large refrigeration house; the method comprises the following steps: analyzing a waste heat source of a large-scale refrigeration house refrigeration system; the waste heat source comprises compression heat generated by the compressor unit and condensation heat generated in the condensation stage of the condenser; determining an application scene of waste heat recovery; configuring a heat recovery system according to the application scene of waste heat recovery; the heat recovery system comprises an air cooler hot fluorine defrosting system, an air cooler hot water defrosting system and a floor heating system, and the heat recovery system is constructed at the preset position of the large refrigeration house.

Description

Technical Field

[0001] The invention relates to the technical field of heat recovery in cold storage, and in particular to an integrated construction method for waste heat recovery of a refrigeration system in a large cold storage. Background Art

[0002] Cold storage consumes a lot of energy during operation. If the waste heat generated by its refrigeration system is directly discharged without treatment, it will not only cause energy waste, but also may cause thermal pollution to the surrounding environment. In the operation mode of traditional large-scale cold storage (cold storage with a building area of ​​not less than 1,000 square meters), the refrigeration system maintains a low-temperature environment through compression, condensation, expansion, evaporation and other links. The refrigeration system mainly includes evaporator, compressor, condenser and throttling device. In the refrigeration cycle, the refrigerant absorbs heat in the evaporator and converts it into low-temperature and low-pressure gas, which returns to the compressor; the compressor compresses the low-temperature and low-pressure gas into high-temperature and high-pressure gas and sends it to the condenser through the exhaust pipe; the high-temperature and high-pressure refrigerant gas is cooled in the condenser, releasing heat (the heat is equal to the sum of the cooling capacity and the compression work) to the external environment, completing the heat exchange process. Among them, electrical energy is converted into mechanical energy and thermal energy during the operation of the compressor, and a large amount of heat is released when the refrigerant changes from gas to liquid in the condenser. These waste heats are usually dissipated into the environment with the cooling medium (such as air or water), resulting in huge energy waste. In this context, waste heat recovery and energy-saving utilization technology came into being. This technology effectively collects the waste heat generated by the refrigeration system through a series of heat recovery equipment and processes, and uses it for various purposes such as preheating the refrigerant entering the evaporator, providing heat for the defrost system, supplying domestic hot water in the warehouse, or providing heat energy for other heat-requiring links, thereby achieving the goals of energy recycling and energy saving.

[0003] However, to successfully apply waste heat recovery and energy-saving utilization technology to large cold storage, a set of perfect construction methods is needed to guide engineering practice, ensuring that all aspects of the system design, installation, commissioning and operation can meet the standards of high efficiency, stability and reliability, so as to give full play to its energy-saving potential and meet the urgent needs of the cold storage industry for energy conservation and environmental protection. Although there are some waste heat recovery technologies on the market, most of them are concentrated in a single application scenario (such as kitchen water heating, floor heating, etc.), which are mainly suitable for small cold storage. For large cold storage, waste heat recovery in a single scenario cannot meet the energy-saving needs. There are also problems such as low system integration, poor compatibility with the original system of the cold storage, complex construction process and lack of pertinence, resulting in low waste heat recovery efficiency, unstable operation or high cost. Summary of the invention

[0004] At least one of the purposes of the present invention is to provide an integrated construction method for waste heat recovery of a large cold storage refrigeration system in order to overcome the problems existing in the above-mentioned prior art, which can utilize the waste heat generated by the large cold storage in multiple scenarios, simplify the construction process, improve the integration and energy utilization efficiency of the heat recovery system, reduce the operating cost of the refrigeration system, and provide scientific and standardized guidance for the energy-saving and emission-reduction transformation and new construction projects of large cold storage.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention includes the following aspects.

[0006] A large cold storage refrigeration system waste heat recovery integrated construction method, comprising the following steps:

[0007] Step S1, analyzing the waste heat sources of the large cold storage refrigeration system; the waste heat sources include compression heat generated by the compressor unit and condensation heat generated in the condenser condensation stage;

[0008] Step S2, determining the application scenario of waste heat recovery;

[0009] Step S3, configuring a heat recovery system according to the application scenario of waste heat recovery; the heat recovery system includes a cold air machine hot fluorine defrosting system, a cold air machine hot water defrosting system and a floor heating system;

[0010] Step S4: construct a heat recovery system at a preset location of the large cold storage.

[0011] Preferably, the air cooler hot fluorine defrost system comprises an air cooler, an air cooler coil is arranged in the air cooler, the air cooler coil is connected to the return air fin, the air cooler coil inlet is connected to the fluorine exhaust main pipe through the fluorine exhaust branch pipe, the fluorine exhaust main pipe is connected to the oil separator, and the oil separator is connected to the compressor;

[0012] The air cooler hot water defrosting system comprises an air cooler, a defrosting water heat exchanger, a first heat recovery water pump, a defrosting water tank and a defrosting water pump, wherein the defrosting water heat exchanger is connected via a fluorine exhaust branch pipe and a fluorine exhaust main pipe, the first heat recovery water pump is connected between the defrosting water heat exchanger and the defrosting water tank, the defrosting water heat exchanger is also connected to the air cooler, and the defrosting water pump is connected between the air cooler and the defrosting water tank;

[0013] The floor heating system includes a floor heating heat exchanger, a second heat recovery water pump, an ethylene glycol supply and collection device, an ethylene glycol return water collector and a floor heating pipe, wherein the floor heating heat exchanger is connected to the fluorine exhaust branch pipe and the fluorine exhaust main pipe, the inlet of the floor heating pipe is connected to the outlet of the ethylene glycol supply and collection device, the outlet of the floor heating pipe is connected to the inlet of the ethylene glycol return water collector, the inlet of the ethylene glycol supply and collection device is connected to the ethylene glycol liquid inlet main pipe, the outlet of the ethylene glycol return water collector is connected to the floor heating heat exchanger through the return water main pipe, the ethylene glycol liquid inlet main pipe is connected to the second heat recovery water pump through the ethylene glycol liquid inlet branch pipe, the second heat recovery water pump is also connected to the floor heating heat exchanger, and the floor heating heat exchanger is also connected to the inlet of the ethylene glycol supply and collection device.

[0014] Preferably, in step S4, the construction heat recovery system includes:

[0015] Construction preparation: clean up the construction site, build temporary construction facilities, set up safety protection facilities and warning signs, and plan the zoning of the construction site;

[0016] Foundation construction: On-site layout and positioning, using a laser level to ensure that the foundation surface is on the same horizontal plane; fix the casting formwork on the boundary line according to the equipment size, then use steel bar horse stools to raise the steel bars and tie the steel bars, pour C30 concrete and maintain for 14 days;

[0017] Construction of hot fluorine defrost system for air cooler: mainly including installation of compressor unit, oil separator, fluorine exhaust pipe, valve, connection between pipeline and air cooler and pipe insulation;

[0018] Construction of hot water defrosting system for air cooler: mainly including installation of fluorine exhaust pipe and defrosting water heat exchanger, defrosting water tank, water pump, water supply pipe and return pipe, and pipe insulation;

[0019] Floor heating system construction: mainly includes floor heating pipe installation, pipe pressure testing, ethylene glycol supply and return water collector installation, fluorine exhaust pipe and floor heating heat exchanger installation, water pump installation, pipe and valve insulation.

[0020] Preferably, the construction of the floor heating system also includes the installation of a constant-pressure water replenishment unit, which is installed on the return water pipeline of the floor heating system to ensure that the water replenishment operation can be carried out effectively.

[0021] Preferably, during the foundation construction, the on-site layout and positioning are carried out according to the equipment foundation deepening point drawing provided by the refrigeration unit, and a laser level is used to ensure that the foundation surface is on the same horizontal plane; after the positioning is completed, the casting template is fixed on the boundary line according to the equipment size, and then the steel bar is raised by a steel horse stool so that the steel bar is 100mm away from the structural floor slab, and the steel bars are tied on-site at a spacing of Φ10@200, and then C30 concrete is poured. After leveling with a horizontal scraper, it is covered with a geotextile and watered for maintenance for 14 days.

[0022] Preferably, in the installation of the fluorine exhaust pipe of the hot fluorine defrost system of the air cooler, a fluorine exhaust main pipe is installed on the top of the oil separator, and then a fluorine exhaust branch pipe is branched from the fluorine exhaust main pipe, the fluorine exhaust branch pipe is connected to the air cooler in the cold storage room, and the fluorine exhaust branch pipe is connected to the coil inlet of the air cooler, and the oil separator and the fluorine exhaust branch pipe are connected by a stainless steel corrugated shock-absorbing flexible connection.

[0023] Preferably, the fluorine exhaust pipe is derusted before installation. After the rust removal is completed, the ports at both ends of each section of the fluorine exhaust pipe are polished to form a groove, and both ends of each section of the fluorine exhaust pipe are wrapped with waterproof tape to prevent moisture.

[0024] Preferably, in the valve installation of the hot fluorine defrost system of the air cooler, a first stop valve, a filter, a first solenoid valve and a second stop valve are installed in sequence on the fluorine exhaust branch pipe between the oil separator and the air cooler, and a third temperature sensor and a first pressure sensor are also installed on the fluorine exhaust branch pipe, the third temperature sensor is connected to the second solenoid valve on the refrigerant supply pipe, and the first pressure sensor is connected to the pressure differential control valve on the refrigerant supply pipe.

[0025] Preferably, the pipe insulation of the air cooler hot fluorine defrost system adopts polyurethane pipe shell and stainless steel outer protection, the pipe insulation of the air cooler hot water defrost system adopts B1 grade rubber-plastic composite insulation cotton, and the insulation material of the pipes and valves in the floor heating system adopts B1 grade rubber-plastic composite insulation cotton.

[0026] Preferably, the ethylene glycol supply water collector and the ethylene glycol return water collector are arranged at the preset wall base, and anti-collision baffles and stainless steel enclosures are arranged on the outside thereof; during the installation of the ethylene glycol supply water collector, a double flange interface is used to connect the ethylene glycol liquid supply main pipe and the ethylene glycol supply water collector, and a pressure gauge and an air release valve are arranged above the ethylene glycol supply water collector; a plurality of liquid supply interfaces are arranged below the ethylene glycol supply water collector, and each liquid supply interface is respectively connected to the corresponding floor heating pipe; a plurality of liquid return interfaces are arranged below the ethylene glycol return water collector, and each liquid return interface is respectively connected to the corresponding floor heating pipe, and a fusion-cast connector, a water flow indicator, a flow regulator and a threaded sleeve are installed between the floor heating pipe and the ethylene glycol return water collector, and the ethylene glycol return water collector is also connected to the ethylene glycol return water main pipe through a double flange interface.

[0027] In summary, due to the adoption of the above technical solution, the present invention has at least the following beneficial effects:

[0028] After the construction of the heat recovery system, the condensing temperature can be lowered by recovering the heat from the refrigeration system, thereby improving the working efficiency of the refrigeration system (for every 1°C reduction in the condensing temperature, the cooling capacity can be increased by 1.3%), optimizing the resource allocation of the refrigerant, and significantly improving the power saving effect.

[0029] By recycling and utilizing the waste heat generated by the refrigeration system, the carbon emissions of the refrigeration system can be reduced, the direct emissions of waste heat and exhaust gas can be reduced, and environmental pollution can be reduced.

[0030] The heat recovery system constructed by the present invention can complete heat transfer by using pipe branches and heat exchangers, thereby recovering and reusing the waste heat generated by the refrigeration system. The waste heat recovery system has a simple structure and stable operation, saves other auxiliary equipment (such as electric heating equipment, centrifugal fans, etc.), reduces the amount of engineering work, reduces safety hazards, shortens the construction period, and improves economic benefits. The construction method of the present invention can also provide scientific and standardized guidance for energy-saving and emission-reduction renovations and new construction projects of large cold storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of an integrated construction method for waste heat recovery of a large cold storage refrigeration system according to an exemplary embodiment of the present invention.

[0032] Figure 2 Schematic diagram of a heat recovery system of a large cold storage refrigeration system according to an exemplary embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the valve and sensor connections on the fluorine exhaust branch pipe connecting the air cooler and the oil separator in the air cooler hot fluorine defrost system.

[0034] Markings in the figure: 1-air cooler, 2-fluorine exhaust branch pipe, 3-refrigerant supply pipe, 4-first stop valve, 5-filter valve, 6-first solenoid valve, 7-second stop valve, 8-third temperature sensor, 9-first pressure sensor, 10-second solenoid valve, 11-differential pressure control valve. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments to make the purpose, technical solutions and advantages of the present invention more clearly understood. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] refer to Figure 1 The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to an exemplary embodiment of the present invention comprises the following steps:

[0037] Step S1, analyzing the waste heat source of the refrigeration system of a large cold storage.

[0038] In the refrigeration system of large cold storage, the countercurrent condenser uses spray water to exchange heat with high-temperature gas to condense the refrigerant gas into liquid. The main source of waste heat is concentrated in the condensation stage of the condenser (condensation heat), which is usually discharged directly into the atmosphere, causing energy waste; compression heat is also generated during the operation of compressors and other units, and usually, compression heat is also directly discharged into the air.

[0039] Step S2: determine the application scenario of waste heat recovery.

[0040] If the heat generated by the refrigeration system is only discharged to the outdoor atmosphere through the condenser, it will cause a huge waste of resources. In order to improve energy efficiency, the heat generated by the refrigeration system can be recycled and reused. For example, the heat recovery of the refrigeration system is mainly used in the following occasions: hot fluorine defrosting of the air cooler, that is, using waste heat to melt the frost layer on the air cooler coil; hot water defrosting of the air cooler, that is, transferring waste heat to water and using hot water to remove the frost layer; floor heating, that is, transferring waste heat to ethylene glycol solution, and heating the ethylene glycol solution through the floor heating pipe to heat the floor; heat recovery of the refrigeration system can also be used in showers, kitchen hot water and other occasions.

[0041] Step S3: configuring a heat recovery system according to the application scenario of waste heat recovery.

[0042] The configured heat recovery system mainly includes the air cooler hot fluorine defrost system, the air cooler hot water defrost system and the floor heating system. By configuring the heat recovery system, waste heat can be recovered and reused to improve energy utilization.

[0043] Among them, the air cooler hot fluorine defrosting system mainly includes an air cooler, which is equipped with an air cooler coil, which is connected to the return air fin, and the air cooler coil inlet is connected to the fluorine exhaust main pipe through the fluorine exhaust branch pipe, the fluorine exhaust main pipe is connected to the oil separator, and the oil separator is connected to the compressor (reference Figure 2 The dotted line in the figure can represent the connection line between devices or the signal transmission line); its working process mainly includes: the fluorine waste heat gas (temperature is about 60℃) passes through the oil separator, enters the air cooler coil from the air cooler coil inlet through the fluorine exhaust branch pipe and flows inside it, and the heat of the fluorine waste heat gas is used to melt the frost layer on the return air fin.

[0044] The air cooler hot water defrosting system includes an air cooler, a defrosting water heat exchanger, a first heat recovery water pump, a defrosting water tank and a defrosting water pump, wherein the defrosting water heat exchanger is connected to the defrosting water heat exchanger and the defrosting water tank through a fluorine exhaust branch pipe and a fluorine exhaust main pipe, the first heat recovery water pump is connected between the defrosting water heat exchanger and the defrosting water tank, the defrosting water heat exchanger is also connected to the air cooler, and the defrosting water pump is connected between the air cooler and the defrosting water tank. Its working process mainly includes: when hot water defrosting is required, the fluorine waste heat gas enters the defrosting water heat exchanger through the fluorine exhaust branch pipe; when the water temperature in the defrosting water tank is lower than the preset temperature, the cold water in the defrosting water tank is transported to the defrosting water heat exchanger for heating through the first heat recovery water pump; when heated to the preset temperature, the cold water enters the air cooler through the water outlet of the defrosting water heat exchanger to defrost the air cooler coil (it can enter the air cooler coil to defrost, or it can directly defrost the surface of the air cooler coil without entering the air cooler coil); when the water in the defrosting water tank is higher than the preset temperature, the first heat recovery water pump stops working, and the defrosting water pump starts to transport the water in the defrosting water tank to the air cooler to defrost the air cooler coil with hot water.

[0045] The floor heating system includes a floor heating heat exchanger, a second heat recovery water pump, an ethylene glycol supply and collection device, an ethylene glycol return water collector and a floor heating pipe, wherein the floor heating heat exchanger is connected to the fluorine exhaust main pipe through a fluorine exhaust branch pipe, the inlet of the floor heating pipe is connected to the outlet of the ethylene glycol supply and collection device, the outlet of the floor heating pipe is connected to the inlet of the ethylene glycol return water collector, the inlet of the ethylene glycol supply and collection device is connected to the ethylene glycol liquid inlet main pipe, the outlet of the ethylene glycol return water collector is connected to the floor heating heat exchanger through the return water main pipe, the ethylene glycol liquid inlet main pipe is connected to the second heat recovery water pump through the ethylene glycol liquid inlet branch pipe, the second heat recovery water pump is also connected to the floor heating heat exchanger, and the floor heating heat exchanger is also connected to the inlet of the ethylene glycol supply and collection device. Its working process mainly includes: ethylene glycol solution enters the floor heating pipe through the ethylene glycol supply main pipe and the ethylene glycol supply collector to prevent the floor from freezing; when the temperature of the ethylene glycol solution is lower than the preset temperature, the ethylene glycol solution stops entering the ethylene glycol supply collector, and the second heat recovery water pump starts to transport the ethylene glycol solution to the floor heating heat exchanger, and the fluorine waste heat gas enters the floor heating heat exchanger through the fluorine exhaust branch pipe to heat the ethylene glycol solution, and the heated ethylene glycol solution enters the floor heating pipe through the ethylene glycol supply collector to circulate and heat the floor to prevent the floor from freezing due to low temperature, and the ethylene glycol solution enters the ethylene glycol return collector through the floor heating pipe outlet, and returns to the floor heating heat exchanger through the ethylene glycol return collector for heating.

[0046] In buildings without basements or overhead floors, there is a significant temperature difference between the cold storage floor and the soil cushion below the cold storage insulation layer (for example: the storage temperature is -20°C and the soil temperature is +20°C). Even if the cold storage floor is installed with an insulation layer, as the cold storage is used for a longer time, the low temperature may still penetrate the floor insulation layer and penetrate into the soil cushion. This temperature difference will cause the soil to freeze in the cushion, thereby causing soil freezing. After freezing, the soil will expand, causing the cold storage floor to frost heave and crack, affecting the normal use of the cold storage. Therefore, arranging floor heating pipes to prevent soil freezing can ensure the long-term stable operation of the cold storage.

[0047] Further, the hot water defrosting system of the air cooler also includes a first temperature sensor for detecting the water temperature in the defrosting water tank, the first temperature sensor is connected to the controller, and the controller is also connected to the first heat recovery water pump and the defrosting water pump respectively; when the first temperature sensor detects that the water temperature in the defrosting water tank is lower than the preset temperature (10°C), the signal is sent to the controller, and after receiving the signal, the controller sends control signals to the first heat recovery water pump and the defrosting water pump respectively, so as to turn off the defrosting water pump, start the first heat recovery water pump to transport the water in the defrosting water tank to the defrosting water heat exchanger for heat exchange, and the water temperature rises to the defrosting temperature (not less than 15°C) and then enters the air cooler to defrost the air cooler coil; when the water temperature in the defrosting water tank is higher than the preset temperature, the first temperature sensor sends a signal to the controller, and the controller sends control signals to the first heat recovery water pump and the defrosting water pump respectively to turn off the first heat recovery water pump and start the defrosting water pump to defrost the air cooler coil with hot water. When defrosting is to be ended, the controller controls the first heat recovery water pump and / or the defrosting water pump to turn off to end defrosting.

[0048] Furthermore, both the defrosting water heat exchanger and the floor heating heat exchanger use plate heat exchangers, which are assembled from multiple alternating plates. One adjacent plate is used to flow the liquid to be heated, and the other plate is used to flow the fluorine waste heat gas. The heat is transferred from the fluorine waste heat gas to the liquid to be heated to achieve the heat exchange process. Compared with other heat exchangers (such as shell and tube heat exchangers), the plate heat exchanger has a compact structure, small footprint, easy maintenance, and strong adaptability; the plates are closely arranged, the fluid channels are narrow and parallel, the heat transfer coefficient is high, and the heat transfer efficiency is improved; in specific applications, it is easy to change the heat exchange area or process combination, and it has high flexibility.

[0049] The defrost water heat exchanger can also be directly connected to the defrost water tank through a connecting pipe. The water heated by the defrost water heat exchanger can return to the defrost water tank. When the water in the defrost water tank reaches the defrost temperature, the first heat recovery water pump stops working, and the defrost water pump introduces the water in the defrost water tank into the air cooler for hot water defrosting.

[0050] When selecting the defrosting water heat exchanger, assume that the defrosting water tank circulating water volume Q1 = 40000 kg / h, the fluorine waste heat gas exhaust hot side water inlet temperature t1 = 60 ° C, the water outlet temperature t2 = 52 ° C, the water mass heat capacity C = 4.2 kJ / (kg·℃), according to The calculated heat exchange capacity is H = 400kW, from which it can be seen that the defrost water heat exchanger should be a plate heat exchanger with a heat exchange capacity of 400kW.

[0051] The floor heating system also includes a second temperature sensor for detecting the temperature of the ethylene glycol solution in the ethylene glycol inlet main pipe. The second temperature sensor is connected to the controller, and the controller is also connected to the second heat recovery water pump. When the second temperature sensor detects that the temperature of the ethylene glycol solution in the ethylene glycol inlet main pipe is lower than the preset temperature (5°C), the controller sends a signal to the controller. After receiving the signal, the controller sends a control signal to the second heat recovery water pump to start the second heat recovery water pump to transport the ethylene glycol solution in the ethylene glycol solution supply main pipe to the floor heating heat exchanger. At the same time, the fluorine waste heat gas enters the floor heating heat exchanger through the fluorine exhaust branch pipe to heat the ethylene glycol solution, so that the temperature of the ethylene glycol solution rises to the floor heating temperature (not less than 15°C).

[0052] When selecting a floor heating heat exchanger, determine the rated power of the floor heating heat exchanger based on the floor heating area; for example, when two buildings share a floor heating system, one or more plate heat exchangers with a rated power of 300kW are configured; when a building uses a separate floor heating system, a plate heat exchanger with a rated power of 50kW is configured for the building.

[0053] The floor heating system also includes a constant pressure water supply unit, which mainly includes an ethylene glycol water supply tank (volume 1m 3 ), a water replenishment pump and a pressure-stabilizing tank, which can automatically replenish water to the floor heating heat exchanger according to the pipeline differential pressure; the constant pressure water replenishment unit is installed on the return pipe of the floor heating system to ensure that the water replenishment operation can be carried out effectively, and the water replenishment pump is installed in or under the ethylene glycol water replenishment tank to ensure that the water pump absorbs water; the water outlet of the ethylene glycol water replenishment tank and the water inlet of the water replenishment pump are connected by a water pipe, and a check valve is provided on the connecting pipe so that the ethylene glycol solution can only flow to the water replenishment pump through the ethylene glycol water replenishment tank; a second pressure sensor is installed at the water outlet of the water replenishment pump, and the water outlet of the water replenishment pump is connected to the floor heating heat exchanger through a pipe.

[0054] Furthermore, in the hot fluorine defrosting system, a first stop valve 4, a filter 5, a first solenoid valve 6 and a second stop valve 7 are sequentially installed on the fluorine exhaust branch pipe 2 between the oil separator and the cold air blower 1 (refer to Figure 3) to adjust the pressure and flow of the fluorine waste heat gas and improve the hot fluorine defrosting effect; a third temperature sensor 8 and a first pressure sensor 9 are also installed on the fluorine exhaust branch pipe 2 near the side of the air cooler 1. The third temperature sensor 8 is connected to the second solenoid valve 10 on the refrigerant supply pipe 3, and the first pressure sensor 9 is connected to the pressure difference control valve 11 on the refrigerant supply pipe 3 to automatically control the flow of the refrigerant medium to ensure that the air cooler is shut down when the hot fluorine defrosts, and no refrigerant enters the air cooler.

[0055] The air cooler is also connected to the outdoor pipe well through the frost drainage pipe (reference Figure 2 ), during the hot fluorine defrosting of the air cooler, the frost on the fins at the return air outlet of the air cooler is defrosted and then drained to the outdoor pipe well through the defrosting drainage pipe. The water receiving pan of the air cooler is also connected to the defrosting water tank. After the hot water of the air cooler defrosts, the defrosting water flows back to the defrosting water tank.

[0056] During the defrosting process of the air cooler, the fluorine waste heat gas can be controlled to enter different fluorine exhaust branch pipes according to the defrosting needs of the air cooler, and the air cooler can be defrosted by using the air cooler hot fluorine defrosting system and / or the air cooler hot water defrosting system to improve the defrosting efficiency of the air cooler.

[0057] In the air cooler hot fluorine defrost system, air cooler hot water defrost system and floor heating system, the fluorine waste heat gas passes through the air cooler coil, defrost water heat exchanger and floor heating heat exchanger respectively, and can return to the compressor through another fluorine exhaust branch pipe (not shown in the figure), so that the refrigerant can be recycled and the utilization rate of the refrigerant is improved.

[0058] Step S4: construct a heat recovery system at a preset location of the large cold storage.

[0059] In the specific application process, the heat recovery system may also include a kitchen hot water system and a shower hot water system. For example, when constructing the heat recovery system, the three systems in step S3 are mainly constructed. The construction process of the heat recovery system includes:

[0060] Construction preparation: Analyze the design drawings of large cold storage and the design plan of the heat recovery system, collect and organize national and industry standards and specifications related to cold storage construction and waste heat recovery, and formulate a construction plan for the heat recovery system; purchase heat recovery system materials and equipment that meet the quality requirements (such as heat exchangers, various pipes, valves, pumps, air coolers, sensors, insulation materials, etc.) according to the design selection list, and conduct on-site inspection and acceptance of the purchased materials and equipment; clean up the construction site, build temporary construction facilities (such as office rooms, material storage warehouses, processing sites, etc.), ensure that the construction site has water, electricity, and access, set up safety protection facilities and warning signs at the construction site, and make reasonable zoning plans for the construction site, including material storage areas, equipment installation areas, and processing and production areas.

[0061] Foundation construction: remove the construction waste from the structural floor, rinse with clean water, and position the equipment foundation on site according to the equipment foundation deepening point drawing provided by the refrigeration unit. Use a laser level to ensure that the foundation surface is on the same horizontal plane. After positioning, fix the casting template on the boundary line according to the equipment size, and then use a steel bar horse stool to raise the steel bar so that the steel bar is 100mm away from the structural floor. Arrange the steel bars on site according to the spacing of Φ10@200, and then pour C30 concrete with a pouring height of 300mm. Use a vibrator to fully stir during pouring, use a horizontal scraper to level, and finally cover with geotextile and sprinkle water for 14 days. The foundation mainly includes the compressor foundation, oil separator foundation, heat exchanger foundation, defrosting water tank foundation, water pump foundation and constant pressure water supply unit foundation.

[0062] Construction of hot fluorine defrosting system for air cooler

[0063] Installation of compressor unit: Check the size and levelness of the compressor foundation and the screw holes of the compressor base to make sure they meet the installation and working requirements of the compressor. Use a crane to lift the compressor unit into the machine room. Use a forklift and a tank to assist in putting the compressor unit in place. After it is in place, align the longitudinal and transverse center lines of the compressor unit with the center lines of the compressor foundation to complete the alignment. Then level the compressor unit so that the levelness of the compressor unit meets the preset requirements (the longitudinal and transverse levelness of the compressor unit does not exceed 1 / 1000). Leveling is done by using support pads. After leveling, grout the anchor bolts. After 7 days of maintenance, tighten the nuts of the compressor unit to fix the compressor unit on the compressor foundation. To avoid deformation and displacement of the compressor unit during transportation, after the compressor unit is installed, re-calibration should be done to make the motor and compressor coaxial, and the coaxiality should meet the technical requirements. When measuring the coaxiality of the motor and compressor, measure at 4 evenly distributed measurement positions on the end face of the coupling.

[0064] Oil separator installation: The oil separator is installed between the compressor exhaust port and the condenser. The oil separator can share a compressor foundation with the compressor unit, or an oil separator foundation can be set up separately for the oil separator. During the installation of the oil separator, expansion bolts are used to fix the channel steel on the oil separator foundation, and then the base of the oil separator is welded to the channel steel. When installing the oil separator, a laser level is used for leveling, and the inlet and outlet of the oil separator are set at an angle to allow the lubricating oil to be separated smoothly from the refrigerant gas. The inlet pipe of the oil separator matches the compressor pipe, and the outlet pipe of the oil separator matches the condenser pipe, and ensure that the connection is tight and leak-free to avoid leakage or accumulation of refrigerant gas and lubricating oil in the pipe.

[0065] Installation of fluorine exhaust pipe: In the hot fluorine defrosting system of the air cooler, the fluorine exhaust pipe adopts 20# seamless steel pipe with nominal diameter D38 and wall thickness 3.25mm. The fluorine exhaust pipe includes fluorine exhaust main pipe and fluorine exhaust branch pipe. During the installation of the fluorine exhaust pipe, the fluorine exhaust main pipe is installed on the top of the oil separator, and then a fluorine exhaust branch pipe is separated from the fluorine exhaust main pipe. The fluorine exhaust branch pipe is connected to the air cooler in the cold storage room, and the fluorine exhaust branch pipe is connected to the coil inlet of the air cooler. The oil separator and the fluorine exhaust branch pipe are connected by a stainless steel corrugated shock-absorbing soft connection. Before the installation of the fluorine exhaust pipe, the rust removal treatment is carried out. After the rust removal is completed, the ports at both ends of each fluorine exhaust pipe are polished to form a groove to facilitate the argon arc welding operation when the adjacent fluorine exhaust pipes are connected. The two ends of each fluorine exhaust pipe are wrapped with waterproof tape to prevent moisture.

[0066] Valve installation: The maximum working pressure of the valve is 25bar, and the minimum working temperature is -40℃. The valve sealing material is suitable for non-corrosive gases and liquids. The valve is connected by welding, and the valve body is made of low-temperature resistant carbon steel. When installing the valve, the first stop valve, filter, first solenoid valve and second stop valve are installed in sequence on the fluorine exhaust branch pipe between the oil separator and the air cooler to adjust the pressure and flow of the fluorine waste heat gas and improve the hot fluorine defrosting effect; the third temperature sensor and the first pressure sensor are also installed on the fluorine exhaust branch pipe. The third temperature sensor is connected to the second solenoid valve on the refrigerant supply pipe, and the first pressure sensor is connected to the pressure difference control valve on the refrigerant supply pipe to automatically control the flow of the refrigerant medium to ensure that the air cooler is shut down when the hot fluorine defrosts, and no refrigerant enters the air cooler. The valve can adopt an angle or straight-through valve body and be used with a universal valve cover; the valve body and the valve cap can be sealed with lead to effectively prevent misoperation; the valve is designed with a two-way flow function for easy installation; the valve adopts a universal valve seat and sealing accessories for easy replacement of functions and accessories.

[0067] Connection of pipes to air coolers: connect the fluorine exhaust branch pipe, refrigerant liquid supply pipe and the coil inlet of the air cooler respectively, and both pipes are installed with a slope of 0.3% toward the air cooler. During the defrosting period (the defrosting time can be 30 minutes, and the specific time can also be determined according to actual requirements), the solenoid valve on the refrigerant liquid supply pipe is closed, and the refrigerant supply is stopped to shut down the air cooler. At this time, the fluorine waste heat gas enters the internal exhaust pipe of the air cooler through the fluorine exhaust branch pipe, and removes the frost on the fins at the return air outlet of the air cooler through the heat exchange. After defrosting is completed, it is discharged to the outdoor pipe well through the defrosting drainage pipe.

[0068] Pipeline insulation: Pipeline insulation adopts insulation layer (polyurethane shell) and outer sheath (stainless steel), equipment insulation adopts polyurethane mechanical spray foaming process, the heat transfer coefficient of polyurethane is not more than 0.031W / (m 2 ℃), density is 35~40Kg / m 3. During the construction of polyurethane pipe shell, special tools (such as wood saw) are used for cutting. The cutting surface is guaranteed to be flat and smooth to avoid bumps and bumps. After cutting, it is classified and stored to avoid mixing. The construction sequence of polyurethane pipe shell is as follows: vertical pipes are first down and then up, horizontal pipes are first large pipes and then small pipes, and first inside and then outside. The longitudinal seams of adjacent sections of polyurethane pipe shells are staggered to avoid being on the same straight line, and the annular seams and brackets are tightly aligned to avoid leakage. Before installing the polyurethane pipe shell, filler is evenly applied to the surface of the polyurethane pipe shell, and the time is selected to fix it on the pipeline according to the performance of the filler. When the pipeline passes through the outer walls and floor slabs of the cold storage and machine room, the insulation layer on it is avoided to be interrupted, and the gap between the insulation layer and the hole is filled by foaming. The insulation layer should be flat and dense without defects such as cracks, gaps and collapse, and the thickness deviation of the insulation layer is 0~+5mm. Oil-soaked and boiled hardwood pads are used between the pipeline insulation and the bracket, and between the pipeline insulation and the equipment foundation. The hardwood pads are machined according to the outer contours of the pipeline and equipment to make them fit more closely. Pipe insulation is mainly used for pipe insulation in refrigeration systems. It can also be used for fluorine exhaust main pipe insulation, fluorine exhaust branch pipe insulation, refrigerant liquid supply pipe insulation to prevent heat loss, and other types of pipe insulation. The thickness of pipe polyurethane insulation is shown in Table 1:

[0069] Table 1 Pipeline polyurethane B1 grade PU insulation thickness

[0070]

[0071]

[0072] Construction of hot water defrosting system for air cooler

[0073] Installation of fluorine exhaust pipe and defrosting water heat exchanger: Lead out a fluorine exhaust branch pipe on the exhaust main pipe of the compressor (it can also be on the fluorine exhaust main pipe connected to the oil separator), and connect the fluorine exhaust branch pipe to the defrosting water heat exchanger. The installation method of the fluorine exhaust branch pipe is the same as that of the fluorine exhaust branch pipe in the hot fluorine defrosting system of the air cooler. The connection process of the fluorine exhaust branch pipe and the defrosting water heat exchanger involves the installation of elbows. The elbows are made of finished stamped elbows. The elbows and fluorine exhaust branches are first welded on the ground by argon arc welding, and then the adjacent fluorine exhaust branches are welded together above the floor to reduce the number of aerial operations. When installing the fluorine exhaust branch pipe, avoid sudden upward and downward continuous bending to reduce pipeline resistance and avoid the formation of air bags and liquid bags. At the same time, its bending radius is not less than 3.5 times the nominal diameter of the fluorine exhaust branch pipe.

[0074] The defrosting water heat exchanger can be moved into place manually or mechanically. During the installation process, according to the size of the defrosting water heat exchanger, the expansion bolts are used to fix the 8# channel steel (the channel steel is spliced ​​into a door shape) on the defrosting water heat exchanger foundation (concrete foundation) to serve as the support of the defrosting water heat exchanger. Then the base of the defrosting water heat exchanger is fixed on the 8# channel steel, and the edge of the base of the defrosting water heat exchanger is welded tightly to the channel steel. A space of about 1m is left around the defrosting water heat exchanger for easy maintenance. The inlet and outlet pipes of the cold and hot media of the defrosting water heat exchanger are installed according to the design requirements. The inlet and outlet pipes of the cold and hot media of the defrosting water heat exchanger are equipped with a third stop valve, a pressure gauge, and a fourth temperature sensor. The inlet of the defrosting water heat exchanger is equipped with a flow control valve and the outlet is equipped with an exhaust valve.

[0075] Installation of defrosting water tank: The defrosting water tank is a rectangular box with specifications of 4m×4m×3m and a nominal volume of V=48m 3 , effective volume V = 40m 3 (The overflow port is 500mm from the top of the defrosting water tank, 4m×4m×(3m-0.5m)=40m 3 ), the defrosting water tank is assembled by an insulation board filled with polyurethane foam inside and wrapped with stainless steel outer protection on the surface. The insulation board is 0.1m thick, 1m long and 1m wide. The defrosting water tank is installed on a defrosting water tank foundation with a length*width*height=7.5m*4.2m*0.3m. During the installation process, after aligning the bottom plate size of the defrosting water tank foundation on the defrosting water tank foundation, the bottom plate is laid out and welded on the defrosting water tank foundation, and then the wall panels are stacked around the bottom plate. After the stacking is completed, the bottom plate and the wall panel are welded, and the gaps on the outside of the bottom plate and the wall panel are repaired with electric welding. After applying anti-corrosion paint, the seams are filled with waterproof sealant, and then the top plate and the wall panel are welded; defrosting The manhole of the water tank is welded at a preset position and is set close to the float ball of the water inlet. The body of the defrost water tank is welded completely. After the water inlet, water outlet, overflow, sewage discharge and fire fighting holes are opened, the escalator is welded and then the weld is oil inspected, that is, kerosene is applied to the gaps between adjacent plates outside the defrost water tank body, and visual leak detection is performed at the weld inside the defrost water tank body. After the weld oil inspection, the weld spots are removed. Then the defrost water tank is filled with water for pressure test and the water in the defrost water tank is ensured to be clean and hygienic.

[0076] Water pump installation: The water pump includes the first heat recovery water pump and the defrosting water pump. The flow rate of the first heat recovery water pump is 80m 3 / h, the head is 25m, and the flow rate of the defrosting water pump is 40m 3 / h, head is 55m; During the installation of the water pump, according to the different water pump sizes, fix 10# channel steel on the corresponding water pump foundation, weld the water pump base to the channel steel, and apply anti-corrosion paint; set channel steel (door shape) as a support bracket at the pipe elbow and pressure gauge, and use a clamp to tightly fix the elbow and pressure gauge. The allowable deviation of the horizontal degree of the water pump is 0.10mm / m, and the allowable deviation of the longitudinal levelness of the installation reference part is 0.05mm / m. For the integrally installed water pump, the longitudinal level deviation is not more than 0.1 / 1000, and the lateral level deviation is not more than 0.2 / 1000, and it is measured on the inlet and outlet flange surfaces of the water pump or other horizontal surfaces.

[0077] After the water pump is installed, install the inlet and outlet pipes of the water pump, and take sealing measures (install rubber flexible joints at the inlet and outlet of the water pump) to ensure the safety and stability of the inlet and outlet pipe connections of the water pump; then install the water pump controller (including the first temperature sensor and the corresponding pressure sensor) at the preset position according to the design requirements to control the start and stop of the water pump; after the water pump controller is installed, a full-process physical and chemical water treatment dosing system can also be set at the front end of the water supply of the water pump, and the full-process physical and chemical water treatment dosing system and the water treatment device are connected to treat the water in the defrosting water tank to achieve the effects of anti-scaling, anti-corrosion and anti-rust, sterilization and algae removal, and intelligent control of water quality. After the water pump is installed, acceptance and testing are carried out to check the sealing and leakage of the water pump to ensure that there is no leakage at the pipe connection where the water pump is installed; conduct a water pump startup test to observe the working status and operation of the water pump, check whether the motor is running normally, and whether there is any abnormal sound or vibration; test the flow and head of the water pump to verify whether the performance parameters of the water pump meet the design requirements; check whether the function of the water pump controller is normal and whether it can realize remote control and automatic control functions.

[0078] Installation of water supply and return pipes: Both water supply and return pipes are made of hot-dip galvanized steel pipes. The installation process includes: installing channel steel brackets according to the pipeline elevation and direction of the detailed drawing, and using a laser level to level the channel steel brackets. After the channel steel brackets are installed, pipe supports are installed on the channel steel brackets according to the slope of the water supply and return pipes to ensure that the pipelines are firm and reliable and will not loosen; the slope of the water supply pipe is 0.3%, and the slope of the return pipe is 0.5%. Installation of water supply pipes: The water supply pipes are connected by electric welding. The water supply pipe entering the defrosting water heat exchanger is set to a 45° elbow to avoid right-angle entry to prevent excessive local resistance. The water supply pipe entering the air cooler is also set to a 45° elbow, and the inclined angle is increased to ensure uniform water flow rate. The return pipe includes a return branch pipe, which is mainly connected to the water receiving pan of the air cooler and the main return pipe of the interlayer. The main return pipe is connected to the defrosting water tank so that the defrosted water flows back to the defrosting water tank. The return pipe is welded and connected in the same way as the water supply pipe. When the water supply pipe and the return pipe need to pass through the wall during installation, a sleeve is set at the wall penetration part of the water supply pipe and the return pipe, and fireproof cotton is filled at 2 / 3 of the sleeve, and then it is sealed tightly with fireproof mud. On the outside of the sleeve, a galvanized bell mouth is used for sealing decoration.

[0079] Pipeline insulation: The insulation material is B1 grade rubber-plastic composite insulation cotton with a thickness of 50mm. During the pipeline insulation process, the insulation material is wrapped on each pipeline, and glue is applied to the opening of the open pipe. After the glue dries, the two ends of the open pipe are first bonded, and then the midpoint of the open pipe is bonded, and then from the two ends to the middle until it is completely sealed. When installing the insulation material, it is installed in the order of large pipes first, small pipes later, elbows first, tees first, straight pipes later, and finally valves and flanges; expansion joints are set at the brackets of the pipeline insulation and filled with rubber-plastic insulation fragments. After the insulation material is installed, a 0.5mm thick stainless steel outer layer is coated on the surface of the insulation material.

[0080] Floor heating system construction

[0081] Installation of floor heating pipe: The floor heating pipe adopts HDPE pipe, which is laid flat in U shape, fixed with clamps at the bottom, the distance between adjacent pipes in the straight pipe section is 600mm, the distance between the curved section is 0.2-0.3m, the bending radius is greater than 50D (D is the nominal outer diameter of the floor heating pipe), the slope of the floor heating pipe is 0.003, and the slope is conducive to exhaust and water discharge; a DN20 drain pipe is configured at the lowest point of the floor heating pipe, and a gate valve of the same diameter is configured, and a DN20 automatic exhaust valve is configured at the highest point of the floor heating pipe, and a DN20 gate valve is set in front of the automatic exhaust valve. After the floor heating pipe is installed, the open end of the floor heating pipe is sealed. A hard casing is set at the wall-penetrating part of the floor heating pipe, and the ambient temperature of the installation is not less than 5℃.

[0082] Pipe pressure testing: Water pressure tests are carried out before pouring the concrete filling layer and after the curing period of the concrete filling layer. The working pressure of the pipeline is 0.4MPa (gauge pressure), and the test pressure is not less than 0.6MPa (gauge pressure). During the water pressure test, a manual pump is used to slowly increase the pressure. During the pressure increase process, it is observed and checked at any time, and no leakage is allowed. The pressure is stabilized for 1 hour under the test pressure, and the pressure drop should not be greater than 0.05Mpa. It is qualified if there is no leakage after 24 hours of pressure stabilization. After the water pressure test and acceptance are qualified, the concrete filling layer is poured while the floor heating pipe is under pressure. During the construction of the concrete filling layer, the water pressure in the floor heating pipe is guaranteed to be no less than 0.6MPa. During the curing process, the pressure in the floor heating pipe is no less than 0.4MPa.

[0083] Installation of ethylene glycol supply and collection device (ethylene glycol liquid supply manifold) and ethylene glycol return water collector (ethylene glycol liquid return manifold): install the ethylene glycol supply and collection device and the ethylene glycol return water collector at the preset wall base, and install anti-collision baffles and stainless steel enclosures on their outside; during the installation of the ethylene glycol supply and collection device, a double flange interface is used to connect the ethylene glycol liquid supply main pipe and the ethylene glycol supply and collection device, and a pressure gauge and an air release valve are installed above the ethylene glycol supply and collection device; multiple liquid supply interfaces are installed below the ethylene glycol supply and collection device, and each liquid supply interface is connected to the corresponding floor heating pipe, providing Supply ethylene glycol solution to the bottom of the floor to maintain the temperature requirement of the floor; multiple return liquid interfaces are arranged under the ethylene glycol return water collector, each return liquid interface is connected to the corresponding floor heating pipe, and a cast connector, a water flow indicator, a flow regulator and a threaded sleeve are installed between the floor heating pipe and the ethylene glycol return water collector. The ethylene glycol return water collector is also connected to the ethylene glycol return water main pipe through a double flange interface (with a sealing ring and a connecting bolt kit), and the cold ethylene glycol solution is returned to the floor heating heat exchanger through the ethylene glycol return water collector and the ethylene glycol return water main pipe.

[0084] Installation of fluorine exhaust pipe and floor heating heat exchanger: The installation method of fluorine exhaust pipe is the same as that of fluorine exhaust pipe in the cold air fan hot water defrosting system, and the installation method of floor heating heat exchanger and defrosting water heat exchanger is the same; similarly, another third stop valve, pressure gauge and fourth temperature sensor are provided on the inlet and outlet pipes of the floor heating heat exchanger, and another flow control valve is provided at the inlet of the floor heating heat exchanger and an exhaust valve is provided at the outlet.

[0085] Water pump installation: In the floor heating system, the water pump includes a second heat recovery water pump. The flow rate and lift of the second heat recovery water pump are determined according to the design requirements.

[0086] Before installing the water pump, fix 8# channel steel (door shape) on the water pump foundation, weld the water pump base to the channel steel, and apply anti-corrosion paint; after the water pump is in place, level and align it according to the standard requirements, and its horizontal levelness shall not exceed 0.1mm / m, the axial inclination of the horizontal coupling shall be 0.8mm / m, and the radial displacement shall not exceed 0.1mm; for the installation and vibration isolation of the vertical water pump, rubber vibration isolation pads and steel plates shall be used for vibration isolation, and there are 4 vibration isolation pads, which are fixed to the water pump foundation. During the installation of the water pump, a bracket shall be installed on the pipe near the water pump so that there is no weight attached to the pump casing. The pipe can avoid transferring the force to the flexible joint and the water pump through independent support; the water inlet and outlet of the water pump are equipped with flanges for pipe connection, and flexible joints are provided for vibration reduction. When connecting the pipe, check the alignment of the pipe and the water pump interface, install the pipe and valve first, and finally install the flexible joint, which is connected in a free state; the pressure gauge shall be installed in a place with small vibration and stable water pressure.

[0087] After the water pump and valve are installed, the pipes and valves attached to the water pump are insulated. The insulation material is B1 grade rubber-plastic composite insulation cotton with an insulation thickness of 50mm. The setting method of the insulation material is the same as that of the insulation material in the defrosting water tank heat exchange system.

[0088] The construction floor heating system also includes the installation of a constant-pressure water-making unit, and the installation process includes: fixing 8# channel steel on the basis of the constant-pressure water-making unit, welding the bases of the ethylene glycol water-making tank, water-making pump and pressure-stabilizing tank to the basis of the constant-pressure water-making unit, and applying anti-corrosion paint; the constant-pressure water-making unit is installed on the return water pipeline of the floor heating system to ensure that the water-making operation can be carried out effectively; the water-making pump is installed in or under the ethylene glycol water-making tank to ensure that the water-making pump absorbs water; the water outlet of the ethylene glycol water-making tank and the water inlet of the water-making pump are connected by a water pipe, and a check valve is provided on the connecting pipe so that the ethylene glycol solution can only flow to the water-making pump through the ethylene glycol water-making tank; a pressure sensor is installed at the water outlet of the water-making pump, and the water outlet of the water-making pump is connected to the water supply pipeline.

[0089] The heat recovery system of the large cold storage refrigeration system constructed by the above method can recover waste heat in multiple scenarios, effectively improve the working efficiency of the refrigeration system, and significantly improve the power saving effect. Taking the CCCC Peddler Operation Headquarters and Agricultural Digital Industrial Park Project as an example, the project includes 5 main building units, among which Building 1# is a processing workshop, Building 2# supporting raw material warehouse is a high-standard full-temperature zone raw material finished product storage warehouse, adopts a double first-floor design, and is equipped with a 20-meter ultra-wide refrigerated platform, Building 3# is a modern food processing center, integrating agricultural products deep processing, central kitchen, pre-prepared food production and agricultural products supply chain, Building 4# is the park equipment room and power center, and Building 5# is a multi-functional comprehensive service center. Specifically, the low-temperature cold storage refrigeration system of Building 3# is taken as an example to illustrate that the waste heat recovery application mainly includes hot fluid defrosting (including hot fluorine defrosting and hot water defrosting) and cold storage floor antifreeze; Building 3# has 3 cold storages, equipped with 6 air coolers in total. During hot fluid defrosting, there is no electric power consumption on the air cooler side, and the energy consumed in the defrosting process is negligible; calculated based on 3 defrosting times a day and a total heating hour, compared with the electric defrosting method (total defrosting power is 248kw, and the daily defrosting power consumption is 248kw.h), hot fluid defrosting can reduce power consumption by 248kw.h per day.

[0090] The total area of ​​the low-temperature cold storage area of ​​Building 3# is 2,890 square meters. The traditional method of floor antifreeze is usually to use mechanical ventilation. Usually, a 20kW centrifugal fan is required to run 24 hours a day, consuming 480kW·h of electricity per day. The use of a floor heating system for floor antifreeze only requires the addition of a 3kW circulation pump, which consumes 72kW·h of electricity per day (24 hours), which can reduce power consumption by 408kW·h compared to mechanical ventilation.

[0091] Waste heat recovery can also be configured with pipelines for use in central kitchen hot water production. Traditional central kitchen hot water production usually uses electric heaters to heat 1.2 tons of purified water at 20°C to 45°C per hour. The power of the electric heater = Q / t = 80% thermal efficiency * 4200 * 1200 * (45-20) / 3600 = 28kW. The electric heater consumes 280kW·h of electricity per day (10 hours). Compared with electric heater heating, waste heat recovery for central kitchen hot water production can reduce electricity by 280kW·h.

[0092] Waste heat recovery can also reduce 15% of the condensing load, greatly improving the operating efficiency of the evaporative condenser. Due to the reduction in condensing load, the evaporative condenser can reduce power consumption by at least 5kW, and can directly reduce power consumption by 120kW·h per day (24 hours). Assuming that the average operating rate of the host of the refrigeration system is 45%, after waste heat recovery, the annual power consumption can be saved (248kW·h+408kW·h+280kW·h+120kW·h)*365 days*45% average host operating rate = 173448kW·h, which is of considerable economic value.

[0093] Through the multi-scenario utilization of waste heat recovery, not only the cooling capacity of the compressor unit and the air cooler is improved, the electricity consumption is significantly reduced, and the electricity bill is saved, but also the procurement cost of heating equipment and auxiliary equipment is greatly reduced; heat recovery for floor antifreeze can also eliminate the need for basement or mezzanine design, reducing structural costs.

[0094] The above is only a detailed description of the specific implementation of the present invention, rather than a limitation of the present invention. Various substitutions, modifications and improvements made by those skilled in the relevant art without departing from the principle and scope of the present invention should be included in the protection scope of the present invention.

Claims

1. A large cold storage refrigeration system waste heat recovery integrated construction method, characterized in that: The following steps are involved: Step S1, analyzing the waste heat sources of the large cold storage refrigeration system; the waste heat sources include compression heat generated by the compressor unit and condensation heat generated in the condenser condensation stage; Step S2, determining the application scenario of waste heat recovery; Step S3, configuring a heat recovery system according to the application scenario of waste heat recovery; the heat recovery system includes a cold air machine hot fluorine defrosting system, a cold air machine hot water defrosting system and a floor heating system; Step S4: construct a heat recovery system at a preset location of the large cold storage.

2. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to claim 1 is characterized in that: The air cooler hot fluorine defrosting system comprises an air cooler, wherein an air cooler coil is arranged in the air cooler, the air cooler coil is connected to the return air fin, the air cooler coil inlet is connected to the fluorine exhaust main pipe through the fluorine exhaust branch pipe, the fluorine exhaust main pipe is connected to the oil separator, and the oil separator is connected to the compressor; The air cooler hot water defrosting system comprises an air cooler, a defrosting water heat exchanger, a first heat recovery water pump, a defrosting water tank and a defrosting water pump, wherein the defrosting water heat exchanger is connected via a fluorine exhaust branch pipe and a fluorine exhaust main pipe, the first heat recovery water pump is connected between the defrosting water heat exchanger and the defrosting water tank, the defrosting water heat exchanger is also connected to the air cooler, and the defrosting water pump is connected between the air cooler and the defrosting water tank; The floor heating system includes a floor heating heat exchanger, a second heat recovery water pump, an ethylene glycol supply and collection device, an ethylene glycol return water collector and a floor heating pipe, wherein the floor heating heat exchanger is connected to the fluorine exhaust branch pipe and the fluorine exhaust main pipe, the inlet of the floor heating pipe is connected to the outlet of the ethylene glycol supply and collection device, the outlet of the floor heating pipe is connected to the inlet of the ethylene glycol return water collector, the inlet of the ethylene glycol supply and collection device is connected to the ethylene glycol liquid inlet main pipe, the outlet of the ethylene glycol return water collector is connected to the floor heating heat exchanger through the return water main pipe, the ethylene glycol liquid inlet main pipe is connected to the second heat recovery water pump through the ethylene glycol liquid inlet branch pipe, the second heat recovery water pump is also connected to the floor heating heat exchanger, and the floor heating heat exchanger is also connected to the inlet of the ethylene glycol supply and collection device.

3. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to claim 1 is characterized in that: In step S4, the construction heat recovery system includes: Construction preparation: clean up the construction site, build temporary construction facilities, set up safety protection facilities and warning signs, and plan the zoning of the construction site; Foundation construction: On-site layout and positioning, using a laser level to ensure that the foundation surface is on the same horizontal plane; fix the casting formwork on the boundary line according to the equipment size, then use steel bar horse stools to raise the steel bars and tie the steel bars, pour C30 concrete and maintain for 14 days; Construction of hot fluorine defrost system for air cooler: mainly including installation of compressor unit, oil separator, fluorine exhaust pipe, valve, connection between pipeline and air cooler and pipe insulation; Construction of hot water defrosting system for air cooler: mainly including installation of fluorine exhaust pipe and defrosting water heat exchanger, defrosting water tank, water pump, water supply pipe and return pipe, and pipe insulation; Floor heating system construction: mainly includes floor heating pipe installation, pipe pressure testing, ethylene glycol supply and return water collector installation, fluorine exhaust pipe and floor heating heat exchanger installation, water pump installation, pipe and valve insulation.

4. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to claim 3 is characterized in that: The construction of the floor heating system also includes the installation of a constant-pressure water replenishment unit, which is installed on the return water pipeline of the floor heating system to ensure that the water replenishment operation can be carried out effectively.

5. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to claim 3 is characterized in that: During the foundation construction, the site is laid out and positioned according to the equipment foundation deepening point drawing provided by the refrigeration unit, and a laser level is used to ensure that the foundation surface is on the same horizontal plane. After the positioning is completed, the casting template is fixed on the boundary line according to the equipment size, and then the steel bar is raised by a steel horse stool so that the steel bar is 100mm away from the structural floor slab. The steel bars are tied on site at a spacing of Φ10@200, and then C30 concrete is poured. After leveling with a horizontal scraper, it is covered with a geotextile and watered for maintenance for 14 days.

6. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to claim 3 is characterized in that: During installation of the fluorine exhaust pipe of the hot fluorine defrost system of the air cooler, a fluorine exhaust main pipe is installed on the top of the oil separator, and then a fluorine exhaust branch pipe is branched off from the fluorine exhaust main pipe, the fluorine exhaust branch pipe is connected to the air cooler in the cold storage room, and the fluorine exhaust branch pipe is connected to the coil inlet of the air cooler. The oil separator and the fluorine exhaust branch pipe are connected by a stainless steel corrugated shock-absorbing flexible connection.

7. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to claim 3 is characterized in that: The fluorine exhaust pipe is subjected to rust removal treatment before installation. After rust removal is completed, ports at both ends of each section of the fluorine exhaust pipe are polished to form grooves, and both ends of each section of the fluorine exhaust pipe are wrapped with waterproof tape to prevent moisture.

8. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to claim 3 is characterized in that: In the valve installation of the hot fluorine defrost system of the air cooler, a first stop valve, a filter, a first solenoid valve and a second stop valve are installed in sequence on the fluorine exhaust branch pipe between the oil separator and the air cooler, and a third temperature sensor and a first pressure sensor are also installed on the fluorine exhaust branch pipe. The third temperature sensor is connected to the second solenoid valve on the refrigerant supply pipe, and the first pressure sensor is connected to the pressure difference control valve on the refrigerant supply pipe.

9. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to claim 3 is characterized in that: The pipe insulation of the cold air machine hot fluorine defrost system adopts polyurethane pipe shell and stainless steel outer protection, the pipe insulation of the cold air machine hot water defrost system adopts B1 grade rubber-plastic composite insulation cotton, and the insulation material of the pipes and valves in the floor heating system adopts B1 grade rubber-plastic composite insulation cotton.

10. The integrated construction method for waste heat recovery of a large cold storage refrigeration system according to any one of claims 3 to 9, characterized in that: The ethylene glycol supply water collector and the ethylene glycol return water collector are arranged at the preset wall base, and anti-collision baffles and stainless steel enclosures are arranged on the outside thereof; during the installation of the ethylene glycol supply water collector, a double flange interface is used to connect the ethylene glycol liquid supply main pipe and the ethylene glycol supply water collector, and a pressure gauge and an air release valve are arranged above the ethylene glycol supply water collector; a plurality of liquid supply interfaces are arranged below the ethylene glycol supply water collector, and each liquid supply interface is respectively connected to the corresponding floor heating pipe; a plurality of liquid return interfaces are arranged below the ethylene glycol return water collector, and each liquid return interface is respectively connected to the corresponding floor heating pipe, and a fusion-cast connector, a water flow indicator, a flow regulator and a threaded sleeve are installed between the floor heating pipe and the ethylene glycol return water collector, and the ethylene glycol return water collector is also connected to the ethylene glycol return water main pipe through a double flange interface.

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