Wastewater heat recovery and reuse system in cold regions

Abstract

Sewage waste heat recovery and reuse system in cold areas. This product is composed of a wastewater waste heat recovery subsystem, which includes a heat pump unit, the heat pump unit is connected to the sewage waste heat exchanger in the box body of the sewage tank through a pipeline, the sewage waste heat exchanger is connected to the heat pump unit through a pipeline, the pipeline is filled with a refrigerant, the box body in the sewage tank is connected to the sewage pump through a pipeline, the sewage pump discharges the sewage, the bathtub drain pipe is connected to the hair collector, the hair collector is connected to the sewage inlet pipe through a pipeline, and the sewage inlet pipe is connected to the sewage distribution pipe in the box body of the sewage tank. The present invention is used for a sewage waste heat recovery and reuse composite system.

Description

Technical field:

[0001] The invention relates to a sewage waste heat recovery and reuse system in cold regions. Background technology:

[0002] Using sewage as a heat source is very energy-efficient, but the biggest technical difficulty in sewage source heat recovery is: because it uses sewage, waste heat recovery from sewage in cold areas is bound to cause blockage, corrosion, and scaling of the heat exchanger, resulting in frequent maintenance, short life, low heat exchange efficiency and other problems, and the sewage waste heat recovery effect is not good. Summary of the invention:

[0003] The purpose of the present invention is to provide a sewage waste heat recovery and reuse system in cold regions.

[0004] The above purpose is achieved through the following technical solutions:

[0005] A waste heat recovery and reuse system for sewage in cold regions, comprising: a waste heat recovery subsystem for waste water, the waste heat recovery subsystem for waste water comprising a heat pump unit, the heat pump unit being connected to a waste heat exchanger for sewage in a box body in a sewage tank through a pipeline, the waste heat exchanger for sewage being connected to the heat pump unit through a pipeline, the pipeline being filled with a refrigerant, the box body in the sewage tank being connected to a sewage pump through a pipeline, the sewage pump discharging sewage, a bathtub drain pipe being connected to a hair collector, the hair collector being connected to a sewage inlet pipe through a pipeline, the sewage inlet pipe being connected to a sewage distribution pipe in a box body in the sewage tank, the heat pump unit being connected to a A high-temperature water pump, the high-temperature water pump is connected to the first insulated water tank through a pipeline, the first insulated water tank is connected to the hot water mixing pump through a pipeline, the hot water mixing pump is connected to the water mixer through a pipeline, the water mixer is connected to the second insulated water tank through a pipeline, the second insulated water tank is connected to the hot water output pipeline, the tap water inlet pipe is connected to the water mixer through a pipeline, the tap water inlet pipe is connected to the fan coil unit through a first electronic descaling device, the fan coil unit is connected to the second electronic descaling device through a pipeline, the second electronic descaling device is connected to the heat pump unit through a pipeline, the heat pump unit is connected to the first insulated water tank through a pipeline, the fan coil unit is connected to the first insulated water tank through a pipeline,

[0006] The tap water inlet pipe is connected to the cold water tank through a pipeline, the cold water tank is connected to the heat pump through a pipeline, the heat pump is connected to the circulation pump through a pipeline, the circulation pump is connected to the drainage tank through a pipeline, the drainage tank is connected to the solar collector through a pipeline, the solar collector is connected to the air energy heat pump unit through a pipeline, the air energy heat pump unit is connected to the water pump through a pipeline, the water pump is connected to the cold water tank through a pipeline, the cold water tank is connected to the medium-temperature water pump through a pipeline, the medium-temperature water pump is connected to the insulation water tank and the heat pump unit through a pipeline;

[0007] Or the cold water tank is connected to the geothermal pump through a pipeline, the geothermal pump is connected to the water pump through a pipeline, the water pump is connected to the cold water tank through a pipeline, the cold water tank is connected to the medium-temperature water pump through a pipeline, and the medium-temperature water pump is connected to the insulation water tank and the heat pump unit through a pipeline.

[0008] The fan coil unit is connected to the electric heater through a pipeline, and the electric heater is connected to the first insulation water tank through a pipeline.

[0009] A group of guide partition plates are installed in the inner box of the sewage tank, and the guide partition plates are arranged in parallel longitudinally. A group of sewage waste heat exchangers are installed in the inner box of the sewage tank, and the sewage waste heat exchangers are parallel to each other laterally. The top of the sewage waste heat exchanger is provided with a sewage distribution pipe, and the sewage distribution pipe is connected to the sewage inlet pipe. The sewage waste heat exchanger is connected to the sewage waste heat connecting pipe. The lower part of the sewage waste heat connecting pipe is connected to the inlet pipe, and the inlet pipe is connected to the heat pump unit. The upper part of the sewage waste heat connecting pipe is connected to the outlet pipe, and the outlet pipe is connected to the heat pump unit. A distributed sewage recovery pipe is installed at the bottom of the inner box of the sewage tank, and the distributed sewage recovery pipe is connected to the sewage pump. The inner box of the sewage tank is installed in the outer box of the sewage tank, and sewage tank insulation material is installed between the inner box of the sewage tank and the outer box of the sewage tank.

[0010] The sewage waste heat exchanger is assembled from a group of heat exchange tubes installed in parallel, each group of heat exchange tubes is composed of multiple pipes installed in parallel from top to bottom, and multiple groups of heat exchange tubes are installed in parallel to ensure that the heat exchanger is fully distributed in the insulated sewage tank;

[0011] A sewage distribution pipe is arranged above the sewage tank body, so that the high-temperature sewage enters the sewage tank in a jet manner. The sewage distribution pipe is evenly distributed above the sewage waste heat exchanger, generating vibrations and enhancing the heat exchange effect. When the sewage is at a high temperature, it exchanges heat with the refrigerant installed in the sewage waste heat exchanger in the middle and upper layers of the sewage tank. As the heat of the sewage is absorbed, the temperature gradually decreases, the specific gravity of the sewage increases, and it falls to the bottom of the sewage tank, generating a temperature gradient. The low-temperature sewage that has absorbed heat sinks to the lower layer, and under the pressure of the new high-temperature sewage, it is discharged in the form of overflow through the distributed sewage recovery pipe, eliminating the loss of heat.

[0012] The low-temperature refrigerant in the sewage waste heat exchanger enters from the bottom inlet of the water inlet pipe at a certain flow rate, and exchanges heat with the sewage with a temperature gradient in the sewage tank in the form of multiple tube layers. The higher the flow rate, the more significant the heat transfer effect. The high-temperature refrigerant flows out from the outlet of the upper water outlet pipe of the sewage waste heat exchanger and enters the evaporator of the unit. The heat in the refrigerant is absorbed by the refrigerant in the unit through conversion, and the low-temperature refrigerant returns to the bottom inlet of the water inlet pipe, circulates and absorbs heat to ensure the progress of the heat transfer process.

[0013] The sewage waste heat exchanger adopts an immersion structure, which immerses the sewage waste heat exchanger in sewage to facilitate cleaning of dirt; the sewage distribution pipe causes lateral scouring and temperature gradient when the high-temperature sewage enters the sewage tank, ensuring that the high-temperature sewage is evenly and fully exchanged with heat. The low-temperature sewage that absorbs heat sinks to the lower layer and is discharged in the form of overflow through the recovery device, i.e. the distributed sewage recovery pipe, under the action of the new high-temperature sewage pressure, to prevent heat loss;

[0014] The guide partitions are designed to be staggered in the sewage tank. The guide partitions increase the flow speed of sewage, extend the flow time, and fully exchange heat to ensure that the sewage with the lowest temperature is discharged evenly and quickly; distributed sewage recovery pipes are arranged at the bottom of the sewage waste heat exchanger to quickly discharge the low-temperature sewage; at the same time, the refrigerant with a certain flow rate enters at the bottom inlet of the sewage waste heat exchanger, flows through the entire sewage waste heat exchanger from bottom to top, and fully exchanges heat with the sewage passing in the opposite direction, so that the refrigerant obtains the maximum amount of heat and the heat recovery efficiency is maximized.

[0015] The cold region sewage waste heat recovery and reuse system also includes a heat protection subsystem, which includes a fan coil unit. The fan coil unit is connected to an electric heater through a pipeline, and the electric heater is connected to a first insulation water tank through a pipeline.

[0016] The cold region sewage waste heat recovery and reuse system also includes a deodorization and sewage discharge subsystem, which is composed of an air duct and a low-noise ventilator, and the air duct is connected to the low-noise ventilator.

[0017] Beneficial effects:

[0018] 1. The present invention is based on the principle of heat pump. Through a small amount of high-level electric energy input, the low-temperature and low-level heat energy in bathing wastewater or domestic sewage is transferred to high-level heat energy to realize heating and cooling functions. It is an efficient, environmentally friendly and energy-saving waste heat recovery and reuse system.

[0019] 2. The temperature of the sewage discharged after bathing is generally around 35°C. The heat in the sewage is efficiently extracted through the heat exchange equipment of the system and added to the hot water for bathing, forming a recycling of waste heat. In this process, the recovered heat accounts for more than 85% of the heat required for heating the hot water for bathing, and the remaining 15% of the heat comes from the heat converted from the input electrical energy when the heat pump is running. The sewage temperature can be reduced to about 4°C before discharge, avoiding the formation of environmental thermal pollution.

[0020] During the heat recovery cycle, the sewage temperature is reduced from an average of 25°C to 35°C to 4°C. At the same time, the tap water for bathing is raised from 10.7°C (the average tap water temperature in Harbin throughout the year) to 40°C-60°C through the work of the heat pump. The temperature of the hot water for bathing can be adjusted according to demand, up to 60°C. The system heating coefficient COP is 5 on average throughout the year, with relatively high energy efficiency, which is a very practical energy-saving and environmentally friendly technology.

[0021] 3. The present invention utilizes renewable energy. Bathing sewage is a waste heat resource that is directly discharged into the environment. It is recycled and reused to heat domestic hot water through this system, which embodies the characteristics of renewable energy.

[0022] 4. The present invention can save energy and reduce emissions. The system replaces coal-fired and gas-fired boiler rooms, reduces land occupation, and realizes environmental protection of a large area integrated with a small area. It does not generate air pollution during operation and also reduces thermal pollution caused by sewage discharge to the environment.

[0023] 5. The present invention is economical in operation. An input of 1kW of electric energy can extract 4.5-6.5kW of heat energy from sewage. The operating cost is 1 / 4 to 1 / 5 of that of a gas boiler and 1 / 5 to 1 / 6 of that of an electric boiler.

[0024] 6. The present invention is safe and reliable. The sewage temperature is relatively stable all year round and is not affected by weather and ambient temperature changes. It is a good low-temperature heat source. No additional heat source is required in winter to meet the needs of hot water production. If extremely cold weather occurs in winter, a small amount of heat source can be supplemented through the security system.

[0025] 7. The present invention is easy to maintain, and the system operation process is easy to maintain. Dirt stuck on the equipment during operation only needs to be cleaned once a year to ensure normal operation of the equipment. Description of the drawings:

[0026] Attached Figure 1 It is a schematic diagram of the structure of the sewage waste heat recovery and reuse system in cold areas of the present invention.

[0027] Attached Figure 2 It is a schematic diagram of the heat pump connection structure of the sewage waste heat recovery and reuse system in cold areas of the present invention.

[0028] Attached Figure 3 This is the three-dimensional structure diagram of the sewage tank of this product.

[0029] Attached Figure 4 This is the main view of the sewage tank of this product.

[0030] Attached Figure 5 This is a top view of the sewage tank of this product.

[0031] Attached Figure 6This is the side view of the sewage tank of this product.

[0032] Attached Figure 7 This is the sewage waste heat exchanger diagram of this product.

[0033] Attached Figure 8 It is the operating principle diagram of the wastewater waste heat recovery subsystem of the present invention.

[0034] Attached Fig. 9 It is a schematic diagram of the composition of the wastewater waste heat recovery subsystem of the present invention.

[0035] Attached Fig.10 It is the architecture diagram of the monitoring system of the present invention.

[0036] Attached Fig.11 It is a schematic diagram of the system operating conditions of the present invention.

[0037] Attached Fig.12 It is a schematic diagram of the single machine working condition of the present invention.

[0038] Attached Fig.13 It is a schematic diagram of the mobile phone APP operation interface of the present invention.

[0039] Attached Fig.14 It is a diagram of the deodorization and sewage discharge structure of the present invention.

[0040] Attached Fig.15 This is a measurement point arrangement diagram of the A17 apartment composite heat pump system of the present invention.

[0041] Attached Fig.16 This is a power distribution system diagram of the A17 apartment composite heat pump system of the present invention.

[0042] Attached Fig.17 It is the PLC system diagram of the A17 apartment composite heat pump system of the present invention.

[0043] Attached Fig.18 It is the plan layout of the public bathroom equipment of the A17 apartment of the present invention. Specific implementation method:

[0044] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention.

[0045] Embodiment 1:

[0046] A waste heat recovery and reuse system for sewage in cold areas, comprising: a waste heat recovery subsystem for waste water, the waste heat recovery subsystem for waste water comprising a heat pump unit 1, the heat pump unit 1 being connected to a waste heat exchanger 3-2 in a box body 3-1 in a sewage tank through a pipeline, the waste heat exchanger 3-2 being connected to the heat pump unit 1 through a pipeline, the pipeline being filled with a refrigerant, the box body 3-1 in the sewage tank being connected to a sewage pump 23 through a pipeline, the sewage pump 23 discharging sewage, the bathtub drain pipe being connected to a hair collector 22, the hair collector 22 being connected to a sewage inlet pipe 3-4 through a pipeline, the sewage inlet pipe 3-4 being connected to a sewage distribution pipe 3-3 in a box body 3-1 in the sewage tank, the heat pump unit 1 being connected to a high temperature Water pump 21, the high-temperature water pump 21 is connected to the first insulated water tank 17 through a pipeline, the first insulated water tank 17 is connected to the hot water mixing pump 20 through a pipeline, the hot water mixing pump 20 is connected to the water mixer 19 through a pipeline, the water mixer 19 is connected to the second insulated water tank 18 through a pipeline, the second insulated water tank 18 is connected to the hot water output pipeline, the tap water inlet pipe is connected to the water mixer 19 through a pipeline, the tap water inlet pipe is connected to the fan coil unit 15 through the first electronic descaling device 11, the fan coil unit 15 is connected to the second electronic descaling device 12 through a pipeline, the second electronic descaling device 12 is connected to the heat pump unit 1 through a pipeline, the heat pump unit 1 is connected to the first insulated water tank 17 through a pipeline, and the fan coil unit 15 is connected to the first insulated water tank 17 through a pipeline.

[0047] Embodiment 2:

[0048] In the sewage waste heat recovery and reuse system for cold areas described in Example 1, the tap water inlet pipe is connected to the cold water tank 5 through a pipeline, the cold water tank 5 is connected to the heat pump 4 through a pipeline, the heat pump 4 is connected to the circulation pump 8 through a pipeline, the circulation pump 8 is connected to the drainage tank 7 through a pipeline, the drainage tank 7 is connected to the solar collector 6 through a pipeline, the solar collector 6 is connected to the air energy heat pump unit 4 through a pipeline, the air energy heat pump unit 4 is connected to the water pump 9 through a pipeline, the water pump 9 is connected to the cold water tank 5 through a pipeline, the cold water tank 5 is connected to the medium-temperature water pump 10 through a pipeline, and the medium-temperature water pump 10 is connected to the insulation water tank 17 and the heat pump unit 1 through a pipeline.

[0049] Or the cold water tank 5 is connected to the geothermal pump 4-1 through a pipeline, the geothermal pump 4-1 is connected to the water pump 9 through a pipeline, the water pump 9 is connected to the cold water tank 5 through a pipeline, the cold water tank 5 is connected to the medium-temperature water pump 10 through a pipeline, and the medium-temperature water pump 10 is connected to the insulation water tank 17 and the heat pump unit 1 through a pipeline.

[0050] The fan coil unit 15 is connected to the electric heater 16 through a pipeline, and the electric heater 16 is connected to the first thermal insulation water tank 17 through a pipeline.

[0051] Embodiment 3:

[0052] In the cold region sewage waste heat recovery and reuse system described in Example 1, a group of guide partition plates 3-10 are installed in the sewage tank inner box 3-1, and the guide partition plates 3-10 are arranged in parallel in the longitudinal direction. A group of sewage waste heat exchangers 3-2 are installed in the sewage tank inner box, and the sewage waste heat exchangers are parallel to each other in the transverse direction. The top of the sewage waste heat exchanger is provided with a sewage distribution pipe 3-3, and the sewage distribution pipe 3-3 is connected to the sewage inlet pipe 3-4. The sewage waste heat exchanger 2 is connected to the sewage waste heat connecting pipe 3-5. The sewage waste heat connecting pipe 3-5 is connected to the water inlet pipe 3-7 at the bottom, the water inlet pipe 3-7 is connected to the heat pump unit 1, the sewage waste heat connecting pipe 3-5 is connected to the water outlet pipe 3-11 at the top, the water outlet pipe 3-11 is connected to the heat pump unit 1, the bottom of the sewage tank inner box body is equipped with a distributed sewage recovery pipe 3-6, the distributed sewage recovery pipe 3-6 is connected to the sewage pump 23, the sewage tank inner box body 3-1 is installed in the sewage tank outer box body 3-8, and the sewage tank insulation material 3-9 is installed between the sewage tank inner box body and the sewage tank outer box body. The insulation material includes: rigid foam polyurethane, extruded polystyrene board, molded polystyrene board, and mineral fiber products.

[0053] The sewage waste heat exchanger 3-2 is assembled by a group of heat exchange tubes installed in parallel, each group of heat exchange tubes is composed of multiple pipes installed in parallel from top to bottom, each group of heat exchange tubes has a certain height, and multiple groups of heat exchange tubes are installed in parallel to ensure that the heat exchanger is fully distributed in the insulated sewage tank;

[0054] As a preferred embodiment, the sewage waste heat exchanger 2 is designed to adopt a multi-pass fin zigzag structure, and the number of passes can be determined by numerical analysis and optimization design combined with model experiments, with the maximum heat transfer area as a constraint;

[0055] A sewage distribution pipe 3-3 is arranged above the box body 3-1 in the sewage tank, so that the high-temperature sewage enters the sewage tank in a jet manner. The sewage distribution pipe 3-3 is evenly distributed above the sewage waste heat exchanger 3-2, generating vibrations and enhancing the heat exchange effect. When the sewage is at a high temperature, it exchanges heat with the refrigerant installed in the sewage waste heat exchanger 3-2 in the middle and upper layers of the sewage tank. As the heat of the sewage is absorbed, the temperature gradually decreases, the specific gravity of the sewage increases, and it falls to the bottom of the sewage tank, generating a temperature gradient. The low-temperature sewage that has absorbed heat sinks to the lower layer, and under the action of the new high-temperature sewage pressure, it is discharged in the form of overflow through the distributed sewage recovery pipe 3-6, eliminating the loss of heat.

[0056] The low-temperature refrigerant in the sewage waste heat exchanger 3-2 enters from the bottom inlet of the water inlet pipe 3-7 at a certain flow rate, and exchanges heat with the sewage with a temperature gradient in the sewage tank in the form of multiple tube layers. The higher the flow rate, the more significant the heat transfer effect. The high-temperature refrigerant flows out from the outlet of the upper water outlet pipe 3-11 of the sewage waste heat exchanger and enters the evaporator of the unit. The heat in the refrigerant is absorbed by the refrigerant in the unit through conversion, and the low-temperature refrigerant returns to the bottom inlet of the water inlet pipe 3-7, circulates and absorbs heat to ensure the progress of the heat transfer process.

[0057] The sewage waste heat exchanger 3-2 can be a non-metallic heat exchanger as a preferred solution, with heat-conducting elements added inside, good thermal conductivity, high strength; no corrosion, no scaling, easy to clean and easy to install.

[0058] The sewage waste heat exchanger 3-2 adopts an immersion structure, and the sewage waste heat exchanger is immersed in sewage to facilitate cleaning of dirt;

[0059] As a preferred solution, an antifreeze heat exchange medium can be injected into the sewage waste heat exchanger 3-2, and non-contact heat exchange can be performed with the sewage through the sewage waste heat exchanger to ensure the safety of the hot water unit.

[0060] It is assembled from several sewage waste heat exchangers and is easy to install and maintain.

[0061] The sewage tank is designed with a distributed sewage distribution and recovery device, specifically: the sewage distribution pipe 3-3 causes lateral scouring and temperature gradient when the high-temperature sewage enters the sewage tank, ensuring that the high-temperature sewage is evenly and fully heat-exchanged, and the low-temperature sewage that has absorbed heat sinks to the lower layer. Under the pressure of the new high-temperature sewage, it is discharged in the form of overflow through the recovery device, i.e., the distributed sewage recovery pipe 3-6, thus preventing heat loss;

[0062] By designing and installing sewage distribution pipe 3-3 and distributed sewage recovery pipe 3-6 in the sewage tank, a distributed sewage distribution and recovery device is formed, which does not destroy the temperature drop layer in the sewage tank and maintains a good temperature layer change caused by water temperature.

[0063] The design and installation of distributed sewage recovery pipes 3-6 aims to concentrate the low-temperature sewage in the lower layer of the water tank and discharge it at the lowest temperature, thereby reducing the energy loss of sewage discharge.

[0064] The guide partition plates 3-10 are designed to be staggered in the sewage tank. The guide partition plates 3-10 increase the flow speed of the sewage, extend the flow time, fully exchange heat, and ensure that the sewage with the lowest temperature is discharged evenly and quickly.

[0065] Distributed sewage recovery pipes 3-6 are arranged at the bottom of the sewage waste heat exchanger to quickly discharge low-temperature sewage. At the same time, a refrigerant with a certain flow rate enters the bottom inlet of the sewage waste heat exchanger, flows through the entire sewage waste heat exchanger from bottom to top, and fully exchanges heat with the sewage passing in the opposite direction, so that the refrigerant obtains the maximum amount of heat and the heat recovery efficiency is the highest.

[0066] Embodiment 4:

[0067] In the cold region sewage waste heat recovery and reuse system described in Example 1, the sewage waste heat exchanger is a titanium alloy metal heat exchanger. a. The sewage waste heat exchanger uses a heat exchanger for bathing sewage. b. It is non-corrosive, non-scaling, easy to clean, and easy to install.

[0068] c. The sewage waste heat exchanger adopts an immersion structure, which immerses the sewage heat exchanger in sewage to facilitate cleaning of dirt.

[0069] d. The sewage waste heat exchanger is a titanium alloy metal heat exchanger, which directly replaces the evaporator of the unit, reducing the indirect heat exchange link in the middle, and performs non-contact heat exchange with sewage through the heat exchanger to ensure the safety of the hot water unit.

[0070] e. It is assembled from several heat exchangers and is easy to install and maintain.

[0071] The sewage distribution and recovery device is designed with a water distribution and water collection system for the sewage tank to ensure rapid discharge of low-temperature sewage and sufficient heat exchange of high-temperature sewage.

[0072] a. A sewage distribution and recovery device is designed and installed in the sewage pool to maintain a stable gradient layer change of sewage temperature from top to bottom caused by gravity without destroying the temperature drop of sewage in the sewage tank.

[0073] b. Design and install sewage discharge equipment to concentrate the low-temperature sewage in the lower layer of the water tank and discharge it at the lowest temperature, reducing the energy loss of sewage discharge.

[0074] The indoor bathing steam waste heat recovery device is provided with a fan coil unit 15 to collect the waste heat of water vapor during bathing in the bathroom, heat the tap water before entering the unit, and increase the temperature by 3 to 5 degrees Celsius.

[0075] The inner box 3-1 of the sewage tank is installed in the outer box 3-8 of the sewage tank to form a heat storage sewage tank. The outer box 3-8 of the sewage tank adopts a steel structure frame, and the skin is made of glass fiber or basalt fiber cloth through bonding. It has the characteristics of corrosion resistance, anti-seepage and durability, and the service life exceeds 20 years. The outer layer is pasted with thermal insulation material, and it is fully enclosed and insulated.

[0076] The hot water tank for bathing comprises a first insulated water tank 17 and a second insulated water tank 18. Both the first insulated water tank 17 and the second insulated water tank 18 adopt a sandwich structure, wherein the inner layer is a stainless steel plate as the water tank body, the outer layer is an ordinary stainless steel plate, and the middle layer is a thermal insulation material as the core layer. The inner and outer stainless steel plates and the thermal insulation core layer are optimized in combination to meet the requirement of maintaining the temperature of the hot water for bathing for a long time.

[0077] The heat pump unit 1 adopts a one-time heating technology, that is, it can heat the source water to 40-60°C, and can be heated to 65°C at the highest.

[0078] The hot water unit 1 is small in size, light in weight, and easy to carry, and is particularly suitable for renovation projects; the unit has a compact structure, small vibration, small footprint, and is easy to install. Multiple units serve as backup for each other, and any failure of any unit will not affect normal bathing water supply.

[0079] The main unit of the hot water unit adopts high-quality flexible scroll compressor, supplemented by a number of noise reduction and vibration reduction measures, the unit has small vibration and low noise.

[0080] The water mixer 19 adjusts the high temperature water (45°C-60°C) heated by the heat pump unit 1 and the tap water (4°C-20°C) to the use temperature directly through the designed water mixer, and enters the mixing tank or is directly used for the bathtub nozzle.

[0081] Embodiment 5:

[0082] The waste heat recovery and reuse system for sewage in cold areas described in Example 4 also includes a heat protection subsystem, which includes a fan coil unit 15, the fan coil unit 15 is connected to an electric heater 16 through a pipeline, and the electric heater 16 is connected to a first thermal insulation water tank 17 through a pipeline. Under the premise of ensuring the power capacity of the power supply, a rapid hot water heating device (electric heater 16) is set in the system or the return water heat energy of the heat network is used as a heat source protection system to directly heat the tap water to 40-60 degrees to supplement the shortage of hot water for bathing, or to increase the tap water temperature by 5-15 degrees under extremely cold conditions in winter, so that the unit can operate normally and stably. (Under normal circumstances, the heat protection subsystem does not need to be started and operated).

[0083] Embodiment 6:

[0084] The cold region sewage waste heat recovery and reuse system described in Example 4 also includes an odor removal and sewage discharge subsystem. An independent system is established for sewage odor discharge. The odor removal and sewage discharge subsystem consists of an air duct 31 and a low-noise ventilator 30. The air duct is connected to the low-noise ventilator to form an independent sewage discharge system. The sewage tank and the heat exchanger in the sewage tank are cleaned once a year.

[0085] The deodorization and sewage discharge subsystem requires the establishment of an independent system for sewage odor discharge to avoid intersection with the building discharge system.

[0086] Clean the sewage tank and the heat exchanger inside the sewage tank once a year to ensure system operating efficiency, system hygiene requirements and avoid accidents.

[0087] Embodiment 7:

[0088] The waste heat recovery and reuse system for sewage in cold regions described in Example 4 also includes a shock absorption, sound insulation, and noise reduction system. The bathhouse renovation projects are all located on the ground floor or basement of the student dormitory. The design and construction are strictly in accordance with the requirements of national standards. Vibration reduction and noise reduction measures are adopted for the equipment units in the equipment room. Specifically: the lower part of the equipment is connected to the vibration reduction base, the vibration reduction base is connected to the ground through a vibration reduction damper, and the outer layer of the equipment is provided with sound insulation material or sound insulation board.

[0089] Embodiment 8:

[0090] The waste heat recovery and reuse system for sewage in cold regions described in Example 4 may also include a monitoring subsystem as a preferred solution, including: temperature sensor, flow sensor, pressure sensor, liquid level sensor, ultrasonic calorimeter, data concentrator, monitoring system software, industrial computer. The monitoring subsystem adopts bus technology to implant microprocessors into traditional measurement and control instruments, form a network control system and transmit data according to standard communication protocols, connect multiple on-site hot water units and instruments with remote monitoring computers through data transmission and information exchange to realize various automatic control systems that meet actual needs.

[0091] The monitoring system software (monitoring system) has the functions of start-stop control and operating status display of a single unit. It can perform local and remote operations on each unit separately. It can also monitor the operating status of the heat pump hot water unit through the mobile phone software to realize the start-stop control of the hot water unit.

[0092] The monitoring system controls the number of units in operation and configures the start-stop program to achieve automatic and continuous operation of the system. During the peak period of bathing, the system unit and the backup unit start at the same time, which basically solves the problem of wastewater heat source loss. When the peak period is over, the number of bathers gradually decreases, the amount of heat that can be recovered also decreases, and the system COP value gradually decreases. At this time, the monitoring system automatically reduces the number of units in operation, reduces the power consumption of the system, and improves the heat recovery efficiency until the insulated hot water tank is full, or a certain amount of hot water is produced according to demand. At this time, the unit automatically stops running and the entire system no longer works, ensuring that the system heat recovery efficiency reaches 100%.

[0093] The monitoring and surveillance system realizes monitoring and display of average temperature of heat source, hot water flow and temperature regulation, instantaneous hot water production display of single unit, heat recovery and percentage display of refrigerant in heat exchanger of single unit, water tank level control, switch control of cold (hot) water valve in fan coil heat recovery system, motor start and stop and speed control, etc.

[0094] The monitoring system has the functions of fault self-diagnosis, alarm, automatic protection, etc. The alarm function is perfect, including over-temperature alarm, under-temperature alarm, power phase sequence error alarm, phase loss alarm, motor overload alarm, water flow fault alarm, water pressure fault alarm, over-pressure alarm, under-pressure alarm, hot water tank full water alarm, etc.

[0095] The monitoring system has the functions of data curve display, printing, and historical data export. At the same time, the data is analyzed, energy consumption is accumulated, and energy saving, emission reduction, production cost, and cost saving are calculated. It can also display basic information such as indoor and outdoor temperature and humidity, number of online nozzles, total number of bathers, weather forecast, etc. You can check the current bathroom usage online through the mobile phone APP and arrange bathing time reasonably.

[0096] The monitoring system can provide multi-user and multi-account management functions, provide managers with a hierarchical management method for online data monitoring and supervision, provide real-time data display functions, and rich historical data analysis methods. It can select historical data of 1 hour, 24 hours, 15 days, 1 month, half a year, and the whole year, and has data curve display, printing, and historical data export functions.

[0097] The system does not require manual care when running, is unattended, and can be monitored remotely.

[0098] While optimizing the original software and hardware, the system uses the latest monitoring software, which responds to hardware information collection more promptly, has higher operating efficiency, and also has the conditions for uninterrupted operation. The computer used in the hardware is an i7 processor, and is equipped with a large-screen TV as a split screen, so that people entering the bath can clearly see the system working screen. At the same time, the data is displayed dynamically, with obvious color distinction, and you can click on the unit or water tank and other equipment to view detailed information.

[0099] The bathhouse wastewater waste heat recovery monitoring system is a product that combines heat pump technology, automatic control technology and computer network technology. The use of this monitoring system can rationally utilize equipment, save energy, save manpower, ensure the safe operation of equipment, extend its service life, strengthen the modern management of bathhouse electromechanical equipment, and create a safe, comfortable and convenient working environment to improve management level.

[0100] Embodiment 9:

[0101] The waste heat recovery and reuse system for sewage in cold areas described in Example 4, as a preferred solution, also includes a free air-conditioning subsystem. While the hot water system produces domestic hot water, a single unit generates about 40kW of cooling capacity, and a dual unit generates about 80kW of cooling capacity, which is used for summer air-conditioning needs; these cooling capacities are transferred to the air-conditioning chilled water system through a plate heat exchanger, or supplied to an independent air-conditioned area. If transferred to an existing air-conditioning chilled water system, the air-conditioning plate heat exchanger can be connected in parallel with the existing chiller host to provide an air-conditioning cold source. If an independent air-conditioned area is supplied, the air-conditioning plate heat exchanger can be used as the cold source host of the air-conditioned area, and a fan coil unit is used at the indoor terminal, with the fan coil unit outlet facing the air-conditioned area, to continuously blow cold air into the interior space of the room.

[0102] A single unit can provide free cooling for an indoor area of ​​400-500 square meters, while a dual unit can provide cooling for an area of ​​800-1000 square meters.

[0103] The device can be selected according to user requirements.

[0104] Embodiment 10:

[0105] The cold region sewage waste heat recovery and reuse system described in Example 4, as a preferred solution, also includes an intelligent control system for electric power appliances, which is composed of an assembly of a programmable controller (PLC), a frequency converter, a multi-function power meter, a low-voltage power distribution and low-voltage control components, etc. The programmable controller (PLC) is respectively connected to the frequency converter, the multi-function power meter, the low-voltage power distribution and low-voltage control components, etc.

[0106] Embodiment 11:

[0107] In the cold region waste heat recovery and reuse system described in Example 4, electronic descaling devices are respectively provided at the cold water inlet main pipe and the cold water inlet of the unit to solve the problem of easy scaling of the evaporator and condenser, and slow down the trend of the unit output and efficiency decreasing year by year;

[0108] The main components of scale are calcium carbonate and magnesium carbonate. When heated, the calcium and magnesium ions in the water gradually form "single crystal" rod-shaped hexagonal prisms with the ion nucleus as the center and condense into dense large needle-shaped particles. When water flows through the alternating electromagnetic field, the dense needle-shaped crystals are changed into loose calcite. Under the flushing of flowing circulating water, the calcite-type calcium carbonate crystals are easy to remove, achieving a relatively significant anti-scaling and descaling effect.

[0109] Features:

[0110] Anti-scaling: After the new equipment is installed, it will never form scale, and prevent scale from adhering to the container and pipe wall.

[0111] Descaling: After the old equipment is reinstalled, the scale on the inner wall of the container and pipe of the old equipment will fall off by itself within 25 to 40 days (Note: open the filter drain valve in time to discharge), and it will never scale again after it falls off.

[0112] Sterilization: The high-frequency electromagnetic field emitted by the electronic descaling filter has a frequency of 10 MHz, which is enough to kill the bacteria in the water and is very beneficial to human drinking water.

[0113] Algae killing: Algae in water, such as green mud, is a kind of microorganism, which can be killed and growth slowed down by high-frequency electromagnetic fields. It is very beneficial to aquaculture, agricultural irrigation and plant growth.

[0114] Water quality change: Through the water treatment of the electromagnetic field of this machine, large molecular water can be turned into small molecular water. No more detergent is needed for bathing the human body, washing clothes, and cleaning the surface of vegetables and fruits.

[0115] Embodiment 12:

[0116] The cold region sewage waste heat recovery and reuse system described in Example 4, the application of sewage source waste heat recovery hot water technology, can not only provide hot water for the bath, but also achieve dehumidification of the bathing area and reduce the impact of hot and humid gas emissions on the surrounding environment.

[0117] In summer, it can provide a cold source for the bath or the ancillary buildings around the bath, replacing the investment and operation costs of central air-conditioning equipment. According to the above calculation of producing 100 tons of hot water per day and 310 days per year, it can guarantee the cooling needs of about 2,000-2,500 square meters of buildings. Not only does it save about 200,000 yuan in central air-conditioning host investment costs, it can also save about 74,000 yuan in air-conditioning operation costs each year.

[0118] Use natural energy to supplement heat. In the coldest period of winter, when natural energy supplement heat cannot meet the use requirements, electric heaters are used to supplement heat. Titanium alloy heat exchanger is used as heat pump evaporator, which not only reduces the process of transferring sewage heat to the evaporation end of the unit through the refrigerant, but also eliminates the power consumption of the circulating motor.

[0119] Embodiment 13:

[0120] The waste heat recovery and reuse system for sewage in cold regions described in the above embodiment,

[0121] The heat pump unit 1 recovers the waste heat from various discharged sewage and converts it into high-grade thermal energy. The sewage is circulated in a closed manner, and the heat is extracted by the sewage waste heat exchanger 2 before returning to the sewage main canal. It does not contact other equipment and has zero pollution to the environment. It can provide high-grade thermal energy for heating or domestic hot water. The water temperature can be set arbitrarily at 40-60℃. The energy efficiency ratio is as high as 4.6-7.0 according to the sewage temperature. In the cold north, solar energy hardly generates much heat in winter; the COP of air energy is also below 2.0, and there is a lot of heat in the sewage source, which is not affected by weather and environment, and the energy efficiency is still 4.6-7.0, so using sewage as a heat source is very energy-saving. However, the biggest technical difficulty of sewage source heat recovery is that because sewage is used, it is bound to cause blockage, corrosion, scaling of the heat exchanger, resulting in frequent maintenance, short life, low heat exchange efficiency and other problems. In response to these problems, an "immersion heat exchanger" is used to solve this series of problems. Maintenance-free, cleaning-free, corrosion-resistant, high heat exchange efficiency, so it saves about 30% energy compared to ordinary sewage source heat pumps, and the unit life is up to 30 years! Greatly improve the user's return on investment!

[0122] Titanium alloy waste water heat exchanger is used, and waste water and refrigerant directly exchange heat, saving the refrigerant loop and reducing the volume of the heat storage waste water tank by 20%.

[0123] By using the energy transfer characteristics of the refrigerant, the refrigerant is allowed to circulate under the action of the compressor, and it continuously evaporates and absorbs the heat energy in the waste water discharged after bathing, while continuously releasing heat in the condenser, thereby heating the cold water flowing through the condenser. Since the entire system only needs to rotate the compressor to circulate the refrigerant, the power consumption required for heating is reduced to the greatest extent, achieving the purpose of high efficiency and energy saving.

[0124] The heat pump unit 1 heats the water to 42℃-60℃ and places it in an insulated water tank. For a well-insulated water tank, the temperature drop is generally less than 2-5℃ per day. As long as you make a good plan and arrange the working time of the machine according to the water usage every day, the amount of water produced will be the same as the amount of water used every day. In this way, the energy loss in insulation is very low. As long as there is water in the water tank, there is hot water to use, and the water temperature is basically stable, which is critical to the comfort of water use.

[0125] The hot water directly heated by the heat pump unit flows from the heat pump into the water tank to reach the set water temperature. When the water temperature and water volume in the insulated water tank reaches the set upper limit, the main unit stops working. When the water temperature is lower than the set lower limit, the main unit starts. This cycle works in this way to keep the hot water in the insulated water tank constant, thereby meeting the daily hot water demand of the bath.

[0126] Air source heat pump unit: The air source heat pump unit is driven by a small amount of electric energy, absorbs a large amount of natural energy, and transmits it to the indoor use end, making it suitable for heating, cooling, bathing hot water, domestic hot water, etc. at various terminals.

[0127] ⑴ Working principle of air energy heat pump unit

[0128] The heat exchanger of the air-source heat pump unit is placed outdoors, and absorbs a large amount of natural energy such as the sun, air, heat, wind, rain, snow, haze, etc. through the medium. The medium after absorbing energy is then transported to the main unit. After being compressed by the compressor in the main unit, it becomes a high-temperature and high-pressure gas, and then enters the heat exchanger for heat exchange. The medium after heat exchange is throttled and reduced in pressure by the expansion valve, and then enters the outdoor heat exchanger to absorb energy. This cycle is repeated to obtain a large amount of energy. It is widely used in a variety of places that require heating, cooling, and hot water.

[0129] ⑵ Save 20-40% more electricity than air energy

[0130] Under the same low temperature conditions as natural energy and air energy, when there is sunshine, the evaporation temperature of the refrigeration system can be increased by absorbing sunlight heat energy, and the energy efficiency of the unit is about 40% higher than that of air source heat pumps. When there is no sunshine, the unit does not need to be defrosted, and the heating performance system is about 20% higher than that of air source. In a low temperature and harsh environment, the unit does not need to be defrosted at all, which can save a lot of electricity. And ensure that the unit provides heat continuously and uninterruptedly.

[0131] ⑶No defrosting problem at low temperature

[0132] The natural energy heat pump heat exchanger is made of aviation aluminum, formed in one step, with a polymer matte coating on the surface, the surface has a self-cleaning function, and the heat-absorbing end absorbs natural energy all day long without defrosting.

[0133] ⑷ Completely eliminate antifreeze problems

[0134] The natural energy heat pump adopts a split structure design, with the heat exchanger outdoors and the main unit and user side indoors. The two circulate through the medium to avoid the risk of freezing at low temperatures.

[0135] ⑸ Fanless design, zero fan noise

[0136] The outdoor heat exchanger of the natural energy heat pump does not have a fan running and is completely silent, thus completely avoiding the fan noise problem of the air energy heat pump.

[0137] ⑹Remote intelligent control

[0138] No matter where and when, you can remotely control the start and stop of the unit, detect the unit's operating status in real time, adjust the unit as needed, and query the unit's operating records.

[0139] High frequency electronic descaling device

[0140] Working principle: The main components of scale are calcium carbonate and magnesium carbonate. When heated, the calcium and magnesium ions in the water gradually form "single crystal" rod-shaped hexagonal prisms with the ion nucleus as the center and condense into dense large needle-shaped particles. When water flows through the alternating electromagnetic field, the dense needle-shaped crystals are changed into loose calcite. Under the flushing of flowing circulating water, the calcite-type calcium carbonate crystals are easy to remove, achieving a relatively significant anti-scaling and descaling effect.

[0141] Features:

[0142] Anti-scaling: After the new equipment is installed, it will never form scale, and prevent scale from adhering to the container and pipe wall.

[0143] Descaling: After the old equipment is reinstalled, the scale on the inner wall of the container and pipe of the old equipment will fall off by itself within 25 to 40 days (Note: open the filter drain valve in time to discharge), and it will never scale again after it falls off.

[0144] Sterilization: The high-frequency electromagnetic field emitted by the electronic descaling filter has a frequency of 10 MHz, which is enough to kill the bacteria in the water and is very beneficial to human drinking water.

[0145] Algae killing: Algae in water, such as green mud, is a kind of microorganism, which can be killed and growth slowed down by high-frequency electromagnetic fields. It is very beneficial to aquaculture, agricultural irrigation and plant growth.

[0146] Water quality change: Through the water treatment of the electromagnetic field of this machine, large molecular water can be turned into small molecular water. No more detergent is needed for bathing the human body, washing clothes, and cleaning the surface of vegetables and fruits.

[0147] This machine takes up little space and consumes low power (5 kWh per month).

[0148] It can both remove scale and filter, solving both major problems in water.

[0149] One machine for multiple uses, install once and use forever.

[0150] Suitable for civil floor heating, wall-mounted boilers, solar energy, water heaters, air energy, etc.; commercial hotels, guesthouses, baths, small and medium-sized boilers, etc.; industrial cooling towers, heat exchange stations, chemical, food, oil refining, papermaking, injection molding and other circulating water systems.

[0151] It is directly connected to the user's tap water inlet and can replace the pre-filter, water softener, and water purifier. It is the best replacement product for whole-house water purification.

[0152] Hair filter

[0153] The hair filter (hair collector) is a necessary equipment for the heat recovery system and is also an existing equipment. It can remove hair in the sewage of the bath and garbage during use from entering the sewage tank and water pump to ensure the normal operation of the entire system. It is mainly composed of a pipe, a cylinder, a filter basket, a flange cover and fasteners. The equipment can remove solid particles in the liquid and also protect the normal operation of subsequent equipment. When the fluid enters the filter cartridge with a certain specification of filter screen, its hair and solid impurity particles are blocked in the filter basket, and the clean fluid flows out of the filter outlet through the filter basket.

[0154] When the hair collector is used for a certain period of time, the water resistance increases due to the blockage of dirt. At this time, you need to open the cover of the collector, take out the filter cartridge inside, clean it, and then continue to use it. When it needs to be cleaned, use a wrench to loosen the screw plug at the bottom of the main pipe, drain the fluid, remove the flange cover, and take out the filter basket. After cleaning, just reinstall it. It is extremely convenient to use and maintain.

[0155] Design Calculation

[0156] The bathing area in A05 apartment has hot water supply at regular intervals. There are 43 showers in the male area and 39 showers in the female area, for a total of 82 showers. This system is calculated based on the number of students staying at 2,000.

[0157] (1) Design hourly hot water volume qrh

[0158] The hourly water consumption of the shower qh is 260L / h (40℃);

[0159] The number of showers n0 is 82;

[0160] The percentage b of sanitary appliances used simultaneously is taken as 100%;

[0161] q rh =q h n0b=260×67×100%=17420L / h=17.42m 3 / h=17.42t / h

[0162] (2) Designed daily hot water quantity qrd;

[0163] The design hourly hot water duration is 2h, q rd =q rh ×2h=34.84t / h(40℃)

[0164] (3) Design hourly heat consumption Qh

[0165] The hot water temperature tr is 40℃;

[0166] The cold water temperature tl is 10℃;

[0167] The hot water density ρr is taken as 0.993 kg / L;

[0168] The specific heat C of water is taken as 4.187 kJ / (kg·℃);

[0169] Q h =q h n0b(t r -t1)ρ r C=q rh (t r -t1)ρ r C=17420×(40-10)×0.993×4.187

[0170] =17420×124.73kJ / h=217296.6kJ / h=603.6W

[0171] Qh=∑qhn0b(tr-tl)ρrC=qrh(tr-tl)ρrC=21320×(40-10)×0.993×4.187=21320×124.73kJ / h

[0172] Qh=∑qhn0b(tr-tl)ρrC=qrh(tr-tl)ρrC=21320×124.73=2659243.6kJ / h=738.7kw

[0173] (4) Design hourly heating supply Qg

[0174] Two LTWZP-12R sewage source heat pump units are selected, each with a heating capacity of 52.5kW, Qg = 105kW

[0175] (5) Hot water tank effective volume Vr

[0176] The design hourly heat consumption duration T is 2h;

[0177] The effective heat storage volume coefficient η is taken as 0.80;

[0178] The safety factor k2 is 1.20;

[0179] The hot water temperature tr is 40℃;

[0180] The cold water temperature tl is 10℃;

[0181] The hot water density ρr is taken as 0.993 kg / L;

[0182] The specific heat C of water is taken as 4.187 kJ / (kg·℃);

[0183]

[0184]

[0185] V r =(2659243.6-2×52.5×3600)×0.024052=54868L=54.87m 3

[0186] Converted to 55℃ hot water, the effective volume of the hot water tank is 36.58m3, and an existing stainless steel water tank with a nominal volume of 40m3 can be used.

[0187] (6) Effective volume of sewage tank Vw

[0188] The coefficient of performance COP of the heat pump is 4;

[0189] The temperature difference between sewage inlet and outlet of the sewage tank Δtju=35-5=30℃;

[0190] The sewage density ρj is taken as 1kg / L;

[0191] The specific heat C of water is taken as 4.187 kJ / (kg·℃);

[0192] The hot water temperature tr is 60℃;

[0193] The cold water temperature tl is 10℃;

[0194] The hot water density ρr is taken as 0.983 kg / L;

[0195] Taking into account the extreme winter conditions, the sewage tank water temperature is lower than 35 ℃, so in order to increase the capacity of the sewage tank, a fiberglass reinforced plastic water tank with a nominal volume of 50m3 should be selected.

[0196] (7) Heat exchanger area Fj in sewage tank

[0197] The coefficient of performance COP of the heat pump is 4;

[0198] The coefficient ε1 that affects the heat transfer effect is taken as 0.8;

[0199] The heat transfer coefficient K of the heat exchanger is 9200kJ / (m2·℃·h);

[0200] The calculated temperature difference Δtj is taken as 5°C;

[0201]

[0202] (8) Heat supplementation measures

[0203] According to the operation data analysis of the wastewater heat recovery units of A02 Apartment, B06 Apartment, A11 Apartment and A15 Apartment for many years, the amount of hot water generated by the units in the cold winter is only 80% of the nameplate parameters, which is equivalent to a lack of heat of 12 tons. In the unfavorable stage of winter, the water supply is 12 tons per day, which is converted into an hourly flow of 0.5 tons.

[0204] One LTZXD-20L air-source heat pump unit (48.7kW each) and eight fan coil units (six 12.4kW units and two 9.15kW units) were selected.

[0205] Floor plan

[0206] The public bathroom layout of Apartment A05. Two 52.5kW sewage source heat pump units plus one 48.7kW air energy heat pump unit (with one 10m3 supplementary heating cold water tank) (two for use and one for standby), one glass fiber reinforced plastic sewage tank with an effective volume of 48.55m3 (currently the effective volume can only be 40m3), and one stainless steel water tank with a nominal volume of 40m3 (55℃ hot water), one stainless steel water tank with a nominal volume of 22m3 (40℃ hot water), converted into a total volume of 82m3 of 42℃ hot water, two supplementary heating hot water supply pumps, one electric heater, and eight fan coil units 15.

[0207] Embodiment 14:

[0208] The waste heat recovery and reuse system for sewage in cold regions described in the above embodiment,

[0209] Harbin Institute of Technology Apartment 17 Student Bathhouse (i.e., Apartment A17) currently has a student bathhouse, of which the male bathing area is equipped with 37 showers and the female bathing area is equipped with 30 showers. The initial heat source of the bathhouse was a gas boiler, and the current heat source is an electric water heater. The bathhouse requires 30 to 40 tons of hot water per day, and the hot water temperature is 40 to 42 degrees. In order to promote the construction of an economical campus, further meet the students' demands for taking a bath without leaving the dormitory and for the supply of hot water in the morning and evening in the dormitory washroom (the total daily hot water demand is 60 tons), and alleviate the problem of queuing in the bathhouse during peak hours, the A17 Apartment bathhouse is now being transformed into a waste heat recovery composite system (the system has a maximum capacity to supply hot water for bathing: 90 tons in summer and 60 tons in winter).

[0210] According to the on-site conditions, if the original gas boiler is dismantled and the location is changed to a sewage tank, the proposed sewage tank can only have a capacity of 35 cubic meters, which is 15 cubic meters short of the design requirements. Therefore, an air source heat pump unit is installed, and the air intake and outlet of the air source heat pump are placed in the garage. The garage has a large area, and the heat source required for the operation of the unit is extracted in the garage. The temperature drop will not exceed 2°C, which will not affect the normal operation in the garage.

[0211] Electronic descaling devices are installed at the main water supply of the system and the water inlet on the cold water side of the unit (two-stage setting: the main water supply is the first stage, and the water inlet of each unit is the second stage) to solve the problem of easy scaling of the evaporator and condenser, and slow down the trend of the unit's COP decreasing year by year.

[0212] The sewage tank’s water distribution and collection systems have been redesigned to ensure rapid discharge of low-temperature sewage and adequate heat exchange of high-temperature sewage.

[0213] A hair collector is installed on the sewage pipe at the entrance of the sewage tank to remove hair from the bathing sewage and garbage from the bathing process before it enters the sewage tank and water pump, ensuring the normal operation of the entire heat recovery system.

[0214] Apartment A17 uses 2 sewage source heat pumps (nominal heating capacity of each unit is 52.5Kw) and 1 air source heat pump (nominal heating capacity of each unit is 41.2Kw).

[0215] Air source heat pump unit

[0216] In view of the actual climate conditions of winter operation in the north, we have overcome the problem of defrosting of low-temperature heat pumps, provided new ideas for improving heat pump technology and defrost control technology, and developed an intelligent video monitoring defrost system, which can defrost when there is frost and not defrost when there is no frost. It saves about 20% energy than conventional ultra-low temperature air source heat pumps on the market. The ultra-low temperature air source cooling and heating machine they developed is not only multi-functional, but also can provide heating + cooling + hot water. It also fills the gap of air source heating in the extremely cold areas of Northeast and Northwest China with a temperature of -30 degrees Celsius. The defrosting of ultra-low temperature air source heat pumps on the market is controlled by temperature and time. When the ambient humidity is high, the heat exchanger will be full of frost after the heat pump runs for 20 minutes, but the heat pump will not enter the defrost program until it runs for (45-55) minutes. The heat pump is not efficient for about 30 minutes. When the humidity of low temperature air is low, the heat exchanger will not frost at all, but it will enter the defrost program after running for (45-55) minutes, wasting energy in vain. Not only does it not heat, but it also uses the heat on the user side to defrost the outdoor heat exchanger. In low temperature and bad weather, it is difficult to meet the heat demand, which is what we often say, one step forward and half a step back. The intelligent defrost system developed by us completely eliminates worthless losses, so it is more energy-saving.

[0217] Design Calculation

[0218] A17 Apartment has a regular hot water supply in the bathing area. There are 37 showers in the male area and 30 showers in the female area, for a total of 67 showers. This system is calculated based on 2,000 students staying in the accommodation.

[0219] (1) Design hourly hot water volume qrh

[0220] The hourly water consumption of the shower qh is 260L / h (40℃);

[0221] The number of showers n0 is 67;

[0222] The percentage b of sanitary appliances used simultaneously is taken as 100%;

[0223] q rh =q h n0b=260×67×100%=17420L / h=17.42m 3 / h=17.42t / h

[0224] qrh=∑qhn0b=260×67×100%=17420L / h=17.42m3 / h=17.30t / h

[0225] (2) Designed daily hot water quantity qrd;

[0226] The design hourly hot water duration is 2h, qrd=34.6t / h(40℃)

[0227] (3) Design hourly heat consumption Qh

[0228] The hot water temperature tr is 40℃;

[0229] The cold water temperature tl is 10℃;

[0230] The hot water density ρr is taken as 0.993 kg / L;

[0231] The specific heat C of water is taken as 4.187 kJ / (kg·℃);

[0232] Q h =q h n0b(t r -t1)ρ r C=q rh (t r -t1)ρ r C=17420×(40-10)×0.993×4.187

[0233] =17420×124.73kJ / h=217296.6kJ / h=603.6W

[0234] Qh=∑qhn0b(tr-tl)ρrC=qrh(tr-tl)ρrC=17420×(40-10)×0.993×4.187=17420×124.73kJ / h

[0235] Qh=∑qhn0b(tr-tl)ρrC=qrh(tr-tl)ρrC=17420×124.73=2172796.6kJ / h=603.6kW

[0236] (4) Design hourly heating supply Qg

[0237] Two LTWZP-12R sewage source heat pump units are selected, each with a heating capacity of 52.5kW, Qg = 105kW

[0238] (5) Hot water tank effective volume Vr

[0239] The design hourly heat consumption duration T is 2h;

[0240] The effective heat storage volume coefficient η is taken as 0.80;

[0241] The safety factor k2 is 1.20;

[0242] The hot water temperature tr is 40℃;

[0243] The cold water temperature tl is 10℃;

[0244] The hot water density ρr is taken as 0.993 kg / L;

[0245] The specific heat C of water is taken as 4.187 kJ / (kg·℃);

[0246]

[0247]

[0248] V r =(2172796.6-2×52.5×3600)×0.024052=43168L=43.17m 3

[0249] Equivalent to 55℃ hot water, the effective volume of the hot water tank is 28.78m3, and a stainless steel water tank with a nominal volume of 40m3 can be set up.

[0250] (6) Effective volume of sewage tank Vw

[0251] The coefficient of performance COP of the heat pump is 4;

[0252] The temperature difference between sewage inlet and outlet of the sewage tank Δtju=35-5=30℃;

[0253] The sewage density ρj is taken as 1kg / L;

[0254] The specific heat C of water is taken as 4.187 kJ / (kg·℃);

[0255] The hot water temperature tr is 60℃;

[0256] The cold water temperature tl is 10℃;

[0257] The hot water density ρr is taken as 0.983 kg / L;

[0258] Choose a glass fiber reinforced plastic water tank with a nominal volume of 30m3.

[0259] (7) Heat exchanger area Fj in sewage tank

[0260] The coefficient of performance COP of the heat pump is 4;

[0261] The coefficient ε1 that affects the heat transfer effect is taken as 0.8;

[0262] The heat transfer coefficient K of the heat exchanger is 9200kJ / (m2·℃·h);

[0263] The calculated temperature difference Δtj is taken as 5°C;

[0264]

[0265] (8) Heat supplementation measures

[0266] According to the operation data analysis of the wastewater heat recovery units of A02 Apartment, B06 Apartment, A11 Apartment and A15 Apartment for many years, the amount of hot water generated by the units in the cold winter is only 80% of the nameplate parameters, which is equivalent to a lack of heat of 12 tons. In the unfavorable stage of winter, the water supply is 12 tons per day, which is converted into an hourly flow of 0.5 tons.

[0267] One LTFXP-15RD air source heat pump unit (41.2kW each, air temperature >12°C) and six fan coil units (four 12.4kW units and two 8.1kW units) were selected.

[0268] Floor plan

[0269] The public bathroom layout of Apartment A17. Two 52.5kW sewage source heat pump units and one 41.2KW air source heat pump unit (with one 10m3 supplementary heating cold water tank) (two for use and one for backup), one glass fiber reinforced plastic sewage tank with a nominal volume of 30m3 (4000×3000×2500), one stainless steel hot water tank with a nominal volume of 52.5m3 (7000×3000×2500), two supplementary heating hot water supply pumps, and six fan coil units (cassette type) are selected.

[0270] Embodiment 15:

[0271] The waste heat recovery and reuse system for sewage in cold regions described in the above embodiment,

[0272] In winter in severe cold and cold regions, in spring and autumn when the outdoor temperature is extremely low or the heating has not yet started, the indoor temperature is also relatively low, and the temperature of the bathing water will drop a lot. At this time, the system will be underheated, and the temperature in the sewage will drop by 8-10 degrees. The maximum underheating of the entire system will reach 25-30%, making the system unable to operate normally. Therefore, in response to the serious underheating phenomenon, we first set the relative protection temperature to be reduced by 1 degree from 5 degrees, start the fan coil unit heat recovery system, increase the tap water temperature by 2-4 degrees, and recover about 20% of the system underheating. The remaining 10% of the underheating part is evenly distributed in the middle and upper layers of the heat exchanger sewage tank through the newly added hot sewage distribution device and cold sewage uniform recovery device in the system. The high-temperature sewage is evenly distributed in the middle and upper layers of the heat exchanger sewage tank and the refrigerant installed in the middle and upper layers of the heat exchanger for heat exchange. As the temperature of the sewage is reduced, the heat is taken away, and the specific gravity of the sewage increases, which naturally leads to the lowest temperature at the bottom, forming a gradient change in temperature from top to bottom. The heat exchanger is set according to the temperature gradient change so that the refrigerant in the heat exchanger takes away the heat in the sewage layer by layer. As the temperature gradually drops, the upper sewage falls into the bottom layer of the sewage tank and is discharged by the recovery device in the form of overflow, eliminating heat loss.

[0273] According to the actual situation of Apartment A05, the sewage tank can only hold 40 tons, while the normal design should be 50 tons. Due to the large space of the bathing pool, the number of bathers is small, and the lack of heat is large. In winter, the temperature of the sewage entering the bathing sewage tank will drop to 26°C, which cannot be used normally. Considering the supplementary heat of 20%-30% (see the calculation book for supplementary heat), we use natural energy supplementary heat. In the coldest period of winter, when the use of natural energy supplementary heat cannot meet the use requirements, electric heaters are used for supplementary heat.

[0274] While drawing on past experience, this renovation solved the problem of insufficient heating in winter when using sewage source heat pumps as the only heat source, and used natural resources such as solar energy and air as heat sources (as auxiliary heating sources in winter) to further improve energy-saving effects and enhance system stability.

[0275] The sewage source heat pump system uses a titanium alloy heat exchanger, which directly exchanges heat between sewage and refrigerant, saves the refrigerant loop, is corrosion-resistant, has high heat exchange efficiency, and greatly reduces the volume of the heat storage sewage tank. As a heat pump evaporator, the titanium alloy heat exchanger not only reduces the process of converting sewage heat to the evaporation end of the unit through the refrigerant, but also eliminates the power consumption of the circulating motor.

[0276] Direct-heating bathing heat pump heats water to 42℃-60℃ once and places it in an insulated water tank. For a well-insulated water tank, the daily temperature drop is generally less than 2-5℃. Under the premise of accurate calculation and planning, the working time of the machine is arranged according to the water usage every day, and hot water is produced according to the water usage. In this way, the energy consumption lost in insulation is very low. As long as there is water in the water tank, there is hot water, and the water temperature is basically stable, thus satisfying the comfort of bathing water.

[0277] The hot water directly heated by the heat pump unit flows from the heat pump into the water tank to reach the set water temperature. When the water temperature in the insulated water tank reaches the set upper limit, the main unit stops working, and when the water temperature is lower than the set lower limit, the main unit starts, and the cycle works in this way to keep the hot water in the insulated water tank constant for 24 hours, so as to meet the daily demand for hot water during bathing.

[0278] Operation process

[0279] During the operation of the system, according to the different media and the differences in the heat exchange process, it is mainly divided into three operation processes, namely the sewage side process, the refrigerant side process, and the bathing hot water side process. The whole system operates automatically to realize the recovery and reuse of sewage waste heat.

[0280] 1. Sewage side travel

[0281] (1) The temperature of hot water in a bathtub is generally between 38°C and 41°C.

[0282] (2) After showering, the sewage enters the insulated sump through the water channel, and the sewage is pumped into the insulated sewage tank using a sewage lift pump. At this time, the sewage temperature is around 30℃-35℃.

[0283] (3) Through the sewage distribution device, the high-temperature sewage enters the sewage tank in a jet manner and is evenly distributed on the heat exchanger, generating vibrations and enhancing the heat exchange effect. When the sewage is at a high temperature, it exchanges heat with the refrigerant in the upper heat exchanger installed in the sewage tank. As the heat of the sewage is absorbed, the temperature gradually decreases, the specific gravity of the sewage increases, and it falls to the bottom of the sewage tank, generating a temperature gradient. The low-temperature sewage that has absorbed heat sinks to the lower layer, and under the pressure of the new high-temperature sewage, it is discharged in the form of overflow through the recovery device, eliminating the loss of heat.

[0284] (4) When the temperature of the discharged sewage is higher than 10.5℃, the two units start at the same time. When the sewage temperature is lower than 7℃, one unit stops running. When the sewage temperature is lower than 4℃, the system generates a "low temperature alarm", all units stop running, and the system is not working. This starts and stops repeatedly, and the control system runs automatically. (Under normal circumstances, the heat source temperature cannot be lower than 2℃ to avoid freezing the evaporator.)

[0285] 2. Coolant side stroke

[0286] (1) The heat exchanger is immersed in the sewage tank. The refrigerant in the heat exchanger is pumped into the heat exchanger from the outlet of the unit through a circulating water pump. The refrigerant enters the heat exchanger from the bottom and is heated by the sewage with a temperature gradient in the sewage tank in the form of multiple tube layers. The high-temperature refrigerant flows out from the upper layer of the heat exchanger.

[0287] (2) The coolant enters the evaporator of the unit from the outlet of the heat exchanger. The heat in the coolant is absorbed by the refrigerant in the unit through the plate exchanger. The low-temperature coolant returns to the bottom inlet of the heat exchanger, circulates and absorbs heat to ensure the heat transfer process.

[0288] (3) In summer, the low-temperature refrigerant bypasses the plate heat exchanger and exchanges heat with the hot air in the dormitory, absorbing the heat in the air, lowering the temperature in the dormitory and achieving the cooling effect. The refrigerant takes away the heat and directly returns to the unit evaporator, where it releases heat and then circulates again.

[0289] 3. Bathing hot water side stroke

[0290] (1) Under the action of pipe network pressure, tap water with an average temperature of 10.7°C first enters the fan coil unit to recover the heat released by the condensation of bath steam in the bathroom, raising the tap water temperature by 2-4°C.

[0291] (2) The preheated tap water enters the inlet of the unit. The heat source in the sewage in the energy storage sewage tank is brought into the unit by the unit's refrigerant to evaporate. Through the work of the refrigeration compressor, the tap water is cooled and released under the high pressure of the condenser to increase the temperature of the tap water to the set value, producing hot water for bathing.

[0292] Generally, the water temperature setting value does not exceed 60℃ and is not lower than 40℃. When the water temperature exceeds the "over-temperature value", the monitoring system generates a "hot water over-temperature" alarm and the unit shuts down. When the water temperature returns to the "set value", the monitoring system cancels the "hot water over-temperature" alarm and the unit returns to normal working condition.

[0293] In winter, due to the lower temperature of the sewage entering the bathing sewage tank, the system will be underheated. At this time, natural energy units or air source units are used for supplementary heating. The monitoring system starts the supplementary heating unit in advance according to the water shortage of the thermal insulation hot water tank or the set time, and circulates and heats the tap water in the cold water tank. When the water temperature reaches the set temperature, the unit is stopped. At the same time, the liquid level in the thermal insulation hot water tank is detected. If the liquid level is lower than the water replenishment level, the medium-temperature water pump is started to inject the hot water in the cold water tank into the thermal insulation hot water tank. When the liquid level in the thermal insulation hot water tank reaches the upper limit or the liquid level in the cold water tank reaches the lower limit, the medium-temperature water pump is stopped. This cycle basically solves the problem of sewage heat source loss and provides guaranteed hot water for bathing in the bathroom.

[0294] During the peak bathing period, the two sewage source units are started at the same time. When the peak period is over, the number of bathers gradually decreases, the amount of heat that can be recovered also decreases, and the system COP value gradually decreases. At this time, the monitoring system automatically stops the operation of one unit, reducing the system power consumption and improving the heat recovery efficiency until the insulated hot water tank is full or the heat in the sewage tank is completely absorbed. At this time, the unit automatically stops running and the entire system no longer works.

[0295] When the water temperature and water volume in the insulated water tank reaches the set upper limit, the unit stops working. When the water temperature is lower than the set lower limit, the unit starts working in this cycle to keep the hot water in the insulated water tank constant for 24 hours.

[0296] (3) The high-temperature water in the insulated hot water tank is mixed with a certain proportion of tap water through a water mixer to become low-temperature water of about 40°C, and then injected into the insulated mixing water tank. After the insulated mixing water tank is full, the mixing water pump automatically stops running, and the hot water at this time can be directly used for bathing.

[0297] Table 2-1 Technical parameters of power electrical control cabinet

[0298]

[0299] Since the first cold-region sewage waste heat recovery and reuse system was put into use in the A02 Apartment Bathing Center of Harbin Institute of Technology in 2016, the system has been continuously upgraded and optimized, with stable operation and significant energy-saving effects.

[0300]

[0301] Economic Benefit Analysis

[0302] 1.5.1. Comparison of energy consumption between sewage source water heaters and other water heaters

[0303]

[0304] 1.5.2. Performance comparison between sewage waste heat recovery and reuse system and other hot water supply equipment in cold regions:

[0305]

[0306] 1.5.3. Comparison of annual operating costs of commonly used hot water production methods (based on 100 tons of 40℃ bathing hot water per day)

[0307] The electricity, water, gas and labor prices implemented in 2019 are as follows:

[0308]

[0309] Cost calculation of various heating methods (heating temperature difference of tap water at 30℃)

[0310]

[0311] The application of waste heat recovery hot water technology from sewage sources can not only provide hot water for the bath, but also dehumidify the bathing area and reduce the impact of hot and humid gas emissions on the surrounding environment.

[0312] In summer, it can provide a cold source for the bath or the ancillary buildings around the bath, replacing the investment and operation costs of central air-conditioning equipment. According to the above calculation of producing 100 tons of hot water per day and 310 days per year, it can guarantee the cooling needs of a building of about 2,000-2,500 square meters. Not only does it save about 200,000 yuan in central air-conditioning host investment costs, it can also save about 74,000 yuan in air-conditioning operation costs each year.

[0313] 1.5.4. Energy saving and environmental protection effects

[0314] Based on the calculation of 100 tons of hot water per day, the energy consumption of the bathhouse throughout the year is compared as follows:

[0315]

[0316] 1.1. Operational data statistics

[0317] Since the first system was put into use in the A02 Apartment Bathing Center of Harbin Institute of Technology in 2016, the system has been continuously upgraded and optimized, with stable operation and significant energy-saving effects.

[0318]

[0319]

[0320]

[0321] In 2018, two new systems were put into use in the bathing centers of A11 Apartment and A15 Apartment of Harbin Institute of Technology. The operating data statistics in 2019 are as follows:

[0322]

[0323]

[0324] Comparative analysis of the data of energy-saving renovation of bathhouses in Harbin Institute of Technology from 2016 to 2017

[0325]

[0326]

[0327] Comparison and economic analysis of equipment investment in various operating modes for producing hot water for bathing (schools with 10,000 people)

[0328]

[0329]

[0330] Note:

[0331] 1. This analysis only considers the salaries of boiler operators, fuel costs, and electricity costs (excluding lighting) in the process of producing hot water for bathing.

[0332] 2. Since the heat pump has a three-year warranty and the gas furnace has a one-year warranty, the maintenance cost of the heat pump after three years is uncertain and will not be compared for now. The heat pump maintenance cost should be less than the gas furnace maintenance cost.

[0333] 3. From the economic analysis, it can be concluded that the operating cost of using electricity or gas is greater than that of gas, and the operating cost of heat pumps is the lowest.

[0334] 4. Compared with gas furnaces, the sum of the operating expenses saved and the remaining costs of the heat pump unit can be recovered in 3 years if it can reach the design capacity. If calculated according to the actual load, it will take 5 years to recover the cost.

Claims

1. A waste heat recovery and reuse system for sewage in cold regions, characterized by: : Its components include: a waste water waste heat recovery subsystem, the waste water waste heat recovery subsystem includes a heat pump unit, the heat pump unit is connected to the waste water waste heat exchanger in the box body of the sewage tank through a pipeline, the waste water waste heat exchanger is connected to the heat pump unit through a pipeline, the pipeline is filled with a refrigerant, the box body in the sewage tank is connected to the sewage pump through a pipeline, the sewage pump discharges the sewage, the bathtub drain pipe is connected to the hair collector, the hair collector is connected to the sewage inlet pipe through a pipeline, the sewage inlet pipe is connected to the sewage distribution pipe in the box body of the sewage tank, the heat pump unit is connected to the high temperature water pump through a pipeline, the high temperature water pump ... high temperature water pump through a pipeline, the The first insulated water tank is connected to the hot water mixing pump through the pipeline, the hot water mixing pump is connected to the water mixer through the pipeline, the water mixer is connected to the second insulated water tank through the pipeline, and the second insulated water tank is connected to the hot water output pipeline; the tap water inlet pipe is connected to the water mixer through the pipeline; the tap water inlet pipe is connected to the fan coil unit through the first electronic descaling device, the fan coil unit is connected to the second electronic descaling device through the pipeline, the second electronic descaling device is connected to the heat pump unit through the pipeline, and the heat pump unit is connected to the first insulated water tank through the pipeline; the fan coil unit is connected to the first insulated water tank through the pipeline; A group of guide partition plates are installed in the inner box of the sewage tank, and the guide partition plates are arranged in parallel in the longitudinal direction. A group of sewage waste heat exchangers are installed in the inner box of the sewage tank, and the sewage waste heat exchangers are parallel to each other in the transverse direction. The top of the sewage waste heat exchanger is provided with a sewage distribution pipe, and the sewage distribution pipe is connected to the sewage inlet pipe, and the sewage waste heat exchanger is connected to the sewage waste heat connecting pipe, and the lower part of the sewage waste heat connecting pipe is connected to the inlet pipe, and the inlet pipe is connected to the heat pump unit, and the upper part of the sewage waste heat connecting pipe is connected to the outlet pipe, and the outlet pipe is connected to the heat pump unit. A distributed sewage recovery pipe is installed at the bottom of the inner box of the sewage tank, and the distributed sewage recovery pipe is connected to the sewage pump, and the inner box of the sewage tank is installed in the outer box of the sewage tank, and sewage tank insulation material is installed between the inner box of the sewage tank and the outer box of the sewage tank; The sewage waste heat exchanger is assembled from a group of heat exchange tubes installed in parallel, each group of heat exchange tubes is composed of multiple pipes installed in parallel from top to bottom, and multiple groups of heat exchange tubes are installed in parallel to ensure that the heat exchanger is fully distributed in the insulated sewage tank; The low-temperature refrigerant in the sewage waste heat exchanger enters from the bottom inlet of the water inlet pipe at a certain flow rate, and exchanges heat with the sewage with a temperature gradient in the sewage tank in the form of multiple tube layers. The higher the flow rate, the more significant the heat transfer effect. The high-temperature refrigerant flows out from the outlet of the upper water outlet pipe of the sewage waste heat exchanger and enters the evaporator of the unit. The heat in the refrigerant is absorbed by the refrigerant in the unit through conversion, and the low-temperature refrigerant returns to the bottom inlet of the water inlet pipe, circulates and absorbs heat to ensure the progress of the heat transfer process; The sewage waste heat exchanger adopts an immersion structure, which immerses the sewage waste heat exchanger in sewage to facilitate cleaning of dirt; the sewage distribution pipe causes lateral scouring and temperature gradient when the high-temperature sewage enters the sewage tank, ensuring that the high-temperature sewage is evenly and fully exchanged with heat. The low-temperature sewage that absorbs heat sinks to the lower layer and is discharged in the form of overflow through the recovery device, i.e. the distributed sewage recovery pipe, under the action of the new high-temperature sewage pressure, to prevent heat loss; A sewage distribution pipe is arranged above the inner body of the sewage tank, so that the high-temperature sewage enters the sewage tank in a jet manner. The sewage distribution pipe is evenly distributed above the sewage waste heat exchanger to generate vibrations and enhance the heat exchange effect. When the sewage is at high temperature, it exchanges heat with the refrigerant installed in the middle and upper sewage waste heat exchangers in the sewage tank. As the heat of the sewage is absorbed, the temperature gradually decreases, the specific gravity of the sewage increases, and it falls to the bottom of the sewage tank, generating a temperature gradient. The low-temperature sewage that has absorbed heat sinks to the lower layer, and is discharged in the form of overflow through the distributed sewage recovery pipe under the pressure of the new high-temperature sewage, thus eliminating heat loss.

2. The cold region sewage waste heat recovery and reuse system according to claim 1 is characterized by: The diversion partition plates are designed to be staggered in the sewage tank. The diversion partition plates increase the flow speed of sewage, extend the flow time, fully exchange heat, and ensure that the sewage with the lowest temperature is discharged evenly and quickly.

3. The cold region sewage waste heat recovery and reuse system according to claim 1 is characterized by: Distributed sewage recovery pipes are arranged at the bottom of the sewage waste heat exchanger to quickly discharge low-temperature sewage; at the same time, a refrigerant with a certain flow rate enters at the bottom inlet of the sewage waste heat exchanger, flows through the entire sewage waste heat exchanger from bottom to top, and fully exchanges heat with the sewage passing in the opposite direction, so that the refrigerant obtains the maximum amount of heat and the heat recovery efficiency is maximized.

4. The cold region sewage waste heat recovery and reuse system according to claim 1 is characterized by: It also includes a deodorization and sewage discharge subsystem, which is composed of an air duct and a low-noise ventilator, and the air duct is connected to the low-noise ventilator.

5. The cold region sewage waste heat recovery and reuse system according to claim 1 is characterized by: It also includes a heat protection subsystem, which includes a fan coil unit. The fan coil unit is connected to an electric heater through a pipeline, and the electric heater is connected to a first thermal insulation water tank through a pipeline.

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