CN101718480B - Heat pump unit for recycling afterheat of wastewater - Google Patents

Abstract

The invention relates to a waste heat recovery heat pump unit, including a hot water tank, a heat pump, a waste water collection well, a waste water storage tank, a preheating heat exchanger, a hot water circulation pump, a waste water preheating submersible pump, a waste water circulation pump, a solenoid valve, Check valve, filter, water level controller, temperature controller. The two ends of the heat release pipeline of the preheating heat exchanger are connected with the wastewater inlet and outlet pipelines, and then the heat release pipelines of the heat pump water-cooled evaporator are divided into two paths, one is connected to the waste water storage tank, and the other is connected to the sewage well; One end of the heat-absorbing pipeline of the heater is connected to tap water, and the solenoid valve controls the water supply of the water tank according to the water level of the hot water tank. The inlet and outlet pipes of the heat-absorbing pipeline of the condenser are respectively connected with the hot water tank. The invention has a reasonable structure, fully recovers waste heat from waste water, and has high heating efficiency.

Description

Waste heat recovery heat pump unit

technical field

The invention relates to a heat pump unit for recovering waste heat from waste water, which belongs to the field of energy technology, in particular to a heat pump unit for recovering waste heat in bathing places and other industrial and civil waste water.

Background technique

We know that domestic bathing places mainly use coal-fired boilers, oil-fired boilers, gas-fired boilers, electric boilers and solar water heaters to prepare hot water for bathing at present. Coal-fired boilers have the disadvantages of environmental pollution and large footprint; oil-fired boilers are greatly affected by fuel supply and price fluctuations; gas-fired boilers have high safety requirements and gas supply problems; electric boilers use high-grade electric energy to produce Hot water is a waste in terms of energy quality, and the cost of use is high, and the power consumption is too large; although the cost of solar water heaters is low, the initial investment cost is high, the site area is large, and the heating time is greatly affected by the weather. long disadvantage. In addition, bathing places use a large amount of hot water, but the bathing wastewater is directly discharged, a large amount of heat in the wastewater is lost, and energy is wasted seriously; moreover, the discharge of hot water also has an impact on the ecological environment, which is another source of environmental pollution. In order to solve these problems, a heat pump unit can be used to recover waste heat from waste water to produce hot water for bathing.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a waste heat recovery heat pump unit with reasonable structure, which can fully recover the heat of waste water and has high heating efficiency.

The technical scheme of the waste heat recovery heat pump unit of the present invention is: the waste water waste heat recovery heat pump unit includes a hot water tank, a heat pump, a waste water collection well, a waste water storage tank, a preheating heat exchanger, a hot water circulation pump, a waste water preheating submersible pump, Waste water circulation pump, solenoid valve one (9), solenoid valve two (10), solenoid valve three (11), check valve, filter, water level controller, temperature controller. The heat pump is provided with: an air-cooled evaporator, a water-cooled evaporator, and a condenser. A compressor is arranged on a refrigerant flow line between the air-cooled evaporator and the condenser, and a compressor is installed between the water-cooled evaporator and the condenser. The other refrigerant circulation pipeline is provided with a throttling valve, and the two ends of the refrigerant circulation pipeline between the air-cooled evaporator and the water-cooled evaporator are connected; connected to the outlet pipe of the wastewater preheating submersible pump, and the other end is connected to the outlet pipe of the wastewater circulation pump of the wastewater storage tank together with one end of the heat release pipeline of the heat pump water-cooled evaporator, and then divided into two routes, one is controlled by solenoid valve 2 (10) and connected to In the waste water storage tank, another route is controlled by electromagnetic valve three (11) and connected to the sewage well; one end of the heat-absorbing pipeline of the preheating heat exchanger is connected with tap water, and the water tank is controlled by electromagnetic valve one (9) according to the water level of the hot water tank. The other end of the heat-absorbing pipeline of the preheating heat exchanger is connected with the inlet of the hot water circulation pump together with the circulating water pipeline at the lower part of the hot water tank. A check valve is installed on the circulating water pipeline at the lower part of the hot water tank. The heat-absorbing pipeline of the condenser is connected to the water inlet pipe, and the heat-absorbing pipeline outlet pipe of the condenser is connected to the upper part of the hot water tank; the water outlet pipe at the bottom of the hot water tank is connected to the bathing place, and a floor drain is installed on the floor of the bathing place, and the floor drain is connected to the waste water collection well through the drainage pipe A filter is arranged on the drainage pipe, the overflow pipe at the upper end of the waste water collecting well is connected with the sewage well, and the overflow pipe at the upper end of the waste water storage tank is connected with the sewage well.

The hot water tank of the waste heat recovery heat pump unit is equipped with a temperature controller to control the start and stop of the heat pump, and a water level controller to control the replenishment of tap water and the start and stop of the hot water circulation pump.

A water level controller is installed in the waste water storage tank of the waste heat recovery heat pump unit to control the start and stop of the waste water circulating pump and the start and stop of the air-cooled evaporator.

A water level controller is installed in the waste water collection well of the waste heat recovery heat pump unit to control the start and stop of the waste water preheating submersible pump.

The heat pump water-cooled evaporator heat release pipeline of the waste water waste heat recovery heat pump unit is divided into two lines, one is connected to the waste water storage tank by the control of solenoid valve two (10), and the other is connected to the waste water storage tank by control of solenoid valve three (11). In the sewage well; a temperature controller is arranged on the waste water drainage pipeline to control the switches of the solenoid valve two (10) and the solenoid valve three (11) according to the set temperature.

The working principle of the waste water waste heat recovery heat pump unit of the present invention is: when starting to operate, when the water level of the bathing wastewater in the waste water storage tank is lower than the low water level, the waste water circulating pump is turned off, and the air-cooled evaporator is started at the same time, and the bathing waste water in the waste water storage tank reaches When the water level is high, turn on the wastewater circulation pump and turn off the air-cooled evaporator at the same time. The waste water (about 35°C) in the waste water collection well reaches the set water level, starts the submersible pump and sends it to the preheating heat exchanger, preheats the tap water (about 15°C), and the preheated cold water (about 20°C) enters the condenser of the heat pump , heated by the heat pump unit into the hot water tank, the heating inlet and outlet pipes of the condenser of the heat pump are connected to the hot water tank, and the hot water circulation pump is turned on to circulate and heat the hot water in the hot water tank to the set temperature (45-55°C) . The bathing wastewater fed into the preheating heat exchanger then enters the water-cooled evaporator of the heat pump (about 30°C), and then returns to the wastewater storage tank (about 25°C). The water-cooled evaporator of the heat pump turns off the electromagnetic valve two (10) on the return pipe until the waste water temperature drops to the set temperature (minimum 5° C.), and simultaneously opens the electromagnetic valve three (11) on the drain pipe to discharge into the sewage well.

The technical features of the present invention include:

1. Before the tap water enters the heat pump, it conducts a heat exchange with the waste water to improve the efficiency of the unit. 1m3 15℃ tap water is preheated to 20℃ through the preheating heat exchanger. The required heating capacity is 5.8KW, the power of the wastewater preheating submersible pump is 200W, and the power consumption is 0.2 degrees per hour; if electric heating is used, the power consumption is 1 hour 5.8 degrees; compared with electric heating, the energy efficiency ratio of this measure is 29 times.

2. In the case of no waste water supply, the air-cooled evaporator can be started first to use the air source heat pump for heating, and when there is waste water supply, then switch to start the water-cooled evaporator to use the waste water source heat pump for heating. This measure ensures that the waste heat recovery heat pump unit of waste water can always operate normally without adding other forms of heat sources to supplement.

3. The conversion of air source and waste water source heat pumps can also set the temperature T2 of waste water at the outlet of the heat pump water-cooled evaporator according to the outdoor air temperature, giving full play to the high-efficiency operation of the air source and waste water source heat pumps. Taking tap water heated at 15°C to 50°C as an example, when the outdoor temperature is 25°C, the thermal efficiency of the air source is 8.43; when the outdoor temperature is -5°C, the thermal efficiency of the air source is 2.91; 10.61 (theoretical); when the wastewater temperature is above 5°C; the average thermal efficiency of the wastewater source heat pump is 4.91.

These measures have improved the efficiency and performance of the waste heat recovery heat pump unit for waste water, and the energy saving effect is remarkable.

Description of drawings

Fig. 1 is the structural representation of heat pump unit of the present invention

Fig. 2 is the position diagram of the water level line of the temperature control sensor and the water level controller of the hot water tank of the present invention

Fig. 3 is the position diagram of the water level line of the water level controller of the waste water storage tank of the present invention

Fig. 4 is the water level line position diagram of the water level controller of the waste water collection well of the present invention

In the figure: 1. Hot water tank, 2. Heat pump, 3. Wastewater collection well, 4. Wastewater storage tank, 5. Preheating heat exchanger, 6. Hot water circulation pump, 7. Wastewater preheating submersible pump, 8. Waste water circulation pump, 9, solenoid valve one (9), 10, solenoid valve two (10), 11, solenoid valve three (11), 12, check valve, 13, filter, 14, air-cooled evaporator, 15 , water-cooled evaporator, 16, condenser, 17, compressor, 18, throttle valve, 19, bathing place, 20, tap water, 21, sewer, 22, water level controller, 23, water level controller, 24, water level control Device, 25, hot water tank temperature control sensor, 26, waste water drainage temperature control sensor, 27, sewage well.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the technical scheme of the present invention is described further:

As shown in Figure 1, the waste heat recovery heat pump unit of the invention consists of a hot water tank 1, a heat pump 2, a waste water collection well 3, a waste water storage tank 4, a preheating heat exchanger 5, a hot water circulation pump 6, and a waste water preheating submersible pump 7. Waste water circulating pump 8, solenoid valve one (9) 9, solenoid valve two (10) 10, solenoid valve three (11) 11, check valve 12, filter 13, etc.

The heat pump contains: an air-cooled evaporator 14, a water-cooled evaporator 15, and a condenser 16. A compressor 17 is arranged on a refrigerant flow line between the air-cooled evaporator 14 and the condenser 16, and a compressor 17 is installed between the water-cooled evaporator 15 and the condenser A throttling valve 18 is provided on the other refrigerant circulation pipeline between the evaporators 16, and the two ends of the refrigerant circulation pipeline between the air-cooled evaporator 14 and the water-cooled evaporator 15 are connected. Also have bathing place 19, tap water 20, sewer 21, water level controller 22, water level controller 23, water level controller 24, hot water tank temperature control sensor 25, waste water drainage temperature control sensor 26, sewage well 27 among the figure.

The waste water from the waste water collecting well 3 is input to the preheating heat exchanger 5 through the waste water preheating submersible pump 7, and then enters the water-cooled evaporator 14 of the heat pump unit; The waste water is input into the water-cooled evaporator 15 of the heat pump unit together, and the outlet is divided into two routes, one is controlled by the solenoid valve 2 (10) 10 and returned to the waste water storage tank 4, and the other is controlled by the solenoid valve 3 (11) 11 and discharged into the sewage well 27 .

The outlet of tap water 20 is divided into two paths, one path of tap water is controlled by electromagnetic valve 1 (9) 9 according to the water level of the hot water tank and enters the preheating heat exchanger 5 for preheating, then enters the heat pump unit condenser 16 for heat exchange, and then enters the hot water tank 1 Inside; another way of cold water for bathing places 19.

The water inlet pipe of the hot water tank 1 is connected to the water outlet of the condenser 16 of the heat pump unit, and the hot water generated enters the hot water tank 1; Together, they enter the heat pump unit condenser 16 through the hot water circulation pump 6 for heat exchange, and then enter the hot water tank 1;

The automatic control system adopts the hot water temperature T1 in the hot water tank, the waste water discharge temperature T2 control and the water level control in the hot water tank, waste water storage tank and waste water collection well. The water level control line is shown in Figure 2. Wherein the hot water tank water level controller 22 includes four control lines V1, V2, V3 and V4, the waste water storage tank water level controller 23 includes two control lines V5 and V6, and the waste water collection well water level controller 24 includes two control lines V7 and V8.

Working process of the present invention is:

1. In the absence of wastewater supply:

When starting to run, there is no waste water in the waste water storage tank. At this time, valve solenoid valve one (9) 9, solenoid valve two (10) 10 are opened, solenoid valve three (11) 11 is closed; heat pump is closed; waste water preheats submersible pump, waste water The circulation pump and hot water circulation pump are turned off; when the water level in the hot water tank reaches V3, the hot water circulation pump is turned on; when T1 is lower than the set temperature by 5°C (40-50°C), the heat pump compressor and the air-cooled evaporator fan When it is turned on, when T1 reaches the set temperature (45~55°C), the heat pump compressor and the air-cooled evaporator fan are turned off. When the water level reaches V1, the solenoid valve one (9) 9 is closed.

2. Where there is a waste water supply:

After using for a period of time, the water level in the wastewater collection well is higher than V7, turn on the wastewater preheating submersible pump, the wastewater enters the preheating heat exchanger, then enters the heat pump water-cooled evaporator and returns to the wastewater storage tank, when the water level in the wastewater storage tank reaches V5 , Turn on the wastewater circulation pump and turn off the air-cooled evaporator fan at the same time. When the temperature T2 of the waste water at the water outlet of the heat pump water-cooled evaporator drops to the set temperature (minimum 5°C), the solenoid valve two (10) 10 is turned off, and the solenoid valve three (11) 11 is opened simultaneously, and the waste water is discharged into the sewage well. When the water level in the wastewater collection well is lower than V8, turn off the wastewater preheating submersible pump.

If the output of waste water exceeds the water consumption of the heat pump water-cooled evaporator during use, the water level in the waste water storage tank will rise. When the water level reaches the overflow pipe of the waste water storage tank, the waste water will overflow into the sewage well through the overflow pipe.

If the output of wastewater is less than the water consumption of the heat pump water-cooled evaporator, the water level will drop and reach V6 to turn off the wastewater circulation pump and turn on the fan of the air-cooled evaporator.

During use, the water supply of tap water should meet the requirements of water consumption for bathing. When the water supply of tap water cannot meet the requirements of water consumption for bathing, a cold water storage tank should be equipped. When the water consumption for bathing is relatively small, the water level in the hot water tank will gradually rise. When the water level reaches V1, the solenoid valve one (9) 9 will be closed; after that, the water level in the hot water tank will drop. When the water level drops to V2, the solenoid valve will One (9) 9 is turned on, and the tap water continues to replenish water.

The wastewater temperature T2 at the water outlet of the heat pump water-cooled evaporator should be set according to the outdoor air temperature. When the outdoor temperature is greater than 25°C, the wastewater temperature T2 is set to 20°C; Below 15°C, the wastewater temperature T2 is set at 5°C.

In order to prevent frequent switching of working states, a certain amount of buffer area needs to be set between V1 and V2, between V3 and V4, between V5 and V6, and between V7 and V8. The size of the area depends on fluctuations in bath water consumption.

Apparently, the waste heat recovery heat pump unit for waste water can also be used for recovery of waste heat from similar waste water in other industries and civil uses.

Claims (5)

1. Waste heat recovery heat pump unit, characterized in that it includes a hot water tank, a heat pump, a waste water collection well, a waste water storage tank, a preheating heat exchanger, a hot water circulation pump, a waste water preheating submersible pump, a waste water circulation pump, and a solenoid valve (9), solenoid valve two (10), solenoid valve three (11), check valve, filter, water level controller, temperature controller; the heat pump is provided with: air-cooled evaporator, water-cooled evaporator, condenser , there is a compressor on a refrigerant flow line between the air-cooled evaporator and the condenser, and a throttle valve is set on the other refrigerant flow line between the water-cooled evaporator and the condenser, and the air-cooled evaporator The two ends of the refrigerant circulation pipeline between the water-cooled evaporator are connected; one end of the heat release pipeline of the preheating heat exchanger is connected with the waste water preheating submersible pump outlet pipe of the waste water collection well, and the other end is connected with the waste water storage tank. The outlet pipe of the wastewater circulation pump is connected to one end of the heat release pipeline of the heat pump water-cooled evaporator, and then divided into two routes, one is connected to the waste water storage tank by the control of solenoid valve 2 (10), and the other is connected to the waste water storage tank by the control of solenoid valve 3 (11). In the sewage well; one end of the heat-absorbing pipeline of the preheating heat exchanger is connected to tap water, and the solenoid valve 1 (9) controls the water supply of the water tank according to the water level of the hot water tank, and the other end of the heat-absorbing pipeline of the preheating heat exchanger is connected to the hot water The circulating water pipeline at the lower part of the tank is connected with the inlet of the hot water circulating pump. A check valve is installed on the circulating water pipeline at the lower part of the hot water tank. The water outlet pipe is connected to the upper part of the hot water tank; the water outlet pipe at the bottom of the hot water tank is connected to the bathing area, and a floor drain is provided on the floor of the bathing area, and the floor drain is connected to the waste water collection well through the drainage pipe. The sewage well is connected, and the overflow pipe at the upper end of the waste water storage tank is connected with the sewage well. 2. The waste heat recovery heat pump unit according to claim 1, characterized in that a temperature controller is installed in the hot water tank to control the start and stop of the heat pump, and a water level controller is also provided to control the replenishment of tap water and the start and stop of the hot water circulation pump . 3. The waste heat recovery heat pump unit according to claim 1, characterized in that a water level controller is installed in the waste water storage tank to control the start and stop of the waste water circulating pump and the start and stop of the air-cooled evaporator. 4. The waste heat recovery heat pump unit according to claim 1, characterized in that a water level controller is installed in the waste water collection well to control the start and stop of the waste water preheating submersible pump. 5. The waste heat recovery heat pump unit according to claim 1, characterized in that a temperature controller is installed on the waste water drainage pipeline to control the switches of solenoid valve two (10) and solenoid valve three (11) according to the set temperature.

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