CN107014076B - A triple-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments - Google Patents

Abstract

The invention provides a triple-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments. The present invention solves the problem of evaporation temperature and the Excessive suction pressure will easily cause excessive motor load and burn the outstanding problem of the motor. It also solves the problem of low evaporation temperature, severe frost on the surface of the evaporator, excessive compression ratio of the compressor, and exhaust temperature in winter low-temperature heating mode. The outstanding problems of overheating, heating capacity and sharp decline in energy efficiency ratio have broadened the application field of air-cooled heat pump water heaters.

Description

A triple-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments

technical field

The invention relates to the technical field of air-conditioning heat pumps, in particular to a triple-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments.

Background technique

Facing the increasingly prominent problems of energy shortage and environmental pollution, coal-fired boilers have been gradually replaced. The development of energy-efficient, comfortable, safe and reliable heat pump water heaters has become the key to the sustainable and rapid development of the heat pump industry. The conventional air source heat pump water heater uses air as the cold and heat source. It has a simple structure, is easy to install and use, and can make full use of the energy in the air. It is an efficient and energy-saving water heater. However, when the outdoor temperature is too high in summer, the evaporation temperature of the air source heat pump device is high, and the suction pressure and exhaust temperature will also be too high, which will easily cause excessive load on the motor, resulting in a protective shutdown of the compressor, or even burning the motor; Also when the outdoor temperature is too low in winter, the evaporation temperature of the air source heat pump device is too low, the surface of the evaporator is severely frosted, the compression ratio of the compressor is too large, and the exhaust temperature is too high, its heating capacity and energy efficiency ratio drop sharply, even The device may not operate properly. In short, when the outdoor temperature is too high or too low, the above-mentioned outstanding problems of conventional air source heat pump water heaters have seriously affected the promotion and application of air source heat pump water heaters.

For the shortcomings of conventional air source heat pump water heaters, there are currently three common solutions: one uses the traditional auxiliary electric heater method, but the efficiency is low and the operating cost is high, which has almost been eliminated. The other two schemes adopt the two-stage compression heating cycle method and the cascade heating cycle method respectively, which to a certain extent solve the problem of excessive compressor compression ratio and exhaust temperature when the air source heat pump is heated under high temperature or low temperature conditions. The problem of too high, too high or too low suction pressure improves the heating capacity of the unit and the energy efficiency ratio, but there are also the following problems in the two schemes: first, the two-stage compression cycle and the cascade cycle vary with the user load The range of energy adjustment is small when changing, and when the load decreases, the reduction in energy consumption in the process of system energy adjustment is small, and the energy efficiency ratio of the system drops significantly; the second is that the cascade cycle system uses two sets of refrigeration cycles and two refrigerants , the structure is complex and bulky; finally, when severe frost occurs on the surface of the evaporator of the two-stage compression cycle and the cascade cycle, how to defrost efficiently has become an urgent problem to be solved.

Contents of the invention

The present invention provides a three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments to solve the problem of excessive compression ratio of the compressor and excessive discharge temperature of the existing air source heat pump water heater when heating in high temperature and low temperature conditions. High, too high or too low suction pressure, system heating capacity and sharp drop in energy efficiency ratio and other prominent technical problems.

In order to solve the problems of the technologies described above, the present invention is achieved through the following technical measures:

A three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments, the water heater includes a main circuit compressor, a main circuit oil separator, a main circuit check valve, a water-cooled condenser, a recooler, a dry filter, Sight glass, first expansion valve, medium pressure gas-liquid separator, second expansion valve, air-cooled evaporator, outdoor fan, low-pressure gas-liquid separator, evaporation pressure regulator, auxiliary compressor, auxiliary oil separator, auxiliary circuit Directional valve, circulating water pump and connecting pipeline; the exhaust port of the main road compressor is connected with the main road oil separator, and the main road oil separator is connected with the main road check valve, and the main road check valve is separated through the connecting pipe. It is connected with the inlet of the water-cooled condenser and the outlet of the auxiliary check valve; the outlet of the water-cooled condenser is connected with the inlet of the main circuit of the subcooler, and the outlet of the main circuit of the subcooler is connected with the outlet of the medium-pressure gas-liquid separator. The inlet is connected, and the pipeline between the two is provided with a dry filter, an observation mirror, and the first expansion valve in sequence; The inlet of the second expansion valve is connected; the outlet of the second expansion valve is connected with the air-cooled evaporator, and the air-cooled evaporator is connected with the low-pressure gas-liquid separator and then connected with the suction port of the main road compressor; The outlet of the auxiliary circuit of the cooler is connected to the suction port of the auxiliary circuit compressor through the evaporation pressure regulator; the exhaust port of the auxiliary circuit compressor is connected to the auxiliary circuit check valve after passing through the auxiliary circuit oil separator, and the outlet of the auxiliary circuit check valve It is connected with the inlet of the water-cooled condenser through a pipeline and then connected with the outlet of the main road check valve.

The main compressor and auxiliary compressor are any one of fixed frequency scroll compressor, fixed frequency scroll compressor, variable frequency scroll compressor, and variable frequency scroll compressor.

The water-cooled condenser is any structural form among shell-and-tube condensers, sleeve-tube condensers, and plate condensers.

The air-cooled evaporator is any one of a finned tube heat exchanger, a stacked heat exchanger, and a parallel flow heat exchanger.

The outdoor fan is any one of variable frequency fan, fixed frequency fan and adjustable fan.

The first expansion valve and the second expansion valve are in the form of any throttling mechanism among manual expansion valves, choke expansion valves, float expansion valves, thermal expansion valves, and electronic expansion valves.

The evaporating pressure regulator is any one of a proportional regulator, a proportional-integral regulator, a proportional-derivative regulator, and a proportional-integral-derivative regulator controlled by the pre-valve pressure (ie, the evaporating pressure).

The subcooler is any structural form of a plate heat exchanger, a casing heat exchanger, and a flasher.

The beneficial effects of the present invention are as follows:

The present invention provides a three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments, which has a novel concept and ingenious optimization of unit design, and has the following main advantages:

(1) Through the first-stage throttling of the first expansion valve and the second-stage throttling of the second expansion valve, the air-cooled heat pump water heater significantly reduces the throttling loss of the system and improves the heating coefficient of the system.

(2) Through the auxiliary adjustment of the sub-cooler and the medium-pressure gas-liquid separator, the air-cooled heat pump water heater increases the subcooling degree before the throttling of the first expansion valve and the second expansion valve, and reduces the suction overpass of the main circuit compressor. Heat, that is, to solve the prominent problem of high evaporation temperature, high suction pressure and exhaust temperature during high temperature heating in summer, which may easily cause excessive motor load and burn the motor, and solve the problem of evaporation in winter low temperature heating mode The outstanding problems of low temperature, severe frost on the surface of the evaporator, excessive compression ratio of the compressor, high exhaust temperature, and a sharp drop in heating capacity and energy efficiency ratio have broadened the application field of air-cooled heat pump water heaters.

(3) Through the auxiliary adjustment of the auxiliary circuit compressor and the evaporation pressure regulator, the heating capacity of the air-cooled heat pump water heater can change rapidly with the change of user load, and the energy adjustment range is wide, which improves the year-round operation of the air-cooled heat pump water heater. reliability, stability and economy.

A triple-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments of the present invention can be widely used in civil buildings, public buildings, villa buildings and other places where air source heat pumps can be used to provide hot water.

Description of drawings

Fig. 1 is the structure schematic diagram of the present invention.

Figure 2 is a flow chart of the three-pressure working mode.

Fig. 3 is a flow chart of single-stage compression working mode.

In the figure: the serial numbers and names of the components are as follows:

1-main road compressor; 2-main road oil separator; 3-main road check valve; 4-water-cooled condenser; 5-subcooler; 6-dry filter; 7-observation mirror; One expansion valve; 9-medium pressure gas-liquid separator; 10-second expansion valve; 11-air-cooled evaporator; 12-outdoor fan; 13-low pressure gas-liquid separator; 14-evaporating pressure regulator; 15-auxiliary road Compressor; 16-auxiliary oil separator; 17-auxiliary check valve; 18-circulating water pump.

Detailed ways

The present invention will be further described below in conjunction with the embodiments (accompanying drawings), but the present invention is not limited.

Example 1

As shown in Figure 1, the present invention provides a three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments. The water heater includes a main circuit compressor 1, a main circuit oil separator 2, a main circuit check valve 3, a water cooling Type condenser 4, recooler 5, dry filter 6, observation mirror 7, first expansion valve 8, medium pressure gas-liquid separator 9, second expansion valve 10, air-cooled evaporator 11, outdoor fan 12, low pressure Gas-liquid separator 13, evaporation pressure regulator 14, auxiliary circuit compressor 15, auxiliary circuit oil separator 16, auxiliary circuit check valve 17, circulating water pump 18 and connecting pipelines. The specific connection relationship is as follows: the exhaust port of the main road compressor 1 passes through the main road oil separator 2 and the main road check valve 3 respectively to the inlet of the water-cooled condenser 4 and the outlet of the auxiliary road check valve 17. connected; the outlet of the water-cooled condenser 4 is connected to the main road inlet of the subcooler 5; the main road outlet of the subcooler 5 passes through the dry filter 6, the observation mirror 7, the first expansion valve 8 and the The inlet of the medium-pressure gas-liquid separator 9 is connected; the two outlets of the medium-pressure gas-liquid separator 9 are respectively connected with the auxiliary road inlet of the recooler 5 and the inlet of the second expansion valve 10; the second expansion valve 10 The outlet of the subcooler 5 is connected to the suction port of the main compressor 1 through the air-cooled evaporator 11 and the low-pressure gas-liquid separator 13 in turn; The suction port of the auxiliary road compressor 15 is connected to the inlet of the water-cooled condenser 4 and the outlet of the main road check valve 3 through the auxiliary road oil separator 16 and the auxiliary road check valve 17 in turn. .

The main circuit compressor 1 and the auxiliary circuit compressor 15 described in the present invention are fixed-frequency scroll compressors. The water-cooled condenser 4 is a shell-and-tube condenser. The air-cooled evaporator 11 is a finned tube heat exchanger. The outdoor fan 12 is a variable frequency fan. The first expansion valve 8 and the second expansion valve 10 are manual expansion valves and choke expansion valves. The evaporating pressure regulator 14 is a proportional regulator controlled by the pre-valve pressure (ie evaporating pressure). The subcooler 5 is a plate heat exchanger.

Example 2

The main circuit compressor 1 and the auxiliary circuit compressor 15 described in the present invention are fixed-frequency rolling rotor compressors. The water-cooled condenser 4 is a sleeve condenser. The air-cooled evaporator 11 is a laminated heat exchanger. The outdoor fan 12 is a fixed frequency fan. The first expansion valve 8 and the second expansion valve 10 are choke expansion valves. The evaporating pressure regulator 14 is a proportional-integral regulator. The subcooler 5 is a casing heat exchanger. Other structures are the same as in Embodiment 1.

Example 3

The main circuit compressor 1 and the auxiliary circuit compressor 15 described in the present invention are variable frequency scroll compressors. The water-cooled condenser 4 is a plate condenser. The air-cooled evaporator 11 is a parallel flow heat exchanger. The outdoor fan 12 is an adjustable fan. The first expansion valve 8 and the second expansion valve 10 are float type expansion valves. The evaporating pressure regulator 14 is a proportional differential regulator. The recooler 5 is a flasher. Other structures are the same as in Embodiment 1.

Example 4

The main circuit compressor 1 and the auxiliary circuit compressor 15 are frequency conversion rolling rotor compressors. The water-cooled condenser 4 is a plate condenser. The air-cooled evaporator 11 is a fin parallel flow heat exchanger. The outdoor fan 12 is an adjustable fan. The first expansion valve 8 and the second expansion valve 10 are thermal expansion valves. The evaporating pressure regulator 14 is a proportional-integral-derivative regulator. The recooler 5 is a flasher. Other structures are the same as in Embodiment 1.

Example 5

The main circuit compressor 1 and the auxiliary circuit compressor 15 are frequency conversion rolling rotor compressors. The water-cooled condenser 4 is a shell-and-tube condenser. The air-cooled evaporator 11 is a parallel flow heat exchanger. The outdoor fan 12 is an adjustable fan. The first expansion valve 8 and the second expansion valve 10 are electronic expansion valves. The evaporating pressure regulator 14 is a proportional-integral-derivative regulator. The recooler 5 is a flasher. Other structures are the same as in Embodiment 1.

The working principle of the present invention is: through the ingenious matching and combination of two expansion valves, a recooler and a medium-pressure gas-liquid separator, and the auxiliary optimization adjustment of the auxiliary circuit compressor and the evaporation pressure regulator, the air-cooled heat pump water heater can realize Two working modes:

(1) Three-pressure working mode

Figure 2 is a flow chart of the three-pressure working mode. This working mode can be used when the outdoor air temperature is between 46°C~55°C or -20°C~-6°C. At this time, the main road compressor 1, the outdoor fan 12, the auxiliary road compressor 15, and the circulating water pump 18 start. The working process of the system: the high-temperature and high-pressure gaseous refrigerant discharged from the main road compressor 1 passes through the main road oil separator 2 and the main road check valve 3 in sequence, mixes with the high-temperature and high-pressure gaseous refrigerant passing through the auxiliary road check valve 17, and then enters the water cooling system. Type condenser 4, which releases heat to heat the cold water introduced by the circulating water pump 18, condenses it into supercooled or saturated liquid refrigerant, and releases heat on the main road side of the subcooler 5 to heat the medium-pressure and medium-temperature refrigerant on the auxiliary road side of the subcooler 5 Saturated gaseous refrigerant, further subcooled into a liquid refrigerant with a relatively high subcooling degree, and then enters the first expansion valve 8 through the dry filter 6 and the observation mirror 7 in sequence, and becomes It is a medium-temperature and medium-pressure gas-liquid two-phase refrigerant, which enters the medium-pressure gas-liquid separator 9 for gas-liquid separation and is divided into two circuits, one of which is the separated medium-pressure and medium-temperature saturated liquid refrigerant, which passes through the medium-pressure gas-liquid separator 9 is discharged from the lower part, and then becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant after throttling adjustment by the second expansion valve 10, enters the air-cooled evaporator 11, absorbs the heat of the air source introduced by the outdoor fan 12, and evaporates into The low-pressure superheated refrigerant vapor is then separated from the gas-liquid by the low-pressure gas-liquid separator 13 and enters the suction port of the main compressor 1. After being compressed by the main compressor 1, the high-temperature and high-pressure gaseous refrigerant is discharged and begins to enter next cycle. The other path is the separated medium-pressure and medium-temperature saturated gaseous refrigerant, which is discharged from the upper part of the medium-pressure gas-liquid separator 9 and enters the auxiliary path side of the subcooler 5 to absorb the supercooled or saturated liquid refrigerant passing through the main path side of the subcooler 5 The heat turns into superheated gaseous refrigerant, and then enters the suction port of the auxiliary circuit compressor 15 through the evaporating pressure regulator 14 to throttle and adjust the pressure, and is compressed by the auxiliary circuit compressor 15 to discharge the high-temperature and high-pressure gaseous refrigerant, and then sequentially passes through the auxiliary circuit oil separator 16. The auxiliary circuit check valve 17 mixes with the high-temperature and high-pressure gaseous refrigerant passing through the main circuit check valve 3, enters the water-cooled condenser 4, and enters the next cycle. The cold water enters the water-cooled condenser 4 through the circulating water pump 18, absorbs the heat released by the condensation of the high-temperature and high-pressure gaseous refrigerant, and raises the temperature, and then delivers it to the hot water user.

(2) Single-stage compression working mode

Figure 3 is a flow chart of the single-stage compression working mode, which can be used when the outdoor air temperature is between -5°C and 45°C. At this time, the main road compressor 1, the outdoor fan 12 and the circulating water pump 18 are started, and the auxiliary road compressor 15 is turned off. The working process of the system: the high-temperature and high-pressure gaseous refrigerant discharged from the main circuit compressor 1 enters the water-cooled condenser 4 through the main circuit oil separator 2 and the main circuit check valve 3 in turn, and releases heat to heat the cold water introduced by the circulating water pump 18. It is condensed into subcooled or saturated liquid refrigerant, and then enters the first expansion valve 8 through the recooler 5, dry filter 6, and observation mirror 7 in sequence, and becomes medium-temperature and medium-pressure after the throttling adjustment of the first expansion valve 8. The gas-liquid two-phase refrigerant enters the medium-pressure gas-liquid separator 9 for gas-liquid separation, and the liquid refrigerant at the lower part of the medium-pressure gas-liquid separator 9 becomes a low-temperature and low-pressure gas-liquid two-phase after throttling adjustment by the second expansion valve 10. phase refrigerant, enters the air-cooled evaporator 11, absorbs the heat of the air source introduced by the outdoor fan 12, evaporates into low-pressure superheated refrigerant vapor, and then enters the main circuit compressor after gas-liquid separation by the low-pressure gas-liquid separator 13 1, after being compressed by the main compressor 1, the high-temperature and high-pressure gaseous refrigerant is discharged, and the next cycle begins. The cold water enters the water-cooled condenser 4 through the circulating water pump 18, absorbs the heat released by the condensation of the high-temperature and high-pressure gaseous refrigerant, and raises the temperature, and then delivers it to the hot water user.

Claims (6)

1. A three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments, characterized in that: the water heater includes a main circuit compressor (1), a main circuit oil separator (2), and a water-cooled condenser (4) , recooler (5), medium-pressure gas-liquid separator (9), air-cooled evaporator (11), low-pressure gas-liquid separator (13), evaporating pressure regulator (14), auxiliary circuit compressor (15), Auxiliary road oil separator (16), circulating water pump (18) and connecting pipes; the exhaust port of the main road compressor (1) is connected with the main road oil separator (2), and the main road oil separator (2) is respectively It is connected with the auxiliary oil separator (16) and the water-cooled condenser (4); the outlet of the water-cooled condenser (4) is connected with the main inlet of the subcooler (5), and the outlet of the subcooler (5) The outlet of the main path is connected to the inlet of the medium-pressure gas-liquid separator (9); the two outlets of the medium-pressure gas-liquid separator (9) are respectively connected to the inlet of the auxiliary path of the subcooler (5) and the second expansion valve (10). The inlet of the second expansion valve (10) is connected to the air-cooled evaporator (11), and the air-cooled evaporator (11) is connected to the low-pressure gas-liquid separator (13) and then connected to the main circuit The suction port of the compressor (1) is connected; the outlet of the auxiliary circuit of the subcooler (5) is connected with the suction port of the auxiliary circuit compressor (15) through the evaporation pressure regulator (14); the auxiliary circuit compressor The exhaust port of (15) is connected to the auxiliary oil separator (16), and the inlet of the auxiliary oil separator (16) and the water-cooled condenser (4) are merged through the pipeline and then connected to the outlet of the main road check valve (3). It also includes main road check valve (3), dry filter (6), observation mirror (7), first expansion valve (8), second expansion valve (10), auxiliary road check valve (17) And the outdoor fan (12), the auxiliary circuit check valve (17) is set between the auxiliary circuit oil separator (16) and the water-cooled condenser (4), the main circuit oil separator (2) and the water-cooled condenser (4) There is a main road check valve (3) between them; a dry filter (6), an observation mirror (7) and a second an expansion valve (8). 2. The three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments according to claim 1, characterized in that: the main circuit compressor (1) and auxiliary circuit compressor (15) are fixed-frequency scroll type Any form of compressor, fixed frequency rolling rotor compressor, variable frequency scroll compressor, variable frequency rolling rotor compressor. 3. The three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments according to claim 1, characterized in that: the water-cooled condenser (4) is a shell-and-tube condenser, a casing condenser, Any structural form in the plate condenser. 4. The three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments according to claim 1, characterized in that: the air-cooled evaporator (11) is a finned tube heat exchanger, a stacked heat exchanger Any structural form of heat exchanger and parallel flow heat exchanger. 5. The three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments according to claim 1, characterized in that: the outdoor fan (12) is any one of a variable frequency fan, a fixed frequency fan, and a variable frequency fan One form; the subcooler (5) is any structural form of a plate heat exchanger, a casing heat exchanger, and a flasher. 6. The three-pressure high-efficiency air-cooled heat pump water heater suitable for high and low temperature environments according to claim 1, characterized in that: the first expansion valve (8) and the second expansion valve (10) are manual expansion valves, Any form of throttling mechanism among choke expansion valves, float expansion valves, thermal expansion valves, and electronic expansion valves; the evaporating pressure regulator (14) is a proportional regulator controlled by the pre-valve pressure Any regulator form among controller, proportional-integral regulator, proportional-derivative regulator, proportional-integral-derivative regulator.

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