WO2007115494A1 - A heat pump air condition system, and the steam jet system and the control method thereof - Google Patents

Abstract

A heat pump air condition system, and the steam jet system and the control method thereof. The heat pump air conditioner comprises a four-way valve (13), an indoor heat exchanger (19), an indoor throttle (20), an outdoor throttle (15) and an outdoor heat exchanger (14), which are connected in series by tubes. The heat pump air condition system also comprises a compressor steam jet system, wherein a compressor (11) has a first inlet (111), a second inlet (112) and an outlet (113). The first inlet (111) is connected to the four-way valve (13) through a gas-liquid splitter (12). The second inlet (112) is connected to the position between the indoor throttle (20) and an outdoor throttle (15) through a bypass tube with an electric expansion valve (21). The outlet (113) is connected to the four-way valve (13). Sensors (201, 201, 203) for detecting the condition of gas are mounted at the two inlets (201, 202) and the outlet (203) of the compressor (11) respectively. The pressure of the second inlet (112) is controlled according to the detecting results.

Description

 Heat pump air conditioning system and compressor steam injection system and control method thereof

 The invention relates to the field of air source heat pump air conditioners, in particular to a heat pump air conditioning system and a control method which have good heating effect under outdoor ultra-low temperature working conditions. Background technique

 At present, the ordinary air source heat pump air conditioners sold in the market, under the low temperature conditions of outdoor, the heat generation attenuation is very serious, and even can not start up normally. Therefore, in the cold regions of northern China, the air source heat pump air conditioner can only be used in the transitional season. Once entering the cold winter air source heat pump air conditioner can hardly meet the basic heating needs. As is known to all, the traditional centralized supply methods in northern China are mainly coal-fired and gas-fired, and these heating methods cannot meet the requirements of social development in terms of energy conservation, environmental protection and safety. Therefore, it is necessary to develop an ultra-low temperature heat pump air conditioning unit to replace the traditional centralized heating method in northern China. Summary of the invention

 The present invention overcomes the shortcomings of the prior art, and an aspect of the present invention provides a heat pump air conditioning system capable of having a good heating effect under outdoor ultra-low temperature conditions, and another aspect of the present invention provides a compression system for a heat pump air conditioning system. Machine steam injection system and its control method.

 In order to solve the above technical problems, the following technical solutions are implemented:

 A heat pump air conditioning system comprising a four-way valve connected in series, an indoor unit heat exchanger, an indoor throttle device, an outdoor throttling device and an outdoor unit heat exchanger, wherein the heat pump air conditioning system further comprises a compressor steam An injection system, the compressor vapor injection system including a compressor having a first intake port, a second intake port, and an air outlet, the first intake port being connected to the air through a gas-liquid separator a four-way valve, the second suction port is connected between the indoor throttle device and the outdoor throttle device through a bypass pipe provided with an electronic expansion valve, and the air outlet port is connected to the four-way valve .

In the present invention, the compressor vapor injection system further includes a first sensor at the first intake port, a second sensor at the second intake port, and a third pass at the air outlet. Confirmation Sensor.

 In the present invention, the indoor throttle device and the outdoor throttle device are connected in series by a reservoir, and the bypass pipe is connected between the indoor throttle device and the accumulator.

 In the present invention, a coil is provided on the bypass pipe.

 In the present invention, the coil is placed in the reservoir.

 In the present invention, a pair of cooling coils are connected between the accumulator and the outdoor heat exchanger. In the present invention, the sensor is a pressure sensor or a temperature sensor. The present invention also provides a compressor vapor injection system for a heat pump air conditioning system, the heat pump air conditioning system comprising a four-way valve connected in series, an indoor heat exchanger, an indoor throttle device, an outdoor throttle device, and The outdoor unit heat exchanger, the compressor steam injection system includes a compressor, the compressor has a first intake port, a second intake port, and an air outlet, and the first intake port passes through the gas-liquid separator Connecting to the four-way valve, the second suction port is connected between the indoor throttle device and the outdoor throttle device through a bypass pipe provided with an electronic expansion valve, and the air outlet is connected to the outlet Said four-way valve.

 In the present invention, the compressor vapor injection system further includes a first sensor at the first intake port, a second sensor at the second intake port, and a third sensor at the air outlet.

 In the present invention, the sensor is a pressure sensor or a temperature sensor.

 In the present invention, a compressor vapor injection control method, the compressor having a first intake port, a second intake port, and an air outlet, comprising the steps of:

 51. Detecting a state of the gas of the first air inlet, the second air inlet, and the air outlet, corresponding to S low, S spray, and S high;

52. Calculate a gas state S _Ψ during operation of the compressor according to the states S _te , S of the first intake port and the gas of the air outlet _;

53. Control an opening degree of the second air inlet according to a relationship between S*, S and a preset target state difference S. In the present invention, step S1 further includes: detecting a pressure of the first intake port, the second intake port, and the gas outlet of the compressor, corresponding to P _3⁄4 , P n , according to the relationship between pressure and temperature, The temperature T spray corresponding to P _L ;

 Step S2 further includes: calculating an intermediate pressure Ρ in the operation of the compressor, = ^^, according to the relationship between pressure and temperature, obtaining a corresponding temperature is Τ Φ;

 Step S3 further includes:

S30, calculating a temperature difference Δ T corresponding to the actual pressure difference between the pressure injected from the second suction port of the compressor and the intermediate pressure of the compressor, Δ T actual=T , _3⁄4 − ;;

. S3 ΔΤ eye "and the actual temperature difference _ΔΤ β is calculated according to the differential pressure corresponding to the set target temperature difference variation amount of the opening of the second intake port _{Ν, Ν = ΔΤ M - Δ} Τ practical;

S32. The actual opening degree of the second air inlet is the sum of the original opening degree and the opening degree change amount Ν. In the present invention, step S1 further includes: detecting a temperature of the first intake port, the second intake port, and the gas outlet of the compressor; corresponding to T _FFI , Τ , , Ί _Μ , according to the relationship between pressure and temperature, The pressures corresponding to low and _Τ7Ϊ are respectively low and low;

 Step S2 further includes: calculating an intermediate pressure P_ in the operation of the compressor, = ^^, and determining a corresponding temperature according to a relationship between pressure and temperature;

 Step S3 further includes:

 530. Calculate a temperature difference ΔT, ΔΤ actual two T唢-T corresponding to the actual pressure difference between the pressure injected from the second suction port of the compressor and the intermediate pressure of the compressor;

531. Calculate, according to the set temperature difference _Δ, the temperature difference _{ΔΤ 3⁄4β,} calculate the opening change amount _所述 of the second air inlet, Ν=ΔΤ - ΔΤ actual;

532. The actual opening degree of the second air inlet is the sum of the original opening degree and the opening degree change amount N. Compared with the prior art, the present invention uses a steam injection system to inject an intermediate pressure refrigerant vapor to the compressor, and through the pressure control of the injection port (the second suction port of the compressor), the refrigerant injection amount to the compressor is maximized. Good value. Under normal working conditions, the same as the ordinary heat pump air conditioning unit for cooling and heating operation; when the outdoor ambient temperature is lowered and the heating capacity is attenuated, the steam injection system in the unit functions, and the saturated refrigerant gas is injected into the compressor at the intermediate pressure. Two-stage compression is realized inside the compressor to improve the heating capacity and energy efficiency ratio of the unit under outdoor low temperature conditions, so that the number and time of defrosting of the unit are greatly reduced. DRAWINGS

1 is a schematic diagram of the principle of the first embodiment of the heat pump air conditioning system;

Figure 2 is a pressure diagram of the heating operation of the heat pump air conditioning system;

3 is a schematic diagram of the principle of the third embodiment of the heat pump air conditioning system. detailed description

 The invention will be described in detail below with reference to the accompanying drawings and embodiments.

 Embodiment 1:

 Please refer to FIG. 1. FIG. 1 is a schematic diagram of the first embodiment of the heat pump air conditioning system. The solid line with an arrow in the figure indicates the flow direction of the refrigerant during heating of the heat pump air conditioning system. Referring to Fig. 1, a heat pump air conditioning system includes an indoor throttle device 20, an indoor unit heat exchanger 19, a four-way valve 13, an outdoor unit heat exchanger 14, an outdoor throttle device 15, a sub-cooling coil 16 and a reservoir 17, These components are connected in series by a copper tube into a one-piece cold heating cycle. The outdoor throttle device 15 is composed of a check valve and an electronic expansion valve in parallel. The heat pump air conditioning system further includes a compressor steam injection system, the compressor steam injection system includes a compressor 11, and the compressor 11 includes an air outlet 113 and a first air inlet 111 and a second air inlet 112. The gas port 113 is connected to the four-way valve 13, the first air inlet 111 is connected to the four-way valve B through a gas-liquid separator, and the second air inlet 112 is connected to the indoor throttle device 15 through a bypass passage provided with the electronic expansion valve 21. It is connected to the accumulator 17, that is to say to the outflow end of the indoor throttling device 15. An absorption coil 18 is attached to the bypass tube, and an absorption coil 18 is placed in the reservoir 17. The compressor 11 may be a jet-enhanced digital scroll compressor, and the indoor throttle device 20 may be an electronic expansion valve.

The heat pump air conditioning system further includes a steam injection control device including three sensors and the above-described electronic expansion valve 21. In one version, the three sensors are a low pressure sensor 201, a high pressure sensor 202, and an injection pressure sensor 203, respectively. The high pressure sensor 202 is placed in the air outlet 113 of the compressor 11, the low pressure sensor 201 is placed in the first air inlet 111 of the compressor 11, and the injection pressure sensor 203 is placed in the second air inlet 112 of the compressor 11, the electronic expansion valve 21 Provided on the bypass pipe. When the heat pump air conditioning system is in a low temperature heating state, the refrigerant flowing out of the indoor unit heat exchanger 19 is divided into two paths, a part of which passes through the electronic expansion valve 21 on the bypass pipe and the disk placed in the liquid storage device 17. The tube 18 is then sucked in by the second suction port 112 of the compressor 11; another portion of the refrigeration The agent directly enters the accumulator, and enters the outdoor unit heat exchanger 14 through the outdoor unit sub-cooling coil 16 and the auxiliary throttle device 15.

 The working principle of the steam injection control device is: detecting the pressure of the compressor gas entering and exiting through the pressure sensor provided at the suction port and the air outlet of the compressor, and controlling the opening degree of the second suction port according to the change of the gas pressure of the compressor. Thereby the amount of steam injected is controlled. Specifically includes the following process:

 (1) The pressure sensor detects the pressures of the first suction port, the second suction port and the gas outlet of the compressor, respectively, corresponding to P low, P3⁄4, P high;

 (2) According to the relationship between pressure and temperature, the temperature corresponding to P« is obtained;

 (3) Calculate the intermediate pressure during compressor operation IN" P = = ^^, according to the relationship between pressure and temperature, find the corresponding temperature is T;

 (4) Calculate the temperature difference Δ T corresponding to the actual pressure difference between the pressure injected from the second suction port of the compressor and the intermediate pressure of the compressor, Δ T actual = T spray Τ;

 (5) The amount of change in the opening degree of the second suction port Ν = Δ Τ Δ Τ actual, wherein the Δ Τ target is the temperature difference corresponding to the set target pressure difference;

 (6) The actual opening degree of the second suction port is the sum of the original opening degree and the opening degree change amount 第二 of the second suction port.

In the present embodiment, the opening degree of the second intake port is controlled by the change in the opening degree of the electronic expansion valve 21. In this case, in step (5), the amount of change in the opening degree of the electronic expansion valve 21 is Ν = Δ _{Τ Β} « - Δ T _{3⁄4fig; in the} step (6), the actual temperature of the electronic expansion valve 21 should be its original There are variations in opening and opening: the sum of N.

The working process of the heat pump air conditioning system will be described below with reference to FIG. When the system is heating under outdoor low temperature conditions, the compressor 11 compresses the low temperature and low pressure refrigerant gas (state point 1) evaporated from the outdoor unit heat exchanger 14 to the intermediate pressure state point 2, in compression The gas in the scroll of the machine 11 is mixed with the intermediate pressure gas (state point 9) sucked from the second suction port 112 of the compressor to the state point 10, and then continues to be compressed by the compressor 11 into a high temperature and high pressure gas (state point 3) The high temperature and high pressure refrigerant gas is cooled and condensed into the high temperature and high pressure refrigerant liquid (state point 4) in the indoor unit heat exchanger 19, and the high pressure liquid is throttled to the gas by the indoor throttle device 20, for example, the electronic expansion valve. Liquid mixture (state point 5); at this time, the refrigerant is divided into two paths, and a part of the refrigerant is throttled by the electronic expansion valve 21 into an intermediate pressure refrigerant gas-liquid mixture (state point 8) into the absorption coil 18 in the accumulator 17, Evaporate after absorbing heat The intermediate pressure saturated vapor (state point 9) is drawn in by the second suction port 112 of the compressor 11, and the other portion of the refrigerant directly enters the container between the outer casing of the accumulator 17 and the absorption coil 18, and the absorption coil. The refrigerant in 18 undergoes heat exchange to release heat and is condensed into supercooled liquid through the outdoor unit sub-cooling coil 16 (state point 6); the supercooled liquid is throttled to the state point 7 by the outdoor throttling device 15 such as an electronic expansion valve Then, the outdoor unit heat exchanger 14 is evaporated to the state point 1 and sucked by the compressor suction port 111 to complete a heating cycle.

 The working principle of the whole heat pump air conditioning system is: under normal working conditions, the same as the ordinary heat pump air conditioning unit for cooling and heating operation; when the outdoor ambient temperature is lowered and the heating capacity is attenuated, the steam injection control device in the unit plays a role, compressing The machine injects the intermediate pressure of the saturated refrigerant gas to achieve two-stage compression in the compressor and the unit to improve the heat generation and energy efficiency ratio of the unit under outdoor low temperature conditions. At the same time, the compression ratio of the compressor in the system and the exhaust temperature of the unit are within a reasonable range. The reliability of the unit operation is verified and verified by a large number of experiments. The unit adopts the intelligent frost mode, and the unit is controlled by the high pressure to enter the defrosting. Running, you can achieve the goal of "with frost and no frost." Example two.

 The difference between this embodiment and the first embodiment is that the sensor used in the steam injection control device in the embodiment is a temperature sensor, and the working principle of the steam injection control device using the temperature sensor is: by setting the suction port of the compressor, The temperature sensor of the port detects the temperature of the compressor gas in and out, and controls the opening degree of the second intake port according to the change in the temperature of the inlet and outlet compressor gas, thereby controlling the amount of steam injection. In the present embodiment, the opening degree of the second suction port is controlled by the change in the opening degree of the electronic expansion valve 21, specifically including the following process:

(1) The temperature sensor detects the temperature of the first suction port, the second suction port and the gas outlet of the compressor, respectively, corresponding to T low, τ _3⁄4 , τ, _3⁄4 ;

(2) According to the relationship between pressure and temperature, the pressures corresponding to T _ffi and T _ffi are respectively P _te and P high;

(3) Calculate the intermediate pressure Ρ _Ψ , Ρ^-^Ρ^ during the operation of the compressor, and obtain the corresponding temperature according to the relationship between pressure and temperature;

(4) Calculate the temperature difference corresponding to the actual pressure difference between the pressure injected from the second suction port of the compressor and the intermediate pressure of the compressor. ΔΤ Actual, AT'«=T T ;

(5) The amount of change in the opening degree of the second intake port Ν = Δ Τ - ΔΤ , where _{ΔΤ Η 3⁄4} is the setting The temperature difference corresponding to the target pressure difference;

 (6) The actual opening degree of the second suction port is the sum of the original opening degree of the second suction port and the amount of change N of the opening degree.

 Embodiment 3:

 As shown in Fig. 3, the difference between this embodiment and the first embodiment is that the sub-cooling coil 16 and the accumulator 17 are not provided in the heat pump system of the present embodiment, and the coil 18 is not provided on the bypass pipe. In addition, the bypass pipe can be directly taken out from the outlet of the indoor unit heat exchanger. The above embodiments are merely illustrative and not limiting of the technical solutions of the present invention. For example, the throttling device electronic expansion valve can be replaced by a common capillary tube, and the indoor unit can be just one; in addition, the bypass pipe can be directly taken out from the outlet of the indoor unit heat exchanger. Therefore, any modifications or sub-commitations of the present invention are intended to be included within the scope of the appended claims.

Claims

Rights request 1. A heat pump air conditioning system comprising a four-way valve (13) connected in series, an indoor heat exchanger (19), an indoor throttling device (20), an outdoor throttling device (15), and an outdoor unit exchange a heat exchanger (14), characterized in that the heat pump air conditioning system further comprises a compressor steam injection system, the compressor steam injection system comprising a compressor (11), the compressor (11) having a first suction a gas port (111), a second suction port (112) and an air outlet (113), wherein the first air inlet (111) is connected to the four-way valve (13) through a gas-liquid separator (12), The second suction port (112) is connected between the indoor throttle device (20) and the outdoor throttle device (15) through a bypass pipe provided with an electronic expansion valve (113), the outlet A port (113) is connected to the four-way valve (13).  2. The heat pump air conditioning system according to claim 1, wherein the compressor vapor injection system further comprises a first sensor (201) located at the first intake port (111), located in the first a second sensor (202) of the two intake ports (112) and a third sensor (203) at the air outlet (113).  The heat pump air conditioning system according to claim 2, wherein the indoor throttle device (20) and the outdoor throttle device (15) are connected in series by a liquid reservoir (17), the bypass A tube is connected between the indoor throttle device (20) and the accumulator (17).  4. The heat pump air conditioning system according to claim 3, wherein the bypass pipe is provided with a coil (18).  The heat pump air conditioning system according to claim 4, characterized in that the coil (18) is placed in the accumulator (17).  The heat pump air conditioning system according to claim 3, characterized in that a pair of cooling coils (16) are connected between the accumulator (17) and the outdoor heat exchanger (15).  The heat pump air conditioning system according to any one of claims 2 to 6, wherein the sensor is a pressure sensor.  The heat pump air conditioning system according to any one of claims 2 to 6, wherein the sensor is a temperature sensor. 9. A compressor steam injection system for a heat pump air conditioning system, the heat pump air conditioning system package The four-way valve (13), the indoor unit heat exchanger (19), the indoor throttle device (20), the outdoor throttle device (15) and the outdoor unit heat exchanger (14) are connected in series. The compressor vapor injection system includes a compressor (11) having a first intake port (111), a second intake port (112), and an air outlet (113), An intake port (111) is connected to the four-way valve (13) through a gas-liquid separator (12), and the second suction port (112) is connected through a bypass pipe provided with an electronic expansion valve (113) Between the indoor throttle device (20) and the outdoor throttle device (15), the air outlet (113) is connected to the four-way valve (13).  10. The compressor vapor injection system according to claim 9, further comprising a first sensor (201) at the first intake port (111) and a second intake port (112) a second sensor (202) and a third sensor (203) at the air outlet (113).  The compressor vapor injection system according to claim 9, wherein the sensor is a pressure sensor or a temperature sensor.  12. A compressor steam injection control method, the compressor having a first intake port, a second intake port, and an air outlet, wherein the compressor comprises the following steps:  51. Detecting a state of the gas of the first air inlet, the second air inlet, and the air outlet, corresponding to S low, S spray, and S high; 52. Calculate a gas state S _Ψ during operation of the compressor according to the states S _1S and S _{ra of} the first intake port and the gas of the air outlet _;  53. Control the opening degree of the second suction port according to the relationship between S, S and a preset target state difference S target. The compressor steam injection control method according to claim 12, wherein the step S1 further comprises: detecting a pressure of the first suction port, the second suction port, and the gas outlet of the compressor, corresponding to Ρ _Λ , Ρ, according to the relationship between pressure and temperature, calculate the temperature corresponding to _{ι ι3⁄4} spray 5 Step S2 further includes: calculating an intermediate pressure Ρ in the operation of the compressor,

According to the relationship between pressure and temperature, the corresponding temperature is obtained as Τ _Ψ; step S3 further includes: S30, calculating a temperature difference Δ T « corresponding to the actual pressure difference between the pressure injected from the second suction port of the compressor and the intermediate pressure of the compressor; Δ T = T spray; S3K calculates the amount of change in the opening degree of the second intake port according to the set temperature difference ΔΤ « with the actual temperature difference ΔΤ ^ Ν, Ν = Δ Τ target - Δ Τ actual;  S32. The actual opening degree of the second air inlet is the sum of the original opening degree and the opening degree change amount N. The compressor steam injection control method according to claim 12, wherein the step S1 further comprises: detecting a temperature of the first intake port, the second intake port, and the gas outlet of the compressor, corresponding to T _te , _{ι ι3⁄4} , _{Ί η} , according to the relationship between pressure and temperature, calculate the pressure corresponding to T _ffi , T _3⁄4 , respectively, Ρ low, Ρ high;  Step S2 further includes: calculating an intermediate pressure Ρ in the operation of the compressor, ^=^ί ^' according to the relationship between pressure and temperature, obtaining a corresponding temperature is Τ;  Step S3 further includes: 530, calculating a temperature difference AT, ΔT _3⁄4PS -T spray - T corresponding to the actual pressure difference between the pressure injected from the second suction port of the compressor and the intermediate pressure of the compressor;  531. Calculate the amount of change in the opening degree of the second intake port according to the temperature difference ΔΤ in the target pressure difference set by the target temperature difference Ν, ? ^ ^! ^ Standard! ^;  532. The actual opening degree of the second air inlet is the sum of the original opening degree and the opening degree change amount N.