Integrated indoor heat pump air conditioning system and control method thereof

Abstract

The present invention discloses a multifunctional integrated indoor heat pump air conditioning system and a control method thereof. The integrated indoor heat pump air conditioning system comprises an indoor unit and an outdoor unit, wherein the indoor unit adopts an integrated unit, comprising a shell, a water storage tank located in the shell, and an indoor heat exchanger, the water inlet pipe and the water outlet pipe of the indoor heat exchanger are respectively connected to the heat exchange coil in the water storage tank and the indoor terminal device, the water outlet pipe of the indoor heat exchanger is provided with a three-way valve connected to the water supply pipe of the indoor terminal device, and the water storage tank is also provided with a domestic hot water outlet and a water replenishment port. The present invention uses the same machine to meet the user's multiple needs for cooling, heating and hot water supply, saves procurement costs and installation space, and has high water temperature control accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a multifunctional integrated indoor heat pump air conditioning system and a control method thereof. Background Art

[0002] With the improvement of living standards, families have the need for cooling, heating and domestic hot water. To meet the above needs, they usually buy separate equipment, for example, a household air conditioner for cooling in summer (wall mounted or cabinet), a gas wall mounted boiler for heating in winter, and another electric heater or air energy water heater for domestic hot water. This method is the least economical in terms of purchase cost and occupies a large installation space. Summary of the invention

[0003] The present invention provides a multifunctional integrated indoor heat pump air conditioning system and a control method thereof, so as to meet the various needs of users for cooling, heating and domestic hot water supply, while reducing the purchase cost and saving the installation space.

[0004] The present invention proposes an integrated indoor heat pump air-conditioning system, comprising an indoor unit and an outdoor unit, wherein the indoor unit adopts an integrated unit, comprising a shell, a water storage tank located in the shell and an indoor heat exchanger, the water inlet pipe and the water outlet pipe of the indoor heat exchanger are respectively connected to the heat exchange coil in the water storage tank and the indoor terminal device, the water outlet pipe of the indoor heat exchanger is provided with a three-way valve connected to the water supply pipe of the indoor terminal device, and the water storage tank is also provided with a domestic hot water outlet and a water replenishment port.

[0005] The heat pump air conditioning system includes three operating modes: cooling, heating and hot water supply.

[0006] A water pump is arranged on the water inlet pipe of the indoor heat exchanger.

[0007] Preferably, an expansion tank is provided on the water inlet pipe of the indoor heat exchanger.

[0008] Preferably, an auxiliary electric heater is provided between the water outlet of the indoor heat exchanger and the three-way valve.

[0009] Preferably, it is characterized in that a water flow switch is provided between the water outlet of the indoor heat exchanger and the auxiliary electric heater.

[0010] Preferably, a safety valve and an automatic exhaust valve are provided between the auxiliary electric heater and the three-way valve.

[0011] Preferably, an electric heater is provided in the water storage tank.

[0012] Preferably, the indoor heat exchanger is a plate heat exchanger.

[0013] Preferably, the refrigerant inlet and outlet, the water side inlet and outlet, and the water storage tank of the indoor heat exchanger are all provided with temperature sensors.

[0014] Preferably, it further comprises a base, and the indoor unit is placed on the base.

[0015] The present invention also provides a control method for the above-mentioned integrated indoor heat pump air-conditioning system, wherein the heat pump air-conditioning system includes four operating modes: cooling, heating, hot water supply and defrosting.

[0016] In cooling mode: the three-way valve is powered off, and the compressor frequency is adjusted or started and stopped according to the difference δTW between the outlet water temperature set by the user and the current outlet water temperature; the opening of the first electronic expansion valve is adjusted according to the suction superheat; the speed of the outdoor heat exchanger fan is adjusted according to the exhaust temperature.

[0017] In heating mode: the four-way valve is reversed, when the compressor frequency is greater than 41Hz, the second electronic expansion valve is opened, and the opening of the second electronic expansion valve is controlled according to the superheat of the economizer; when the compressor frequency is ≤41Hz, the second electronic expansion valve is closed; the first electronic expansion valve is adjusted according to the suction superheat; the outdoor heat exchanger fan is adjusted according to the defrost temperature T; when the ambient temperature is less than or equal to the set value e℃, the auxiliary electric heater is turned on.

[0018] In the hot water making mode: open the three-way valve, the circulating water of the indoor heat exchanger enters the water tank for heat exchange, and when the ambient temperature is less than or equal to the set value f℃, turn on the water tank electric heater to shorten the time users wait for hot water.

[0019] In defrost mode: defrost temperature T 化 When the setting conditions are met at the same time as the heating operation time, the defrost mode is entered. At this time, the four-way valve is powered off and reversed, and the outdoor heat exchanger fan stops running. When the ambient temperature is less than or equal to the set value, the auxiliary electric heater is turned on; when the ambient temperature is greater than or equal to the set value d℃, the defrost ends.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. Use the same machine to meet the user's various needs for cooling, heating and hot water supply, saving procurement costs and installation space.

[0022] 2. The distance between the indoor heat exchanger and the water tank is short, the connecting pipe is short, the water temperature difference is small, and the water temperature control accuracy is high.

[0023] 3. The integrated indoor unit is assembled before leaving the factory, making it easy for users to install. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0025] Figure 1 is a system diagram of the heat pump air conditioning system proposed by the present invention;

[0026] Figure 2 is a schematic diagram of an integrated internal unit in the present invention;

[0027] Figure 3 It is the control flow chart of the integrated heat pump in the water tank;

[0028] Figure 4 It is a flow chart of the cooling mode;

[0029] Figure 5 It is a flow chart of heating mode. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and do not constitute a limitation to the present invention.

[0031] The present invention designs a multifunctional heat pump air conditioning system, which can meet the needs of users for cooling, heating and hot water supply. Figure 1 As shown, the integrated indoor heat pump system consists of an outdoor unit and an integrated unit indoor unit. The main function of the integrated unit indoor unit is to provide cold water or hot water to the terminal device through heat exchange between the refrigerant and the circulating water, or to provide domestic hot water through the water storage tank.

[0032] like Figure 1 As shown, the outdoor unit includes a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, a first electronic expansion valve 14 located in the main circuit and a gas-liquid separator 15, and is also provided with an economizer 16 and a second electronic expansion valve 17 for replenishing air to the compressor. The outdoor heat exchanger can be a fin-tube heat exchanger. The main function of the outdoor unit is to provide refrigerant circulation power, absorb heat from the environment during heating, and provide indoor heating or domestic hot water; cool the high-temperature gaseous refrigerant discharged by the compressor during cooling, and provide cooling to the indoor room.

[0033] The exhaust side of the compressor is equipped with an exhaust temperature sensor T 高 , high-voltage switch 18 and high-voltage sensor P 高 The outdoor heat exchanger is equipped with an environmental temperature sensor T 环境 And defrost temperature sensor T 化 The inlet and outlet of the economizer are both equipped with temperature sensing packages T1 and T2. A first low-pressure switch 19 for cooling and a second low-pressure switch 20 for heating are also provided between the gas-liquid separator and the suction side of the compressor. 吸气The economizer is used to increase the enthalpy of the compressor during heating. After the refrigerant passes through the economizer, the compressor exhaust volume can be increased, the flow rate of the refrigerant system can be increased, and the heating capacity of the heat pump can be increased, and the exhaust temperature of the compressor at low temperatures can be reduced. The first electronic expansion valve 14 on the main circuit is used for both cooling and heating, and the second electronic expansion valve 17 on the auxiliary circuit only operates under heating conditions, and the operating conditions are to open when the compressor frequency is greater than 41Hz and to close when it is less than 41Hz.

[0034] The indoor unit adopts an integrated unit, including a housing 2, a water storage tank 21 and an indoor heat exchanger 22. The indoor heat exchanger can be a plate heat exchanger. The water inlet pipe and the water outlet pipe of the indoor heat exchanger are respectively connected to the heat exchange coil 23 in the water storage tank and the indoor terminal device (not shown in the figure). The water outlet pipe of the indoor heat exchanger is provided with a three-way valve 24 connected to the water supply pipe of the indoor terminal device, and the water storage tank is also provided with a domestic hot water outlet 35 and a water replenishment port 36.

[0035] like Figure 2 As shown, from the outside, the indoor unit is a whole, and the interior is mainly divided into four parts, the water storage tank 21 located at the bottom of the integrated unit, the outer side of which can be provided with an insulation layer, the indoor heat exchanger 22 located at the top, the control box 25 and the base 34. The refrigerant inlet and outlet, water side inlet and outlet of the indoor heat exchanger and the water storage tank are all equipped with temperature sensors, including the indoor heat exchanger gas pipe temperature sensing package T3, the indoor heat exchanger liquid pipe temperature sensing package T4, the indoor heat exchanger water inlet temperature sensing package T5, the indoor heat exchanger water outlet temperature sensing package T6 and the water tank temperature sensing package T 水箱 The water inlet pipe of the indoor heat exchanger is also equipped with a water pump 27, an expansion tank 28 (used to maintain a stable water pressure in the water system), and a water pressure gauge P. The water outlet pipe of the indoor heat exchanger is equipped with a three-way valve 24 connecting the water storage tank and the terminal device, an automatic exhaust valve 29, a safety valve 30, and an auxiliary electric heating water outlet temperature sensing package T. 7 , auxiliary electric heater 31 and water flow switch 32. An electric heater 33 is provided in the water storage tank.

[0036] Since the indoor unit adopts an integrated unit, the distance between the indoor heat exchanger and the water tank is short, the connecting pipe is short, the water temperature difference is small, and the water temperature control accuracy is high. In addition, the integrated indoor unit is assembled before leaving the factory, which is convenient for users to install.

[0037] Figure 3 The control principle diagram of the integrated heat pump in the water tank is displayed. In the temperature, pressure and component marks detected in the figure, C represents the relevant parameters for cooling, H represents the relevant parameters for heating, W represents the relevant parameters for hot water, and A represents the common parameters. The components are tested for faults throughout the startup and operation process. When a fault occurs, an alarm is issued and the machine is shut down immediately. If there is no fault, it will start and run according to the timing.

[0038] Cooling mode:

[0039] The cooling mode process is as follows: Figure 4 As shown. The user selects the cooling mode through the controller set on the indoor unit housing or on the online controller, sets the required outlet water temperature, and presses the power button. At this time, the unit first performs a self-check to troubleshoot possible faults. If there is no fault, the ambient temperature is detected. Within the ambient temperature range allowed for the unit to operate, the unit is turned on, the first electronic expansion valve 14 of the main circuit is initialized, and the three-way valve 24 remains closed (disconnecting the passage into the water tank). After completion, the difference between the user-set outlet water temperature and the current outlet water temperature is detected and set as δT W , the difference determines whether the compressor is turned on and the specific adjustment method. When the unit meets the startup conditions, the water pump is first turned on and runs for 15 seconds. After 15 seconds, the water flow switch fault is detected. If there is no fault, the fan is turned on. The fan is turned on and first initialized for 2 minutes at a medium or high level. After 2 minutes, the compressor starts running at the initialization frequency. The initialization time is 3 minutes. After 3 minutes, the compressor frequency, the opening of the first electronic expansion valve, and the fan gear are adjusted until the user's set target is reached. The adjustment rules are as shown in the following table. The compressor and fan are adjusted once every 1 minute, and the electronic expansion valve is adjusted once every 40 seconds:

[0040]

[0041] Heating mode:

[0042] The process of heating mode is as follows Figure 5 The startup process is similar to the refrigeration process, except that the four-way valve is reversed 25 seconds after the compressor is started. When the first electronic expansion valve is initialized, the initialization of the second electronic expansion valve in the auxiliary circuit is added. After the second electronic expansion valve is initialized, it is closed to the 0B (fully closed) position, and then its opening is determined by the compressor frequency:

[0043] When the compressor frequency is greater than 41Hz, the second electronic expansion valve is opened. When the compressor frequency is less than or equal to 41Hz, the second electronic expansion valve is closed. After opening, the second electronic expansion valve opening is controlled according to the economizer superheat (economizer outlet temperature - economizer inlet temperature). New opening = current opening + (economizer outlet temperature - economizer inlet temperature) * λ 2 ,λ 2 ≥1. The compressor adjustment is similar to refrigeration. The first electronic expansion valve of the main circuit is adjusted according to the suction superheat (suction temperature - defrost temperature). The new first electronic expansion valve opening = current opening + (current superheat - target superheat) * λ1. The outdoor heat exchanger fan is adjusted according to the defrost temperature T 化 adjust:

[0044] T 化 When the temperature is above a2℃, the fan is adjusted down by one gear based on the current gear.

[0045] b2℃≤T 化When the temperature is less than a2℃, the fan maintains the current gear;

[0046] T 化 When the temperature is less than b2℃, the fan speed will be increased by 1 gear based on the current gear.

[0047] When heating in a low temperature and high humidity environment, the fin heat exchanger will frost, which involves the defrosting process and needs to meet the defrosting temperature T 化 The defrosting process can only be started when the heating operation time reaches the set conditions at the same time. During defrosting, the compressor frequency is first reduced to 45Hz, and the first electronic expansion valve of the main circuit is adjusted to the defrosting step number. After 20s, the four-way valve is powered off and reversed, and the fan stops running at the same time. The compressor is then increased to the defrosting frequency and continues until T 化 Defrosting ends when ≥d℃, d can be set between 10-20. After defrosting, the compressor frequency is first reduced to 45Hz, and the four-way valve is reversed after 15s. The first electronic expansion valve of the main circuit is opened to the initial opening, and the fan is adjusted to the initial gear. After running for 1min, it is adjusted normally according to the heating mode.

[0048] According to the ambient temperature T 环 The set condition determines whether to turn on the auxiliary electric heater 31, which is generally T 环境 When defrosting when the temperature is ≤e℃ and e≤0℃, the auxiliary electric heater is turned on, and the auxiliary electronic heating is always on to prevent the water temperature from being too low and to speed up defrosting.

[0049] Hot water mode:

[0050] The hot water supply mode is the same as the heating mode. In addition, the three-way valve needs to be opened in the initialization stage to allow circulating water to enter the water tank and exchange heat with cold water inside the electric heater 33 coil in the water tank to produce hot water. 环 ≤f℃, f≤0℃, the performance of the heat pump decays, and the heat pump alone cannot heat the water in the water tank to the required temperature. At this time, the water tank electric heater needs to be turned on to shorten the time users wait for hot water.

[0051] The specific control methods are as follows:

[0052] 1. Compressor control

[0053] After entering the water temperature control, adjust the compressor operating frequency according to the calculated temperature difference ΔT (set water tank temperature - actual water tank temperature) according to the following conditions. Each adjustment must be maintained for 90 seconds, and each detected ΔT must last for 3 seconds:

[0054] When T 水箱 When the temperature is ≤10℃, the compressor runs at 45Hz, and the unit increases or decreases the frequency according to the heating mode;

[0055] When 10℃<T 水箱 When the temperature is ≤20℃, the compressor runs at 60Hz;

[0056] When 20℃<T 水箱 When the temperature is ≤30℃, the compressor runs at 60Hz;

[0057] When 30℃<T 水箱 When the temperature is ≤40℃, the compressor runs at 60Hz

[0058] When 40℃<T 水箱 When the temperature is ≤45℃, the compressor runs at 65Hz;

[0059] When 45℃<T 水箱 When the temperature is ≤50℃, the compressor runs at 65Hz;

[0060] When 50℃<T 水箱 When the temperature is ≤55℃, the compressor runs at 60Hz;

[0061] 55℃<T 水箱 When the temperature is ≤60℃, the compressor runs at 40Hz.

[0062] At any time, T 水箱 ≥The maximum water temperature setting of heat pump hot water T 设定 , T 水箱 ≥T 设定 , the compressor stops running, and the water pump stops running after a delay of 120s;

[0063] After the compressor has been running for more than 6 minutes, if T is detected for 60 seconds continuously, 环境 >47℃, or T 环境 When the unit's minimum operating ambient temperature is less than 0.01°C, the unit stops running, and the whole unit's water pump stops running after a delay of 120 seconds. At this time, if the hot water operation conditions are met, the electric heater 33 in the water tank is put into operation.

[0064] 2. Outdoor heat exchanger fan control

[0065] Control the defrost tube temperature at 0-3℃.

[0066] When the evaporation temperature (defrost pipe temperature) is detected to be less than 0°C for 5 consecutive seconds, the fan gear is raised by one gear;

[0067] When the evaporation temperature (defrost pipe temperature) is detected to be 0℃≤3℃ for 5 consecutive seconds, the fan maintains the current gear;

[0068] When the evaporation temperature (defrost pipe temperature) is detected to be 3℃ lower than that for 5 consecutive seconds, the fan gear will be reduced by one gear.

[0069] 3. Electronic expansion valve control

[0070] Control of the first electronic expansion valve 14: control the liquid pipe temperature to be close to the inlet water temperature, heat exchange temperature difference = liquid pipe temperature - inlet water temperature:

[0071] When the heat exchange temperature difference is detected to be less than 0°C for 5 consecutive seconds, the first electronic expansion valve 14 is opened by (2-heat exchange temperature difference);

[0072] When the heat exchange temperature difference is detected to be 0 ≤ ≤ 2°C for 5 consecutive seconds, the first electronic expansion valve 14 maintains the current step number;

[0073] When the heat exchange temperature difference is detected to be 2°C < 5 seconds continuously, the first electronic expansion valve 14 is closed down (heat exchange temperature difference - 0).

[0074] The adjustment range of the first electronic expansion valve 14 is 60-480B.

[0075] The initial number of steps of the first electronic expansion valve 14 is changed as follows:

[0076] The initial number of steps of the first electronic expansion valve when heating water is as follows:

[0077]

[0078] The second electronic expansion valve 17 is adjusted to control the superheat of the supplementary air to be 0-3°C:

[0079] (1) Superheat of air supply = economizer outlet temperature - economizer inlet temperature, controlled as follows:

[0080] When the air supply superheat is detected to be less than 3°C for 5 consecutive seconds, the second electronic expansion valve 17 is closed by (3-air supply superheat) steps;

[0081] When 0 ≤ air supply superheat ≤ 3°C is detected for 5 consecutive seconds, the second electronic expansion valve 17 maintains the current number of steps;

[0082] When 3°C < air supply superheat is detected for 5 consecutive seconds, the second electronic expansion valve 17 is opened one step larger (air supply superheat - 0).

[0083] (2) When the exhaust temperature is lower than the condensing temperature (exhaust pressure saturation temperature) + 10°C, the second electronic expansion valve is closed to the 0B (closed) position.

[0084] 4. Water pump control

[0085] The water temperature difference is controlled at 5-9℃, and the water pump gear range is 2-6, with the lowest gear being 2 and the highest gear being 6.

[0086] When the inlet and outlet water temperature difference is detected to be less than 5°C for 5 consecutive seconds, the water pump gear will be reduced by one gear;

[0087] When the inlet and outlet water temperature difference is detected to be 5 ≤ ≤ 9°C for 5 consecutive seconds, the water pump gear will maintain the gear position;

[0088] When the inlet and outlet water temperature difference is detected to be 9℃<5 seconds continuously, the water pump gear will be raised by one gear;

[0089] In heating and hot water modes, if the exhaust pressure saturation temperature - plate exchange water temperature is detected to be higher than 2°C at any time, it will be raised by one level.

[0090] 5. In the test mode, the oil return is blocked, and the charging of the mainboard is blocked to prevent the water pump from suddenly starting for a few seconds during the standby stage.

[0091] 6. After the heating and hot water production are stopped, the fan and water pump will stop directly.

[0092] When the unit is shut down, the fan is shut down immediately after the compressor stops, and the water pump is shut down immediately after the compressor stops.

[0093] The present invention solves the user's needs for cooling, heating, and domestic hot water with one device, which not only saves procurement costs but also saves installation space. In addition, the integrated unit indoor unit is adopted, the distance between the indoor heat exchanger and the water storage tank is short, the water temperature difference is small, the water temperature control is accurate, and the installation is convenient.

[0094] The above description is only a specific implementation of the present invention. It should be pointed out that any modification, equivalent substitution and change made within the spirit and framework of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated indoor heat pump air conditioning system, comprising an indoor unit and an outdoor unit, characterized in that: The indoor unit adopts an integrated unit, including a shell, a water storage tank located in the shell, and an indoor heat exchanger. The water inlet pipe of the indoor heat exchanger is connected to one end of the heat exchange coil in the water storage tank. The water outlet pipe of the indoor heat exchanger is provided with a three-way valve connected to the water supply pipe of the indoor terminal device and the other end of the heat exchange coil in the water storage tank. An auxiliary electric heater is provided between the water outlet of the indoor heat exchanger and the three-way valve. The water storage tank is also provided with a domestic hot water outlet and a water replenishment port.

2. The heat pump air conditioning system according to claim 1, characterized in that: A water pump is arranged on the water inlet pipe of the indoor heat exchanger.

3. The heat pump air conditioning system according to claim 1, characterized in that: An expansion tank is arranged on the water inlet pipe of the indoor heat exchanger.

4. The heat pump air conditioning system according to claim 1, characterized in that: A water flow switch is arranged between the water outlet of the indoor heat exchanger and the auxiliary electric heater.

5. The heat pump air conditioning system according to claim 1, characterized in that: A safety valve and an automatic exhaust valve are arranged between the auxiliary electric heater and the three-way valve.

6. The heat pump air conditioning system according to claim 1, characterized in that: An electric heater is arranged in the water storage tank.

7. The heat pump air conditioning system according to claim 1, characterized in that: The indoor heat exchanger is a plate heat exchanger.

8. The heat pump air conditioning system according to claim 1, characterized in that: The refrigerant inlet and outlet, the water side inlet and outlet, and the water storage tank of the indoor heat exchanger are all provided with temperature sensors.

9. The heat pump air conditioning system according to claim 1, characterized in that: It also includes a base, and the indoor unit is placed on the base.

10. A control method for an integrated indoor heat pump air conditioning system according to any one of claims 1 to 9, characterized in that: The heat pump air conditioning system includes three operating modes: cooling, heating and hot water supply.

11. The control method according to claim 10, characterized in that: In cooling mode: the three-way valve is powered off, and the compressor frequency is adjusted or started and stopped according to the difference δTW between the outlet water temperature set by the user and the current outlet water temperature; the opening of the first electronic expansion valve is adjusted according to the suction superheat; the speed of the outdoor heat exchanger fan is adjusted according to the exhaust temperature.

12. The control method according to claim 10, characterized in that: In heating mode: the four-way valve is switched. When the compressor frequency is greater than 41Hz, the second electronic expansion valve is opened and the opening degree of the second electronic expansion valve is controlled according to the superheat of the economizer. When the compressor frequency is less than or equal to 41Hz, the second electronic expansion valve is closed. The first electronic expansion valve is adjusted according to the suction superheat. The outdoor heat exchanger fan is set according to the defrost temperature T 化 Adjustment; when the ambient temperature is less than or equal to the set value e℃, turn on the auxiliary electric heater.

13. The control method according to claim 10, characterized in that: In the hot water making mode: open the three-way valve, the circulating water of the indoor heat exchanger enters the water tank for heat exchange, and when the ambient temperature is less than or equal to the set value f℃, turn on the water tank electric heater to shorten the time users wait for hot water.

14. The control method according to claim 10, characterized in that: It also includes defrost mode: when the defrost temperature T and the heating operation time reach the set conditions at the same time, the defrost mode is entered. At this time, the four-way valve is powered off and reversed, and the outdoor heat exchanger fan stops running. When the ambient temperature is less than or equal to the set value, the auxiliary electric heater is turned on; when the ambient temperature is greater than or equal to the set value d℃, the defrost ends.

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