A heating and water two combined supply system and a control method

Abstract

The application provides a novel heating and hot water two combined supply system and a control method, and the core key component is a double-temperature-zone plate heat exchanger. Hot water and high-temperature refrigerant exchange heat in the heat exchanger to perform hot water production or heating, and hot water production and heating can be simultaneously realized. For the two operation modes of hot water and heating, hot water temperature set value and return water temperature set value are respectively used as control targets, and the compressor operation frequency is adjusted. For the hot water + heating mode, the maximum value of the hot water temperature set value and the return water temperature set value is used as a target to control the compressor operation frequency. A mixed water proportion three-way valve is arranged between a heating outlet pipe and a return pipe. When the hot water and heating modes are simultaneously operated and the hot water temperature set value is used as a control target, the three-way valve is used to adjust the heating return water temperature. Compared with a conventional heating and hot water heat pump two combined supply system, the unit has simple structure, low cost, and can simultaneously meet the hot water production and heating requirements, does not need to be stopped for switching, and is stable and reliable in operation.

Description

TECHNICAL FIELD

[0001] The present application relates to an air energy heat pump system, more particularly to a novel heating and hot water two combined supply system and control method. BACKGROUND

[0002] With the rapid development of economy and the continuous improvement of people's living standards, the demand for heating equipment and water heaters is showing a rapid growth trend. Heat pump units gradually replace traditional electric water heaters and coal-fired boiler heating methods and become the mainstream of market development due to their mature technology, high comfort and energy-saving and environmentally friendly characteristics. At present, the common heat pump products on the market mainly include air energy water heaters and heating heat pumps, but these products have single functions and can only meet the demand for domestic hot water or heating. In order to simultaneously achieve heating and domestic hot water supply, users usually need to install two independent devices, which not only increases the purchase and installation cost, but also brings compatibility problems due to different brands of devices, and occupies a large installation space.

[0003] To solve the above problems, a multifunctional heat pump emerges as the times require, aiming to simultaneously provide domestic hot water and heating demand. However, the multifunctional heat pumps on the market still have significant defects. For example, when switching between domestic hot water and heating hot water, an electric three-way valve is usually relied on for mode conversion, resulting in that the production of domestic hot water and heating cannot be performed simultaneously. To make up for this deficiency, some products increase the volume of the water tank to store the domestic hot water produced during the day to meet the demand for night use, but this way requires a high space for the family, especially not suitable for the two combined supply demand of ordinary domestic houses in China. In addition, the existing heat pump two combined supply products generally use water-water heat exchange design for the heat preservation water tank, that is, the heating water pipeline is wound around the outer wall of the water tank inner container, and the water in the water pipeline is used to heat the water in the water tank. This design has low heat exchange efficiency, long heating time and low energy efficiency, which is difficult to meet the actual demand of users. SUMMARY

[0004] Therefore, in order to overcome the above technical defects, the present application proposes a novel heating and hot water two combined supply system and control method, the double-temperature-zone plate heat exchanger of the system is the core component, and the integrated design of the heat pump main module, the heating water circulation system and the hot water circulation system is combined to realize the function of simultaneously producing domestic hot water and heating, and the operation mode does not need to be switched off.

[0005] In order to realize the above technical advantages, the technical scheme of the present application is as follows:

[0006] A novel heating and hot water two combined supply system, comprising a heat pump main module, a heating module and a hot water module; the heat pump main module comprises a variable frequency compressor, an oil separator, a four-way valve, a double-temperature-zone plate heat exchanger, an electronic expansion valve, an outdoor heat exchanger and a gas-liquid separator connected in sequence, and forms a refrigerant circulation main loop;

[0007] The double-temperature-zone plate heat exchanger is provided with a heating heat exchange flow channel and a hot water heat exchange flow channel, the heating heat exchange flow channel is connected with a heating module, the hot water heat exchange flow channel is connected with a hot water module, and the heating heat exchange flow channel and the hot water heat exchange flow channel are respectively provided for hot water to flow through, so that the heating module and the hot water module can exchange heat with refrigerant flowing through the double-temperature-zone plate heat exchanger independently or synchronously.

[0008] Further, the heating module comprises a hot water return pipe, a hot water outlet pipe, a proportional three-way valve, a heating water pump and a buffer tank, the hot water return pipe and the hot water outlet pipe are respectively connected with the heating heat exchange flow channel, the heating water pump is installed on the hot water return pipe, the proportional three-way valve comprises an a interface, a b interface and an f interface, the a interface and the b interface of the proportional three-way valve are connected on the hot water return pipe, the f interface of the proportional three-way valve is connected to the hot water outlet pipe through the buffer tank, and the proportional three-way valve adjusts the proportion of hot water flowing through the heating heat exchange flow channel and the buffer tank by adjusting the proportion of hot water flowing from the a interface to the b interface and the f interface.

[0009] Further, the hot water module comprises a hot water tank and a hot water pump, the hot water tank is connected with the hot water heat exchange flow channel through a hot water circulation pipeline and forms a hot water circulation loop, and the hot water pump drives hot water to circulate between the hot water tank and the double-temperature-zone plate heat exchanger, so that the hot water exchanges heat with refrigerant flowing through the double-temperature-zone plate heat exchanger.

[0010] Further, the discharge pipe of the variable frequency compressor is connected to the d pipe of the four-way valve through an oil separator, the e pipe of the four-way valve is connected to the inlet pipe of the double-temperature-zone plate heat exchanger through a main gas pipe, the outlet pipe of the double-temperature-zone plate heat exchanger is connected to one end of the electronic expansion valve through a main liquid pipe, the other end of the electronic expansion valve is connected to one end of the outdoor heat exchanger, the other end of the outdoor heat exchanger is connected to the c pipe of the four-way valve, the s pipe of the four-way valve is connected to the inlet pipe of the gas-liquid separator, and the outlet pipe of the gas-liquid separator is connected to the gas return pipe of the variable frequency compressor.

[0011] Further, the temperature detection module comprises an exhaust temperature sensor, an environment temperature sensor, a coil temperature sensor, a gas return temperature sensor, a water return temperature sensor, a water outlet temperature sensor and a hot water temperature sensor,

[0012] The exhaust temperature sensor is used to detect the exhaust temperature T d , the environment temperature sensor is used to detect the environment temperature T ao , the coil temperature sensor is used to detect the coil temperature T def , the gas return temperature sensor is used to detect the gas return temperature T s , the water return temperature sensor is used to detect the water return temperature T w,inThe outlet water temperature sensor is used to detect the outlet water temperature T of the hot water flowing out of the heating heat exchange channel w,out The hot water temperature sensor is used to detect the tank hot water temperature T of the hot water tank tank .

[0013] A control method of a novel heating and hot water two-supply system, the control method is configured with a heating opening condition, a hot water opening condition and a heating+hot water operation opening condition,

[0014] If the preset heating opening condition is met, the heating operation control is entered, so that the heating module exchanges heat with the refrigerant flowing through the double-temperature-zone plate heat exchanger,

[0015] If the preset hot water opening condition is met, the hot water operation control is entered, so that the hot water module exchanges heat with the refrigerant flowing through the double-temperature-zone plate heat exchanger,

[0016] If the preset heating+hot water operation opening condition is met, the synchronous operation control is entered, so that the heating module and the hot water module synchronously exchange heat with the refrigerant flowing through the double-temperature-zone plate heat exchanger, if the preset heating closing condition is met, the hot water operation control is entered, and if the preset hot water closing condition is met, the heating operation control is entered.

[0017] Further, the heating opening condition includes the difference between the current return water temperature T detected by the return water temperature sensor w,in and the set return water temperature target T w,in,set and the preset return water temperature difference ΔT w,in,set .

[0018] The heating closing condition includes the sum of the current return water temperature T w,in and the set return water temperature target T w,in,set and the preset return water temperature difference ΔT w,in,set .

[0019] Further, the hot water opening condition includes the difference between the current tank hot water temperature T detected by the hot water temperature sensor w,tank and the set tank hot water temperature target T w,tank,set and the preset hot water temperature difference ΔT w,tank,set .

[0020] The hot water closing condition includes the sum of the current tank hot water temperature T w,tank and the set tank hot water temperature target T w,tank,set and the preset hot water temperature difference ΔT w,tank,set .

[0021] Further, the heating+hot water operation opening condition includes the difference between the current return water temperature T detected by the return water temperature sensor w,inless than a set return water temperature target T w,in,set a difference from a preset return water temperature ΔT w,in and a current water tank hot water temperature T w,tank less than a set water tank hot water temperature target T w,tank,set a difference from a preset hot water temperature ΔT w,tank,set ;

[0022] The total shutdown closing condition includes a current return water temperature T w,in greater than a set return water temperature target T w,in,set a difference from a preset return water temperature ΔT w,in,set and a current water tank hot water temperature T w,tank greater than a set water tank hot water temperature target T w,tank,set a difference from a preset hot water temperature ΔT w,tank,set .

[0023] Further, the control method is configured with an operation control strategy, including

[0024] obtaining a set return water temperature target T w,in,set and a hot water tank temperature target T w,tank,set ,

[0025] When performing heating operation control, adjusting the operation frequency of the variable frequency compressor with the return water temperature target T w,in,set as the control target;

[0026] When performing hot water operation control, adjusting the operation frequency of the variable frequency compressor with the water tank hot water temperature target T w,tank,set as the control target;

[0027] When performing synchronous operation control, comparing the larger value of the return water temperature target and the hot water tank temperature target and adjusting the operation frequency of the variable frequency compressor as the compressor control target, and if the return water temperature target is greater than the hot water tank temperature target, adjusting the proportional three-way valve to perform water mixing control, and if the return water temperature target is less than the hot water tank temperature target, the proportional three-way valve does not participate in adjustment.

[0028] Further, the synchronous operation control is configured with a three-way valve proportional adjustment strategy, including:

[0029] When the water tank hot water temperature target T w,tank,set is greater than the return water temperature target T w,in,set ,

[0030] If T w,in <T w,in,set -ΔT w,in,set , the proportional three-way valve a interface to b interface flows, a interface to f interface does not flow,

[0031] When T w,in,set -ΔT w,in,set ≤T w,in <T w,in,set +ΔT w,in,set , the proportional three-way valve a interface to b interface to flow, and a interface to f interface to flow,

[0032] When T w,in ≥T w,in,set +ΔT w,in,set , heating reaches the set temperature, heating stops running, the proportional three-way valve switches to a interface to b interface to flow, and a interface to f interface to not flow;

[0033] When the return water temperature target T w,in,set is greater than the water tank hot water temperature target T w,tank,set ,

[0034] The proportional three-way valve a interface to b interface to flow, and a interface to f interface to not flow.

[0035] Further, define the flow ratio X ab as the ratio of hot water flowing through the b interface to the hot water flowing through the a interface, the flow ratio X af as the ratio of hot water flowing through the f interface to the hot water flowing through the a interface, the three-way valve proportional regulation strategy includes a flow ratio adjustment sub-strategy, when the proportional three-way valve a interface to b interface to flow, and a interface to f interface to flow, the flow ratio adjustment sub-strategy is executed, including

[0036] When the current return water temperature T w,in rises, the flow ratio X ab is adjusted smaller, the flow ratio X af is adjusted larger, and the flow ratio X ab is set with a lower threshold, when X ab is adjusted to the lower threshold, the return water temperature T w,in still rises, the flow ratio X ab is maintained at the lower threshold;

[0037] When the current return water temperature T w,in falls, the flow ratio X ab is adjusted larger, and the flow ratio X af is adjusted smaller.

[0038] The technical effects of the present application mainly reflect in the following aspects:

[0039] As a core component, the double-temperature zone plate heat exchanger in the application realizes efficient heat exchange between refrigerant and water, supports simultaneous preparation of domestic hot water and heating hot water, and avoids the shutdown problem caused by mode switching in the traditional system. Further, the proportional three-way valve solves the problem of excessively high heating return water temperature through water mixing control, improving the system energy efficiency. In particular, the multi-mode operation mechanism supports heating, hot water, and hot water+heating three operation modes, which can flexibly meet the diversified needs of users. In addition, the system realizes intelligent control through various sensors and control algorithms, ensuring stable and reliable system operation and improving energy utilization efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 : A schematic diagram of the overall structure of a new heating and hot water two combined supply system;

[0041] Figure 2 : A schematic diagram of the system flow path of a new heating and hot water two combined supply system in a heating operation mode;

[0042] Figure 3 : A schematic diagram of the system flow path of a new heating and hot water two combined supply system in a hot water mode;

[0043] Figure 4 : A schematic diagram of the system flow path of a new heating and hot water two combined supply system in a heating+hot water operation mode;

[0044] Figure 5 : A schematic diagram of the control process of a new heating and hot water two combined supply system.

[0045] REFERENCE SIGNS:

[0046] 1, frequency conversion compressor; 2, high-pressure pressure sensor; 3, oil separator; 4, four-way valve; 5, double-temperature zone plate heat exchanger; 6, electronic expansion valve; 7, outdoor heat exchanger; 8, gas-liquid separator; 9, oil return capillary; 10, heating water pump; 11, proportional three-way valve; 12, buffer tank; 13, exhaust gas temperature sensor; 14, ambient temperature sensor; 15, coil temperature sensor; 16, return gas temperature sensor; 17, return water temperature sensor; 18, outlet water temperature sensor; 21, hot water tank; 22, hot water pump; 23, hot water temperature sensor. DETAILED DESCRIPTION

[0047] The specific embodiments of the application are further described in detail below with reference to the accompanying drawings, so that the technical scheme of the application is easier to understand and master.

[0048] EMBODIMENT:

[0049] A new heating and hot water two combined supply system, please refer to Figure 1, including a heat pump host module, a heating module and a hot water module; the heat pump host module includes a variable frequency compressor 1, an oil separator 3, a four-way valve 4, a double-temperature zone plate heat exchanger 5, an electronic expansion valve 6, an outdoor heat exchanger 7 and a gas-liquid separator 8 connected in sequence, and forms a refrigerant circulating main loop;

[0050] The double-temperature zone plate heat exchanger 5 is provided with a heating heat exchange flow channel and a hot water heat exchange flow channel, the heating heat exchange flow channel is connected with the heating module, the hot water heat exchange flow channel is connected with the hot water module, and the heating heat exchange flow channel and the hot water heat exchange flow channel are respectively provided for hot water flow, so that the heating module and the hot water module can be independently or synchronously heat exchanged with the refrigerant flowing through the double-temperature zone plate heat exchanger 5.

[0051] Further, the heating module includes a hot water return pipe, a hot water outlet pipe, a proportional three-way valve 11, a heating water pump 10 and a buffer tank 12, the hot water return pipe and the hot water outlet pipe are respectively connected with the heating heat exchange flow channel, the heating water pump 10 is installed on the hot water return pipe, the proportional three-way valve 11 includes a, b and f interfaces, the a and b interfaces of the proportional three-way valve 11 are connected on the hot water return pipe, the f interface of the proportional three-way valve 11 is connected to the hot water outlet pipe through the buffer tank 12, and the proportional three-way valve 11 is used for adjusting the proportion of hot water flowing through the heating heat exchange flow channel and the buffer tank 12.

[0052] Further, the hot water module includes a hot water tank and a hot water pump, the hot water tank is connected with the hot water heat exchange flow channel through a hot water circulating pipeline and forms a hot water circulating loop, and the hot water pump drives the hot water to circulate between the hot water tank and the double-temperature zone plate heat exchanger 5, so that the hot water is heat exchanged with the refrigerant flowing through the double-temperature zone plate heat exchanger 5.

[0053] Further, the exhaust pipe of the variable frequency compressor 1 is connected to the d pipe of the four-way valve 4 through the oil separator 3, the e pipe of the four-way valve 4 is connected to the gas inlet pipe of the double-temperature zone plate heat exchanger 5 through the main gas pipe, the liquid outlet pipe of the double-temperature zone plate heat exchanger 5 is connected to one end of the electronic expansion valve 6 through the main liquid pipe, the other end of the electronic expansion valve 6 is connected to one end of the outdoor heat exchanger 7, the other end of the outdoor heat exchanger 7 is connected to the c pipe of the four-way valve 4, the s pipe of the four-way valve 4 is connected to the gas inlet pipe of the gas-liquid separator 8, and the gas outlet pipe of the gas-liquid separator 8 is connected to the gas return pipe of the variable frequency compressor 1.

[0054] Further, it also includes a temperature detection module, the temperature detection module includes an exhaust temperature sensor, an environment temperature sensor, a coil temperature sensor, a return gas temperature sensor, a return water temperature sensor, an outlet water temperature sensor and a hot water temperature sensor 23,

[0055] The exhaust temperature sensor is used for detecting the exhaust temperature T dThe ambient temperature sensor is used to detect ambient temperature T ao The coil temperature sensor is used to detect coil temperature T def The return gas temperature sensor is used to detect return gas temperature T s The return water temperature sensor is used to detect return water temperature T w,in The outlet water temperature sensor is used to detect outlet water temperature T of hot water flowing out of the heating heat exchange flow channel w,out The hot water temperature sensor 23 is used to detect tank hot water temperature T of water in the hot water tank w,tank .

[0056] The system circulation flow path is further described below according to the operation mode:

[0057] 1. Operation mode

[0058] 1.1 Heating operation mode

[0059] The unit receives a "heating" operation instruction, the unit starts the soft start operation mode, the heating water pump 10 is started, the hot water pump 22 is closed, the variable frequency compressor 1 is operated at a certain frequency, the fan of the outdoor heat exchanger 7 is started, the opening degree of the electronic expansion valve 6 is opened according to a certain initial opening degree, after the soft start is completed, the variable frequency compressor 1 controls the operation frequency according to a certain return water temperature target, and the opening degree of the electronic expansion valve 6 is adjusted according to a certain return gas superheat target.

[0060] Heating pump circulation flow path combination Figure 2 The circulation process is as follows:

[0061] The refrigerant discharged by the variable frequency compressor 1 passes through the oil separator 3, the d pipe of the four-way valve 4, the e pipe of the four-way valve 4, and then enters the double-temperature-zone plate heat exchanger 5 to exchange heat, after the heat exchange, the refrigerant passes through the electronic expansion valve 6, the outdoor heat exchanger 7, and then passes through the c pipe and s pipe of the four-way valve 4, and then returns to the variable frequency compressor 1 through the gas-liquid separator 8, the heating water pump 10 pumps hot water to be transported from the a interface to the b interface of the proportional three-way valve 11, and the proportional three-way valve 11 maintains X ab =100% state, the hot water flowing out of the b interface exchanges heat with the refrigerant flowing through the double-temperature-zone plate heat exchanger 5 through the heating heat exchange flow channel, and the hot water absorbs the heat released by the refrigerant to increase the hot water temperature.

[0062] 1.2 Hot water operation mode

[0063] The unit receives a hot water operation instruction, the unit starts soft start mode, the hot water pump 22 is started, the heating water pump 10 is closed, the variable frequency compressor 1 is operated at a certain frequency, the fan of the outdoor heat exchanger 7 is started, the opening degree of the electronic expansion valve 6 is opened according to a certain initial opening degree, after the soft start is completed, the variable frequency compressor 1 controls the operation frequency according to a certain water tank hot water temperature target, and the opening degree of the electronic expansion valve 6 is adjusted according to a certain gas overheating target.

[0064] Hot water heat pump heat cycle flow path combination Figure 3 The circulation process is as follows:

[0065] The refrigerant discharged from the variable frequency compressor 1 passes through the oil separator 3, the d pipe of the four-way valve 4, the e pipe of the four-way valve 4, and then enters the double-temperature-zone plate heat exchanger 5 to exchange heat, and after heat exchange, the refrigerant passes through the electronic expansion valve 6, the outdoor heat exchanger 7, the c pipe and the s pipe of the four-way valve 4, and then returns to the variable frequency compressor 1 through the gas-liquid separator 8. The hot water pump 22 pumps hot water from the hot water tank 21 into the hot water heat exchange flow path, exchanges heat with the refrigerant flowing through the double-temperature-zone plate heat exchanger 5, and absorbs the heat released by the refrigerant.

[0066] 1.3 Heating + hot water operation control mode

[0067] The unit receives a hot water operation instruction, the unit starts soft start mode, the hot water pump 22 is started, the heating water pump 10 is closed, the variable frequency compressor 1 is operated at a certain frequency, the fan of the outdoor heat exchanger 7 is started, the opening degree of the electronic expansion valve 6 is opened according to a certain initial opening degree, after the soft start is completed, the variable frequency compressor 1 controls the operation frequency according to a certain water tank hot water temperature target and the maximum value of the return water set temperature as the control target to adjust the operation frequency of the variable frequency compressor 1, and the opening degree of the electronic expansion valve 6 is adjusted according to a certain gas overheating target. In this mode, when the water tank hot water temperature target is greater than the return water set temperature, the flow ratio of the proportional three-way valve 11 is adjusted, and when the water tank hot water temperature target is less than or equal to the return water set temperature, the variable frequency compressor 1 adjusts the operation frequency according to the set return water set temperature as the control target.

[0068] Hot water-heating two combined supply operation heat cycle combination Figure 4 The circulation process is as follows:

[0069] The refrigerant discharged from the variable frequency compressor 1 passes through the oil separator 3, the d pipe of the four-way valve 4, the e pipe of the four-way valve 4, and then enters the double-temperature-zone plate heat exchanger 5 to exchange heat, and after heat exchange, the refrigerant passes through the electronic expansion valve 6, the outdoor heat exchanger 7, the c pipe and the s pipe of the four-way valve 4, and then returns to the variable frequency compressor 1 through the gas-liquid separator 8.

[0070] When the water tank hot water temperature target T w,tank,set is greater than the return water temperature target T w,in,setAt that time, the heating water pump 10 pumps hot water from port a to port b and port f of the proportional three-way valve 11. The proportional three-way valve 11 can adjust the proportion of hot water flowing out from port b and port f. The hot water flowing out from port b exchanges heat with the refrigerant flowing through the dual-temperature zone plate heat exchanger 5 through the heating heat exchange channel. The hot water absorbs the heat released by the refrigerant and increases the hot water temperature. The hot water flowing out from port f merges with another hot water after passing through the buffer tank 12.

[0071] When the return water temperature target T w,in,set Greater than the target temperature T of the hot water in the water tank w,tank,set At that time, the heating water pump 10 pumps hot water from port a to port b of the proportional three-way valve 11, and the proportional three-way valve 11 maintains X ab =100% state.

[0072] Hot water pump 22 pumps hot water from hot water tank 21 into hot water heat exchange channel, where it exchanges heat with the refrigerant flowing through dual-temperature plate heat exchanger 5 and absorbs the heat released by the refrigerant.

[0073] A novel control method for a combined heating and hot water supply system, the control method comprising:

[0074] S1: Unit power-on initialization;

[0075] S2: Configured with preset heating start conditions, hot water start conditions, and heating + hot water operation start conditions.

[0076] If the heating start-up conditions are met, proceed to S3 for heating operation control;

[0077] If the hot water activation conditions are met, proceed to step S4 to control the hot water operation.

[0078] If the conditions for starting the heating and hot water operation are met, then proceed to S5 for synchronous operation control;

[0079] S3: In heating mode, the target return water temperature T is set. w,in,set To control the target and adjust the operating frequency of the variable frequency compressor 1, a preset heating shutdown condition is configured. If the heating shutdown condition is met, the heating operation will stop.

[0080] S4: In hot water mode, the target hot water temperature T in the water tank is set. w,tank,set To control the target and adjust the operating frequency of the variable frequency compressor 1, a preset hot water shut-off condition is configured. If the hot water shut-off condition is met, the hot water operation will stop.

[0081] S5: In heating + hot water operation control mode, compare with the set return water temperature target T. w,in,set and the set target hot water temperature T in the water tankw,tank,set The parameter with larger value is taken as the control target to adjust the operation frequency of the variable frequency compressor 1, and preset all-stop closing condition, hot water closing condition and heating closing condition are configured, if the all-stop closing condition is met, the heating module and the hot water module are all stopped, if the hot water closing condition is met, the hot water operation is stopped and S3 is entered to control the heating operation, if the heating closing condition is met, the heating operation is stopped and S4 is entered to control the hot water operation.

[0082] Further, the heating opening condition includes the current return water temperature T w,in less than the set return water temperature target T w,in,set the return difference ΔT w,in,set of the preset return water temperature.

[0083] The heating closing condition includes the current return water temperature T w,in greater than the set return water temperature target T w,in,set the return difference ΔT w,in,set of the preset return water temperature.

[0084] Further, the hot water opening condition includes the current tank hot water temperature T w,tank less than the set tank hot water temperature target T w,tank,set the return difference ΔT w,tank,set of the preset hot water temperature.

[0085] The hot water closing condition includes the current tank hot water temperature T w,tank greater than the set tank hot water temperature target T w,tank,set the return difference ΔT w,tank,set of the preset hot water temperature.

[0086] Further, the heating+hot water operation opening condition includes the current return water temperature T w,in less than the set return water temperature target T w,in,set the return difference ΔT w,in of the preset return water temperature, and the current tank hot water temperature T w,tank less than the set tank hot water temperature target T w,tank,set the return difference ΔT w,tank,set of the preset hot water temperature.

[0087] The all-stop closing condition includes the current return water temperature T w,in greater than the set return water temperature target T w,in,set the return difference ΔT w,in,set of the preset return water temperature, and the current tank hot water temperature Tw,tank greater than a set hot water tank temperature target T w,tank,set and a preset hot water temperature return difference ΔT w,tank,set .

[0088] Further, in step S5, when the hot water tank temperature target T w,tank,set is greater than the hot water return temperature target T w,in,set , a three-way valve proportional adjustment strategy is configured, defining a flow ratio X ab as the ratio of hot water flowing through the b interface to hot water flowing through the a interface, the flow ratio X af as the ratio of hot water flowing through the f interface to hot water flowing through the a interface, the three-way valve proportional adjustment strategy comprising

[0089] If T w,in <T w,in,set -ΔT w,in,set , the proportional three-way valve a to b flows, the flow ratio X ab =100%, a to f does not flow, and the flow ratio X af =0;

[0090] When T w,in,set -ΔT w,in,set ≤T w,in <T w,in,set +ΔT w,in,set , the proportional three-way valve distributes the flow in a certain ratio, a to b flows, and a to f flows: when the current hot water return temperature T w,in rises, the flow ratio X ab is reduced, the flow ratio X af is increased, and the flow ratio X ab is provided with a lower limit threshold, when X ab is reduced to the lower limit threshold, and the hot water return temperature T w,in still rises, the flow ratio X ab maintains the lower limit threshold; when the current hot water return temperature T w,in falls, the flow ratio X ab is increased, and the flow ratio X af is reduced;

[0091] When T w,in ≥T w,in,set +ΔT w,in,set , the heating reaches the set temperature, the heating stops running, and the proportional three-way valve switches to X ab =100% state and remains.

[0092] In step S5, when the hot water return temperature target T w,in,set is greater than the hot water tank temperature target T w,tank,set , the proportional three-way valve 11a to b flows, the flow ratio Xab =100%, a to f not flow, the proportion of X af =0.

[0093] The following further introduces in combination with specific operation modes:

[0094] 2. Control of various operation modes

[0095] 2.1 Heating operation control

[0096] 2.1.1 Start condition

[0097] The unit receives the "heating" operation instruction, the heating water pump 10 starts to run, at the same time, the return water temperature sensor 17 and the outlet water temperature sensor 18 detect the return water temperature T w,in and the outlet water temperature T w,out , meet all the following heating start conditions, the unit starts to heat.

[0098] 1) The current return water temperature T w,in detected by the return water temperature sensor 17 is less than the set return water temperature target T w,in,set and the difference between the return water temperature difference ΔT w,in,set , that is: T w,in <T w,in,set -ΔT w,in,set , the return water temperature difference ΔT w,in is generally 1-2℃;

[0099] 2) The water flow switch detects normal water flow;

[0100] 3) The unit does not detect fault, and the shutdown is more than 3min.

[0101] 2.1.2 Operation control

[0102] At the same time, meet all the above heating start conditions, the unit starts to run, the compressor starts, the fan on the outdoor heat exchanger 7 starts to run, the hot water pump 22 stops, the electronic expansion valve 6 adjusts its opening according to a certain superheat, the specific control is as follows:

[0103] The variable frequency compressor 1 first performs soft start control, the variable frequency compressor 1 starts to run to the reference frequency Fr0, and then runs at the frequency for a soft start running time t0, and then adjusts the frequency with the set return water temperature target T w,in,set as the control target.

[0104] When the current return water temperature T w,in is less than the set return water temperature target T w,in,set and the difference between the return water temperature difference ΔT w,in,set , that is T w,in <T w,in,set -ΔTw,in,set The variable frequency compressor 1 is adjusted at a certain frequency increasing rate Fr up every certain time t ad .

[0105] When the current return water temperature T w,in is greater than or equal to the set return water temperature target T w,in,set plus the return water temperature difference ΔT w,in,set , but less than or equal to the set return water temperature target T w,in,set , that is, T w,in,set - ΔT w,in,set ≤ T w,in ≤ T w,in,set , the variable frequency compressor 1 maintains the current operating frequency.

[0106] When the current return water temperature T w,in is greater than the set return water temperature target T w,in,set , but less than or equal to the sum of the set return water temperature target T w,in,set and the return water temperature difference ΔT w,in,set , that is, T w,in,set < T w,in ≤ T w,in,set + ΔT w,in , the compressor is adjusted at a certain frequency decreasing rate Fr down every certain time t ad .

[0107] When the current return water temperature T w,in is greater than the set return water temperature target T w,in,set plus the return water temperature difference ΔT w,in,set (typically 1-2℃), that is, T w,in > T w,in,set + ΔT w,in,set , it indicates that the unit reaches the set control target, the unit stops running, the variable frequency compressor 1 stops, the fan of the outdoor heat exchanger 7 stops running, and the heating water pump 10 stops after running for a certain time t on-off .

[0108] In the soft start stage, the main electronic expansion valve 6 is opened at a certain initial opening degree, and the set value is V0. After the soft start operation is completed, the opening degree is adjusted according to a certain suction superheat degree target value ΔT s,set , and the superheat degree ΔT s is defined as the suction temperature T s detected by the suction temperature sensor minus the temperature T def detected by the coil temperature sensor 15 of the outdoor heat exchanger 7.

[0109] 2.2 Hot water operation control

[0110] 2.2.1 Start-up condition

[0111] The unit receives a hot water operation instruction, the hot water pump 22 starts to operate, and the heating water pump 10 stops to operate. At the same time, the hot water temperature sensor 23 detects the hot water temperature T w,tank , and all the following hot water start-up conditions are met, the unit starts to produce hot water.

[0112] 1) The current water tank hot water temperature T w,tank detected by the hot water temperature sensor 23 is less than the set water tank hot water temperature target T w,tank,set minus the hot water temperature hysteresis ΔT w,tank,set (generally 1-2℃), that is: T w,tank <T w,tank,set -ΔT w,tank,set ;

[0113] 2) The water flow switch detects normal water flow;

[0114] 3) The unit does not detect a fault, and the shutdown is more than 3 min.

[0115] 2.2.2 Operation control

[0116] The unit starts to operate, the variable frequency compressor 1 starts, the fan on the outdoor heat exchanger 7 starts to operate, the heating water pump 10 stops, and the electronic expansion valve 6 adjusts its opening degree according to a certain superheat degree. The specific control is as follows:

[0117] The variable frequency compressor 1 first performs soft start control, and after starting to operate to the reference frequency Fr0 operating frequency, it operates at the frequency for a soft start operating time t0, and then adjusts the frequency with the set water tank hot water temperature target T w,tank,set as the control target.

[0118] When the current water tank hot water temperature T w,tank is less than the difference between the set water tank hot water temperature target T w,in,set and the hot water temperature hysteresis ΔT w,tank,set , that is, T w,tank <T w,tank,set -ΔT w,tank,set , the variable frequency compressor 1 adjusts according to a certain frequency increasing rate, and adjusts once every certain time t ad .

[0119] When the current water tank hot water temperature T w,tank is greater than or equal to the difference between the set water tank hot water temperature target T w,tank,set and the set hot water temperature hysteresis ΔT w,tank,set , but is less than or equal to the set water tank hot water temperature target T w,tank,set , that is, T w,tank,set -ΔTw,tank,set ≤T w,tank ≤T w,tank,set , the variable frequency compressor 1 keeps the current operating frequency.

[0120] When the current water tank hot water temperature T w,tank is greater than the set water tank hot water temperature target T w,tank,set , but less than or equal to the set water tank hot water temperature target T w,tank,set plus the hysteresis ΔT w,tank,set of the hot water temperature, that is, T w,tank,set <T w,tank ≤T w,tank,set + ΔT w,tank,set , the variable frequency compressor 1 is adjusted at a certain frequency reduction rate, and is adjusted once every certain time t ad .

[0121] When the current water tank hot water temperature T w,tank is greater than the set water tank hot water temperature target T w,tank,set plus the hysteresis ΔT w,tank.set of the hot water temperature (generally 1-2°C), that is, T w,tank >T w,tank,set + ΔT w,tank,set , it indicates that the unit reaches the set control target, the unit stops running, the variable frequency compressor 1 stops, the fan on the outdoor heat exchanger 7 stops running, and the hot water pump 22 stops running after running for a period of time t on-off .

[0122] In the soft start stage, the main machine electronic expansion valve 6 opens a certain initial opening degree, and the set value is V0. After the soft start operation is completed, the opening degree is adjusted according to a certain suction superheat degree target value ΔT s,set , and the superheat degree ΔT s is defined as the suction temperature T s detected by the suction temperature sensor minus the temperature T def detected by the coil temperature sensor of the outdoor heat exchanger.

[0123] 2.3 Hot water + heating operation control

[0124] 2.3.1 Start condition

[0125] When the unit receives the "heating + hot water" operation instruction, the heating water pump 10 starts running, the hot water pump 22 starts running, and at the same time, the return water temperature sensor 17 and the outlet water temperature sensor 18 detect the return water temperature and the outlet water temperature respectively, and the hot water temperature sensor 23 detects the hot water temperature T w,tank , all of the following heating + hot water operation start conditions are met, and the unit starts to produce hot water and heating operation.

[0126] 1) Current return water temperature T detected by return water temperature sensor 17 w,in Less than set return water temperature target T w,in,set Subtract return water temperature difference ΔT w,in That is: T w,in <T w,in,set - ΔT w,in .

[0127] 2) Current tank hot water temperature T detected by hot water temperature sensor 23 w,tank Less than set tank hot water temperature target T w,tank,set Subtract hot water temperature difference ΔT w,tank,set That is: T w,tank <T w,tank,set - ΔT w,tank,set .

[0128] 3) Water flow switch detects normal water flow;

[0129] 4) Unit does not detect fault, and shutdown for more than 3 min.

[0130] If all the above heating + hot water operation opening conditions are met, the unit opens the "heating + hot water" mode operation.

[0131] If the above conditions cannot be met at the same time, the "hot water" opening condition and the "heating" opening condition are determined respectively, and the opening conditions of each operation mode are met. Corresponding control of each operation mode is carried out.

[0132] 2.3.2 Operation control

[0133] At the same time, the above heating + hot water operation opening conditions are met, the unit is opened and operated, the frequency conversion compressor 1 is started, the fan on the outdoor heat exchanger 7 is opened and operated, the heating water pump 10 is opened and operated, the hot water pump 22 is opened and operated, and the main machine electronic expansion valve 6 is opened to a certain initial opening degree.

[0134] 1) Frequency conversion compressor 1 operation control

[0135] If the heating + hot water operation opening condition is met, compare the set hot water temperature T w,tank,set and the set return water set water temperature T w,in,set of the heating operation mode, take the larger target value max {T w,tank,set ,T w,in,set as the control target, and control the operation frequency of the frequency conversion compressor 1.

[0136] The frequency conversion compressor 1 first performs soft start control, starts to run to the reference frequency Fr0 operation frequency, and then runs at the frequency for a soft start running time t0, and then runs at max {T w,tank,set ,T w,in,setis taken as the control target to adjust the frequency.

[0137] The first case:

[0138] The water tank hot water temperature T w,tank,set is greater than the return water temperature target T w,in,set of the heating operation mode.

[0139] The variable frequency compressor 1 first performs soft start control, and after starting to run at the reference frequency Fr0, it runs at this frequency for a soft start running time t0, and then runs at the set water tank hot water temperature target T w,tank,set is taken as the control target to adjust the frequency.

[0140] When the current water tank hot water temperature T w,tank is less than the difference between the set water tank hot water temperature target T w,tank,set and the return difference ΔT w,tank,set of the hot water temperature, that is: T w,tank <T w,tank,set -ΔT w,tank.set , the variable frequency compressor 1 adjusts at a certain frequency increasing rate, and adjusts once every certain time t ad .

[0141] When the current water tank hot water temperature T w,tank is greater than or equal to the difference between the set water tank hot water temperature target T w,tank,set and the set hot water temperature return difference ΔT w,tank,set , but is less than or equal to the set water tank hot water temperature target T w,tank,set , that is: T w,tank,set -ΔT w,tank,set ≤T w,tank ≤T w,tank,set , the variable frequency compressor 1 maintains the current running frequency.

[0142] When the current water tank hot water temperature T w,tank is greater than the set water tank hot water temperature target T w,tank,set , but is less than or equal to the sum of the set water tank hot water temperature target T w,tank,set and the hot water temperature return difference ΔT w,tank,set , that is: T w,tank,set <T w,tank ≤T w,tank,set +ΔT w,tank,set , the variable frequency compressor 1 adjusts at a certain frequency decreasing rate, and adjusts once every certain time t ad .

[0143] When the current water tank hot water temperature T w,tank is greater than the set water tank hot water temperature target T w,tank,setThe temperature difference ΔT of hot water temperature w,tank,set (usually 1-2℃), that is, T w,tank > T w,tank,set + ΔT w,tank,set , indicating that the unit reaches the set control target, hot water stops heating, and the hot water pump 22 runs for a period of time t on-off and then stops.

[0144] Next, it is determined whether the heating operation mode is reached, and if the heating-off condition is not reached, the heating operation mode is maintained, and the control method is controlled according to the heating operation mode. If both operation modes meet the off condition, the unit stops running.

[0145] When both modes are running at the same time, for the heating operation mode: A, the return water temperature target T w,in,set is higher than the hot water tank temperature target T w,tank,set , the frequency of the variable frequency compressor 1 is adjusted according to the set return water temperature target T w,in,set , the proportional three-way valve 11 does not need to be adjusted, and at this time the proportional three-way valve a to b is in flow, the flow ratio X ab = 100%, a to f is not in flow, the flow ratio X af = 0, otherwise both the frequency of the variable frequency compressor 1 and the proportional three-way valve 11 are adjusted, and the system is difficult to run stably. B, the hot water tank temperature target T w,tank,set is higher than the return water temperature target T w,in,set , because the variable frequency compressor 1 runs at the frequency adjusted according to the set hot water tank temperature target T w,tank,set , in order to ensure the stability of the water temperature on the heating side, reduce the number of heating side temperature rises, and avoid frequent start and stop of the system, the proportional three-way valve 11 is used to participate in the water mixing control to achieve: the proportional three-way valve 11 participates in the water mixing control, adjusts the water flow of the return water into the double-temperature zone plate heat exchanger 5, and the specific control is as follows:

[0146] If T w,in <T w,in,set - ΔT w,in,set , the proportional three-way valve a to b is in flow, the flow ratio X ab = 100%, a to f is not in flow, and the flow ratio X af = 0.

[0147] When T w,in,set - ΔT w,in,set ≤ T w,in <T w,in,set + ΔT w,in,set , the proportional three-way valve distributes the flow according to a certain proportion, a to b is in flow, and a to f is in flow: when the current return water temperature T w,in rises, the flow ratio X ab is reduced, the flow ratio Xaf increased, and the flow ratio X ab is set with a lower limit threshold value when X ab is decreased to the lower limit threshold value, the return water temperature T w,in still rises, the flow ratio X ab maintains the lower limit threshold value; when the current return water temperature T w,in drops, the flow ratio X ab is increased, and the flow ratio X af is decreased;

[0148] When T w,in > T w,in,set + ΔT w,in,set , the heating reaches the set temperature, the heating stops running, the proportional three-way valve switches to X ab = 100% state and remains.

[0149] The second case:

[0150] The return water temperature target T w,in,set of the heating operation mode is greater than the hot water tank hot water temperature target T w,tank,set of the hot water operation mode, and the variable frequency compressor 1 is controlled as follows:

[0151] The variable frequency compressor 1 first performs soft start control, and after starting to run at the reference frequency Fr0, it runs at the frequency for a soft start running time t0, and then adjusts the frequency with the set return water temperature target T w,in,set as the control target.

[0152] When the current return water temperature T w,in is less than the difference between the set return water temperature target T w,in,set and the return water temperature difference ΔT w,in,set , that is, T w,in < T w,in,set - ΔT w,in,set , the compressor adjusts according to a certain frequency increasing rate, and adjusts once every certain time t ad .

[0153] When the current return water temperature T w,in is greater than or equal to the difference between the set return water temperature target T w,in,set and the return water temperature difference ΔT w,in,set , but is less than or equal to the set return water temperature target T w,in,set , that is, T w,in,set - ΔT w,in,set ≤ T w,in ≤ T w,in,set , the variable frequency compressor 1 maintains the current running frequency.

[0154] When the current return water temperature T w,ingreater than the set return water temperature target T w,in,set but less than or equal to the set return water temperature target T w,in,set and the return difference ΔT w,in,set of the return water temperature, i.e. T w,in,set <T w,in ≤T w,in,set +ΔT w,in , the compressor is adjusted at a certain frequency reduction rate Fr down , and adjusted once every certain time t ad .

[0155] When the current return water temperature T w,in is greater than the set return water temperature target T w,in,set plus the return difference ΔT w,in,set of the return water temperature (generally 1-2℃), i.e. T w,in >T w,in,set +ΔT w,in,set , it indicates that the unit reaches the set control target, and the heating operation stops, and the heating water pump 10 stops after running for a period of time t on-off .

[0156] In this case, the proportional three-way valve 11 does not participate in the adjustment, and the flow ratio X ab =100%.

[0157] Determine the hot water operation mode, and if the shutdown condition is not met, maintain the hot water operation mode, and the control method is controlled according to the hot water operation mode. If both operation modes meet the shutdown condition at the same time, the unit stops running.

[0158] 2) Control of electronic expansion valve 6

[0159] The control of the electronic expansion valve 6, the soft start stage, the electronic expansion valve 6 is opened to a certain initial opening degree, and the set value is V0. After the soft start operation is completed, the opening degree of the electronic expansion valve 6 is adjusted according to a certain suction superheat degree target value ΔT s,set , and the superheat degree ΔT s is defined as the suction temperature T s detected by the suction temperature sensor minus the temperature T def detected by the coil temperature sensor of the outdoor heat exchanger.

[0160] 2.4 Operation mode addition

[0161] When the heating operation mode is performed, the "hot water" is turned on, and the control method is the same as that in 2.3. The larger value of the water tank hot water temperature target and the return water temperature target in the two operation modes is taken as the control target of the frequency of the variable frequency compressor 1.

[0162] Likewise, when the hot water operation mode is performed, "heating" is turned on, and the control method is the same as that in 2.3. The greater value between the water tank hot water temperature target and the return water temperature target in the two operation modes is taken as the control target of the frequency of the variable frequency compressor 1.

[0163] Of course, the above is only a typical example of the present application, in addition to which the present application can have other various specific embodiments, and any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of the present application.

Claims

1. A combined heating and hot water supply system, characterized in that: The heat pump main module, the heating module and the hot water module; the heat pump main module comprises a variable frequency compressor (1), an oil separator (3), a four-way valve (4), a double-temperature zone plate heat exchanger (5), an electronic expansion valve (6), an outdoor heat exchanger (7) and a gas-liquid separator (8) connected in sequence, and forms a refrigerant circulating main circuit; The double-temperature zone plate heat exchanger (5) is provided with a heating heat exchange flow channel and a hot water heat exchange flow channel, the heating heat exchange flow channel is connected with the heating module, the hot water heat exchange flow channel is connected with the hot water module, and the heating heat exchange flow channel and the hot water heat exchange flow channel are respectively provided for hot water flow, so that the heating module and the hot water module can be independently or synchronously heat exchanged with the refrigerant flowing through the double-temperature zone plate heat exchanger (5); The heating module comprises a hot water return pipe, a hot water outlet pipe, a proportional three-way valve (11), a heating water pump (10) and a buffer tank (12), the hot water return pipe and the hot water outlet pipe are respectively connected with the heating heat exchange flow channel, the heating water pump (10) is installed on the hot water return pipe, the proportional three-way valve (11) comprises a port a, a port b and a port f, the port a and the port b of the proportional three-way valve (11) are connected on the hot water return pipe, the port f of the proportional three-way valve (11) is connected to the hot water outlet pipe through the buffer tank (12), and the proportional three-way valve (11) adjusts the proportion of hot water flowing from the port a to the port b and the port f to adjust the proportion of hot water flowing through the heating heat exchange flow channel and the buffer tank (12).

2. The combined heating and hot water supply system according to claim 1, characterized by: The hot water module comprises a hot water tank (21) and a hot water pump (22), the hot water tank is connected with the hot water heat exchange flow channel through a hot water circulating pipeline and forms a hot water circulating circuit, and the hot water pump drives the hot water to circulate between the hot water tank and the double-temperature zone plate heat exchanger (5), so that the hot water is heat exchanged with the refrigerant flowing through the double-temperature zone plate heat exchanger (5).

3. The combined heating and hot water supply system according to claim 1, characterized by: The exhaust pipe of the variable frequency compressor (1) is connected to the d pipe of the four-way valve (4) through the oil separator (3), the e pipe of the four-way valve (4) is connected to the gas inlet pipe of the double-temperature zone plate heat exchanger (5) through the main gas pipe, the liquid outlet pipe of the double-temperature zone plate heat exchanger (5) is connected to one end of the electronic expansion valve (6) through the main liquid pipe, the other end of the electronic expansion valve (6) is connected to one end of the outdoor heat exchanger (7), the other end of the outdoor heat exchanger (7) is connected to the c pipe of the four-way valve (4), the s pipe of the four-way valve (4) is connected to the gas inlet pipe of the gas-liquid separator (8), and the gas outlet pipe of the gas-liquid separator (8) is connected to the gas return pipe of the variable frequency compressor (1).

4. The combined heating and hot water supply system according to claim 2, characterized by: Further comprising a temperature detection module, the temperature detection module comprises an exhaust temperature sensor (13), an environment temperature sensor (14), a coil temperature sensor (15), a gas return temperature sensor (16), a water return temperature sensor (17), a water outlet temperature sensor (18) and a hot water temperature sensor (23), The exhaust temperature sensor (13) is used to detect the exhaust temperature T d The ambient temperature sensor (14) is used to detect the ambient temperature T ao The coil temperature sensor (15) is used to detect the coil temperature T def The return gas temperature sensor (16) is used to detect the return gas temperature T s The return water temperature sensor (17) is used to detect the return water temperature T w,in The outlet water temperature sensor (18) is used to detect the outlet water temperature T w,out The hot water temperature sensor (23) is used to detect the tank hot water temperature T w,tank in the hot water tank.

5. A control method of a heating and hot water two-in-one system, applied to the heating and hot water two-in-one system according to any one of claims 1-4, characterized in that: The control method is configured with a heating opening condition, a hot water opening condition and a heating+hot water operation opening condition, If the preset heating opening condition is met, the heating operation control is entered, so that the heating module is heat exchanged with the refrigerant flowing through the double-temperature zone plate heat exchanger (5), If the preset hot water opening condition is met, the hot water operation control is entered, so that the hot water module exchanges heat with the refrigerant flowing through the double-temperature-zone plate heat exchanger (5), If the preset heating + hot water operation opening condition is met, the synchronous operation control is entered, so that the heating module and the hot water module synchronously exchange heat with the refrigerant flowing through the double-temperature-zone plate heat exchanger (5), if the preset heating closing condition is met, the hot water operation control is entered, and if the preset hot water closing condition is met, the heating operation control is entered; The control method is configured with an operation control strategy, including: Obtaining a set return water temperature target T w,in,set and a water tank hot water temperature target T w,tank,set , When the heating operation control is performed, the return water temperature target T w,in,set is used as a control target to adjust the operation frequency of the variable frequency compressor (1); When the hot water operation control is performed, the water tank hot water temperature target T w,tank,set adjusts the operation frequency of the variable frequency compressor (1) as a control target; When the synchronous operation control is performed, the larger value of the return water temperature target and the water tank hot water temperature target is compared and taken as a compressor control target to adjust the operation frequency of the variable frequency compressor (1), and if the return water temperature target is greater than the water tank hot water temperature target, the proportional three-way valve is adjusted for water mixing control, and if the return water temperature target is less than the water tank hot water temperature target, the proportional three-way valve does not participate in adjustment.

6. The control method of a combined heating and hot-water supply system according to claim 5, characterized by, The synchronous operation control is configured with a three-way valve proportional adjustment strategy, including: When the hot water tank temperature target T w,tank,set is greater than the return water temperature target T w,in,set , If T w,in <T w,in,set -ΔT w,in,set When T -ΔT w,in,set When T -ΔT w,in,set When T -ΔT w,in,set When T -ΔT w,in,set When T -ΔT w,in,set When T -ΔT w,in,set When T -ΔT w,in,set When T -ΔT <000001 When T w,in,set - ΔT w,in,set ≤ T w,in < T w,in,set + ΔT w,in,set , the proportional three-way valve (11) a interface to b interface to the flow, and a interface to f interface to the flow, When T w,in ≥ T w,in,set + ΔT w,in,set , heating reaches the set temperature, heating stops running, and the proportional three-way valve switches to a interface to b interface to flow, and a interface to f interface to not flow. When the return water temperature target T w,in,set is greater than the water tank hot water temperature target T w,tank,set , The a interface to the b interface of the proportional three-way valve (11) is open to flow, and the a interface to the f interface is open to not flow.

7. The control method of the combined heating and hot-water supply system according to claim 6, characterized by: Definition of flow ratio X ab is the ratio of hot water flowing through the b port to the hot water flowing through the a port, the flow ratio X af is the ratio of hot water flowing through the f port to the hot water flowing through the a port, the three-way valve ratio regulation strategy comprises a flow ratio regulation sub-strategy, which is executed when the a port to b port of the ratio three-way valve (11) is flowing to the flow and the a port to f port is flowing to the flow, comprising When the current backwater temperature T w,in increases, the flow ratio X ab is decreased, the flow ratio X af is increased, and the flow ratio X ab is set with a lower threshold value when X ab decreases to the lower threshold value, the backwater temperature T w,in still increases, the flow ratio X ab is maintained at the lower threshold value; When the current backwater temperature T w,in decreases, the flow ratio X ab increases, the flow ratio X af decreases. 8.The control method of the combined heating and hot water supply system according to claim 5, characterized in that: The heating opening condition includes a current return water temperature T detected by a return water temperature sensor (17) w,in Less than a set return water temperature target T w,in,set A return water temperature difference ΔT from a preset return water temperature w,in,set The difference value; The heating-off condition includes a current return water temperature T w,in greater than a set return water temperature target T w,in,set a return water temperature difference ΔT w,in,set from a preset return water temperature; The hot water opening condition includes a current water tank hot water temperature T detected by a hot water temperature sensor (23) w,tank Less than a set water tank hot water temperature target T w,tank,set A difference from a preset hot water temperature ΔT w,tank,set The difference value; The hot water off condition comprises a current water tank hot water temperature T w,tank greater than a set water tank hot water temperature target T w,tank,set a back difference ΔT from a preset hot water temperature w,tank,set the sum; When the heating opening condition and the hot water opening condition are met at the same time, the heating + hot water operation opening condition is considered to be met.

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