Test device and test method for heat output of heat pump water heater

Abstract

A test device and test method for a heat output of a heat pump water heater. The device comprises: a water tank (5) water inlet temperature sensor (1) and a water tank (5) water outlet temperature sensor (2); a flow meter (3), which is provided on a refrigerant liquid return pipe (6) between a heat pump water heater main unit (4) and the water tank (5); a sampling tank (7), which is provided on the refrigerant liquid return pipe (6); a refrigerant pipe inlet-to-water-tank temperature sensor (11) and a refrigerant pipe outlet-from-water-tank temperature sensor (12); two pressure sensors; an electric heating tank (8), which is connected in series between the water inlet and the water outlet of the water tank (5); and a circulating water pump (9), which is connected in series between the electric heating tank (8) and the water tank (5). The power supply end of an electric heating element is connected to an electric energy meter. The technical problems in the prior art of test failure and increased test cost caused by failing to accurately control the test duration for a heat pump water heater and the average temperature of a water tank during heat pump water heater performance testing can be solved.

Description

A heat pump water heater heat quantity detection device and detection method

[0001] The present application claims priority from Chinese Patent Application No. CN202411139548.4, filed on August 20, 2024, entitled "A heat pump water heater heat quantity detection device and detection method", which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of heat pump water heaters, and in particular to a heat pump water heater heat quantity detection device and detection method. BACKGROUND

[0003] A heat pump water heater is a device that, based on the inverse Carnot cycle, transfers heat energy in a low-temperature heat source to a high-temperature heat source through the circulation of refrigerant between an evaporator and a condenser, thereby heating the water temperature. However, the test method and test device provided in the existing standard are affected by pipe and standard water tank heat leakage, and there is a large test uncertainty in itself, with large deviation and poor consistency of the measured results.

[0004] To solve the above problems, the patent document with authorization announcement No. CN106768495B discloses a commercial circulating heat pump water heater performance test device and test method. The device includes a water outlet temperature measuring element, a water inlet temperature measuring element, a standard water tank, a three-way valve, and a connecting pipeline. The three ports of the three-way valve are respectively connected with the water outlet pipeline of the measured machine, the constant temperature water inlet pipeline, and the standard water tank. A flow meter is arranged on the water inlet pipeline between the three-way valve and the standard water tank. A water pump is arranged on the water outlet pipeline of the standard water tank. The heat pump heat quantity of the measured machine is directly calculated by the measured inlet and outlet water temperature and water flow. The water injection quantity is controlled by the three-way valve and the flow meter, which reduces the interference factors in the test process and improves the test precision of the heat pump heat quantity.

[0005] However, for the heat pump water heater equipped with a water tank, it is mostly static heating type, mainly by embedding heating coil in the water tank, using the heating coil to transfer the heat of the refrigerant to the water in the water tank to heat the water in the water tank, and the water in the water tank has poor flowability, so that the water in the water tank can only rely on static heat transfer, which makes the heating uneven and there is obvious temperature gradient, resulting in that the water temperature detected by the sensor of the product is not the average temperature of the water tank in the true sense, so that after the test is completed, the temperature of the water tank after mixing water exceeds the requirement of 55±0.5℃ according to the standard, the test fails, and additional time, manpower and material resources need to be invested to retest, resulting in increased cost of performance test; in addition, the above test device and test method calculate the heating capacity of the host side by measuring the water temperature at the inlet and outlet of the host, the circulating water flow and the heating time, which does not consider the heat leakage and heat storage of the pipeline and the water tank, so that the test result has large deviation from the actual use, losing practical significance. SUMMARY

[0006] The present application provides a heat pump water heater heating capacity detection device and detection method to solve the technical problems that the heat pump water heater performance test in the prior art cannot realize accurate control of the test duration and the average temperature of the water tank during the test of the heat pump water heater, resulting in test failure and increased test cost.

[0007] To solve the above problems, the heat pump water heater heating capacity detection device provided by the present application adopts the following technical scheme:

[0008] A heat pump water heater heating capacity detection device, comprising a water tank inlet temperature sensor and a water tank outlet temperature sensor, further comprising:

[0009] A flow meter arranged on a refrigerant return pipe between a heat pump water heater host and a water tank for measuring the refrigerant flow;

[0010] A sampling tank arranged on the refrigerant return pipe for sampling the mixture of refrigerant and oil in the refrigerant return pipe;

[0011] A refrigerant pipe inlet water tank temperature sensor and a refrigerant pipe outlet water tank temperature sensor;

[0012] Two pressure sensors, respectively located at the refrigerant pipe inlet water tank temperature sensor and the refrigerant pipe outlet water tank temperature sensor;

[0013] An electric heating tank connected in series between the inlet and outlet of the water tank, and an electric heating pipe detachably installed in the electric heating tank;

[0014] A circulating water pump connected in series between the electric heating tank and the water tank;

[0015] The power supply end of the electric heating pipe is connected with an electric energy integrator.

[0016] The heat pump water heater heat output detection device provided by the application has the beneficial effects that: temperature sensors are arranged at the water inlet and outlet of the water tank, an electric heating tank and a circulating water pump are arranged between the water inlet and outlet of the water tank, the heat loss and heat storage of the water tank can be calculated by the weight of the water in the water tank, the change of the water temperature, the specific heat capacity of the water, the heating power of the electric heating pipe in the electric heating tank and the heating time, the flow meter and the sampling tank are arranged on the refrigerant return pipe, the refrigerant is sampled by the sampling tank, the refrigerant flow data are collected by the flow meter, the temperature and pressure of the refrigerant entering and leaving the water tank are measured by the temperature sensor and the pressure sensor on the refrigerant pipe, the enthalpy of the refrigerant can be obtained by referring to the table according to the pressure and temperature, the refrigerant is weighed after sampling is completed and is recovered in the sampling tank, the specific gravity and density of the refrigerant in the mixture are obtained, and the refrigerant heat output can be calculated according to the weight of the refrigerant, the refrigerant flow and the enthalpy difference; the total heat absorbed by the water to reach the target temperature can be obtained according to the specific heat capacity, the weight and the temperature change of the water, the total heat is compared with the cumulative refrigerant heat output per second, and the unit stops working when the two are equal, so that the water meeting the temperature requirement can be obtained, and the precise control of the test duration and the average temperature of the water tank of the heat pump water heater is realized.

[0017] Further, the sampling tank is provided with a heating belt.

[0018] Beneficial effect: the refrigerant is evaporated and absorbs heat when being recovered, in order to make the refrigerant fully evaporate and avoid liquid refrigerant with oil being recovered, the heating belt is arranged on the sampling tank, the temperature of the refrigerant extracted in the sampling tank can be kept constant, and the detection accuracy is improved.

[0019] Further, the heating belt is a sheet-shaped heating belt.

[0020] Beneficial effect: the sheet-shaped heating belt is compact in design, the heating elements are uniformly distributed, heat can be quickly transferred to the heated object, the purpose of rapid heating is achieved, the sheet-shaped heating belt has excellent heat conduction performance, heat loss can be minimized in the heating process, and the heat efficiency is improved.

[0021] A heat pump water heater heat output detection method, comprising the following steps:

[0022] S1: calibrating the heat loss and heat storage Q1 of the water tank:

[0023] a. measuring the weight g of the empty water tank and the weight G when the water tank is filled with water;

[0024] b. emptying the water tank, connecting the electric heating tank and the circulating water pump in series between the water inlet and outlet of the water tank, arranging temperature sensors at the water inlet and outlet, connecting an electric energy integrator at the power supply end of the heating pipe, then filling the water tank with water, the water temperature is T1, the heating power P of the electric heating tank is set according to the nominal heat output of the measured heat pump water heater host,标 And set the flow of the circulating water pump, then power operation, heating the water to T2 temperature, and record the heating time H;

[0025] c. Calculate Q1 according to formula (1);

[0026] S2: According to the water quality and temperature difference obtained by S1, the heat Q2 required for water heating is calculated by formula (2);

[0027] S3: Measure the heat Q3 of the refrigerant side heat pump;

[0028] a. Empty the water tank and the water in the pipeline, remove the electric heating pipe in the electric heating tank, and install pressure and temperature sensors on the water inlet tank refrigerant pipe and the water storage tank refrigerant pipe, a flow meter and a sampling tank;

[0029] b. After vacuumizing the refrigerant pipeline, charge the weight of the refrigerant claimed by the manufacturer, and then charge M2-M3 weight of refrigerant, then fill the water tank, the water temperature is T1, after the enthalpy difference laboratory condition is stable, start the machine, at the same time start to collect the refrigerant flow V i And the temperature and pressure of the refrigerant into and out of the water tank, after the heat pump water heater runs stably for t1 time, start sampling, the weight of the sampling tank is M1, after inserting the sampling port for t2 time, pull out and weigh M2, the weight of the refrigerant in the sampling tank after recovery is M3, when the water temperature in the water tank reaches T2, turn off the heat pump water heater and record the time n, measure the pressure and temperature on the refrigerant pipe into and out of the water tank every second, and according to the pressure and temperature, query the enthalpy value table to obtain the corresponding enthalpy value, and further calculate the inlet and outlet enthalpy difference;

[0030] c. Calculate the heating capacity Q3 of the refrigerant side according to formula (3);

[0031] S4: Calculate the heating capacity Q'3 required for the refrigerant side according to formula (4), when the value of Q3 is equal to the value of Q'3, stop the unit operation.

[0032] The heat pump water heater heating capacity detection method provided in the present application has the following beneficial effects:

[0033] 1. By measuring the weight of the empty water tank and the weight when it is filled with water, setting the heating power of the electric heating pipe in the electric heating tank, setting the flow of the circulating water pump, then heating the water to the target temperature, the heat generated by the electric heating pipe can be calculated from the heating power, and the heat loss and heat storage calibration of the water tank can be calculated from the specific heat capacity of water, the weight of water, the temperature change value and the heating time.

[0034] 2. By installing a flow meter and a sampling tank on the refrigerant return pipe, removing the electric heating tube in the electric heating tank, weighing the empty sampling tank, collecting refrigerant flow data using the flow meter, measuring the temperature and pressure of the refrigerant entering and exiting the water tank using temperature and pressure sensors, obtaining the enthalpy of the refrigerant according to the pressure and temperature, continuously sampling the liquid in the refrigerant return pipe using the sampling tank, weighing after sampling, recovering the refrigerant in the sampling tank, weighing after recovery, obtaining the specific gravity and density of the refrigerant in the mixture, and obtaining the refrigerant heating capacity from the refrigerant weight, refrigerant flow, and enthalpy difference;

[0035] 3. According to the specific heat capacity, weight, and temperature change of water, the total heat absorbed by water to reach the target temperature can be obtained. By comparing the total heat with the cumulative refrigerant-side heating capacity per second, the unit stops working when they are equal, and the water that meets the temperature requirement can be obtained.

[0036] Further, the formula (1) is: Q1 = PH × 3.6 × 10 3 -C × (G - g) × (T2 - T1), wherein: Q1 - the calibration of heat loss and heat storage of the water tank, unit: kJ; P - electric heating power, calculated by integrating the power consumption in the heating period H, unit: kW; C - specific heat capacity of water at average temperature, unit: kJ / (kg·℃); G - weight of the water tank and water after filling, unit: kg; g - weight of the empty water tank, unit: kg; T1 - initial water temperature, i.e. average temperature of water in the water tank at the beginning of the timing point, unit: ℃; T2 - final water temperature, i.e. average temperature of water in the water tank at the end of the timing point, unit: ℃; H - heating time, i.e. time used from the beginning of the timing point to the end of the timing point, unit: h.

[0037] Further, the formula (2) is: Q2 = C × (G - g) × (T2 - T1), wherein: Q2 - heat required for water heating, unit: kJ; C - specific heat capacity of water at average temperature, unit: kJ / (kg·℃); G - weight of the water tank and water after filling, unit: kg; g - weight of the empty water tank, unit: kg; T1 - initial water temperature, i.e. average temperature of water in the water tank at the beginning of the timing point, unit: ℃; T2 - final water temperature, i.e. average temperature of water in the water tank at the end of the timing point, unit: ℃.

[0038] Further, the formula (3) is: wherein: Q3 - the sum of dynamic heating capacity on the refrigerant side, unit: kJ; M1 - weight of the sampling tank, unit: kg; M2 - total weight of refrigerant, oil, and sampling tank, unit: kg; M3 - total weight of oil and sampling tank, unit: kg; v - volume of the sampling tank, unit: m 3 ; V i - flow rate of the mixture of refrigerant and oil, unit: m3 / s;h i 、h i-1 - the enthalpy of the refrigerant into and out of the water tank, which is obtained by a pressure-temperature table, and the unit is kJ / kg.

[0039] Further, the formula (4) is: Q'3=Q1+Q2, wherein: Q1- the calibration of the heat leakage and heat storage of the water tank, and the unit is kJ; Q2- the heat required for water heating, and the unit is kJ; Q'3- the refrigerant-side heat pump heating capacity, and the unit is kJ.

[0040] Beneficial effect: the calibration of the heat leakage and heat storage of the water tank is a constant value, and the heat required for water heating is also a constant value, so the refrigerant-side heat pump heating capacity obtained by adding the two is also a constant value, which provides a clear and specific reference point for evaluating and judging whether the water in the water heater is heated to the target temperature.

[0041] Further, the temperature T2 is 55±0.5℃.

[0042] Further, the stable operation time t1 of the water heater is 30min, and the continuous sampling time t2 is 5min.

[0043] Beneficial effect: the water heater is first stabilized for 30min, which can ensure that the internal system of the water heater reaches equilibrium, reduce test errors caused by unstable system, and make the test results representative.

[0044] Through the above settings, the present application completes the improvement and upgrading of the existing heat pump water heater heating capacity detection device and detection method, effectively solves the technical problems that the existing technology cannot realize accurate control of the test duration and the average temperature of the water tank during the performance test of the heat pump water heater, leading to test failure and increased test cost. BRIEF DESCRIPTION OF DRAWINGS

[0045] The above and other objects, features and advantages of the exemplary embodiments of the present application will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which several embodiments of the present application are shown by way of example, and wherein like reference numerals refer to like elements throughout. In the drawings:

[0046] FIG. 1 is a schematic structural diagram of the application of the heat pump water heater heating capacity detection device provided by the present application in calibrating the heat leakage and heat storage of the water tank;

[0047] FIG. 2 is a schematic structural diagram of the application of the heat pump water heater heating capacity detection device provided by the present application;

[0048] FIG. 3 is a flow chart of the heat pump water heater heating capacity detection method provided by the present application;

[0049] Fig. 4 is a pressure-temperature query enthalpy table used in the heat pump water heater heat production detection method provided by the present application.

[0050] Reference signs:

[0051] 1, water tank inlet temperature sensor; 2, water tank outlet temperature sensor; 3, flow meter; 4, heat pump water heater main unit; 5, water tank; 6, refrigerant return pipe; 7, sampling tank; 8, electric heating tank; 9, circulating water pump; 10, heating coil; 11, refrigerant pipe water tank inlet temperature sensor; 12, refrigerant pipe water tank outlet temperature sensor. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Those skilled in the art should know that the embodiments described below are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0053] It should be noted that the main idea of the present application is to first calibrate the heat leakage and heat storage of the water tank, and then calculate the heat required for water heating according to the water mass and the water temperature difference obtained by weighing. After that, online testing is performed, the refrigerant side dynamic heat production is integrated within its working time, and the sum of the refrigerant side dynamic heat production is obtained. Finally, the heat leakage and heat storage calibration of the water tank and the heat required for water heating are added, and the refrigerant side heat production is obtained. When the sum of the refrigerant side dynamic heat production is equal to the refrigerant side heat production, the unit stops running, and the water with the required temperature can be obtained.

[0054] After introducing the basic principles of the present application, the various non-limiting embodiments of the present application will be specifically introduced below. Any number of elements in the drawings is used for example and not limitation, and any naming is only used for distinction and does not have any limiting meaning.

[0055] The principles and spirits of the present application will be explained in detail below with reference to several representative embodiments of the present application.

[0056] Embodiment 1 of the heat pump water heater heat production detection device provided by the present application:

[0057] As shown in Figs. 1 and 2, the heat pump water heater heat production detection device includes a water tank inlet temperature sensor 1, a water tank outlet temperature sensor 2, a flow meter 3, a sampling tank 7, a pressure sensor (not shown in the figure), an electric heating tank 8, a circulating water pump 9, a refrigerant pipe water tank inlet temperature sensor 11, and a refrigerant pipe water tank outlet temperature sensor 12.

[0058] The water tank inlet temperature sensor 1 and the water tank outlet temperature sensor 2 are respectively arranged at the water inlet and the water outlet of the water tank 5, and are used for measuring the water temperature at the water inlet and the water outlet of the water tank; the refrigerant pipe water tank inlet temperature sensor 11 and the refrigerant pipe water tank outlet temperature sensor 12 are both arranged on the refrigerant pipe, and are respectively located at the water inlet and the water outlet of the water tank 5; the flow meter 3 is arranged on the refrigerant return pipe 6 between the heat pump water heater host 4 and the water tank 5, and is used for measuring the refrigerant flow; the sampling tank 7 is arranged on the refrigerant return pipe 6, and is used for sampling the liquid in the refrigerant return pipe 6; the number of pressure sensors is two, and the two pressure sensors are both arranged on the refrigerant pipe, and are respectively connected with the refrigerant pipe water tank inlet temperature sensor 11 and the refrigerant pipe water tank outlet temperature sensor 12; the electric heating tank 8 is connected in series between the water inlet and the water outlet of the water tank 5; and the circulating water pump 9 is connected in series between the electric heating tank 8 and the water outlet of the water tank 5.

[0059] Specifically, the water tank 5 is provided with a heating coil 10.

[0060] Specifically, the sampling tank 7 is provided with a sheet-shaped heating belt, so that the refrigerant is fully evaporated when the refrigerant is recovered, and the accuracy of the test data is improved.

[0061] Specifically, the electric heating tank 8 is detachably provided with an electric heating pipe, and a power integrator (not shown in the figure) is connected to the power supply end of the electric heating pipe, and the power integrator is used for recording the cumulative power used during the operation of the electric heating tank 8.

[0062] Specifically, the material of the pipeline for connecting various measuring instruments is a heat-resistant synthetic resin pipe.

[0063] It should be noted that, since the material of the pipeline for connecting various measuring instruments is a heat-resistant synthetic resin pipe, and only when the heat pump water heater is stably running before sampling, the pipeline has heat leakage and heat storage, and the heat leakage and heat storage time is very short compared with the whole test process, and the material is non-metallic, the heat leakage and heat storage amount is very small, therefore, the heat leakage and heat storage amount of the pipeline can be ignored.

[0064] The working principle of the heat pump water heater heating capacity detection device provided in the application is as follows:

[0065] First, the weight of the empty water tank 5 and the weight of the water tank 5 filled with water are measured, and after the measurement, the water tank 5 is emptied, the electric heating tank 8 and the circulating water pump 9 are connected in series between the water inlet and outlet of the water tank 5, and temperature sensors are arranged at the water inlet and outlet, then the water tank 5 is filled with water, the heating power of the electric heating pipe in the electric heating tank 8 is set, and the flow rate of the circulating water pump 9 is set, after the setting, the power is turned on to run, the water is heated to the target temperature, and the heating time is recorded, the heat generated by the electric heating pipe is subtracted from the heat absorbed by the water (according to the water quality and the water temperature difference obtained by weighing, the heat required for water heating can be calculated), and the calibration of the heat leakage and heat storage of the water tank 5 can be obtained;

[0066] Then, the water in the water tank 5 is emptied, the electric heating pipe in the electric heating tank 8 is removed, and a flow meter 3 and a sampling tank 7 are added to the refrigerant return pipe 6, the refrigerant pipeline is vacuumized, and then the refrigerant is injected, and the water tank 5 is filled with water at a specified temperature, after the steady state of the enthalpy difference laboratory is reached, the machine is started, and the refrigerant flow rate and the temperature and pressure of the refrigerant entering and leaving the water tank 5 are collected at the same time, after the heat pump water heater runs stably for a certain period of time, sampling is started, the weight of the empty sampling tank 7, the weight of the sampling tank 7 after continuous sampling for a specified time, and the weight of the sampling tank 7 after the refrigerant is completely recovered are measured, and by collecting the refrigerant pressure and temperature and flow rate entering and leaving the water tank 5 every second, the sum of the dynamic heat of the refrigerant side is obtained.

[0067] Finally, the heat required for water heating is added to the calibration of the heat leakage and heat storage of the water tank 5 to obtain the heat pump heating capacity of the refrigerant side, when the sum of the dynamic heat of the refrigerant side is equal to the heat pump heating capacity of the refrigerant side, the unit is stopped, and the water meeting the temperature requirement can be obtained.

[0068] Embodiment 2 of the heat pump water heater heat capacity detection device provided in the present application:

[0069] The main difference between the embodiment 1 and the embodiment 2 is that:

[0070] In the embodiment 1, the material of the pipeline for connecting each measuring instrument is heat-resistant synthetic resin pipe.

[0071] In the present embodiment, the material of the pipeline for connecting each measuring instrument is rubber hose.

[0072] Embodiment 1 of the heat pump water heater heat capacity detection method provided in the present application:

[0073] As shown in FIG. 3, the heat pump water heater heat capacity detection method includes the following steps:

[0074] S1: Calibrate the heat leakage and heat storage Q1 of the water tank:

[0075] a. Measure the weight g of the empty water tank and the weight G when filled with water;

[0076] b, empty the water tank, connect the electric heating tank and the circulating water pump in series between the inlet and outlet of the water tank, and set temperature sensors at the inlet and outlet, connect the electric energy integrator to the power supply end of the heating pipe, then fill the water tank with water, the water temperature is T1, set the heating power P of the electric heating tank according to the nominal heating capacity of the measured heat pump water heater host 标 , and set the flow of the circulating water pump, then power on and run, heat the water to T2, and record the heating time H;

[0077] c, calculate Q1 according to formula (1);

[0078] S2: calculate the heat Q2 required for water heating according to the water mass and temperature difference obtained by S1 weighing;

[0079] S3: measure the refrigerant-side heat pump heating capacity Q3:

[0080] a, empty the water tank and the pipeline, remove the electric heating pipe in the electric heating tank, and add pressure and temperature sensors to the water tank inlet and outlet, and add a pressure and temperature sensor, a flow meter and a sampling tank to the water tank refrigerant pipe;

[0081] b, after vacuumizing the refrigerant pipeline, charge the refrigerant weight claimed by the manufacturer, and then charge M2-M3 weight of refrigerant, then fill the water tank with water, the water temperature is T1, and after the enthalpy difference laboratory condition is stable, start the machine, and start collecting the refrigerant flow V i , the temperature and pressure of the refrigerant inlet and outlet of the water tank, after the heat pump water heater is stable for t1 time, start sampling, the weight of the sampling tank is M1, after inserting the sampling port for t2 time, the weight is M2, and after the refrigerant in the sampling tank is recovered, the weight is M3, when the water temperature in the water tank reaches T2, the heat pump water heater is turned off and the time n is recorded, the pressure and temperature of the refrigerant pipeline inlet and outlet of the water tank are measured every second, the enthalpy value corresponding to the pressure and temperature is obtained by querying the enthalpy table, and the inlet and outlet enthalpy difference is further calculated;

[0082] c, calculate the refrigerant-side heating capacity Q3 according to formula (3);

[0083] S4: calculate the refrigerant-side heating capacity Q'3 according to formula (4), when the value of Q3 is equal to the value of Q'3, stop the unit operation.

[0084] Specifically, formula (1) is: Q1=PH×3.6×10 3Q1 = C x (G - g) x (T2 - T1), wherein: Q1 - the calibration of the heat leakage and heat storage of the water tank, in kJ; P - the electric heating power, calculated by the integral power consumption in the heating period H, in kW; C - the specific heat capacity of water at average temperature, in kJ / (kg oC); G - the weight of the water tank and water after being filled with water, in kg; g - the weight of the empty water tank, in kg; T1 - the initial water temperature, i.e. the average temperature of the water in the water tank at the beginning of the timing point, in oC; T2 - the final water temperature, i.e. the average temperature of the water in the water tank at the end of the timing point, in oC; H - the heating time, i.e. the time used from the beginning of the timing point to the end of the timing point, in h.

[0085] Specifically, formula (2) is: Q2 = C x (G - g) x (T2 - T1), wherein: Q2 - the heat required for water heating, in kJ; C - the specific heat capacity of water at average temperature, in kJ / (kg oC); G - the weight of the water tank and water after being filled with water, in kg; g - the weight of the empty water tank, in kg; T1 - the initial water temperature, i.e. the average temperature of the water in the water tank at the beginning of the timing point, in oC; T2 - the final water temperature, i.e. the average temperature of the water in the water tank at the end of the timing point, in oC.

[0086] Specifically, formula (3) is: wherein: Q3 - the sum of the dynamic heating amounts of the refrigerant side, in kJ; M1 - the weight of the sampling tank, in kg; M2 - the total weight of the refrigerant, oil and sampling tank, in kg; M3 - the total weight of the oil and sampling tank, in kg; v - the volume of the sampling tank, in m 3 ; V i - the flow rate of the mixture of the refrigerant and oil, in m 3 / s; h i , h i-1 - the enthalpy of the refrigerant entering and leaving the water tank, obtained by querying the pressure-temperature table, in kJ / kg.

[0087] Specifically, formula (4) is: Q'3 = Q1 + Q2, wherein: Q1 - the calibration of the heat leakage and heat storage of the water tank, in kJ; Q2 - the heat required for water heating, in kJ; Q'3 - the heating amount of the refrigerant side heat pump, in kJ.

[0088] Specifically, the stable operation time t1 of the water heater is 30 min, the time t2 is 5 min, and the temperature T2 is 55±0.5 oC.

[0089] Specifically, the pressure-temperature query enthalpy table is shown in FIG. 4.

[0090] According to the above description of the present specification, those skilled in the art can also understand that the terms used such as "upper", "lower", "front", "back", "left", "right", "width", "horizontal", "top", "bottom", "inner", "outer" and the like indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings of the present specification, which are only for the purpose of facilitating the description of the present application and simplifying the description, and are not explicitly or implicitly indicated that the devices or elements involved must have the specific orientation, be constructed and operated in a specific orientation, therefore the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as a limitation on the present application.

[0091] In addition, in the description of the present specification, the meaning of "a plurality of" is at least two, such as two, three or more, etc., unless otherwise explicitly and specifically limited.

Claims

1. A method for detecting the heating capacity of a heat pump water heater, characterized by, It comprises the following steps: S1: calibrate the heat leakage and heat storage of the water tank Q1: a, measure the weight g of the empty water tank and the weight G when filled with water; b, empty the water tank, connect the electric heating tank and the circulating water pump in series between the water inlet and outlet of the water tank, and set temperature sensors at the water inlet and outlet, connect the electric energy integrator at the power supply end of the heating pipe, then fill the water tank with water, the water temperature is T1, set the heating power P of the electric heating tank according to the rated heating capacity of the measured heat pump water heater host, and set the flow rate of the circulating water pump, then power on and run, heat the water to T2 temperature, and record the heating time H; 标 ​ c. calculating Q1 according to formula (1); S2: calculating the heat Q2 required for water heating according to the water mass and the water temperature difference obtained from S1 through formula (2); S3: measure the refrigerant side heat pump heating capacity Q3: a, empty the water tank and the pipeline, remove the electric heating tube in the electric heating tank, and install pressure and temperature sensors on the water tank refrigerant pipe and the water storage tank refrigerant pipe, install a flow meter and a sampling tank; b, after vacuumizing the refrigerant pipeline, charge the weight of the refrigerant claimed by the manufacturer, then charge M2-M3 weight of refrigerant, then fill the water tank with water, the water temperature is T1, after the enthalpy difference laboratory condition is stable, start the machine, at the same time start collecting the refrigerant flow V i and the temperature and pressure of the refrigerant into and out of the water tank, after the heat pump water heater runs stably for t1 time, start sampling, the weight of the sampling tank is M1, after it is inserted into the sampling port for continuous sampling for t2 time, it is pulled out and weighed M2, the weight of the refrigerant in the sampling tank after recovery is M3, when the water temperature in the water tank reaches T2, the heat pump water heater is turned off and the time n is recorded, the pressure and temperature on the refrigerant pipe into and out of the water tank are measured every second, and the corresponding enthalpy value is found according to the pressure temperature query enthalpy table, and the inlet and outlet enthalpy difference is further calculated; c. calculating the heating capacity Q3 of the refrigerant side according to formula (3); S4: calculating the heating capacity Q'3 required for the refrigerant side according to formula (4), and stopping the operation of the unit when the value of Q3 is equal to the value of Q'3; Formula (1) is: Q1=PHx3.6x10 3 C x (G-g) x (T2-T1), wherein: Q1 - the heat loss and heat storage of the water tank, in kJ; P - the electric heating power, calculated by the integral power consumption in the heating period H, in kW; C - the specific heat capacity of water at average temperature, in kJ / (kg·℃); G - the weight of the water tank and water after filling, in kg; g - the weight of the empty water tank, in kg; T1 - the initial water temperature, i.e. the average temperature of the water in the water tank at the beginning of the timing point, in ℃; T2 - the final water temperature, i.e. the average temperature of the water in the water tank at the end of the timing point, in ℃; H - the heating time, i.e. the time used from the beginning of the timing point to the end of the timing point, in h; Formula (2) is: Q2=C×(G-g)×(T2-T1), wherein: Q2 is the heat required for water heating, in kJ; C is the specific heat capacity of water at an average temperature, in kJ / (kg·℃); G is the weight of the water tank and water after being filled with water, in kg; g is the weight of the empty water tank, in kg; T1 is the initial water temperature, i.e. the average temperature of the water in the water tank at the beginning of the timing point, in ℃; and T2 is the final water temperature, i.e. the average temperature of the water in the water tank at the end of the timing point, in ℃; Equation (3) is: wherein: Q3 - the sum of the refrigerant-side dynamic heating amounts, in kJ; M1 - the weight of the sampling tank, in kg; M2 - the total weight of the refrigerant, oil and sampling tank, in kg; M3 - the total weight of the oil and sampling tank, in kg; v - the volume of the sampling tank, in m 3 ; V i - the flow rate of the mixture of refrigerant and oil, in m 3 / s; h i , h i-1 - the enthalpy of the refrigerant into and out of the water tank, obtained by a pressure temperature table, in kJ / kg; Formula (4) is: Q'3=Q1+Q2, wherein: Q1 is the calibration of heat leakage and heat storage of the water tank, in kJ; Q2 is the heat required for water heating, in kJ; and Q'3 is the heating capacity of the refrigerant side heat pump, in kJ.

2. The heat pump water heater heat production detection method of claim 1, wherein, The temperature T2 is 55±0.5℃.

3. The heat pump water heater heat production amount detection method according to claim 1, characterized by, The stable operation time t1 of the water heater is 30 min, and the time t2 is 5 min.

4. A heat pump water heater heat quantity detecting device, characterized by, The method for detecting the heating capacity of a heat pump water heater according to claim 1 comprises a water tank inlet temperature sensor and a water tank outlet temperature sensor, further comprising: a flow meter arranged on a refrigerant return pipe between a heat pump water heater main unit and a water tank for measuring the refrigerant flow; a sampling tank arranged on the refrigerant return pipe for sampling the mixture of refrigerant and oil in the refrigerant return pipe; a refrigerant pipe inlet water tank temperature sensor and a refrigerant pipe outlet water tank temperature sensor; two pressure sensors, which are respectively located at the refrigerant pipe inlet water tank temperature sensor and the refrigerant pipe outlet water tank temperature sensor; an electric heating tank connected in series between the inlet and outlet of the water tank, and an electric heating pipe detachably installed in the electric heating tank; a circulating water pump connected in series between the electric heating tank and the water tank; and an electric energy integrator connected to the power supply end of the electric heating pipe.

5. The heat pump water heater heat production detecting apparatus according to claim 4, wherein The sampling tank is provided with a heating belt.

6. The heat pump water heater heat production detecting apparatus according to claim 5, wherein The heating belt is a sheet-shaped heating belt.

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