Refrigerating capacity measurement system and method for ice slurry refrigeration plant

Abstract

The application discloses a kind of ice slurry refrigeration device's refrigeration capacity measurement system and method, measurement system includes ice slurry dynamic preparation system, ice slurry heat exchange system, heat exchange system import and export kors force mass flowmeter and heat exchange system import and export temperature sensor;Measurement method is by heat exchange system import and export kors force mass flowmeter, respectively measured before and after the density of ice slurry entering ice slurry heat exchange system and the mass flow of ice slurry, by calculating the product of the difference of mass flow value and two density values, obtain the refrigeration capacity of ice slurry in ice slurry heat exchange system output, two temperature sensors are to ensure that there is no temperature difference before and after ice slurry in ice slurry heat exchange system heat exchange, not absorbing sensible heat.The application has the advantages that the number of measured physical quantities is small, and the temperature is stable during the measurement process, the uncertainty of the refrigeration capacity measurement system of ice slurry refrigeration device is reduced, so that the ice slurry refrigeration device can become a standard cold source device and be used for accurate and comparison of the refrigeration capacity measurement results of air conditioners in different enthalpy difference laboratories.

Description

Technical Field

[0001] This invention relates to the field of refrigeration capacity measurement technology, and more specifically, to a refrigeration capacity measurement system and method for a standard cold source device. Background Technology

[0002] The inconsistency in the measurement results of room air conditioner cooling capacity between different enthalpy difference laboratories continues to plague the Chinese air conditioning industry and is a metrological issue prone to disputes in international trade. There is an urgent need to research standard cold source devices that can calibrate enthalpy difference laboratories. Currently, research on standard cold source devices is limited. The industry's previous approach was to use calibrated window-type standard air conditioners as standard cold sources, but this essentially involves using a high-precision enthalpy difference laboratory to calibrate a low-precision one, and the reproducibility and stability of window-type air conditioners are difficult to guarantee. Only a few researchers have studied standard cold source devices using the water enthalpy method. These devices rely on dynamically compensated, constant-temperature chilled water as the cold source, and while the relative uncertainty of the output cooling capacity is lower than that of the air enthalpy method, its stability is limited by the speed of feedback adjustment. The current methods involve many physical quantities in the cooling capacity measurement process, resulting in significant measurement uncertainty. Summary of the Invention

[0003] The purpose of this invention is to solve the problem of large measurement uncertainty in existing standard cold source methods, and to provide a cooling capacity measurement system and method for ice slurry refrigeration devices. The cooling capacity measurement process involves only three physical quantities to be measured, and can be used as a standard cold source device to calibrate and compare the cooling capacity measurement results of enthalpy difference laboratories.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A cooling capacity measurement system for an ice slurry refrigeration device includes: an ice slurry dynamic production system, an ice slurry heat exchange system, a Coriolis mass flow meter, and a temperature sensor. The ice slurry heat exchange system is connected to the ice slurry dynamic production system. The Coriolis mass flow meter is installed at the inlet and outlet of the ice slurry heat exchange system, and the temperature sensor is installed at the inlet and outlet of the ice slurry heat exchange system. The temperature sensor is located between the ice slurry heat exchange system and the Coriolis mass flow meter.

[0006] Preferably, the ice slurry dynamic production system and the ice slurry heat exchange system are connected by pipelines, and the Coriolis mass flow meter and temperature sensor are both installed on the pipelines adjacent to the inlet and outlet of the ice slurry heat exchange system.

[0007] Preferably, the pipeline connecting the ice slurry heat exchange system and the Coriolis mass flow meter is an insulated section pipeline.

[0008] Preferably, the dynamic ice slurry production system includes a low-temperature water bath, an ice slurry storage tank, a stirrer, and a slurry pump.

[0009] Preferably, the low-temperature water bath includes a compressor, a condenser, an axial fan, a thermal expansion valve, an evaporator, a water bath, a drain pipe, and a water pump.

[0010] Preferably, the ice slurry heat exchange system includes an axial flow fan and a tube-fin heat exchanger.

[0011] A method for measuring the cooling capacity of an ice slurry refrigeration device, applied to the cooling capacity measurement system of any of the above-described ice slurry refrigeration devices, includes the following steps:

[0012] Obtain the density, mass flow rate, and temperature of the ice slurry before it enters the ice slurry heat exchange system;

[0013] Obtain the density, mass flow rate, and temperature of the ice slurry exiting the ice slurry heat exchange system;

[0014] Based on the formula for calculating cooling capacity, the cooling capacity output by the ice slurry heat exchange system is obtained.

[0015] Preferably, the formula for calculating the cooling capacity is:

[0016]

[0017] In the formula, The average mass flow rate of the ice slurry flowing through the inlet and outlet of the ice slurry heat exchange system; r is the latent heat of phase change of ice at 0°C and standard atmospheric pressure; IPF1 is the ice content of the ice slurry before entering the ice slurry heat exchange system; IPF2 is the ice content of the ice slurry after exiting the ice slurry heat exchange system; c p t1 is the specific heat capacity of water at constant pressure; t2 is the temperature of the ice slurry before entering the ice slurry heat exchange system; t3 is the temperature of the ice slurry exiting the ice slurry heat exchange system; Q is the cooling capacity output by the ice slurry heat exchange system.

[0018] Preferably, the formula for calculating the ice content of the ice slurry is:

[0019]

[0020] In the formula, is the measured density of the ice slurry.

[0021] Preferably, when t2 = t1, the ice content of the ice slurry is sufficient, and the ice slurry only absorbs latent heat in the ice slurry heat exchange system, without absorbing sensible heat and rising in temperature. The cooling capacity output by the ice slurry heat exchange system is:

[0022]

[0023] In the formula, ρ1 is the density of the ice slurry before entering the ice slurry heat exchange system; ρ2 is the density of the ice slurry exiting the ice slurry heat exchange system. This represents the difference in ice content between the inlet and outlet of the ice slurry in the ice slurry heat exchange system.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] This invention, under the premise of controlling the ice slurry temperature, only requires measuring three physical quantities to calculate the output cooling capacity. Moreover, the ice slurry is kept at its phase change temperature during the heat exchange process, and the heat exchange temperature is stable. It can be used as a standard cold source device to calibrate and compare the cooling capacity measurement results of the enthalpy difference laboratory, filling the gap in the research of standard cold source devices at home and abroad. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the cooling capacity measurement system for an ice slurry refrigeration device.

[0027] Figure 2 This is a schematic diagram of the cooling capacity measurement system for an ice slurry refrigeration device.

[0028] Figure 3 A schematic diagram illustrating the method for artificially producing and replenishing ice slurry.

[0029] Figure 4 This is a schematic diagram of the density measurement calibration method. Detailed Implementation

[0030] The cooling capacity measurement system and method of the ice slurry cooling device of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] This invention discloses a cooling capacity measurement system for an ice slurry refrigeration device. The system includes an ice slurry dynamic production system, an ice slurry heat exchange system, a Coriolis mass flow meter, and a temperature sensor. The ice slurry heat exchange system is connected to the ice slurry dynamic production system. The Coriolis mass flow meter is installed at both the inlet and outlet of the ice slurry heat exchange system, and the temperature sensor is also installed at both the inlet and outlet of the system, positioned between the ice slurry heat exchange system and the Coriolis mass flow meter. The ice slurry dynamic production system and the ice slurry heat exchange system are connected via pipelines. The Coriolis mass flow meter and the temperature sensor are both installed on pipelines adjacent to the inlet and outlet of the ice slurry heat exchange system. The pipeline connecting the ice slurry heat exchange system and the Coriolis mass flow meter is an insulated section.

[0032] like Figure 1As shown in the schematic diagram of the cooling capacity measurement system of the ice slurry refrigeration device, the system includes an ice slurry dynamic production system 1, an ice slurry heat exchange system 2, a Coriolis mass flow meter at the inlet of the heat exchange system 3, a Coriolis mass flow meter at the outlet of the heat exchange system 4, a temperature sensor at the inlet of the ice slurry heat exchange system 2 5, and a temperature sensor at the outlet of the ice slurry heat exchange system 2 6. The ice slurry dynamic production system 1 continuously supplies ice slurry for heat exchange to the ice slurry refrigeration device, while the ice slurry heat exchange system 2 promotes the exchange of heat between the ice slurry inside the heat exchanger and the air outside the heat exchanger.

[0033] like Figure 2 As shown, the specific implementation method of the ice slurry dynamic production system 1 is described in [reference needed]. Figure 2 The outdoor unit section within the dashed box on the right includes the ice slurry dynamic production system 1, which comprises a low-temperature water bath, an ice slurry storage tank, a stirrer, and a slurry pump. The low-temperature water bath further includes a compressor, a condenser, an axial fan, a thermal expansion valve, an evaporator, a water bath, a drain pipe, and a water pump.

[0034] The water bath contains pre-set low-temperature water, providing the cooling energy for the continuous generation of ice slurry in the ice slurry storage tank. The water temperature in the water bath is maintained by the low-temperature refrigerant in the evaporator, and an internal circulation is formed by a water pump to promote heat exchange between the water and the refrigerant in the evaporator. After releasing cooling energy in the evaporator to maintain the water temperature in the water bath, the refrigerant is then heated and pressurized by the compressor, and then dissipated to the outside in the condenser through enhanced heat exchange by the axial flow fan. After dissipating heat, the refrigerant returns to a low-temperature, low-pressure state through the throttling effect of the thermostatic expansion valve and returns to the evaporator to release cooling energy, thus completing the cycle.

[0035] The ice slurry storage tank contains distilled water, which is the raw material for generating ice slurry. The method for generating ice slurry in this invention is the subcooled water method. The distilled water in the ice slurry storage tank absorbs the cold energy from the low-temperature cold water in the water bath and is cooled to a subcooled state, first becoming subcooled water, and then being transformed into ice slurry by the subcooling action of a stirrer. The stirrer's function is to promote ice crystal nucleation, facilitate the transformation of the subcooled water into ice slurry, and maintain the homogeneous solid-liquid two-phase state of the ice slurry to prevent ice-water stratification. The slurry pump's function is to transport the ice slurry to the indoor unit side for heat exchange.

[0036] like Figure 2 As shown, the specific implementation method of the ice slurry heat exchange system 2 is described in [reference needed]. Figure 2 The indoor unit section within the dashed box on the left includes the ice slurry heat exchange system 2, which comprises an axial flow fan and a tube-fin heat exchanger.

[0037] This invention also discloses a method for measuring the cooling capacity of an ice slurry refrigeration device, comprising the following steps:

[0038] Obtain the density, mass flow rate, and temperature of the ice slurry before it enters the ice slurry heat exchange system; obtain the density, mass flow rate, and temperature of the ice slurry exiting the ice slurry heat exchange system; and obtain the cooling capacity output by the ice slurry heat exchange system according to the cooling capacity calculation formula.

[0039] The formula for calculating cooling capacity is as follows:

[0040]

[0041] In the formula, The average mass flow rate of the ice slurry flowing through the inlet and outlet of the ice slurry heat exchange system; r is the latent heat of phase change of ice at 0℃ and standard atmospheric pressure, r = 334.3 kJ / kg; IPF1 is the ice content of the ice slurry before entering the ice slurry heat exchange system; IPF2 is the ice content of the ice slurry after exiting the ice slurry heat exchange system; c p c is the specific heat capacity of water at constant pressure. p The value is 4.2 kJ / (kg·℃); t1 is the temperature of the ice slurry before entering the ice slurry heat exchange system; t2 is the temperature of the ice slurry after leaving the ice slurry heat exchange system; Q is the cooling capacity output by the ice slurry heat exchange system.

[0042] The formula for calculating the ice content of ice slurry is:

[0043]

[0044] In the formula, is the measured density of the ice slurry.

[0045] When t2 = t1, the ice slurry has sufficient ice content. The ice slurry only absorbs latent heat in the ice slurry heat exchange system, without absorbing sensible heat and rising in temperature. The cooling capacity output by the ice slurry heat exchange system is:

[0046]

[0047] In the formula, ρ1 is the density of the ice slurry before entering the ice slurry heat exchange system; ρ2 is the density of the ice slurry exiting the ice slurry heat exchange system. This represents the difference in ice content between the inlet and outlet of the ice slurry in the ice slurry heat exchange system.

[0048] In this embodiment, the Coriolis mass flow meter 3 at the inlet of the heat exchange system measures the ice slurry density ρ1 and ice slurry mass flow rate at the inlet of the ice slurry heat exchange system 2. Coriolis mass flow meter 4 measures the ice slurry density ρ2 and ice slurry mass flow rate at the outlet of ice slurry heat exchange system 2. Based on the law of conservation of mass and The values ​​are basically the same. and The slight difference between the values ​​may be caused by factors such as electromagnetic interference and electrical signal fluctuations. In order to more accurately measure the mass flow rate of the ice slurry in the system flow path, the average mass flow rate of the ice slurry at the inlet and outlet of the ice slurry heat exchange system 2 is used. To express.

[0049] Temperature sensor 5 at the inlet of ice slurry heat exchange system 2 measures the inlet temperature t1 of ice slurry, and temperature sensor 6 at the outlet temperature measures the outlet temperature t2 of ice slurry, ensuring that t1 = t2. During the heat exchange process, the ice slurry only absorbs latent heat and not sensible heat. The cooling capacity output of ice slurry heat exchange system 2 is given by the formula... The calculations show that only three physical quantities need to be measured, which solves the problem of large measurement uncertainty in existing standard cold source methods. It can be used as a standard cold source device to calibrate and compare the refrigeration capacity measurement results of the enthalpy difference laboratory.

[0050] Traditionally, subcooled water is used to dynamically produce ice slurry. However, the resulting ice slurry has a low ice content, making it difficult to guarantee t1 = t2. Furthermore, the ice slurry only absorbs latent heat during heat exchange, not sensible heat. For example... Figure 3 As shown, this invention employs a method for the artificial production and replenishment of ice slurry. Specifically, the method involves: in an indoor environment at -10°C, using an ice crusher to crush ice blocks frozen from distilled water, filtering out ice particles smaller than 1mm using a sieve, and then pouring the ice particles into pre-cooled distilled water and stirring evenly to provide a certain amount of pure water ice slurry solution for the continuous cooling of a standard cold source device.

[0051] The cooling capacity output of an ice slurry refrigeration device is calculated by density measurement. The accuracy of the density measurement value has a significant impact on the uncertainty of the output cooling capacity. The key to whether the cooling capacity measurement system and method of the ice slurry refrigeration device provided by this invention can be used as a standard cold source device to calibrate and compare the cooling capacity measurement results of the enthalpy difference laboratory is to improve the accuracy of the density measurement value.

[0052] This invention provides a method for calibrating density measurement values, the specific implementation process of which is as follows: Figure 4 As shown. All operations must be performed in a constant temperature and humidity laboratory at 0℃, and the equipment used must be pre-cooled in the laboratory to avoid the heat of the instruments themselves causing errors in the calibration process. An ice slurry solution with a specific ice content is prepared using an ice crusher, stirring rod, absorbent paper, and a ten-thousandth-degree balance. The ice slurry solution is then injected into a Coriolis flowmeter using a large syringe to measure the density of the prepared ice slurry.

[0053] In summary, the present invention has the following advantages and beneficial effects:

[0054] This invention, under the premise of controlling the ice slurry temperature, only requires measuring three physical quantities to calculate the output cooling capacity. Moreover, the ice slurry is kept at its phase change temperature during the heat exchange process, and the heat exchange temperature is stable. It can be used as a standard cold source device to calibrate and compare the cooling capacity measurement results of the enthalpy difference laboratory, filling the gap in the research of standard cold source devices at home and abroad.

[0055] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit disclosed in the present invention should fall within the patent scope covered by the present invention.

Claims

1. A refrigerating capacity measuring system of an ice slurry refrigerating apparatus, characterized by, Comprise: Ice slurry dynamic preparation system, ice slurry heat exchange system, Coriolis force mass flowmeter and temperature sensor, ice slurry heat exchange system is connected with ice slurry dynamic preparation system, Coriolis force mass flowmeter is arranged in the import and export of ice slurry heat exchange system respectively, temperature sensor is arranged in the import and export of ice slurry heat exchange system respectively, temperature sensor is arranged between ice slurry heat exchange system and Coriolis force mass flowmeter; Ice slurry dynamic preparation system comprises low-temperature water bath box, ice slurry storage tank, stirrer and slurry pump, low-temperature water bath box comprises compressor, condenser, axial flow fan, thermal expansion valve, evaporator, water bath box and water pump; The low-temperature water in water bath box is set temperature, provides the cold energy for the ice slurry storage tank; The water temperature in water bath box is maintained by the low-temperature refrigerant in evaporator, and the water and the refrigerant exchange heat through the internal circulation of water pump; The refrigerant releases cold energy in evaporator to maintain the water temperature in water bath box, and then is heated and pressurized by compressor, and then is cooled by the heat exchange of axial flow fan, and then is throttled by thermal expansion valve to return to evaporator to release cold energy, and the cycle is repeated. The inside of ice slurry storage tank is distilled water, which is the raw material for producing ice slurry; The method for producing ice slurry is supercooled water method, the distilled water in ice slurry storage tank is cooled to supercooled state by absorbing the cold energy of low-temperature water in water bath box, and then is converted into ice slurry by the supercooling removal of stirrer; The function of stirrer is to promote ice crystal nucleation, promote supercooled water to convert into ice slurry from supercooled state, and maintain the uniform state of ice slurry and solid-liquid two-phase, avoiding ice-water stratification; The function of slurry pump is to transport ice slurry to indoor unit side to participate in heat exchange.

2. The refrigerating capacity measuring system of the ice slurry plant according to claim 1, characterized by, Ice slurry dynamic preparation system and ice slurry heat exchange system are connected by pipeline, Coriolis force mass flowmeter and temperature sensor are arranged on the pipeline close to the import and export of ice slurry heat exchange system.

3. The refrigerating capacity measuring system of the ice slurry plant according to claim 2, characterized by, The pipeline connected with Coriolis force mass flowmeter of ice slurry heat exchange system is adiabatic section pipeline.

4. The refrigerating capacity measuring system of the ice slurry plant according to claim 1, characterized by, Ice slurry heat exchange system comprises axial flow fan and tube-fin heat exchanger.

5. A method of measuring the refrigerating capacity of an ice slurry refrigerating apparatus, characterized by, The refrigerating capacity measurement system applied to the ice slurry refrigerating device of any one of claims 1 to 4 comprises the following steps: Obtain the density, mass flow and temperature of ice slurry before entering ice slurry heat exchange system; Obtain the density, mass flow and temperature of ice slurry after exiting ice slurry heat exchange system; Obtain the refrigerating capacity outputted by ice slurry heat exchange system according to refrigerating capacity calculation formula; The refrigerating capacity calculation formula is: wherein is the average of the ice slurry mass flow rate through the ice slurry heat exchange system inlet and outlet; r is the latent heat of phase change of ice at 0°C and standard atmospheric pressure; IPF1 is the ice fraction of the ice slurry before entering the ice slurry heat exchange system; IPF2 is the ice fraction of the ice slurry after coming out of the ice slurry heat exchange system; c p is the specific heat capacity of water at constant pressure; t1 is the temperature of the ice slurry before entering the ice slurry heat exchange system; t2 is the temperature of the ice slurry after coming out of the ice slurry heat exchange system; Q is the refrigeration output of the ice slurry heat exchange system.

6. The method of claim 5, wherein the refrigerating capacity of the slush refrigerating apparatus is measured by the steps of: The ice slurry ice content calculation formula is: In the formula, ρ is the measured ice slurry density.

7. The method for measuring the cooling capacity of the ice slurry refrigeration device according to claim 6, characterized in that, In the case of t2=t1, the ice content of ice slurry is sufficient, the ice slurry only absorbs latent heat in ice slurry heat exchange system, does not absorb sensible heat to increase temperature, and the refrigerating capacity outputted by ice slurry heat exchange system is: In the formula, p1 is the density of the ice slurry before entering the ice slurry heat exchange system; p2 is the density of the ice slurry after exiting the ice slurry heat exchange system; is the ice content rate difference between the ice slurry at the inlet and the outlet of the ice slurry heat exchange system.

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