CN107436058A - Heat exchanger and heat pump water heater with same - Google Patents

Abstract

The invention relates to a heat exchanger and a heat pump water heater with the heat exchanger. Wherein, the heat exchanger may include: a heat exchanging part configured to transfer the heat of the working fluid entering it to the water entering it, so as to heat the water flowing through it; The water inlet of the part is connected, configured to receive water and gaseous substances, and to mix the gaseous substances with water, so that the mixed water and gaseous substances enter the heat exchange part; wherein the gaseous substances are acid gases or mixed gases containing acid gases. The heat exchanger and the heat pump water heater provided with the heat exchanger of the present invention can make the acid gas mixed into the heated water, suppress the generation of scale in the heat exchange part, and affect the heat exchange effect.

Description

Heat exchanger and heat pump water heater having the heat exchanger

technical field

The invention relates to the technical field of water heating, in particular to a heat exchanger and a heat pump water heater provided with the heat exchanger.

Background technique

At present, heat pump water heaters generally include a heat pump heating system and a water tank. The heat pump heating system is mainly composed of several major components such as a compressor, a heat exchanger, a throttling device, and an evaporator. The high-pressure and high-temperature refrigerant gas enters the heat exchanger and is condensed to cool down, then goes to the throttling device for throttling and expansion, and then enters the evaporator to absorb the heat of the air and evaporates into low-pressure steam, which is sucked into the compressor and recompressed into High temperature and high pressure gas. Cold water can be introduced into the heat exchanger, heated by the refrigerant in the heat exchanger, and then enter the water tank for storage.

During the use of the heat exchanger, due to improper operation of the water treatment equipment and poor water quality control, the circulating water that does not meet the water quality standards is injected into the heat exchanger, and some substances in the water such as Ca ²⁺ and Mg ²⁺ are heated These deposits will stick to the heating surface to form vertical hard scale. Due to the extremely poor thermal conductivity of the scale, the heat transfer efficiency of the heat exchanger will be reduced, resulting in a serious waste of heat energy. Scaling of heat exchangers in heat pump water heaters is a difficult problem in the industry.

Existing commonly used scale suppression methods include adding soft water equipment, pickling after scaling, magnetization scale suppression, electronic scale suppression, etc., but the effects are not satisfactory. Adding soft water equipment will greatly increase user investment and increase the difficulty of installation, and softened water will greatly change the physical indicators of tap water, and people who drink softened water by mistake will cause health effects. Pickling after fouling not only does not solve the problem of reduced energy efficiency caused by fouling in the water heater, or reduces the risk of blockage of the heat exchanger, but also increases labor costs and causes equipment downtime. The scale inhibition effect of magnetization scale inhibition and electronic scale inhibition method is not ideal.

Contents of the invention

The purpose of the present invention is to overcome at least one defect of existing heat exchanger scale inhibition, to provide a novel heat exchanger and a heat pump water heater with the heat exchanger, which can prevent the water from being heated as much as possible by using acid gas. Scaling inside the heat exchanger prevents the reduction of the heat exchange efficiency of the heat exchanger and does not change the physical indicators of the water.

Specifically, the present invention provides a heat exchanger for a heat pump water heater, which includes:

a heat exchange unit configured to transfer heat from the working fluid entering it to the water entering it, so as to heat the water flowing through it; and

The water-air mixing part communicates with the water inlet of the heat exchange part, and is configured to receive water and gaseous substances, and mix the gaseous substances with water, so that the mixed water and the gaseous substances enter the heat exchange department; of which

The gaseous substance is acid gas or a mixed gas containing acid gas.

Optionally, the water-air mixing unit includes:

a venturi tube having an inlet configured to receive water and an outlet connected to the water inlet of said heat exchange section;

a gas inlet pipe having inlet holes and communicating with the throat and/or diffuser section of the venturi; and

Blocking, arranged in the gas inlet pipe, configured to: block the air inlet hole of the gas inlet pipe, and open the gas inlet pipe under the action of negative pressure formed when water flows through the venturi tube The air inlet of the air inlet, so that the gaseous substance enters the Venturi tube through the gas inlet pipe.

Optionally, the plug is a float.

Optionally, the water-air mixing part is an ejector.

Optionally, the heat exchange part includes working fluid pipes and water pipes.

Optionally, the heat exchange part is a plate heat exchange device or a sleeve heat exchange device.

The present invention also provides a heat pump water heater, which includes:

a water tank configured to contain water;

A heat pump heating system includes any one of the above-mentioned heat exchangers, and the water outlet of the heat exchange part of the heat exchanger communicates with the water tank through a pipeline.

Optionally, the gaseous substance is carbon dioxide or air.

Optionally, the heat pump water heater further includes a float valve configured to connect or disconnect the pipeline between the water outlet of the heat exchange part and the water tank according to the water level in the water tank.

Optionally, the water-air mixing part of the heat exchanger is configured to receive water from a tap water network.

The heat exchanger of the present invention and the heat pump water heater having the heat exchanger can mix the acid gas into the heated water, for example, add air before the tap water enters the heat exchange part, and use _CO2 and other acid gases in the air to mix with water, Ca ²⁺ , Mg ²⁺ , Ca ₂ CO ₃ , etc. generate Ca(HCO ₃ ) ₂ , Mg(HCO ₃ ) ₂ , etc., inhibit the formation of Ca ₂ CO ₃ , etc., and deposit on the tube wall of the water pipe in the heat exchanger, thereby Suppresses the formation of scale in the heat exchange part and affects the heat exchange effect. Furthermore, adding gas to the water can also increase the heating rate of the water and improve the heat exchange efficiency.

Those skilled in the art will be more aware of the above and other objects, advantages and features of the present invention according to the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of illustration and not limitation with reference to the accompanying drawings. The same reference numerals in the drawings designate the same or similar parts or parts. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the attached picture:

Fig. 1 is a schematic structural diagram of a heat exchanger according to an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a heat pump water heater according to an embodiment of the present invention.

detailed description

FIG. 1 is a schematic structural diagram of a heat exchanger 220 according to an embodiment of the present invention. As shown in FIG. 1 , an embodiment of the present invention provides a heat exchanger 220 for a heat pump water heater. The heat exchanger 220 may include a heat exchanging part 10 and a water-air mixing part 20 .

The heat exchange part 10 is configured to transfer the heat of the working fluid entering it to the water entering it, so as to heat the water flowing through it. Specifically, the heat exchange part 10 may include a water inlet, a water outlet, a working fluid inlet and a working fluid outlet to receive water and working fluid, and allow the water and working fluid to flow out after heat exchange between the water and working fluid. The heated water can flow to the water tank 100 for storage, or be used directly. The working medium can be refrigerant, and after absorbing heat again, it returns to the heat exchange part 10 to heat hot water again. The working medium can also be other heat-carrying substances such as flue gas.

The water-air mixing part 20 communicates with the water inlet of the heat exchange part 10 , and is configured to receive water and gaseous substances, and mix the gaseous substances with the water so that the mixed water and gaseous substances enter the heat exchange part 10 . In particular, the gaseous substance is acid gas or a mixed gas containing acid gas. For example, gaseous substances can be carbon dioxide or air containing carbon dioxide, and acid gases such as CO ₂ can be used to form Ca(HCO ₃ ) ₂ and Mg(HCO ₃ ) ₂ with water, Ca ²⁺ , Mg ²⁺ , Ca ₂ CO ₃ , etc. etc., suppress the formation of Ca ₂ CO ₃ and the like and deposit on the tube wall of the water pipe 12 in the heat exchanger 220 to affect the heat exchange effect.

The embodiment of the present invention creatively uses acid gas such as carbon dioxide which does not affect the water quality to react with water, and suppresses the formation of scale in the process of heating water in the heat exchange unit 10, which not only prevents the heat exchange efficiency of the heat exchanger 220 from decreasing, but also does not affect Water physical indicators have no effect on the human body, and will not cause equipment shutdown and increase labor costs due to maintenance. At the same time, experiments have shown that the scale inhibition effect is higher than that of magnetization scale inhibition, electronic scale inhibition and other methods. In order to further improve the scale suppression effect, the method of using acid gas scale suppression according to the embodiment of the present invention may also be combined with magnetization scale suppression and electronic scale suppression.

In order to allow gaseous substances such as air to enter the water conveniently and quickly, in some embodiments of the present invention, the water-air mixing unit 20 may include a venturi tube 21 , a gas inlet tube 22 and a plug 23 .

Venturi tube 21 generally can be made up of the following parts: inlet section, such as a short cylindrical section; Constriction section, such as a tapered tube, the cone angle is about 21 ° ± 5 °, preferably 20 °, 21 ° or 22 ° The throat is generally a short straight pipe section, the diameter is about 1/4 to 1/3 of the diameter of the inlet section, and the length is equal to the diameter of the throat; the diffusion section can be a cone with a cone angle of 8° to 30° tube, preferably 15°, 20°, etc. The inlet of the venturi tube 21 is configured to receive water, and the outlet is connected to the water inlet of the heat exchange part 10 . The throat wall of the venturi tube 21 or the beginning of the diffuser section has an opening communicating with the gas inlet tube 22 . In this embodiment, the structure of the Venturi tube 21 can be designed according to Bernoulli's law, which should satisfy that when tap water flows, the pressure in the middle is lower than the atmospheric pressure to form a negative pressure.

The gas inlet pipe 22 may have an inlet hole, and its gas outlet end is connected to the opening on the Venturi pipe 21 to communicate with the throat and/or the diffuser section of the Venturi pipe 21 . The gas inlet pipe 22 may comprise a short straight pipe, a cover plate arranged at the inlet end of the short straight pipe, and an air inlet hole is opened on the cover plate. In this embodiment, the size of the air intake hole is determined by the heating capacity of the heat pump water heater.

The stopper 23 can preferably be a float, which is arranged in the gas inlet pipe 22 and configured to: block the air inlet of the 23 gas inlet pipe 22, and open the gas inlet pipe under the negative pressure formed when the water flows through the Venturi tube 21 22, so that the gaseous substance enters the Venturi tube 21 through the gas inlet pipe 22.

Specifically, the working principle of the water-air mixing part 20 is as follows, when the water in the Venturi tube 21 does not flow, the water in the Venturi tube 21 and the gas inlet pipe 22 makes the plug 23 against the gas inlet pipe 22 The cover plate seals the air inlet to prevent water from flowing out of the Venturi pipe 21 and the gas inlet pipe 22, that is, to prevent water from overflowing. When the water in the Venturi tube 21 flows, through the action of the throat, the air pressure in the throat and/or the diffusion section drops, forming a negative pressure, and the atmospheric pressure moves the plug 23 to open the air inlet, allowing gaseous substances such as air to enter the Venturi Mix with water in the inner tube 21.

In some alternative embodiments of the present invention, the water-air mixing part 20 may be an eductor. Ejectors may also be referred to as jet vacuum pumps, jet vacuum ejectors, jet pumps, water ejectors, vacuum ejectors. It uses water flow with a certain pressure to spray out through nozzles symmetrically arranged to form a certain side slope, and gathers at a focal point. Because the flow rate of the sprayed water is particularly high, the pressure energy is converted into velocity energy, so that the pressure in the suction area is reduced. A vacuum is created so that air is sucked in. The high-speed water flow snatches the air away, passes through the constricted section of the Venturi tube (ie, the Venturi tube), fully mixes with the throat diameter, and then flows out to the heat exchange part 10 of the heat exchanger 220 . The gas inlet of the injector can also be provided with a plug 23 to control the opening or closing of the gas inlet according to whether the inside of the injector is negative pressure. In this embodiment, the structure of the injector can be designed according to Bernoulli's law, which should meet the requirement that when the tap water flows, the internal pressure of the injector is lower than the atmospheric pressure, so as to form a negative pressure.

In some alternative embodiments of the present invention, there may also be other structures for causing negative pressure during flow, instead of the Venturi tube 21 and the injector in the above embodiments.

In some embodiments of the present invention, the heat exchange part 10 may include a working fluid tube 11 and a water tube 12 . For example, the heat exchange part 10 is a sleeve-type heat exchange device, and the water pipe 12 can be sleeved on the outside of the working fluid tube 11 , or can be arranged inside the working fluid tube 11 . The working medium pipe 11 can adopt internally threaded copper pipe. For another example, the working fluid tube 11 and the water tube 12 are arranged parallel and juxtaposed, and the tube walls of the working fluid tube 11 and the water tube 12 are in contact with each other to exchange heat. In other embodiments of the present invention, the heat exchange part 10 may also be a plate heat exchange device.

Fig. 2 is a schematic structural diagram of a heat pump water heater according to an embodiment of the present invention. As shown in FIG. 2 , an embodiment of the present invention also provides a heat pump water heater, which may include a water tank 100 and a heat pump heating system 200 .

The water tank 100 can be an open water tank or a wall-closed water tank to accommodate water.

The heat pump heating system 200 may include a compressor 210, a heat exchanger 220 in any of the above embodiments, a throttling device 230, an evaporator 240, and the like. The water-air mixing part 20 of the heat exchanger 220 is configured to receive water from the tap water network, and the water outlet of the heat exchange part 10 of the heat exchanger 220 communicates with the water tank 100 through a pipeline. Alternatively, the water-air mixing part 20 of the heat exchanger 220 can also be configured to receive the water in the water tank 100 , so as to realize the circulation heating of the water in the water tank 100 .

The working principle of the heat pump heating system 200 is that the high-pressure and high-temperature refrigerant gas generated by the compressor 210 enters the heat exchanger 220 and is condensed and cooled by water (that is, the water is heated), and then goes to the throttling device 230 for throttling and expansion, and then enters the The evaporator 240 absorbs the heat of the air and evaporates into a low-pressure steam, and the low-pressure refrigerant steam is sucked into the compressor 210 to be recompressed into a high-temperature and high-pressure gas. After the water is heated, it enters the water tank 100 and is stored or used. In this embodiment, the gaseous substance can be carbon dioxide or air, preferably air.

In some embodiments of the present invention, the heat pump water heater may further include a float valve 140 configured to connect or disconnect the pipeline between the water outlet of the heat exchange part 10 and the water tank 100 according to the water level in the water tank 100 . In some alternative embodiments, a solenoid valve may also be provided at the water inlet of the water-air mixing part 20 .

The scale inhibition principle of the heat pump water heater in the embodiment of the present invention is that when the heat pump water heater is working, the air is introduced into the water that is about to enter the heat exchange part 10 of the heat exchanger 220, and the _CO in the air can be mixed with the water and the water that may produce scale. The chemical reaction of the substance avoids the generation of scale or attachment to the heat exchange surface, which is not only low in cost, but also simple in structure, environmentally friendly and healthy.

So far, those skilled in the art should appreciate that, although a number of exemplary embodiments of the present invention have been shown and described in detail herein, without departing from the spirit and scope of the present invention, the disclosed embodiments of the present invention can still be used. Many other variations or modifications consistent with the principles of the invention are directly identified or derived from the content. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (10)

1. A heat exchanger for a heat pump water heater, characterized in that it comprises: a heat exchange unit configured to transfer heat from the working fluid entering it to the water entering it, so as to heat the water flowing through it; and The water-air mixing part communicates with the water inlet of the heat exchange part, and is configured to receive water and gaseous substances, and mix the gaseous substances with water, so that the mixed water and the gaseous substances enter the heat exchange department; of which The gaseous substance is acid gas or a mixed gas containing acid gas. 2. The heat exchanger according to claim 1, wherein the water-air mixing part comprises: a venturi tube having an inlet configured to receive water and an outlet connected to the water inlet of said heat exchange section; a gas inlet pipe having inlet holes and communicating with the throat and/or diffuser section of the venturi; and Blocking, arranged in the gas inlet pipe, configured to: block the air inlet hole of the gas inlet pipe, and open the gas inlet pipe under the action of negative pressure formed when water flows through the venturi tube The air inlet of the air inlet, so that the gaseous substance enters the Venturi tube through the gas inlet pipe. 3. The heat exchanger according to claim 2, characterized in that, The plug is a float. 4. The heat exchanger according to claim 1, characterized in that, The water-air mixing part is an injector. 5. The heat exchanger according to claim 1, characterized in that, The heat exchange part includes working fluid pipes and water pipes. 6. The heat exchanger according to claim 1, characterized in that, The heat exchange part is a plate heat exchange device or a casing heat exchange device. 7. A heat pump water heater, characterized in that it comprises: a water tank configured to contain water; A heat pump heating system comprising the heat exchanger according to any one of claims 1 to 6, wherein the water outlet of the heat exchange part of the heat exchanger communicates with the water tank via a pipeline. 8. The heat pump water heater according to claim 7, characterized in that, The gaseous substance is carbon dioxide or air. 9. The heat pump water heater according to claim 7, further comprising: The float valve is configured to connect or disconnect the pipeline between the water outlet of the heat exchange part and the water tank according to the water level in the water tank. 10. The heat pump water heater according to claim 7, characterized in that, The water-air mixing part of the heat exchanger is configured to receive water from a tap water network.