Multi-stage evaporator system

Abstract

The utility model provides a multi-stage evaporator system which comprises a lower evaporator and an upper evaporator, and a first spraying pipe used for introducing refrigerants is arranged above a second heat exchange tube bundle in the upper evaporator. A plurality of refrigerant outlet pipes are arranged at the bottom end of the side face of the upper evaporator in the height direction at intervals, each refrigerant outlet pipe is communicated with the lower evaporator, and valves are installed on the other refrigerant outlet pipes except the refrigerant outlet pipe at the topmost end. According to the multi-stage evaporator system, the storage space of the upper evaporator water disc can be fully utilized, and the adverse effects of refrigerant overflow, liquid shortage, non-continuous operation of refrigerant pumps and the like caused by refrigerant water weight change due to working condition fluctuation are eliminated; the load deviation caused by the enthalpy difference of refrigerant water at the two-stage evaporation temperature due to the fact that a refrigerant pump arranged on the lower evaporator sprays to the two-stage evaporator is eliminated; and the problem of vibration or noise generated by a connecting pipe from the refrigerant water of the upper evaporator to the lower evaporator is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to multistage evaporator system technical field especially is related to a multistage evaporator system. BACKGROUND

[0002] Current lithium bromide absorption heat pump unit is widely used in various waste heat recovery fields, for extracting the heat of circulating water, exhaust steam, deslagging water, sewage, geothermal water in power plant and industrial production process to heat the heat network water of central heating or the hot water needed by production process. Compared with the international or domestic general working condition parameters of refrigerating machine's chilled water 12 / 7, cooling water 32 / 37, the working condition range of absorption heat pump is very wide, especially when used in central heating field, because the demand for heat network water temperature is very different in the initial and final cold period and severe cold period, so the absorption heat pump is required to have good working condition adaptability, and can operate efficiently and stably under various working conditions. Since lithium bromide solution and coolant water are used as absorbent and refrigerant respectively in lithium bromide absorption heat pump, and it is a closed cycle, lithium bromide solution exists in the generator and absorber, and coolant water exists in the evaporator and condenser, and mainly exists in the evaporator; when the working condition changes, the concentration of the corresponding lithium bromide solution will change, when the concentration is high, the weight of the lithium bromide solution will decrease, and the amount of decrease is also the amount of condensed coolant water, which will cause the coolant water to increase by the same amount, and conversely, when the concentration of lithium bromide solution becomes dilute, its weight will increase, and the amount of increase is also completely from the coolant water.

[0003] Lithium bromide solution and coolant water are in a state of mutual growth and decline, and since the coolant water is mainly stored in the evaporator liquid pan, therefore the requirement of variable working condition on structural design is that the evaporator water pan should have sufficient capacity to adapt to the fluctuation of the amount of coolant water, so as to achieve that the coolant water does not overflow when the concentration is high, and the evaporator liquid pan does not lack water when the concentration is low.

[0004] When the temperature difference of waste heat water exceeds 10 DEG C or the unit capacity is too large (such as single-stage refrigerating capacity exceeding 15MW), a two-stage absorption two-stage evaporation process is generally used, which divides the evaporator into two sections, fully utilizes the advantage of high evaporation temperature in the high-temperature section, and is beneficial to improve the unit energy efficiency and reduce the equipment cost; the unit with such two-stage evaporation process generally has large capacity, and the demand for lithium bromide solution is also large, therefore when the concentration changes, the weight fluctuation of the coolant will also be large, and the conventional design is that the coolant water from the condenser enters the lower or upper evaporator, the coolant pump is arranged in the lower evaporator, the coolant water that needs to be sprayed and distributed is distributed to the two-stage evaporator, and the water that is not evaporated in the upper evaporator flows to the lower evaporator, therefore the liquid storage space of the lower evaporator needs to be enlarged, and even an external coolant water tank is needed, and the water pan of the upper evaporator almost does not store water, and the liquid storage space thereof is not utilized.

[0005] In addition, the above-mentioned mode has two disadvantages: one is that the evaporation temperatures of the two-stage evaporators are different, so the enthalpy values of the refrigerant water are also different, when the lower evaporator is the low-temperature stage, the enthalpy value of the refrigerant water from the upper evaporator of the high-temperature stage is large, which increases the load of the lower evaporator, on the contrary, when the lower evaporator is the high-temperature stage and the upper evaporator is the low-temperature stage, the refrigerant pump is connected to the lower evaporator, the enthalpy value of the refrigerant water sprayed and distributed from the lower evaporator to the upper evaporator is larger than the enthalpy value corresponding to the evaporation temperature of the upper evaporator, which correspondingly increases the load of the upper evaporator; the other is that the connecting pipe of the refrigerant water from the upper evaporator to the lower evaporator is generally non-full pipe flow, which will take part of the bubbles to the lower evaporator, and the breakage of the part of the bubbles in the water tray of the lower evaporator will generate large vibration or noise. Practical new type content

[0006] The utility model discloses a multistage evaporator system, realize adaptive control to refrigerant water according to unit load working condition.

[0007] The utility model provides a multistage evaporator system, including lower evaporator and upper evaporator arranged in upside and downside, the inside of lower evaporator is equipped with first heat exchange tube bundle, the inside of upper evaporator is equipped with second heat exchange tube bundle, the inside of upper evaporator is equipped with first spray pipe for introducing refrigerant in the upper of second heat exchange tube bundle, the bottom end position of upper evaporator side is intervalled and is equipped with a plurality of refrigerant outlet pipes along height direction, every refrigerant outlet pipe all communicates with lower evaporator, and the valve is installed on the refrigerant outlet pipe except the topmost refrigerant outlet pipe, the top end of lower evaporator inside is equipped with second spray pipe, and second spray pipe communicates with the bottom end of lower evaporator through refrigerant pump, the top end of upper evaporator inside is equipped with third spray pipe, and third spray pipe communicates with the bottom end of upper evaporator through refrigerant pump.

[0008] Further, the bottom end of the side of the lower evaporator is provided with a liquid level meter.

[0009] Further, the lower evaporator is provided with a refrigerant inlet, and the plurality of refrigerant outlet pipes are connected in parallel and communicated with the refrigerant inlet.

[0010] Further, the bottom end position of the side of the upper evaporator is provided with three refrigerant outlet pipes, and the two refrigerant outlet pipes located below are each provided with a valve.

[0011] Further, the valve is an electric valve, a solenoid valve, or a manual valve.

[0012] Further, the refrigerant pump of the lower evaporator is communicated with the bottom of the water tray of the lower evaporator, and the refrigerant pump of the upper evaporator is communicated with the bottom of the water tray of the upper evaporator.

[0013] Further, the refrigerant pump is a variable frequency refrigerant pump.

[0014] Further, a bottom end inside the lower evaporator is provided with a liquid level sensor.

[0015] Further, the third spray pipe is arranged between the first spray pipe and the second heat exchange pipe bundle.

[0016] Further, the first heat exchange pipe bundle and the second heat exchange pipe bundle are in series or parallel with each other.

[0017] The multi-stage evaporator system can make full use of the storage space of the upper evaporator water tray, eliminates the adverse effects of refrigerant overflow, liquid deficiency and refrigerant pump discontinuous operation caused by refrigerant water weight changes due to working condition fluctuations, and eliminates load deviation caused by the enthalpy difference of refrigerant water at two-stage evaporating temperature due to the configuration of refrigerant pumps for two-stage evaporators from the lower evaporator. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0019] Figure 1 The present application is a structural diagram.

[0020] Reference signs: 1-upper evaporator, 2-lower evaporator, 3-first spray pipe, 4-refrigerant outlet pipe, 5-valve, 6-liquid level meter, 7-refrigerant pump, 8-second spray pipe, 9-third spray pipe, 10-first heat exchange pipe bundle, 11-second heat exchange pipe bundle. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described below in conjunction with examples. Obviously, the described examples are some embodiments of the present application, not all embodiments. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0024] Example 1

[0025] like Figure 1 As shown, the utility model provides a multi-stage evaporator system, comprising a lower evaporator 2 and an upper evaporator 1 arranged in an upper and lower manner, wherein a first heat exchange tube bundle 10 is provided inside the lower evaporator 2, and a second heat exchange tube bundle 11 is provided inside the upper evaporator 1, wherein the first heat exchange tube bundle 10 and the second heat exchange tube bundle 11 are connected in series or in parallel with each other; a first spray pipe 3 for introducing refrigerant is provided above the second heat exchange tube bundle 11 inside the upper evaporator 1; three refrigerant outlet pipes are provided at intervals along the height direction at the bottom end position of the side surface of the upper evaporator 1 4. Each refrigerant outlet pipe 4 is connected to the lower evaporator 2. A valve 5 is installed on the refrigerant outlet pipes 4 except the top refrigerant outlet pipe 4. A second spray pipe 8 is provided at the top of the lower evaporator 2. The second spray pipe 8 is connected to the bottom of the water pan of the lower evaporator 2 through a refrigerant pump 7. A third spray pipe 9 is provided at the top of the upper evaporator 1. The third spray pipe 9 is arranged between the first spray pipe 3 and the second heat exchange tube bundle 11. The third spray pipe 9 is connected to the bottom of the water pan of the upper evaporator 1 through a refrigerant pump 7.

[0026] The bottom end of the side of the lower evaporator 2 is provided with a liquid level meter 6. The liquid level meter 6 is used to detect the water level in the lower evaporator 2 and control the opening of the valve 5.

[0027] The upper end of the lower evaporator 2 is provided with a refrigerant inlet above the liquid level meter 6. The plurality of refrigerant outlet pipes 4 are connected in parallel and communicate with the refrigerant inlet.

[0028] The valve 5 in the embodiment can be an electric valve, a solenoid valve or a manual valve. The refrigerant pump 7 is a variable frequency refrigerant pump 7.

[0029] The bottom end of the inside of the lower evaporator 2 is provided with a liquid level sensor. The liquid level sensor can be controlled by an external controller. According to the signal feedback of the liquid level sensor, the controller controls the opening of the valve 5 to realize intelligent control of the refrigerant water.

[0030] In the embodiment, a plurality of refrigerant outlet pipes 4 are provided on the upper evaporator 1. Except that the topmost refrigerant outlet pipe 4 is not provided with a valve 5, the remaining refrigerant outlet pipes 4 are all provided with a valve 5. The topmost evaporator outlet pipe serves as the highest liquid level control point of the upper evaporator 1. When the system is running, the control method for the refrigerant water is as follows: when the unit load is large and the solution concentration is high, the refrigerant amount will increase. According to the liquid level set by the liquid level meter 6, the valves 5 on the refrigerant outlet pipes 4 are closed in turn from low to high, and the excess refrigerant water is stored in the water tray of the upper evaporator 1. When the unit load decreases and the solution concentration decreases, the refrigerant water amount will decrease. According to the liquid level set by the liquid level meter 6, the valves 5 on the refrigerant outlet pipes 4 are opened in turn from high to low, and part of the refrigerant water originally stored in the upper evaporator 1 is discharged into the water tray of the lower evaporator 2.

[0031] The refrigerant storage and control method using two-stage evaporators fully utilizes the water tray space of the upper evaporator 1, balances the change of the refrigerant water amount during the working condition fluctuation, ensures that the refrigeration machine does not overflow or lack of liquid during the variable working condition, and guarantees the continuous and efficient operation of the refrigerant pump 7, thereby ensuring the continuous and efficient operation of the unit. Through the setting of the plurality of refrigerant outlet pipes 4 and the valves 5, the refrigerant water is in a full pipe state when entering the lower evaporator 2, which eliminates the vibration or noise problem caused by the connection pipe of the refrigerant water from the upper evaporator 1 to the lower evaporator 2.

[0032] The system can be expanded to multiple (≥3) stages of evaporators. The multiple stages of evaporators are also arranged from high to low. The primary refrigerant is preferentially introduced into the uppermost evaporator. The refrigerant that is not evaporated in the uppermost evaporator is sequentially supplemented into the lower evaporators. The upper evaporators can also be provided with a plurality of refrigerant outlet pipes 4 and valves 5 from high to low, which can fully utilize the storage space of the water tray of the upper evaporators.

[0033] Finally, it should be noted that: the above embodiments are used to illustrate the technical solutions of the present application, but not limited to them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A multi-stage evaporator system, characterized by, The application relates to a refrigerant evaporator, which comprises a lower evaporator and an upper evaporator arranged in an up-down mode, wherein the lower evaporator is internally provided with a first heat exchange pipe bundle, and the upper evaporator is internally provided with a second heat exchange pipe bundle; a first spray pipe for introducing refrigerant is arranged above the second heat exchange pipe bundle in the upper evaporator; a plurality of refrigerant outlet pipes are arranged at the bottom end of the side of the upper evaporator in a height direction, each of the refrigerant outlet pipes is communicated with the lower evaporator, and valves are arranged on the refrigerant outlet pipes except the topmost refrigerant outlet pipe; a second spray pipe is arranged at the top end of the lower evaporator, and the second spray pipe is communicated with the bottom end of the lower evaporator through a refrigerant pump; and a third spray pipe is arranged at the top end of the upper evaporator, and the third spray pipe is communicated with the bottom end of the upper evaporator through a refrigerant pump.

2. The multi-stage evaporator system of claim 1, wherein, A liquid level meter is arranged at the bottom end of the side of the lower evaporator.

3. The multi-stage evaporator system of claim 2, wherein, A refrigerant inlet is arranged on the lower evaporator, and the refrigerant outlet pipes are communicated with the refrigerant inlet in parallel.

4. The multi-stage evaporator system of claim 3, wherein, Three refrigerant outlet pipes are arranged at the bottom end of the side of the upper evaporator, and valves are arranged on the lower two refrigerant outlet pipes.

5. The multi-stage evaporator system of claim 4, wherein, The valve is an electric valve, an electromagnetic valve or a manual valve.

6. The multi-stage evaporator system of claim 1, wherein, The refrigerant pump of the lower evaporator is communicated with the bottom of a water tray of the lower evaporator, and the refrigerant pump of the upper evaporator is communicated with the bottom of a water tray of the upper evaporator.

7. The multi-stage evaporator system of claim 6, wherein, The refrigerant pump is a variable frequency refrigerant pump.

8. The multi-stage evaporator system of claim 1, wherein, A liquid level sensor is arranged at the bottom end of the lower evaporator.

9. The multi-stage evaporator system of claim 1, wherein, The third spray pipe is arranged between the first spray pipe and the second heat exchange pipe bundle.

10. The multi-stage evaporator system of claim 1, wherein, The first heat exchange pipe bundle and the second heat exchange pipe bundle are connected in series or in parallel.

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