A system and method for a marine air conditioner utilizing LNG cold energy

Abstract

The present application discloses a system and method for a marine air conditioner to utilize LNG cold energy. The system includes an LNG fuel supply system and an air conditioner heat exchange circulation system. The LNG fuel supply system includes an LNG storage tank, an LNG vaporizer, and a natural gas heater connected in sequence. The LNG vaporizer is further provided with a first circulation inlet and a first circulation outlet. The air conditioner heat exchange circulation system includes a first heat exchange circulation pipeline, and an air conditioner heat exchange device, a first circulation pump, and a supplementary heater sequentially arranged on the first heat exchange circulation pipeline. The first heat exchange circulation pipeline is filled with a first heat exchange liquid. The inlet of the air conditioner heat exchange device is communicated with the first circulation outlet, and the outlet of the supplementary heater is communicated with the first circulation inlet to provide the first heat exchange liquid within a predetermined temperature range at the first circulation inlet. Under the condition of ensuring the normal supply of LNG fuel for the ship, the cold energy released during its use can be maximally utilized.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG cold energy utilization, and particularly to a system and method for a marine air conditioner to utilize LNG cold energy. Background Art

[0002] With the increasing pressure of environmental emission reduction and the continuous improvement of the social demand for clean energy, the trend of ships using LNG fuel is becoming more and more obvious. However, when LNG fuel is heated to become combustible gas, a large amount of cold energy contained therein is completely not utilized, which is a serious waste of energy. At the same time, large air conditioning systems are often required on ships to provide the necessary refrigeration capacity. Especially for some passenger ships with a large number of people living on board, the demand for the refrigeration energy of the air conditioning system is even greater.

[0003] Therefore, introducing the cold energy released during the process of heating LNG fuel into a gas into the ship's air conditioning system can effectively alleviate the energy demand of the ship's air conditioning system and reduce the use cost.

[0004] Currently, although there are also systems and methods that associate air conditioning systems with LNG cold energy utilization, in the field of marine air conditioners, due to the limitations of ship space and boundary conditions, these existing methods are not fully applicable. Especially for some methods, special limitations are imposed on both the air conditioning system and the LNG fuel system, making it difficult to fully take into account the specific requirements of both in various working conditions, with low cold energy utilization rate, excessive restrictions on the original system, and difficult equipment implementation. Summary of the Invention

[0005] One advantage of the present invention is to provide a system for a marine air conditioner to utilize LNG cold energy. By adding a set of air conditioning heat exchange cycle system, it can fully meet the usage requirements of the ship's LNG fuel supply system under various working conditions without affecting the use of the original ship air conditioning system at all. It enables the marine air conditioning system and the ship's LNG fuel supply system to be both interconnected and relatively independent, and can make full use of the cold energy released by LNG, maximizing the reduction of the use cost of the ship's air conditioning system.

[0006] One advantage of the present invention is to provide a system for a marine air conditioner to utilize LNG cold energy. By setting up an engine waste heat exchange cycle system, it effectively utilizes the waste heat of the engine to supplement heat to the first heat exchange liquid in the supplementary heater, keeping the first heat exchange liquid within a predetermined temperature range, so as to ensure that the LNG fuel supply system can operate stably under any circumstances and is not affected by whether the air conditioning system is operating and the magnitude of the operating power, meeting the needs of various working conditions during the actual operation of the ship's LNG fuel supply system and the air conditioning system.

[0007] One advantage of the present invention is to provide a system for a marine air conditioner to utilize the cold energy of LNG. By arranging a three-way flow control valve in the air conditioner heat exchange circulation system, the flow rate of the first heat exchange liquid flowing to the air conditioner heat exchange device can be effectively controlled, thereby controlling the cold energy entering the air conditioner heat exchange device and facilitating the stable operation of the air conditioner system.

[0008] One advantage of the present invention is to provide a system for a marine air conditioner to utilize the cold energy of LNG. By arranging a flow regulating valve in the engine waste heat exchange circulation system, the flow rate of the second heat exchange liquid flowing to the supplementary heat exchanger can be effectively controlled, thereby controlling the heat entering the air conditioner heat exchange cycle and meeting the stable operation requirements of the LNG fuel supply system.

[0009] One advantage of the present invention is to provide a method for utilizing the cold energy of marine LNG. By controlling the temperature of the first heat exchange liquid near the first circulation inlet, it can ensure that the first heat exchange liquid can not only meet the heat exchange requirements of the air conditioner system, but also maximize the utilization of the cold energy of LNG and reduce the waste of cold energy; controlling the temperature at the first circulation outlet can not only meet the requirements of air conditioner heat exchange and cold storage, but also prevent the air conditioner cooling water from freezing and affecting the normal operation of the air conditioner system.

[0010] One advantage of the present invention is to provide a method for utilizing the cold energy of marine LNG. By using the waste heat of the engine to provide supplementary heat to the first heat exchange liquid in the supplementary heater, it will not freeze in the LNG vaporizer under any circumstances, thus meeting the stable operation requirements of the LNG fuel supply system.

[0011] One advantage of the present invention is to provide a method for utilizing the cold energy of marine LNG. By controlling the flow rate of the first heat exchange liquid and the temperature at the first circulation inlet, the temperature of the natural gas flowing out of the LNG vaporizer can be kept above zero degrees, and the cold energy released by the LNG fuel can be maximally utilized under different working conditions.

[0012] To achieve at least one of the above advantages of the present invention, the present invention provides a system for a marine air conditioner to utilize the cold energy of LNG, wherein the system for a marine air conditioner to utilize the cold energy of LNG:

[0013] An LNG fuel supply system, wherein the LNG fuel supply system includes an LNG storage tank, an LNG vaporizer, and a natural gas heater connected in sequence, and a first circulation inlet and a first circulation outlet are further arranged on the LNG vaporizer;

[0014] and

[0015] Air-conditioning heat exchange cycle system, wherein the air-conditioning heat exchange cycle system includes a first heat exchange cycle pipeline and an air-conditioning heat exchange device, a first circulation pump and a supplementary heater that are sequentially arranged on the first heat exchange cycle pipeline. The first heat exchange cycle pipeline is filled with a first heat exchange liquid. The inlet of the air-conditioning heat exchange device is communicated with the first circulation outlet, and the outlet of the supplementary heater is communicated with the first circulation inlet to provide the first heat exchange liquid within a predetermined temperature range at the first circulation inlet.

[0016] According to an embodiment of the present invention, the air-conditioning heat exchange cycle system further includes a three-way flow control valve, which is arranged on the first heat exchange cycle pipeline and is close to the inlet of the air-conditioning heat exchange device. The bypass outlet of the three-way flow control valve is connected to the outlet of the air-conditioning heat exchange device to control the flow rate entering the air-conditioning heat exchange device.

[0017] According to an embodiment of the present invention, the air-conditioning heat exchange device is implemented as an air-conditioning heat exchange cold storage tank with cold storage capacity.

[0018] According to an embodiment of the present invention, the first heat exchange liquid is implemented as an ethylene glycol aqueous solution with a predetermined concentration.

[0019] According to an embodiment of the present invention, the supplementary heater is further provided with a second circulation inlet and a second circulation outlet;

[0020] The system for a marine air conditioner to utilize LNG cold energy further includes an engine waste heat exchange cycle system, wherein the engine waste heat exchange cycle system includes a second heat exchange cycle pipeline and a second circulation pump and an engine waste heat exchanger arranged on the second heat exchange cycle pipeline. The second circulation inlet of the supplementary heater is communicated with the outlet of the engine waste heat exchanger, and the second circulation outlet of the supplementary heater is communicated with the inlet of the second circulation pump. The second heat exchange cycle pipeline is filled with a second heat exchange liquid.

[0021] According to an embodiment of the present invention, the engine waste heat exchange cycle system further includes a flow regulating valve, which is arranged on the second heat exchange cycle pipeline and is between the engine waste heat exchanger and the second circulation inlet of the supplementary heater.

[0022] According to an embodiment of the present invention, the engine waste heat exchange cycle system further includes a pipeline system for supplying a natural gas heater, wherein one end of the pipeline system for supplying the natural gas heater is connected to the outlet of the engine waste heat exchanger, and the other end is connected to the inlet of the second circulation pump after flowing through the natural gas heater, so that the second heat exchange liquid flowing through the natural gas heater and the second heat exchange liquid flowing through the supplementary heater flow in the second heat exchange circulation pipeline after being combined by the second circulation pump, and the second heat exchange liquid at the outlet of the engine waste heat exchanger meets a preset temperature.

[0023] According to an embodiment of the present invention, both the first circulation pump and the second circulation pump include at least two water glycol circulation pumps arranged in parallel, and at least one of the water glycol circulation pumps is implemented as a standby circulation pump.

[0024] According to an embodiment of the present invention, the second heat exchange liquid is implemented as a water glycol solution with a predetermined concentration.

[0025] This application also provides a method for a marine air conditioner to utilize LNG cold energy using the above-mentioned system for a marine air conditioner to utilize LNG cold energy. The method for a marine air conditioner to utilize LNG cold energy includes the following steps:

[0026] Heat the LNG fuel in the LNG storage tank 100 sequentially through the LNG vaporizer and the natural gas heater, and control the temperature of the natural gas flowing out of the LNG vaporizer to be higher than 0°C and not exceed 5°C;

[0027] Provide supplementary heat to the first heat exchange liquid through the supplementary heater, so that the temperature of the first heat exchange liquid near the first circulation inlet is not higher than 12°C and not lower than 6°C, so that the LNG cold energy can be fully utilized and the temperature of the first heat exchange liquid will not be too low to cause the LNG vaporizer to freeze and affect the normal use of the LNG fuel supply system; and

[0028] Control the temperature of the first heat exchange liquid near the first circulation inlet to be not lower than -2°C, so that the temperature of the first heat exchange liquid can exchange heat with the chilled water of the air conditioning system and will not cause the chilled water to freeze and affect the normal use of the air conditioning system.

[0029] According to an embodiment of the present invention, the method for a marine air conditioner to utilize LNG cold energy further includes the following steps:

[0030] Use the second heat exchange liquid in the engine waste heat exchange cycle system to provide a heat source for the supplementary heater, and use the flow regulating valve to regulate the flow rate of the second heat exchange liquid entering the supplementary heat exchanger.

[0031] According to an embodiment of the present invention, the method for the marine air conditioner to utilize the cold energy of LNG further includes the following steps:

[0032] Utilize the waste heat of the ship engine to heat the second heat transfer fluid to a predetermined temperature, so as to heat the natural gas to a preset temperature in the natural gas heater through the second heat transfer fluid.

[0033] These and other objects, features, and advantages of the present invention are fully embodied through the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The schematic diagram of the system for the marine air conditioner to utilize the cold energy of LNG according to the present application is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and other obvious variations can be conceived by those skilled in the art. The basic principles defined in the following description can be applied to other implementation schemes, variation schemes, improvement schemes, equivalent schemes, and other technical schemes that do not deviate from the spirit and scope of the present invention.

[0036] Those skilled in the art should understand that in the disclosure of the specification, the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention.

[0037] It can be understood that the term "one" should be understood as "at least one" or "one or more". That is, in one embodiment, the number of an element can be one, while in other embodiments, the number of the element can be multiple. The term "one" should not be construed as limiting the quantity.

[0038] Reference Figure 1, a system for a marine air conditioner utilizing the cold energy of LNG according to a preferred embodiment of the present invention will be elaborated in detail hereinafter. The system for a marine air conditioner utilizing the cold energy of LNG includes an LNG fuel supply system, an air conditioner heat exchange circulation system, and an engine waste heat exchange circulation system, so that the cold energy released during the use of LNG fuel can be utilized by the marine air conditioner to the greatest extent. According to the present invention, only a few devices need to be added to effectively connect the marine air conditioner system and the LNG fuel supply system, realizing the full utilization of LNG cold energy while still maintaining the stable operation of the marine air conditioner system and the LNG fuel supply system. The present invention basically does not affect the design and implementation of the original system equipment of the marine air conditioner system and the LNG fuel supply system, is simple and easy to implement, and has the greatest convenience and feasibility.

[0039] The LNG fuel supply system includes an LNG storage tank 100, an LNG vaporizer 11, and a natural gas heater 12 connected in sequence. The LNG fuel in the LNG storage tank 100 first undergoes vaporization by the LNG vaporizer 11 to reach a certain temperature, and then the temperature is further increased to a suitable temperature required for engine combustion by the natural gas heater 12. The LNG vaporizer 11 is further provided with a first circulation inlet P 11 and a first circulation outlet P 12 .

[0040] The specific process is as follows: The LNG fuel in the LNG storage tank 100 flows out to the LNG vaporizer 11, and the temperature at the outflow point, that is, the temperature at point P1, is about -162°C. The LNG fuel undergoes heat exchange in the LNG vaporizer 11, and the temperature of the outflowing natural gas, that is, the temperature at point P2, is controlled within the range of 0°C to 5°C, and the cold energy contained in the LNG can be fully extracted. Finally, the natural gas is heated by the natural gas heater 12, and the temperature is raised to about 30°C for use in the ship's engine combustion.

[0041] The air conditioner heat exchange circulation system includes a first heat exchange circulation pipeline and an air conditioner heat exchange device 200, a first circulation pump 21, and a supplementary heater 13 sequentially arranged on the first heat exchange circulation pipeline. The first heat exchange circulation pipeline is filled with a first heat exchange liquid. The inlet of the air conditioner heat exchange device 200 is connected to the first circulation outlet P 12 , the outlet of the supplementary heater 13 is connected to the first circulation inlet P 11 , so as to provide the first heat exchange liquid within a predetermined temperature range at the first circulation inlet P 11 .

[0042] Through the heat exchange between the first heat exchange liquid in the first heat exchange circulation pipeline and the LNG fuel in the LNG vaporizer 11, the first heat exchange liquid fully absorbs the cold energy released by the LNG fuel. The first heat exchange liquid exchanges heat with the chilled water of the marine air conditioning system in the air conditioning heat exchange device 200, thereby greatly reducing the energy required for the refrigeration of the air conditioning system and even fully meeting the cold energy required by the marine air conditioning system.

[0043] The specific process is as follows: Start the first circulation pump 21 to make the first heat exchange liquid start from the air conditioning heat exchange device 200 and first pass through the supplementary heater 13. Regardless of the temperature of the first heat exchange liquid at this time, adjust the temperature of the first heat exchange liquid through the supplementary heater 13, and control the temperature of the first heat exchange liquid at point P 11 not to be lower than 6°C and not to be higher than 12°C, so that the first heat exchange liquid will not freeze in the LNG vaporizer under any circumstances, meeting the need for the stable operation of the LNG fuel supply system.

[0044] After that, the first heat exchange liquid flows through the LNG vaporizer 11 and exchanges heat with the LNG fuel to fully obtain the cold energy of the LNG fuel. By setting, even in the case of the maximum supply flow rate of the LNG fuel, the lowest temperature of the first heat exchange liquid at point P 12 is not lower than -2°C, thereby preventing the temperature of the first heat exchange liquid from being too low, causing the chilled water for air conditioning to freeze and affecting the normal operation of the marine air conditioning system. The "by setting" here is the flow rate value obtained through heat exchange calculation according to the characteristics of the heat exchanger itself. As long as the calculated flow rate is met, the temperature will not exceed the set -2°C;

[0045] Thereafter, the first heat exchange liquid enters the air-conditioning heat exchange device 200 and exchanges heat with the chilled water of the air-conditioning system. In addition, to flexibly respond to the intermittent use of the air-conditioning system, preferably, the air-conditioning heat exchange circulation system further includes a three-way flow control valve 22, where the three-way flow control valve 22 is disposed on the first heat exchange circulation pipeline and close to the inlet of the air-conditioning heat exchange device 200, such that the first heat exchange liquid first passes through the three-way flow control valve 22 and then enters the air-conditioning heat exchange device 200, and the bypass outlet of the three-way flow control valve 22 is connected to the outlet of the air-conditioning heat exchange device 200. Thus, when the air-conditioning system stops using or does not require more cold energy, the flow rate entering the air-conditioning heat exchange device 200 can be flexibly controlled by the opening degree of the three-way flow control valve 22. The chilled water of the air-conditioning system enters from the air-conditioning chilled water inlet 201, exchanges heat with the first heat exchange liquid in the air-conditioning heat exchange device 200, and flows out from the air-conditioning chilled water outlet 202. In addition, the air-conditioning heat exchange device 200 is preferably implemented as an air-conditioning heat exchange cold storage tank with cold storage capacity, which can store a certain amount of cold energy that the air-conditioning system cannot temporarily use on the basis of exchanging heat between the first heat exchange liquid and the cooling water of the air-conditioning system for subsequent use, so as to balance the fluctuation of the cold energy released by the LNG fuel and release the cold energy evenly, which is more conducive to the stable operation of the air-conditioning system.

[0046] Briefly, the system for the marine air conditioner to utilize the cold energy of LNG maximizes the utilization of the cold energy released during the use of LNG fuel by controlling the temperature of the first heat exchange liquid entering the LNG vaporizer 11 (i.e., the temperature at point P 11 ), the temperature of the first heat exchange liquid flowing out of the LNG vaporizer 11 (i.e., the temperature at point P 12 ), and the temperature of the natural gas flowing out of the LNG vaporizer 11 (i.e., the temperature at point P2), and provides this cold energy for use by the air-conditioning system on the ship, which can ensure the stable and effective operation of the LNG fuel supply system and the marine air-conditioning system.

[0047] To ensure the continuous and uninterrupted operation of the air-conditioning heat exchange circulation system, the first circulation pump 21 includes at least two first water-glycol circulation pumps arranged in parallel, and at least one of the first water-glycol circulation pumps is implemented as a first standby circulation pump. During normal operation, the first standby circulation pump does not work. Only when an abnormal problem occurs with the first water-glycol circulation pump operating normally, the first standby circulation pump will be automatically activated and continue to work, thereby ensuring the continuous circulation of the first heat exchange liquid.

[0048] To make full use of the waste energy of the ship, the system of the marine air conditioner using LNG cold energy further includes an engine waste heat heat exchange cycle system. The engine waste heat heat exchange cycle system includes a second heat exchange cycle pipeline, and a second circulation pump 32 and an engine waste heat exchanger 31 disposed in the second heat exchange cycle pipeline. The supplementary heater 13 is provided with a second circulation inlet and a second circulation outlet. The second circulation inlet of the supplementary heater 13 is communicated with the outlet of the engine waste heat exchanger 31, and the second circulation outlet of the supplementary heater 13 is communicated with the inlet of the second circulation pump 32. A second heat exchange liquid is filled in the second heat exchange cycle pipeline. The second heat exchange liquid is used to absorb the waste heat of the engine on the ship to provide heat for the supplementary heater 13. By controlling the flow rate of the second heat exchange liquid flowing into the supplementary heater 13, the temperature of the first heat exchange liquid in the supplementary heater 13 is controlled so that its temperature at point P 11 is maintained within a temperature range not lower than 6°C and not higher than 12°C.

[0049] Further preferably, the engine waste heat heat exchange cycle system further includes a flow regulating valve 14. The flow regulating valve 14 is disposed in the second heat exchange cycle pipeline and is between the outlet of the engine waste heat exchanger 31 and the second circulation inlet of the supplementary heater 13, so as to flexibly adjust the flow rate of the second heat exchange liquid flowing into the supplementary heater 13 through the opening degree of the flow regulating valve 14 to control the temperature of the first heat exchange liquid at point P 11 point.

[0050] Further preferably, the engine waste heat heat exchange cycle system further includes a pipeline system for supplying the natural gas heater. One end of the pipeline system for supplying the natural gas heater is connected to the outlet of the engine waste heat exchanger 31, and the other end is connected to the inlet of the second circulation pump 32 after flowing through the natural gas heater 12, so that the second heat exchange liquid flowing through the natural gas heater 12 and the second heat exchange liquid flowing through the supplementary heater 13 are combined and then flow in the second heat exchange cycle pipeline through the second circulation pump 32, and the second heat exchange liquid at the outlet of the engine waste heat exchanger 31 meets a preset temperature.

[0051] By controlling the flow rate of the engine cooling water flowing into the engine waste heat exchanger 31, the temperature of the second heat exchange liquid flowing out of the engine waste heat exchanger 31 reaches the required temperature, generally above 30°C, such as 34°C, 37°C or 40°C, to meet the requirement of heating the natural gas to about 30°C in the natural gas heater 12.

[0052] In the engine waste heat exchanger 31, engine cooling water enters through the engine cooling water inlet 311 and flows out through the engine cooling water outlet 312.

[0053] To ensure the continuous and uninterrupted operation of the engine waste heat exchange cycle system, the second circulation pump 32 includes at least two second water glycol circulation pumps arranged in parallel, and at least one of the second water glycol circulation pumps is implemented as a second standby circulation pump. During normal operation, the second standby circulation pump does not work. Only when an abnormal problem occurs with the second water glycol circulation pump operating normally, the second standby circulation pump will be automatically activated and continue to work as a standby water pump, thereby ensuring the continuous circulation of the second heat exchange liquid.

[0054] In addition, the present invention also provides a method for a marine air conditioner to utilize the cold energy of LNG using the above-mentioned system for a marine air conditioner to utilize the cold energy of LNG, and the method includes the following steps:

[0055] By heating the LNG fuel in the LNG storage tank 100 successively through the LNG vaporizer 11 and the natural gas heater 12, and controlling the temperature of the natural gas flowing out of the LNG vaporizer 11 to be higher than 0°C and not exceeding 5°C, the cold energy released by the LNG fuel can be utilized to the greatest extent under different working conditions;

[0056] By providing supplementary heat to the first heat exchange liquid through the supplementary heater 13, the temperature of the first heat exchange liquid near the first circulation inlet P 11 is not higher than 12°C and not lower than 6°C, so that the cold energy of LNG can be fully utilized and the temperature of the first heat exchange liquid will not be too low, so that it will not freeze in the LNG vaporizer 11 under any circumstances, thus meeting the need for the stable operation of the LNG fuel supply system; and

[0057] Controlling the temperature of the first heat exchange liquid near the first circulation inlet P 12 so that it is not lower than -2°C can prevent the temperature of the first heat exchange liquid from being too low, causing the air-conditioning chilled water to freeze and affecting the normal operation of the marine air-conditioning system.

[0058] Preferably, the second heat exchange liquid in the engine waste heat exchange cycle system can be used to provide a heat source for the supplementary heater 13, and the flow regulating valve 14 is used to adjust the flow rate of the second heat exchange liquid entering the supplementary heat exchanger 13, so as to achieve the purpose of controlling the temperature of the second heat exchange liquid at P 11 Thereby effectively utilizing the waste energy of the ship engine operation, saving energy and reducing the operation cost.

[0059] Further preferably, the waste heat of the ship engine is utilized to heat the second heat exchange liquid to a predetermined temperature, generally a temperature above 30°C, such as 34°C, 37°C or 40°C, so as to heat the natural gas to a preset temperature in the natural gas heater 12 through the second heat exchange liquid, meeting the requirement for direct utilization of LNG fuel.

[0060] It is worth mentioning that both the first heat exchange liquid and the second heat exchange liquid are preferably implemented as an aqueous ethylene glycol solution with a predetermined concentration.

[0061] It should be noted that in the present invention, the terms "first" and "second" are only used for descriptive purposes, do not represent any order, and cannot be understood as indicating or implying relative importance. These terms can be interpreted as names.

[0062] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The advantages of the present invention have been fully and effectively realized. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments. Without departing from the above principles, the embodiments of the present invention can have any deformation or modification.

Claims

1. A system for a marine air conditioner utilizing LNG cold energy, characterized in that, The system for a marine air conditioner to utilize LNG cold energy includes: An LNG fuel supply system, wherein the LNG fuel supply system includes an LNG storage tank, an LNG vaporizer, and a natural gas heater connected in sequence, and wherein the LNG vaporizer is further provided with a first circulation inlet and a first circulation outlet; And An air-conditioning heat exchange circulation system, wherein the air-conditioning heat exchange circulation system includes a first heat exchange circulation pipeline, and an air-conditioning heat exchange device, a first circulation pump, and a supplementary heater sequentially arranged in the first heat exchange circulation pipeline. A first heat exchange liquid is filled in the first heat exchange circulation pipeline. The inlet of the air-conditioning heat exchange device communicates with the first circulation outlet, and the outlet of the supplementary heater communicates with the first circulation inlet to provide the first heat exchange liquid within a predetermined temperature range at the first circulation inlet; The supplementary heater is further provided with a second circulation inlet and a second circulation outlet; The system for the marine air conditioner to utilize LNG cold energy further includes an engine waste heat exchange circulation system, wherein the engine waste heat exchange circulation system includes a second heat exchange circulation pipeline, and a second circulation pump and an engine waste heat exchanger arranged in the second heat exchange circulation pipeline. The second circulation inlet of the supplementary heater communicates with the outlet of the engine waste heat exchanger, and the second circulation outlet of the supplementary heater communicates with the inlet of the second circulation pump. A second heat exchange liquid is filled in the second heat exchange circulation pipeline.

2. The system for a marine air conditioner utilizing LNG cold energy as claimed in claim 1, wherein, The air-conditioning heat exchange circulation system further includes a three-way flow control valve, wherein the three-way flow control valve is arranged in the first heat exchange circulation pipeline and is close to the inlet of the air-conditioning heat exchange device. The bypass outlet of the three-way flow control valve is connected to the outlet of the air-conditioning heat exchange device to control the flow rate entering the air-conditioning heat exchange device.

3. The system for a marine air conditioner utilizing LNG cold energy as described in claim 1, wherein The air-conditioning heat exchange device is implemented as an air-conditioning heat exchange cold storage tank having a cold storage capacity.

4. The system for a marine air conditioner utilizing LNG cold energy as claimed in claim 1, wherein, The engine waste heat exchange circulation system further includes a flow regulating valve, wherein the flow regulating valve is arranged in the second heat exchange circulation pipeline and is between the engine waste heat exchanger and the second circulation inlet of the supplementary heater.

5. The system for marine air conditioner utilizing LNG cold energy according to claim 4, characterized in that, The engine waste heat exchange circulation system further includes a pipeline system for supplying the natural gas heater, wherein one end of the pipeline system for supplying the natural gas heater is connected to the outlet of the engine waste heat exchanger, and the other end is connected to the inlet of the second circulation pump after flowing through the natural gas heater, so that the second heat exchange liquid flowing through the natural gas heater and the second heat exchange liquid flowing through the supplementary heater are combined and then flow in the second heat exchange circulation pipeline through the second circulation pump, and the second heat exchange liquid at the outlet of the engine waste heat exchanger meets a preset temperature.

6. The system for a marine air conditioner utilizing LNG cold energy as claimed in claim 5, wherein, Both the first circulation pump and the second circulation pump include at least two water-glycol circulation pumps arranged in parallel, and at least one of the water-glycol circulation pumps is implemented as a standby circulation pump.

7. A method for a marine air conditioner to utilize the cold energy of LNG in a system for a marine air conditioner to utilize the cold energy of LNG according to any one of claims 4 to 6, characterized in that, The method for the marine air conditioner to utilize LNG cold energy includes the following steps: Heat the LNG fuel in the LNG storage tank 100 sequentially through the LNG vaporizer and the natural gas heater, and control the temperature of the natural gas flowing out of the LNG vaporizer to be higher than 0°C and not exceed 5°C; Provide supplementary heat to the first heat exchange liquid through the supplementary heater, so that the temperature of the first heat exchange liquid near the first circulation inlet is not higher than 12°C and not lower than 6°C, so that the LNG cold energy can be fully utilized without causing the temperature of the first heat exchange liquid to be too low, resulting in freezing of the LNG vaporizer and affecting the normal use of the LNG fuel supply system; and Control the temperature of the first heat exchange liquid near the first circulation outlet to be not lower than -2°C, so that the temperature of the first heat exchange liquid can exchange heat with the chilled water of the air conditioning system without causing the chilled water to freeze and affecting the normal use of the air conditioning system.

8. The method for a marine air conditioner to utilize LNG cold energy as claimed in claim 7, wherein, The method for the marine air conditioner to utilize LNG cold energy further includes the following steps: Use the second heat exchange liquid in the engine waste heat heat exchange circulation system to provide heat source for the supplementary heater, and use the flow regulating valve to regulate the flow of the second heat exchange liquid entering the supplementary heat exchanger.

9. The method for a marine air conditioner to utilize LNG cold energy according to claim 8, characterized in that, The method for the marine air conditioner to utilize LNG cold energy further includes the following steps: Use the waste heat of the marine engine to heat the second heat exchange liquid to a predetermined temperature, so as to heat the natural gas to a preset temperature in the natural gas heater through the second heat exchange liquid.

Images