Energy-saving refrigeration unit and air conditioning system for offshore drilling platform

Abstract

The present application relates to a kind of offshore drilling platform energy-saving refrigeration unit, including cold storage module and refrigeration module;Cold carrier circulates in cold storage module to cool air, and cold storage module can simultaneously store excess cold capacity;Refrigeration module uses double-effect absorption chiller unit, including high-pressure generator, low-pressure generator, first condenser, evaporator, absorber, low-temperature heat exchanger, high-temperature heat exchanger, also including heat storage fresh water circulation loop, utilize drilling platform diesel engine main engine cooling water waste heat and solar energy collector heat as heat source.The present application uses solar energy in double-effect absorption chiller unit lithium bromide dilute solution heating concentration link, simultaneously utilize the waste heat of cooling water and steam of diesel engine main engine to heat and concentrate high-pressure generator lithium bromide dilute solution, realize the purpose of energy saving and environmental protection;Refrigeration module uses double-effect absorption unit, and its combustion efficiency is high, occupies small area, noise is small, and has no special requirements to operating personnel.

Description

Technical Field

[0001] This invention relates to the field of refrigeration system technology, specifically to an energy-saving refrigeration unit and air conditioning system for offshore drilling platforms. Background Technology

[0002] Offshore drilling platforms are located in the middle of the ocean, in harsh climates with high solar radiation and consistently high temperatures. Taking the South China Sea as an example, data shows the average annual temperature is 26.8℃, with the average high temperature in the hottest month reaching 31.5℃ and the average low temperature in the coldest month averaging 22℃. Furthermore, the South China Sea experiences high humidity throughout the year, with an annual average relative humidity of around 81% and monthly relative humidity ranging from 78% to 84%, making it unsuitable for habitation.

[0003] To improve the harsh working and living environment at sea, enhance platform quality, and protect the physical and mental health of platform personnel, the selection of air conditioning system configuration is crucial, and the state has also imposed stringent requirements on the indoor air conditions of drilling platforms. Firstly, regarding temperature requirements, my country's design standards for marine air-conditioned cabins are: winter room temperature 19–22℃; summer room temperature 24–28℃; and temperature differences between different areas within the room controlled within 3–5℃. Secondly, regarding humidity requirements, relative humidity should be within the range of 30%–70%. In summer, air conditioning uses cooling and dehumidification methods, with indoor humidity generally controlled at 40%–50%; in winter, indoor humidity should ideally be 30%–40%.

[0004] Currently, the traditional compression-type refrigeration units commonly used on offshore drilling platforms are large in size and noisy. For example, Chinese patent CN115158616A proposes a submarine air conditioning system with a cold storage module. This module stores cold energy when the submarine is not submerged and uses the stored energy to cool the refrigerant when the submarine is submerged. The cooled refrigerant is then passed to a temperature and humidity control unit, effectively reducing the energy consumption of the air conditioning system and extending battery life during submerged operation. However, this patent uses a traditional compression-type refrigeration unit, which has the disadvantages of large footprint and high noise levels. Furthermore, the patent does not include a recovery path for solar energy and waste heat from the main engine.

[0005] Chinese patent CN216203959U proposes an air conditioning system for offshore platforms, which also fails to fully utilize the abundant solar energy on offshore drilling platforms, and other heat cascade utilization schemes can be further optimized. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an energy-saving refrigeration unit and air conditioning system for offshore drilling platforms, which addresses the shortcomings of the existing technology. The system adopts a double-effect absorption chiller unit, which has high combustion efficiency, small footprint, low noise, and no special requirements for operators. At the same time, it sets up recovery paths for solar energy and waste heat from the main unit, which is energy-saving and environmentally friendly.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] An energy-saving refrigeration unit for offshore drilling platforms includes a cold storage module and a refrigeration module;

[0009] The refrigeration module includes a high-pressure generator, a low-pressure generator, a first condenser, an evaporator, an absorber, a low-temperature heat exchanger, and a high-temperature heat exchanger, all connected sequentially by pipelines to form a circulation loop. It also includes a thermal storage freshwater circulation loop connected to the high-pressure generator. This loop includes a solar collector panel that uses solar energy to heat freshwater and exchange heat with a dilute lithium bromide solution in the high-pressure generator. The high-pressure generator is also connected to the cooling water and steam pipelines of the drilling platform's diesel engine, simultaneously using the engine's cooling water and steam to exchange heat with the dilute lithium bromide solution in the high-pressure generator. The high-pressure refrigerant steam generated from the boiling of the lithium bromide solution, along with the cooled diesel engine water and steam after heat exchange, enter the low-pressure generator, where they heat the intermediate concentration lithium bromide solution. The diesel engine's cooling water and steam, after cooling, enter the atmospheric condenser for liquefaction and are then used in the domestic hot water section. High-pressure refrigerant steam, after cooling, becomes low-pressure refrigerant steam and enters the first condenser for condensation. The condensate enters the evaporator, absorbs heat, and evaporates into secondary steam, which is then collected in the absorber. The concentrated lithium bromide solution, heated in the low-pressure generator, is cooled by a low-temperature heat exchanger and returned to the absorber. The secondary steam liquefies and dilutes the concentrated lithium bromide solution in the absorber, turning it into a dilute lithium bromide solution. The dilute lithium bromide solution enters the low-temperature heat exchanger from the absorber, exchanges heat with the concentrated lithium bromide solution from the low-pressure generator, and then enters the high-temperature heat exchanger to exchange heat with an intermediate-concentration lithium bromide solution from the high-pressure generator. After heating, it enters the high-pressure generator. The intermediate-concentration lithium bromide solution after heat exchange enters the low-pressure generator.

[0010] The cold storage module includes a first circulation loop and a second circulation loop. The first circulation loop includes an air cooler and a refrigeration end connected in sequence. The refrigeration end exchanges heat with the evaporator of the refrigeration module to cool the refrigerant. The low-temperature refrigerant returns to the air cooler to participate in air cooling. The second circulation loop includes an air cooler, a storage refrigerator, and a cold storage end connected in sequence. The cold storage end exchanges heat with the evaporator of the refrigeration module to cool the refrigerant. A portion of the low-temperature refrigerant is directly stored in the storage refrigerator, and another portion of the low-temperature refrigerant returns to the air cooler to participate in air cooling.

[0011] In the above scheme, the thermal storage freshwater circulation loop also includes a thermal storage freshwater tank, in which the desalinated seawater is stored, and the freshwater heated by the solar collector is also stored in the thermal storage freshwater tank.

[0012] In the above scheme, a hot water well is provided downstream of the first atmospheric condenser for storing excess domestic hot water.

[0013] In the above scheme, a No. 4 control valve is installed on the pipeline between the high-pressure generator and the low-pressure generator. The high-pressure refrigerant water vapor generated by heating in the high-pressure generator enters the low-pressure generator through the No. 4 control valve.

[0014] In the above scheme, a No. 2 throttling valve is installed on the pipeline between the first condenser and the evaporator, and the condensate generated in the first condenser enters the evaporator through the No. 2 throttling valve.

[0015] In the above scheme, a pressure reducing valve No. 2 is installed on the pipeline between the low-temperature heat exchanger and the absorber, and the concentrated lithium bromide solution in the low-temperature heat exchanger enters the absorber through the pressure reducing valve No. 2; a solution pump No. 1 is installed on the pipeline between the absorber and the low-temperature heat exchanger, and the dilute lithium bromide solution in the absorber enters the low-temperature heat exchanger to exchange heat with the concentrated lithium bromide solution under the action of the solution pump No. 1.

[0016] In the above scheme, a pressure reducing valve No. 1 is installed on the pipeline between the high-temperature heat exchanger and the low-pressure generator. The intermediate concentration lithium bromide solution in the high-temperature heat exchanger enters the low-pressure generator after passing through the pressure reducing valve No. 1.

[0017] In the above scheme, a cold release pump and a No. 1 throttling valve are installed on the pipeline between the refrigerator and the cold storage end. The refrigerant in the refrigerator enters the cold storage end for cooling through the cold release pump and the No. 1 throttling valve in sequence. A No. 3 control valve is installed on the pipeline between the cold storage end and the refrigerator. The cooled refrigerant returns to the refrigerator through the No. 3 control valve.

[0018] Accordingly, the present invention also proposes an energy-saving air conditioning system for offshore drilling platforms, comprising an air handling unit, a solution dehumidification unit, and the aforementioned refrigeration unit; the air handling unit comprises, in sequence, a heat pipe heat exchanger, an air filter, an air dehumidifier, a fan, an air cooler, an air heater and humidifier, and an air outlet, arranged in the air intake channel; an air inlet valve No. 1 is provided on the front side of the air filter and an air inlet valve No. 2 is provided on the upper side; the exhaust duct outlets of the living area cabins are respectively located on the front side of the heat pipe heat exchanger at the air inlet and on the upper side of the air inlet valve No. 2 of the air filter; the air outlets are connected to the living area cabins; the solution dehumidification unit is connected to the air dehumidifier, supplying dehumidifying liquid to the air dehumidifier for dehumidification; the refrigeration unit is connected to the air cooler, supplying refrigerant to the air cooler for cooling the air.

[0019] In the above scheme, the solution dehumidification unit includes a solution regenerator, which includes a steam overflow hood, a guide plate, an inclined heating plate, a dilute solution inlet, a concentrated solution outlet, and a vacuum pump interface. A dilute solution inlet is provided above the guide plate for connecting to an air dehumidifier. A steam overflow hood is provided above the inclined heating plate, and a vacuum pump interface connected to a vacuum pump is provided at the upper end of the steam overflow hood. A reserved space is provided below the inclined heating plate for connecting cooling water and steam from the main engine of the drilling platform diesel engine. A concentrated solution outlet is provided at the lower end of the inclined heating plate.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The refrigeration unit of this invention is equipped with a solar collector panel, which uses its heat energy for heating and concentrating the lithium bromide dilute solution in the high-pressure generator of the double-effect absorption chiller. Simultaneously, the waste heat from the cooling water and steam of the diesel engine on the offshore drilling platform is used to heat and concentrate the lithium bromide dilute solution in the high-pressure generator, achieving energy saving and environmental protection. Furthermore, if the offshore drilling platform's main engine stops operating, solar energy can still be used to heat water to drive the high-pressure generator, and the refrigerator can supplement the cooling capacity for energy saving. In addition, the 50°C low-temperature hot water after heat exchange can be reused in the domestic hot water section.

[0022] 2. The refrigeration unit of this invention is designed with a cold storage module. The purpose is to follow the principle of "peak shaving and valley filling" to store the excess cold energy during peak refrigeration periods. When solar energy is insufficient and the diesel engine stops working, the energy stored in the refrigerator can be released for use.

[0023] 3. The refrigeration module used in the refrigeration unit of the present invention is a double-effect absorption chiller, which has high combustion efficiency, small footprint, low noise, and no special requirements for operators.

[0024] 4. The air conditioning system of the present invention adopts an independent temperature and humidity control method, the dehumidifying liquid is selected as a liquid with bactericidal ability, the air filter adopts a multi-layer composite structure, and the air will undergo strict sterilization treatment through the TiO2 photocatalytic mesh.

[0025] 5. The solution regenerator housing designed in this invention is divided into upper and lower layers. The upper layer is filled with dehumidifying liquid, and the lower layer is filled with diesel engine cooling water and steam heating. Combined with a vacuum pump to change the boiling point of the solution, it is more energy-efficient. A dedicated steam hood is provided for the recovery of dehumidifying agent water vapor, making the structure simpler and easier to manufacture. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of the structure of the energy-saving air conditioning system for offshore drilling platforms according to the present invention;

[0028] Figure 2 yes Figure 1 The diagram shows the structure of the refrigeration unit in the air conditioning system shown.

[0029] Figure 3 yes Figure 1 A schematic diagram of the solution dehumidification unit in the air conditioning system shown.

[0030] Figure 4 yes Figure 3 The diagram shows the structure of the solution regenerator of the solution dehumidification unit, where (a) is the overall structure diagram and (b) is the structure diagram of the guide plate and the inclined heating plate.

[0031] In the diagram: 100, Air handling unit; 110, Heat pipe heat exchanger; 120, Air filter; 121, No. 1 air inlet valve; 122, No. 2 air inlet valve; 130, Air dehumidifier; 131, Humidity sensor; 132, Solution nozzle; 133, Water baffle; 134, Annular conical liquid baffle; 135, Metal packing; 140, Fan; 150, Air cooler; 160, Air heater and humidifier; 170, Air outlet;

[0032] 200. Solution dehumidification unit; 210. Solution regenerator; 211. Steam overflow hood; 212. Baffle plate; 213. Inclined heating plate; 214. Dilute solution inlet; 215. Concentrated solution outlet; 216. Cooling water inlet; 217. Cooling water outlet; 218. Vacuum pump interface; 220. Second condenser; 230. Fresh water tank; 240. First solution pump; 250. Concentrated solution tank; 260. Concentration meter; 270. Solenoid three-way valve; 280. Second solution pump; 290. Vacuum pump;

[0033] 300. Refrigeration unit; 310. Cold storage module; 311. Cold storage refrigerator; 312. Refrigerant water pump; 313. Cold release pump; 314. Refrigeration end; 315. Cold storage end;

[0034] 320. Refrigeration module; 321. High-pressure generator; 322. Low-pressure generator; 323. First condenser; 324. Evaporator; 325. Absorber; 326. Low-temperature heat exchanger; 327. High-temperature heat exchanger; 328. Solar collector panel; 329. Thermal storage freshwater tank;

[0035] Control valves 331, 1; 332, 2; 333, 3; 334, 4; 335, 5; 336, 6; 337, 7.

[0036] 341, Throttle valve No. 1; 342, Throttle valve No. 2; 343, Throttle valve No. 3;

[0037] 351, Pressure reducing valve No. 1; 352, Pressure reducing valve No. 2;

[0038] 361, Solution Pump No. 1; 362, Solution Pump No. 2;

[0039] 400. Living quarters compartment; 410. Temperature sensor; 420. VAV air distributor;

[0040] 500. Diesel engine main unit;

[0041] 601. Atmospheric condenser; 602. Domestic hot water section; 603. Hot water well. Detailed Implementation

[0042] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] This invention provides an energy-saving air conditioning system for offshore drilling platforms, applicable to both fixed and jack-up offshore drilling platforms, installed within the platform's living quarters. Figure 1As shown, the system includes an air handling unit 100, a solution dehumidification unit 200, and a refrigeration unit 300. The air handling unit 100 includes a heat pipe heat exchanger 110, an air filter 120, an air dehumidifier 130, a fan 140, an air cooler 150, an air heater / humidifier 160, and an air outlet 170, arranged sequentially within the airflow duct. Along the airflow direction, it is divided into a filtration section, a dehumidification section, a cooling section, and a heating section. The air filter 120 has a No. 1 air inlet valve 121 at its front and a No. 2 air inlet valve 122 at its upper side. The exhaust outlets of the living area compartment 400 are located at the air inlet, in front of the heat pipe heat exchanger 110 and above the No. 2 air inlet valve 122 of the air filter 120. The air outlet 170 is connected to the living area compartment 400. The solution dehumidification unit 200 is connected to the air dehumidifier 130, supplying dehumidifying liquid to the air dehumidifier 130 to dehumidify the air, and then discharging the gas into the original exhaust duct. The refrigeration unit 300 is connected to the air cooler 150, supplying refrigerant to the air cooler 150 to cool the air. The air handling unit 100 first dehumidifies the air through the solution dehumidification unit 200, and then blows the dehumidified air into the refrigeration unit 300 through the fan 140 for cooling. The dehumidified and cooled air is then discharged to the living area compartment 400 through the air outlet 170. The living area compartment 400 is equipped with a temperature sensor 410 and a VAV distributor 420. The VAV distributor 420 is used to distribute air from the air conditioning system into the compartment, and the temperature sensor 410 controls the indoor temperature by controlling the speed of the exhaust fan motor in conjunction with the VAV variable air volume terminal.

[0044] When the air conditioning system is running, the high-temperature and high-humidity fresh air from the sea is introduced by the heat pipe heat exchanger 110. At the same time, it exchanges heat with the return air discharged from the exhaust duct of the living area to become pre-cooled fresh air. It is sent into the filter section through the No. 1 air inlet valve 121 and mixed with the indoor return air introduced by the No. 2 air inlet valve 122. First, it enters the air dehumidifier 130 and is dehumidified by the bactericidal dehumidifying liquid. Then, the air is blown into the air cooler 150 by the fan 140 and cooled by the refrigerant in the air cooler 150. In winter, the air is heated and humidified by the air heating humidifier 160. Finally, the air is discharged from the air outlet 170 and enters the living area cabin 400. The indoor temperature sensor 410 analyzes the temperature of the incoming air. The VAV air distributor 420 delivers the clean air that has been cooled or heated and dehumidified or humidified to each room.

[0045] See Figure 1-2The refrigeration unit 300 in the air conditioning system of the present invention includes a cold storage module 310 and a refrigeration module 320. The cold storage module 310 is connected to the air cooler 150, and the refrigerant circulates in the cold storage module 310 to cool the air. The cold storage module 310 can also store excess cold energy. The refrigeration module 320 adopts a double-effect absorption chiller unit, which is connected to the cold storage module 310 to cool its refrigerant. The refrigeration module 320 is a hot water type lithium bromide chiller unit that uses the waste heat of the cooling water of the drilling platform diesel engine 500 and the heat collected by the solar collector 328 as heat sources.

[0046] See details Figure 2The refrigeration module 320 includes a high-pressure generator 321, a low-pressure generator 322, a first condenser 323, an evaporator 324, an absorber 325, a low-temperature heat exchanger 326, and a high-temperature heat exchanger 327, which are connected in sequence through pipelines to form a circulation loop. It also includes a thermal storage freshwater circulation loop connected to the high-pressure generator 321. The thermal storage freshwater circulation loop includes a solar collector plate 328 and a thermal storage freshwater tank 329. Desalinated seawater is stored in the thermal storage freshwater tank 329. Freshwater flows through the solar collector plate 328 and is heated. The generated hot water enters the thermal storage freshwater tank 329 through control valve 337. Cold water and hot water are continuously mixed and circulated until boiling, reaching a temperature of approximately 90°C. This hot water is then pumped into the high-pressure generator 321 through solution pump 362 and throttle valve 343 to heat the dilute lithium bromide solution within the high-pressure generator 321. The high-pressure generator 321 is also connected to the cooling water and steam pipes of the drilling platform's diesel engine 500. Simultaneously, it utilizes the cooling water and steam from the diesel engine 500 to exchange heat with the dilute lithium bromide solution within the high-pressure generator 321. The fluid in the left-side pipe of the high-pressure generator 321 is the cooling water and steam from the drilling platform's diesel engine 500, with a temperature of approximately 75°C. The fluid in the right-side pipe is fresh seawater heated by the solar collector 328, with a temperature as high as 90°C. Both pipes indirectly exchange heat with the dilute lithium bromide solution within the high-pressure generator 321. The high-pressure refrigerant steam generated by the boiling of the dilute lithium bromide solution enters the upper pipe of the low-pressure generator 322 through control valve 334. The cooling water and steam from the diesel engine 500 enter the lower pipe of the low-pressure generator 322, both participating in the heating process of the low-pressure generator 322. The dilute lithium bromide solution in the high-pressure generator 321 is heated to become an intermediate-concentration lithium bromide solution. This intermediate-concentration solution is cooled by the high-temperature heat exchanger 327 and then enters the low-pressure generator 322 via pressure reducing valve 351. In the low-pressure generator 322, high-pressure refrigerant steam in the upper pipe and cooling water and steam from the diesel engine 500 in the lower pipe heat the intermediate-concentration lithium bromide solution. The high-pressure refrigerant steam in the upper pipe is cooled to become low-pressure refrigerant steam, which enters the first condenser 323 for condensation. The condensate enters the right-side pipe of the evaporator 324 via throttle valve 342. The two pipes on the left side of the evaporator 324 contain a higher-temperature refrigerant, which corresponds to the refrigeration end 314 and the cold storage end 315 of the cold storage module 310, respectively. The evaporator 324 stores heat exchanger, and through indirect heat exchange with the heat exchanger, the condensate absorbs heat and evaporates into secondary steam, which is collected by the absorber 325. The diesel engine main unit 500 cooling water and steam in the lower pipe inside the low-pressure generator 322 are cooled and then enter the atmospheric condenser 601 for liquefaction. The liquefied water then enters the domestic hot water section 602 for use, while the remaining hot water flows into the hot water well 603 for storage.The intermediate-concentration lithium bromide solution in the low-pressure generator 322 is heated to become a concentrated lithium bromide solution. This concentrated lithium bromide solution is cooled by the low-temperature heat exchanger 326 and then recovered to the absorber 325 via pressure reducing valve 352. Secondary steam liquefies and dilutes the concentrated lithium bromide solution in the absorber 325, turning it into a dilute lithium bromide solution. The dilute lithium bromide solution then enters the low-temperature heat exchanger 326 from the absorber 325 via solution pump 361. After heat exchange with the concentrated lithium bromide solution from the low-pressure generator 322, it enters the high-temperature heat exchanger 327, where it exchanges heat with the intermediate-concentration lithium bromide solution from the high-pressure generator 321. After being heated, it enters the high-pressure generator 321. The intermediate-concentration lithium bromide solution, after heat exchange in the high-temperature heat exchanger 327, enters the low-pressure generator 322. This cycle repeats, using lithium bromide solution as the working fluid in a double-effect absorption-type water-cooled refrigeration cycle.

[0047] See also Figure 2 The cold storage module 310 includes a first circulation loop and a second circulation loop. The first circulation loop includes an air cooler 150 and a refrigeration end 314 connected in sequence. The refrigeration end 314 exchanges heat with the evaporator 324 of the refrigeration module 320 to cool the refrigerant. The low-temperature refrigerant returns to the air cooler 150 to participate in air cooling. After the refrigerant cools the air in the air duct in the air cooler 150, the refrigerant absorbs heat and its temperature rises. It then enters the evaporator 324 through the No. 1 control valve 331 for heat exchange and cooling, and flows back to the air cooler 150 through the refrigerant water pump 312, completing the first cycle. The second circulation loop includes an air cooler 150, a refrigerator 311, and a cold storage end 315 connected in sequence. The cold storage end 315 exchanges heat with the evaporator 324 of the refrigeration module 320 to cool the refrigerant. A portion of the low-temperature refrigerant is directly stored in the refrigerator 311, while the other portion returns to the air cooler 150 to participate in air cooling. The refrigerant enters the refrigerator 311 through control valve 2 332, and then enters the evaporator 324 through the cold release pump 313 and throttle valve 1 341. At this time, the temperature of the heat exchanger in the evaporator 324 is lower than that of the refrigerant in the left pipe, and heat exchange occurs to obtain low-temperature refrigerant. The low-temperature refrigerant flows back through the refrigerant water pump 312. A portion of the low-temperature refrigerant is directly stored in the refrigerator 311, while the other portion returns to the air cooler 150 to participate in air cooling, completing the second type of circulation.

[0048] The refrigerator 311 is placed in a cool, sparsely populated location such as a medical ward. Because the temperature difference between the water in the thermal storage freshwater tank 329 and the ambient temperature is large, it is difficult to store heat. During the day, solar energy can be used to heat the water to 80-90℃. Once the heat is fully stored, the high-temperature freshwater in the tank is immediately put into use, simultaneously assisting the high-pressure generator 321 in heating while absorbing solar energy to raise the temperature until the temperature is insufficient to heat the high-pressure generator 321. At this point, auxiliary heating is stopped, and only the heat storage process continues.

[0049] When the temperature difference between day and night is large, and the set temperature during the day is much lower than the ambient temperature, the liquid working fluid in the refrigerator 311 completes a phase change using some of the cooling capacity generated during off-peak electricity cooling at night, and stores the cooling capacity using the latent heat of phase change of ice. The cooling capacity is released during the next day to assist in a significant cooling effect. When the temperature difference between day and night is small, the heat released by the thermal storage freshwater tank 329 during the day causes the refrigeration unit 320 to generate a large amount of cooling capacity, and the supply of cooling capacity exceeds the demand. At this time, the refrigerator 311 completes the ice-making phase change process during the day, and prioritizes the use of the cooling capacity in the refrigerator at night. After the cooling capacity is released, the refrigeration unit 320 starts working again.

[0050] Specifically, the refrigerator 311 starts the cold storage unit 310 to store cold energy by opening control valves 332 and 333. The cold energy storage process employs a stepped-up cold storage method. Stepped-up cold storage refers to the process where, as the indoor temperature decreases, the required cold energy for cooling decreases, and the flow rate of the low-temperature gas entering the cold storage tank through control valve 333 steadily increases according to a set curve. During the start-up phase of the refrigeration unit 320, the system automatically adjusts the flow rate of the control valves so that approximately 80% of the cold energy is directly used for indoor cooling, and 20% is stored. As the temperature difference between the indoor temperature and the set temperature gradually decreases, the flow rate of the control valves is changed to reduce the cold energy directly used for indoor cooling and increase the energy stored, until the cold storage unit 310 is full. For the environment, the total cold release (the cold energy produced by the refrigeration unit 320 plus the cold energy released by the refrigerator 311) remains constant.

[0051] During the cooling release phase, the flow rate of the storage refrigerator 311 is initially high and then decreases to ensure that all the cooling capacity is released, minimizing energy loss. Later, as the cooling capacity is about to be exhausted, the refrigeration unit 320 gradually starts working.

[0052] Further optimization involves the thermal storage freshwater tank 329, which comprises an outer shell, an insulation layer, and an inner shell. The insulation layer is filled with one or more insulation materials, including polyurethane foam, aerogel felt, and glass wool. Both the inner and outer shells are coated with insulation paint. The thermal storage freshwater tank 329 uses the MPPT algorithm to determine its suitable maximum operating power and is positioned in locations with high population density and high cabin temperature, such as the kitchen and laundry room, to reduce heat loss.

[0053] Further optimization involves using R170 as the refrigerant, which does not damage the ozone layer and has a very small greenhouse effect, making it an environmentally friendly working fluid.

[0054] Further optimization involves selecting a flat-plate solar collector for the solar collector panel 328. This collector employs a Fresnel lens cover plate with a Fresnel lens, a heat absorption plate located inside the casing, and a serpentine heat collection tube connected to the lower surface of the heat absorption plate. It has a good heat collection effect and can heat water to 90°C, which is sufficient to drive the high-pressure generator 321.

[0055] Further optimized, the air filter 120 is installed on the right side of the heat pipe heat exchanger 110, with an air inlet valve 121 on the left side to introduce air that has undergone heat exchange treatment, and an air inlet valve 122 on the upper side to connect to the exhaust duct of the living area. To improve air quality and simultaneously achieve sterilization and disinfection, the air filter 120 adopts a multi-layer composite structure. The air first passes through the TiO2 photocatalytic mesh at the inlet, which purifies harmful gases and bacteria in the incoming air. Next, the air passes through ultra-fine glass fiber filter paper, a high-voltage electric field, and an electrostatic dust removal mesh to purify most of the suspended inorganic particles in the air. Finally, the air passes through the TiO2 photocatalytic mesh at the end for further inactivation of suspended pathogens, bacteria, viruses, and other organic matter in the air.

[0056] Further optimization, such as Figure 3 As shown, the solution dehumidification unit 200 is connected to the air dehumidifier 130 of the air handling unit 100, and includes a solution regenerator 210, a second condenser 220, a fresh water tank 230, a first solution pump 240, a concentrated solution tank 250, a concentration meter 260, a solenoid three-way valve 270, a second solution pump 280, and a vacuum pump 290.

[0057] Among them, such as Figure 4 As shown, the solution regenerator 210 includes a steam overflow hood 211, a guide plate 212, an inclined heating plate 213, a dilute solution inlet 214, a concentrated solution outlet 215, a cooling water inlet 216, a cooling water outlet 217, and a vacuum pump interface 218. The dilute solution inlet 214 is located above the guide plate 212 for connecting to the air dehumidifier 130; the steam overflow hood 211 is located above the inclined heating plate 213, and its upper end has a vacuum pump interface 218 connected to the vacuum pump 290; a reserved space is provided below the inclined heating plate 213 for connecting cooling water and steam from the drilling platform diesel engine 500; the concentrated solution outlet 215 is located at the lower end of the inclined heating plate 213 for connecting to the concentration meter 260. The cooling water inlet 216 is connected to the cooling water outlet pipe of the drilling platform diesel engine 500, and the cooling water outlet 217 is connected to the cooling water inlet of the drilling platform diesel engine 500, serving to divert cooling water from the engine.

[0058] Specifically, lithium bromide aqueous solution was chosen as the desiccant. Data shows that when a vacuum pump is used to evacuate air to a vacuum level exceeding 53.9 kPa, water in the lithium bromide solution can boil at temperatures below 80°C.

[0059] The specific process of solution regeneration is as follows: The dilute solution discharged from the air dehumidifier 130 enters the solution regenerator 210 through the dilute solution inlet 214, flows downwards through the guide plate 212 and the inclined heating plate 213, and the space reserved under the two plates is preheated by the cooling water inlet 216 with cooling water and steam from the drilling platform diesel engine 500 at about 85°C. Part of the cooling water and steam from the drilling platform diesel engine 500 flows to the solution regenerator 210 through control valve 335 to heat the solution, and the other part enters the high-pressure generator 321 through control valve 336. The low-pressure environment created by the vacuum pump 290 for the solution regenerator 210 lowers the boiling point of water in the lithium bromide solution to below 80°C. Driven by the cooling water and steam heat source of the diesel engine 500, the water in the lithium bromide aqueous solution boils, evaporates and concentrates into a concentrated solution, and is discharged from the concentrated solution outlet 215 at the bottom of the solution regenerator 210.

[0060] The working principle of the solution dehumidification unit 200 is as follows: The concentrated solution regenerated in the solution regenerator 210 is discharged through the concentrated solution outlet 215. The concentration of the discharged concentrated solution is checked by the concentration meter 260. If the concentration is lower than the threshold, it is reintroduced into the dilute solution inlet 214 at the top of the solution regenerator 210 by the electromagnetic three-way valve 270 and the first solution pump 240. If the concentration meets the requirements, it is introduced into the concentrated solution tank 250. The outside of the concentrated solution tank 250 is cooled by low-temperature seawater. The concentrated solution is sent to the air dehumidifier 130 by the second solution pump 280 to dehumidify the supply air. The concentrated solution absorbs water and becomes a dilute solution. It flows into the solution regenerator 210 along the pipeline under gravity.

[0061] In this embodiment, further, as Figure 3 and Figure 4 As shown, the steam overflow hood 211 has two operating modes. One mode is that the vent is open and the vacuum pump interface 218 is not connected, and the water vapor is blown out by the return air through the small holes on the steam overflow hood 211. The other mode is that the vent is closed and the vacuum pump 290 is directly connected by the vacuum pump interface 218 on the top of the steam overflow hood 211 to extract the water vapor and enter the second condenser 220, where it is condensed into fresh water and stored in the fresh water tank 230 for later use.

[0062] The solution regenerator 210 designed in this invention has a box body divided into upper and lower layers. The upper layer is filled with dehumidifying liquid, and the lower layer is filled with cooling water and steam heating from the diesel engine 500. Combined with the vacuum pump 290 to change the boiling point of the solution, it is more energy-efficient. A dedicated steam hood is provided for the recovery of desiccant water vapor, making the structure simpler and easier to manufacture. It realizes the recycling of solution desiccant and diesel engine cooling water.

[0063] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. An air conditioning system for an offshore drilling platform, characterized in that, It includes an air handling unit (100), a solution dehumidification unit (200), and a refrigeration unit (300). The air handling unit (100) includes a heat pipe heat exchanger (110), an air filter (120), an air dehumidifier (130), a fan (140), an air cooler (150), an air heater and humidifier (160), and an air outlet (170) arranged sequentially in the air intake channel. The air filter (120) has a No. 1 air inlet valve (121) on its front side and a No. 2 air inlet valve (122) on its upper side. The exhaust pipe outlets of the living area cabin (400) are respectively located in front of the heat pipe heat exchanger (110) at the air inlet and above the No. 2 air inlet valve (122) of the air filter (120). The air outlet (170) is connected to the living area cabin (400). The solution dehumidification unit (200) is connected to the air dehumidifier (130) and supplies dehumidifying liquid to the air dehumidifier (130) to dehumidify the air. The solution dehumidification unit (200) includes a solution regenerator (210), which includes a steam overflow hood (211), a guide plate (212), an inclined heating plate (213), a dilute solution inlet (214), a concentrated solution outlet (215), and a vacuum pump interface (218). A dilute solution inlet (214) is provided above the guide plate (212) for connecting to the air dehumidifier (130). A steam overflow hood (211) is provided above the inclined heating plate (213), and a vacuum pump interface (218) connected to the vacuum pump is provided at the upper end of the steam overflow hood (211). A reserved space is provided below the inclined heating plate (213) for connecting to cooling water and steam from the main diesel engine (500) of the drilling platform. A concentrated solution outlet (215) is provided at the lower end of the inclined heating plate (213). The refrigeration unit (300) is connected to the air cooler (150) and supplies refrigerant to the air cooler (150) to cool the air. The refrigeration unit (300) includes a cold storage module (310) and a refrigeration module (320). The refrigeration module (320) includes a high-pressure generator (321), a low-pressure generator (322), a first condenser (323), an evaporator (324), an absorber (325), a low-temperature heat exchanger (326), and a high-temperature heat exchanger (327) connected in sequence by pipelines to form a circulation loop. It also includes a heat storage freshwater circulation loop, which is connected to the high-pressure generator (321) to store and store freshwater. The hot freshwater circulation loop includes a solar collector plate (328) that uses solar energy to heat fresh seawater and exchange heat with a dilute lithium bromide solution in a high-pressure generator (321). The hot freshwater circulation loop also includes a hot freshwater tank (329) in which desalinated seawater is stored, and fresh seawater heated by the solar collector plate (328) is also stored. The high-pressure generator (321) is also connected to the cooling water and steam pipes of the drilling platform diesel engine (500), and the cooling water and steam of the diesel engine (500) exchange heat with the dilute lithium bromide solution in the high-pressure generator (321). The high-pressure refrigerant steam generated by the boiling of the dilute lithium bromide solution, along with the cooling water and steam from the diesel engine (500) after heat exchange, enter the low-pressure generator (322) respectively. Both heat the intermediate concentration lithium bromide solution in the low-pressure generator (322). After cooling, the cooling water and steam from the diesel engine (500) enter the atmospheric condenser (601) for liquefaction and are then used in the domestic hot water section (602). The high-pressure refrigerant steam, after cooling, becomes low-pressure refrigerant steam and enters the first condenser (323) for condensation. The condensate enters the evaporator (324) to absorb heat and evaporate into secondary steam, which is then collected in the absorber (325). The low-pressure generator (322)... The internally heated concentrated lithium bromide solution is cooled by a low-temperature heat exchanger (326) and then returned to the absorber (325). Secondary steam is liquefied and diluted in the absorber (325) to make it a dilute lithium bromide solution. The dilute lithium bromide solution enters the low-temperature heat exchanger (326) from the absorber (325), exchanges heat with the concentrated lithium bromide solution from the low-pressure generator (322), and then enters the high-temperature heat exchanger (327) to exchange heat with the intermediate concentration lithium bromide solution from the high-pressure generator (321). After being heated, it enters the high-pressure generator (321). The intermediate concentration lithium bromide solution after heat exchange enters the low-pressure generator (322). The cold storage module (310) includes a first circulation loop and a second circulation loop. The first circulation loop includes an air cooler (150) and a refrigeration end (314) connected in sequence. The refrigeration end (314) exchanges heat with the evaporator (324) of the refrigeration module (320) to cool the refrigerant. The low-temperature refrigerant returns to the air cooler (150) to participate in air cooling. The second circulation loop includes an air cooler (150), a cold storage refrigerator (311), and a cold storage end (315) connected in sequence. The cold storage end (315) exchanges heat with the evaporator (324) of the refrigeration module (320) to cool the refrigerant. A portion of the low-temperature refrigerant returns to the air cooler (150) to participate in air cooling. The refrigerant is directly stored in the refrigerator (311), and another part of the low-temperature refrigerant returns to the air cooler (150) to participate in air cooling. When the temperature difference between day and night is large, the liquid working fluid in the refrigerator (311) uses part of the cold energy generated during the off-peak electricity cooling at night to complete the ice-making phase change and store the cold energy. The cold energy is released during the day the next day to assist in a significant cooling. When the temperature difference between day and night is small, the heat released by the heat storage fresh water tank (329) during the day causes the supply of cold energy generated by the refrigeration module (320) to be greater than the demand. The refrigerator (311) completes the ice-making phase change process during the day and prioritizes the use of the cold energy in the refrigerator (311) at night. After the cold energy is released, the refrigeration module (320) starts working again.

2. The air conditioning system for offshore drilling platforms according to claim 1, characterized in that, A hot water well (603) is provided downstream of the atmospheric condenser (601) for storing excess domestic hot water.

3. The air conditioning system for offshore drilling platforms according to claim 1, characterized in that, A control valve (334) is provided on the pipeline between the high-pressure generator (321) and the low-pressure generator (322). The high-pressure refrigerant water vapor generated by heating in the high-pressure generator (321) enters the low-pressure generator (322) through the control valve (334).

4. The air conditioning system for offshore drilling platforms according to claim 1, characterized in that, A No. 2 throttling valve (342) is provided on the pipeline between the first condenser (323) and the evaporator (324). The condensate generated in the first condenser (323) enters the evaporator (324) through the No. 2 throttling valve (342).

5. The air conditioning system for offshore drilling platforms according to claim 1, characterized in that, A pressure reducing valve (352) is installed on the pipeline between the low-temperature heat exchanger (326) and the absorber (325). The concentrated lithium bromide solution in the low-temperature heat exchanger (326) enters the absorber (325) through the pressure reducing valve (352). A solution pump (361) is installed on the pipeline between the absorber (325) and the low-temperature heat exchanger (326). The dilute lithium bromide solution in the absorber (325) enters the low-temperature heat exchanger (326) under the action of the solution pump (361) to exchange heat with the concentrated lithium bromide solution.

6. The air conditioning system for offshore drilling platforms according to claim 1, characterized in that, A pressure reducing valve (351) is installed on the pipeline between the high-temperature heat exchanger (327) and the low-pressure generator (322). The intermediate concentration lithium bromide solution in the high-temperature heat exchanger (327) enters the low-pressure generator (322) after passing through the pressure reducing valve (351).

7. The air conditioning system for offshore drilling platforms according to claim 1, characterized in that, A cooling pump (313) and a throttle valve (341) are installed on the pipeline between the refrigerator (311) and the cold storage end (315). The refrigerant in the refrigerator (311) enters the cold storage end (315) for cooling through the cooling pump (313) and the throttle valve (341). A control valve (333) is installed on the pipeline between the cold storage end (315) and the refrigerator (311). The cooled refrigerant returns to the refrigerator (311) through the control valve (333).

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