Application of Coolant in Hydrogenation Station
Hydrogen has a wide range of sources and no pollution of combustion products. It is expected to become one of the main energy carriers in the future.At present, hydrogen fuel cell vehicles have been commercialized, but a considerable number of hydrogenation stations are needed for further promotion.In 2020, China Society of automotive engineering issued the construction goal of China’s hydrogen refueling stations. From 2025 to 2030, the number of hydrogen refueling stations will increase from 1000 and 5000.By the end of 2020, 118 have been built in China, but hydrogen energy vehicles are still in its infancy.
At present, the hydrogenation station is mainly externally supplied, and the filling system generally consists of: hydrogen supply source, compressor, station side storage tank (high-pressure storage tank, medium pressure storage tank, etc.), pressure reducing valve, precooling and hydrogenation machine.Generally, the long tube trailer transports the hydrogen of about 20MPa to the hydrogenation station and pressurizes and fills it into the in-car automotive gas cylinder or high-pressure storage tank through the compressor. The compression process is generally a constant entropy process, which will increase the temperature of hydrogen. Under the rated pressure of limited space, the amount of stored hydrogen will be greatly reduced, so it must be cooled in the hydrogenation process.The cooling system will be one of the main costs of the operation cost of the later hydrogenation station. In Germany, the cooling cost of hydrogenation station exceeds 10kwh / kg H2. If the utilization rate of hydrogenation station is low, the cooling cost will be greatly increased.
In order to reduce the operation energy consumption of the cooling system, the carrier cooling system is generally used. The carrier cooling system can ensure the stability of hydrogenation process, reduce the starting frequency of refrigeration equipment and improve the cop of refrigeration system.
At present, the traditional coolant is mainly calcium chloride brine and ethylene glycol aqueous solution, but the service temperature of the hydrogenation station is low, which can generally be as low as – 40 ℃. The viscosity of ethylene glycol aqueous solution is too large to be used, and most choose calcium chloride aqueous solution.However, calcium chloride aqueous solution is particularly corrosive to the system. Generally, the equipment needs to be replaced in 3-5 years, which increases the fixed cost.At present, there are successful application cases of glacier coolant in hydrogenation station. It has high thermal conductivity, high specific heat, low viscosity and non corrosivity, and can be highly suitable for the cooling system of hydrogenation station.
Cooling Application of Coolant in Power Lithium Battery
Lithium battery is the power battery used in new energy vehicles at present. The power battery has high energy density and obvious heat generation during large rate charge and discharge, which is mainly caused by internal resistance and electrochemical polarization. The existing technology is mainly to cool it and ensure that the battery works at a stable temperature.
The best working temperature of lithium battery is 20~40℃. If the local temperature is higher than 80℃, it will run out of control and cause the battery to burn. Therefore, each power battery has its own set of heat pipe system.At present, there are many cooling methods studied, mainly including air cooling, liquid cooling, phase change material cooling and heat pipe cooling.
At present, the commercial lithium battery cooling technology is mainly air cooling and double circuit liquid cooling.Air cooling is forced convection heat transfer through natural wind. When the battery capacity increases, the heat dissipation effect is poor.Large capacity batteries are generally liquid cooled, which is mainly shared with the automobile air conditioning system. The coolant is cooled through the air conditioning system, and the coolant is circulated through the pump to cool the battery.This scheme is mainly concerned about the corrosivity of coolant and short circuit caused by liquid leakage.At present, glacier coolant LM-8 coolant has no corrosion and has corresponding applications in power batteries.
The cooling channel of power battery is characterized by large aspect ratio, and the width is generally less than 1mm, which belongs to the category of microchannel. The traditional automobile coolant is ethylene glycol solution, which has high viscosity and large thermal boundary layer, which is not conducive to microchannel heat exchange, and the temperature field in the battery is easy to be uneven, resulting in the decline of efficiency and life of the battery.LM-8 glacier coolant has large unit capacity and small viscosity change within – 40 ~ 40 ℃. It is especially suitable for the power battery of new energy vehicles used in the north. In the long-term low-temperature environment, it can ensure the circulation of coolant and the uniformity of flow field in the flow channel. Some dead corners can be recycled through injection, so that the temperature at each point during battery operation does not exceed the optimal temperature zone.Improve the efficiency and stability of the battery and provide favorable guarantee for the thermal management system of the battery.
Application of Coolant in Controlled Atmosphere Cold Storage
Controlled atmosphere cold storage is an advanced storage technology that combines the technologies of regulating low temperature and controlled atmosphere components.Controlled atmosphere components include:Nitrogen production equipment, ethylene removal equipment, carbon dioxide removal equipment, humidification equipment, gas analysis equipment, pressure balance bag, safety valve. Regulated low temperature includes: refrigeration host, circulating water pump, cooling fan, coolant, temperature control system. Different storage products require different temperatures and different indoor gas composition.
Nitrogen production equipment is mainly used to replace indoor oxygen, reduce the oxygen content in the controlled atmosphere cold storage to 5%, reduce the respiration of fruits and vegetables, effectively delay the aging of products, prevent diseases and bacteria, and inhibit the production of ethylene.Carbon dioxide removal is mainly to prevent high concentration of carbon dioxide, which will cause carbon dioxide poisoning. In general, the concentration of carbon dioxide must be controlled in the controlled atmosphere cold storage.Some fruits breathe actively, which will release plant hormone ethylene, leading to the maturity and aging of products. Therefore, the controlled atmosphere cold storage needs to be equipped with ethylene removal equipment.
controlled atmosphere cold storage has high requirements for the sealing of the storage body. At present, the assembled gas controlled storage is widely used, with fast cycle and good sealing performance. Generally, after completion, the atmospheric pressure test shall not be lower than 196pa, the half pressure drop shall be kept for 20 minutes, and the pressure shall not be lower than 78pa after the atmospheric pressure test. In order to reduce the impact of differential pressure caused by temperature change on he storage body, a pressure balance bag and a safety valve are set in the controlled atmosphere cold .
The refrigeration system of controlled atmosphere cold storage generally has direct cooling and indirect cooling. In terms of product storage quality, it is more appropriate to use coolant indirect refrigeration.The stable environment with small heat exchange temperature difference and high humidity provides better conditions for the preservation of products.
The coolant indirect cooling system has stable control and is suitable for the setting of storage conditions of different products.At present, the application proportion of controlled atmosphere cold storage in China’s high-temperature refrigeration system is still small, generally accounting for 5% ~ 7%.With the development of market demand, many unknown products still lack storage conditions, and more high-performance controlled atmosphere cold storage need to be put into use.In the future, the controlled atmosphere cold storage indirectly cooled by coolant will have a great market prospect. Glacier Coolant focuses on high-end controlled atmosphere cold storage system.
Application of Glacier Coolant in air separation system of LNG gasification station
At present, LNG cold energy utilization includes air separation, light hydrocarbon separation, power generation, refrigeration, etc., In air separation, the temperature region is close to each other, and the high-grade cold energy of LNG cooling can get high value.Air separation is mainly used to produce liquid oxygen, liquid nitrogen and liquid argon. Compared with the traditional air separation process, it saves 50% electricity, saves 90% water and has less carbon emissions.
Air separation system mainly includes filter compression system, air purification system, air separation distillation system, LNG heat exchanger cold box system, low-temperature liquid storage system, Coolant cooling system and nitrogen pipe network system. The interstage and final stage coolers of air compressors are cooled by Glacier Coolant as coolant.Air compressors and oil coolers use reheated Glacier Coolant to continue cooling.The heated Glacier Coolant is then cooled by centrifugation by pumping to a lower LNG heat exchanger to cycle cooling.
The cooling capacity of air separation unit is generally provided by liquid nitrogen.The high-pressure nitrogen is liquefied in the LNG-nitrogen heat exchanger, throttled to medium pressure and reduced liquid nitrogen temperature again , partially stored in the total pressure liquid nitrogen tank, partially throttled again and stored in the pressure liquid nitrogen tank. The pressure liquid nitrogen enters the liquid nitrogen separation heat exchanger, high-pressure nitrogen is liquefied, and the vaporized pressure nitrogen enters the low-temperature circulating nitrogen compressor to transfer the LNG cold energy to the air separation system.the heat exchange temperature of LNG-nitrogen heat exchanger is-120℃, divided into three pressure intervals, vaporized by different pressure, compression cycle.This process uses nitrogen as an inert gas,The heat transfer process is mainly nitrogen cycle, the system is more efficient and safe.
The pressurized low-temperature LNG is transported to the LNG-nitrogen heat exchanger through pipelines, part of it is directly vaporized to the NG pipe network, part of it is used to cool coolant, and also to the ng pipe network after vaporization.The utilization efficiency and technology of air separation system can be improved in theory.More technicians are needed to explore and improve LNG gasification air separation projects.
Glacier Coolant focuses on Coolantt, and will continue to focus on and study LNG gasification air separation system.
Use of Glacier Coolant in Cultivation of Needle Mushroom
There is a great market demand on needle mushroom in China, which is of high nutrition. The conditions of cultivation need be carefully controlled, to which the quality of mushroom can be really sensitive. Industrial cultivation of needle mushroom has become more and more popular in China with precise control of its growing conditions, ensuring the production level with satisfying quality. Glacier coolant has been utilized in many refrigeration systems for cultivation of needle mushroom.
The main production flow of needle mushroom is: Cultivation of raw material – Sterilization by steam – Cooling – Inoculation – Budding -Forcing – Germination – Adaption – Maturation – Package – Out of stock. It requires different humidity and ventilation level at individual stage. The refrigeration system must deliver the right temperature, humidity and amount of air. The detailed requirements are listed in Table-1:
At the moment, small capacity refrigeration systems for cultivation of needle mushroom deploy direct refrigeration system which consists of compressor, air condenser, air cooler and expansion control valve. There are some manufactures utilizing refrigerated storage system. Although direct air coolers have high heat capacity, the distance between fins is quite small (2~2.8mm). Frost forms on the surfaces of fins blocking the gaps between them, resulting in loss or even no heat transfer of cooling circuits. Due to the fire-proofing nature of insulation material, only natural deforest is allowed, which is time consuming. Mushroom’s quality is also reduced by variation of refrigerated storage system’s temperature. Utilization of Glacier Coolant as secondary refrigerant for large capacity refrigeration systems are strongly recommended. The refrigerated storage system is stable with temperature variation within 0.5℃. The refrigeration system consists of primary refrigeration system including screw compressor, evaporative condenser、secondary refrigerant pump、buffer station、indirect air cooler and weighted percentage motorized control valve.
Glacier Coolant Refrigeration system is selected for a project which produces 160 ton/day needle mushroom. Based on the operating temperature of each room, we proposed the solution of providing two coolant streams: -5℃ for product storage (0-4℃) and maturation room (4-6℃); 3℃ for cooling room, incubation room, inoculation room and package room. There are multiple primary refrigeration systems and corresponding evaporative condensers which can be standby system for one or another. No redundant fans are required. The whole site is segmented and each segment is installed with two variable speed pumps which adjust the coolant flow rate depending on demand. Heat recovered from the primary refrigeration system is used for defrost as well as heat input required for incubation room. The production site is located in Northern China and the load capacity can be adjusted by switching on/off systems based on ambient temperature during winter, minimizing the power consumption. The Glacier Coolant type is LM-4, featuring great heat capacity and low viscosity at operating temperature. The system is highly energy efficient and there is no flashing point for the coolant, eliminating risk of fire. The coolant is highly anti-corrosive, much lowering the deterioration rate of the equipment and saving maintenance cost during production life.
Refrigeration systems utilizing Glacier Coolant designed for cultivation of needle mushroom provide high level of automation and can be delivered in completed assembly. It is energy efficient, requires minimum level of maintenance and can be applied to large scale of industrial production.
Effect of coolant cycle specific heat and density
In the coolant application system, the system is usually determined in the design stage. In the later stage, It is necessary to replace the coolant with different physical properties of the system. there will be some mismatches, and the final result is the reduction of energy efficiency.from the perspective of heat transfer and fluid, It is found that the specific heat and density have a great impact on the system.
The specific heat usually refers to the heat required for 1kg homogeneous material to increase by 1K without phase change and chemical change. Generally, this value will decrease with the decrease of temperature. this parameter is usually used in design calculation, and the density of coolant is calculated jointly with this parameter. it is one-sided to comment on the quality of the coolant by talking about a specific heat.
The specific heat can be combined with the density to calculate the circulating volume of the system. From the perspective of fluid, the circulating volume is directly related to the circulating energy consumption of the coolant. The pump power can be determined by combining the viscosity and flow rate of the coolant. Another is to determine the material and pipe diameter of the circulating system pipeline and its impact on the initial investment of the system. From the perspective of heat transfer, under the unit circulating volume, the larger the volume specific heat is, the greater the heat exchange is, which is more beneficial to the circulation of the system. The efficiency of the heat exchanger is different according to the parameters of the heat exchanger，ε=（t2-t1）/（T1-t1），或ε=（T2-T1）/（T1-t1）.With large volume specific heat, the available temperature difference of T2-T1 will increase, and the heat exchange efficiency ε will improve.
Obtaining a higher volume specific heat can improve the fluid heat transfer efficiency, but it also needs to be combined with the thermal conductivity, kinematic viscosity and Pr number of the coolant. The comprehensive efficiency of these parameters is to finally determine which coolant is more suitable. Glacier Coolant provides professional coolant and professional coolant system scheme for customers.
Application of Glacier Coolant in Cold Storage
For the cold storage system, a shell and tube heat exchanger, a set of circulating pump unit and a set of water supply and constant pressure device are designed in the refrigeration plant room.Through shell and tube heat exchanger and fluorine in the direct refrigeration system for heat exchange, through the circulation pump group of continuous pressure transmission, so that the cold storage special coolant in the system continuous circulation. The specific workflow of the system is：The LM-4 Glacier Coolant in the system exchanges heat with low-temperature fluorine in the plate heat exchanger, reduce the temperature of the special coolant for the cold storage, and then through the pump unit of the special coolant system for the cold storage, the LM-4 coolant reaching – 30 ℃ is sent to the cold storage for heat exchange , absorb the heat of the cooled goods in the cold storage and maintain the storage temperature at – 18 ℃, The temperature of the coolant increases to -25℃ after absorbing the heat,and returns to the shell and tube heat exchanger in the refrigeration plant room through the pipeline for heat exchange, and the low temperature fluorine is cooled again.
Through the continuous circulation of the coolant solution in the system, the heat is brought back to the refrigeration plant room, and the heat is discharged outdoors through the phase change heat exchange of Freon. The temperature in the cold storage is to maintain the temperature required by the goods, so as to achieve the best environment for preserving the goods.
According to the actual situation of the old cold storage, the system fully considers the specific historical conditions and the existing operation status of the cold storage.The scheme of replacing only the refrigerating machine, the main pipeline of the system and the medium flowing in the pipeline without changing the enclosure structure and pipe arrangement of the existing cold storage .According to the requirements of the scheme, the main pipeline from the cold storage to the the refrigeration plant room is rearranged, and the newly arranged main pipeline is connected with the evaporator in the cold storage to form a closed loop of the coolant system. Change the transmission medium in the system from ammonia to LM-4 Glacier Coolant.
After the transformation, the system operates well. Through data observation, the refrigeration system of the cold row pipe cold storage fully meets the temperature requirements of the goods in the cold storage, but the temperature of the two cooling fans cold storage can only be maintained at -12℃. At present, these two cold storage are mainly used as ice storage.The specific reason is that the clooant of the heat exchange efficiency of the cooling fan is lower than that of the pipe, so it is necessary to appropriately increase the end heat exchange equipment and meet the requirements. Therefore, the practical application of refrigeration system conversion cooling system is feasible.According to the actual operation of special coolant for Glacier Coolant, the advantages of using coolant are summarized as follows:The direct refrigerant system is gathered in the refrigeration plant room, facilitating the manufacturing, installation, operation and management of overall system ,and improves the refrigeration efficiency.Reduce the refrigerant charge in the direct refrigeration system, reduce the pipeline layout area of the direct refrigeration system and reduce the leakage coefficient.The use of coolant system can facilitate the transmission of cooling capacity and the distribution and control of cooling capacity.The temperature control in the cold storage is more accurate, the temperature fluctuation is small, and the refrigeration quality of food is improved.
The new special coolant for cold storage has more advantages and application cases, and has better application prospects.
Glacier Coolant: The Best Option of Heat Transfer Media for API and Intermediate Processing
In API and intermediate manufacturing industries, chemical synthesis takes place in reactors where normally requiring heating or cooling to facilitate the yield. Heat transfer media exchanges heat with reactants in jacket of reactors. Disadvantages of using primary refrigeration include safety and explosion risks (e.g. Ammonia) and environmental concerns (e.g. HCFC has high global warming potential). Use of freon us also not cost competitive especially in scenario of API manufacturing. CO2 involves high pressure operation, which is not suitable for batch process due to the instability of compressor for short period operation. It requires high purity of primary refrigerant (>99.5%) in close loop systems, which is a huge challenge for API manufacturing. Both low and high temperature operations can be required in chemical synthesis, leading to change over of primary refrigerant which further increases the system complexity. Therefore, secondary refrigeration is the best choice for API synthesis.
Common secondary refrigerants include glycol, brine, water and heating oil. One of the key issues for secondary refrigerant is corrosion, which can cause leakage and even equipment damage. Switching between low and high temperature heat transfer media might result in residue left in the system, impacting heat transfer performance and system operation.
Glacier coolant, our patented engineered heat transfer fluid, can either be utilized as low or high heat transfer media, with high anti-corrosion property and avoid the necessity of heat transfer media switching. It is the perfect choice for API and intermediate manufacturing.
Comparison between Ammonia+CO2 integrated refrigeration system and Glacier Coolant refrigeration system
1. Safety
Ammonia as primary refrigerant is toxic, flammable and explosive. CO2 which is the secondary refrigerant operates at pressure five times higher than Glacier Coolant. The Glacier coolant secondary refrigeration system runs at almost ambient pressure and the pump is only designed for overcoming system hydraulic loss.
Due to the characteristics of ammonia, the project can be identified as high hazardous project and requires frequent round checks. The pipework of CO2 needs to be designed to withstand high pressure (GC2 grade) and be closely monored as well. Glacier Coolant refrigeration system is not required to comply with such regulations due to its safe characteristics.
2. Cost
The equipment cost of ammonia+CO2 refrigeration system is 10% higher than that of Glacier Coolant refrigeration system. Ammonia and CO2 system requires dedicated compressor. For CO2 system, higher pressure head is required than that of ammonia or Freon compressor. Subsequently, higher pressure grading is required for its auxiliary systems such as pipes and valves.
As Glacier Coolant refrigeration systems operates at much lower pressure, it saves significant equipment cost. Standard pipes and valves can be selected. Apart from equipment cost, ammonia system also requires safety measures of fencing wall and impoundment. The coexisting of ammonia and CO2 systems requires dedicated ventilation systems due to their different density, adding further cost of ammonia+CO2 refrigeration system.
3. Operation conditions
Phase transition take place in both ammonia and CO2 refrigeration systems at uncontrolled rate resulting in temperature fluctuation. It requires more complicated process control system and instrumentation, which further increases cost. Intensive training of labor is also required.
If there is a fire incident, both ammonia and CO2 need to be discharged in a safe way. Regular training is pivotal and mandatory. The system cannot be shut down for long period of time otherwise the pressure of CO2 will continue to increase in the system. It is also not energy efficient to run CO2 system at low demand of cooling.
Diagram of indirect refrigeration optimization scheme of cold storage
The Glacier Coolant refrigeration system works together with primary refrigerant of Freon and it utilizes sensible heat. It stabilizes the system and the automation is simple. The temperature of coolant is controlled by varying flow rate which is driven by the compressor. Under emergency situation, Glacier Coolant can be remained in the system as long as needed, without concerns of over- pressurization, even during long term shut down.
Application of Fluorinated Liquid in Data Processing Centers
The rapid growth of cloud technology, edge computing, large scale internet of things and AI has increased the demand of data processing centers significantly. There is ever more challenging requirements of capacity and energy efficiency for data processing centers, along with growing number of IT equipment and servers. It is projected that air cooling will no longer be able to cope with stringent requirement of future national standard energy efficiency. Liquid cooling will dominate the market for data processing centers and the selection of cooling media is pivotal.
In response to the current trend, the research team of Glacier Coolant developed the modified fluorinated liquid coolant, targeting systems demanding high efficiency cooling such as data processing centers, heating elements and electrical chips. Modified Glacier Fluorinated Liquid is transparent, tasteless, non-toxic, safe and un-dissoluble in water. It is thermally stable and environmentally friendly.
The boiling point of Modified Glacier Fluorinated Liquid is moderate and (~50℃) and the latent heat is around 121.7 kJ/kg. By evaporating fluorinated liquid coolant which immerses data processing centers, the heat is taken away from the facilities. It eliminates the use of air conditioning and the energy efficiency is really high. The power usage effectiveness (PUE) is below 1.1, saving more than 85% power consumption compared to air conditioning. It also has very high insulation property against electric conduction. Its dielectric strength up to 55 kV and therefore it will not damage electrical instrumentation. It is chemically inert with no ignition and flashing points, non-combustible and non-explosive. Modified Glacier Fluorinated Liquid gas excellent thermal conductivity, good flowability and system compatibility. The Ozone Depletion Potential is 0 and the global warming potential is 7 making it suitable for many applications. Apart from data processing center, it is also applied in power inverter for high speed rails, hydrogen fuel cell and electrical battery vehicles, semi-conductor equipment cooling, wind power, nuclear, ultra-high voltage power gird and military radar systems.
A well-known research institution conducted a few measurements on Modified Glacier Fluorinated Liquid in our R&D center in April, 2021 and the results were illustrated in the table in below. All the figures meet the requirements for use.
Table.1 Physical properties of Modified Glacier Fluorinated Liquid
As shown in Figure.1, CPU are placed in the cooling box of fluorinated liquid immersion cooling system where heat of elements of CPU is dissipated. When servers are in operation, heat generated by the server’s elements boils fluorinated liquid due to its low boiling point. The evaporated coolant is condensed when it contacts with tubes of condenser located above CPU. The condensed fluorinated liquid is re-utilized, continuously cooling CPU elements.
Figure.1 Process Flow Diagram of Fluorinated Liquid Immersion Cooling System for Data Processing Center
It saves more than 85% of power consumption by making direct contact between the elements of data processing system and Modified Glacier Fluorinated Liquid to achieve effective cooling. The system configuration is simple, enabling compact server assembly, which saves space. The water and coolant consumption is relatively low with only internal recirculation, saving significant OPEX.