Energy storage systems are widely used in many fields, and their performance is hugely dependent on the effectiveness of the cooling system. Within this paper, we will go into detail comparing the two dominant ESS cooling methods: air cooling and liquid cooling. We hope to help you make an informed decision on which cooling solution is best for your energy storage needs.
Air cooling in Energy Storage Systems is a cooling method that is dependent on the flow of air to dissipate heat. Herein is presented some basic information about the technology of air cooling.
Fan: generates air flow and belongs to one of the most important parts of an air cooling system.
Duct: Guides the direction of airflow to ensure that the air flows evenly through the battery module and other heat-generating parts.
Heat sink: in close contact with the battery module to help transfer heat into the air. Temperature sensor: monitors the temperature in the system in real time, controls the fan startup, and regulates the air cooling effect.
In the processes of charging and discharging, heat generation is perceived by a temperature sensor due to the rise in temperature; the control system then drives the fan to drive air through the system. This allows the air, after traveling through the heat sink, to carry with it the generated heat and eventually release the heat through the airways out of the system; this completes the process for cooling of the battery module and other parts.
The Liquid cooling system mainly consists of the following parts in energy storage:
Liquid cooling plate: The liquid cooling plate is one of the key components, as it conducts heat and absorbs it by contact with energy storage equipment such as batteries.
Liquid Cooling Unit: Utilized for monitoring the temperature of the coolant, ensuring that it operates within the right flow range.
Liquid-cooled piping: includes temperature sensors, valves, and other components used in circulating and monitoring the temperature of coolants.
Coolant: The common coolant used in the above is the glycol aqueous solution, etc. with large thermal conductivity and can take internal heat away from energy storage equipment effectively.
The working principle of the energy storage liquid cooling technique is to make use of high thermal conductivity liquid, such as a glycol solution, as its medium for heat exchange. The heat produced in running an energy storage facility transfers to the coolant through the liquid-cooled plate and takes part in the liquid cooling system circulation flow to the cooling tower or any heat dissipation device with a load of heat. The coolant, via the action of the pump after heat dissipation, is returned for circulation to the energy storage equipment, thus realizing continuous heat dissipation and temperature control of the energy storage equipment.
Through comparison, we summarize the difference between air-cooled energy storage and liquid-cooled energy storage.
In principle, air-cooling technology uses air flow to take away the heat and decrease the equipment temperature, although the effective factors are usually related to ambient temperature and flow. Due to the airflow inside an air-cooled system, room has to be reserved between the components of the equipment to leave channels of air, meaning that the actual equipment and protection grades are larger than those requested.
Liquid-cooling technology depends on the flow of liquid to regulate the inner temperature of the device, and for that, the heated components must have good contact with the heat sink, and the surface of the heat sink should be flat and regular. The liquid-cooled equipment can realize a higher degree of protection because the system contains liquid.
Air-cooled systems are preferred because they have minimal noise and lesser impact on the environment. Although it will occupy a certain room space, they can easily be applied to a variety of energy storage systems but most especially in outdoor applications. Being a mature technology, air cooling dominates the low to medium power field and is suitable for very low-power applications like house energy storage and small backup power.
Liquid-cooled systems are noisy, though this can be mitigated by good design; they are more compact due to smaller heat sinks. Suitable for very large-scale energy storage projects with high energy density; when the energy density of batteries is very high, while charging/discharging speeds and temperature differences are large, this method should be adopted. Liquid cooling technology can be applied to high-temperature working conditions, as in the case of electric vehicles and large-scale electrical energy storage stations, which offer effective heat management for their equipment to improve stability and prolong life.
Air cooling is more susceptible to the external environment, which may not achieve the desired cooling effect that high-power equipment requires. Liquid cooling has higher cooling efficiency, which helps in effectively control the internal temperature of the equipment, ensuring stability for the device and prolonging its working life.
Air-cooled systems are preferred because of their low cost and simplicity of maintenance, but they sometimes require the addition of heat sinks or increased fan speeds, which may increase energy use and maintenance. Besides, cleaning must be performed periodically to prevent dust buildup.
Liquid-cooled systems have higher initial investments but offer higher efficiency in cooling and are thus fit for high-power applications. Their construction is hermetically better, hence safer, but requires periodic checking of coolant evaporation to ensure stability in the system operation.
The energy consumption of air cooling and liquid cooling is composed differently. Air cooling mainly includes the energy consumption of air conditioners and fans, while liquid cooling contains the energy consumption of liquid cooling units and fans. Under the same conditions, to achieve the same temperature control effect, the energy consumption of air cooling is usually lower compared to liquid cooling.
It was in the process of these comparisons that, from the principles of heat dissipation, applicable scenarios, the effects of dissipation of heat, cost, maintenance, operating power consumption, and so on, we are able to further our understanding of the big differences between air-cooled and liquid-cooled energy storage systems and, therefore, can provide a reference for selecting the appropriate cooling solution to suit an application.
This is a medium-scale energy storage system installed in a temperate region where there is low heat generated, and the ambient conditions are not stressing the cooling system. With proper spacing for fans and heat exchangers, the operating temperatures have remained within optimum limits to illustrate feasibility in air cooling where the environmental and operating conditions are favorable.
Due to the features of simple structure, easy maintenance, and low cost, air-cooled systems are widely used in the field with relatively low power density, such as communication base stations and small ground power stations. In these occasions, the rate of heat production is very low. It is effective to adopt air cooling to reduce the temperature of an electric core effectively. Practical Application and Advantage of Liquid Cooling System.
The high-density energy storage system feeds the electric vehicle’s fast-charging station, which is under operation with higher thermal loads. For heat management of such an enormous amount of heat that is generated in the fast charging cycle, liquid cooling was chosen. A network of pumps, coolants, and radiators efficiently works to take away heat from sensitive components and keep up performance without overheating.
In fact, the heat dissipation requirement for data centers is very high. Liquid cooling can ensure high-precision temperature control to guarantee stability in the operation of servers and other equipment without failure due to overheating. Meanwhile, for large-scale, high-energy-density energy storage power plants, especially those in hot areas, liquid cooling technology has played very well, further ensuring system operation stability and prolonging battery life.
These examples reflect the application and respective merits of both air-cooled and liquid-cooled systems in energy storage systems. At a relatively lower cost with easy maintenance, an air-cooled system fits those scenarios that feature good environmental condition and low heat dissipation requirement. While in the process of high power density or even high-temperature environments, liquid cooling will present evident advantages with high efficiency in heat dissipation and precision in temperature control.
The first thing to be determined in selecting the perfect energy storage system is the environment in which your energy storage system will operate at home, commercial, or wider grid application. It will help you to define how much energy you need to store and how long that energy will be maintained, hence defining the size and capacity of your system. Meanwhile, system flexibility and ease of maintenance must be considered in your future experiences and costs. If possible, this is the right time to seek experts in the energy sector, their important insights will guide you on reputed brands and reliable suppliers.
