HVAC system is the heating, ventilation, and air conditioning which is an important part of energy storage and battery rooms
HVAC systems in Energy storage systems
With the increase in demand for solar energy storage, a parallel increase in battery storage system (BSS) installation has highlighted the importance of a successful HVAC system design. The Unique challenges of lithium ion battery systems require careful system design. The low design battery operating temperature (around 20°- 25°C), requires a refrigeration cooling system not a direct ambient air cooling and the narrow allowable variation of temperature requires really good air distribution. Also, tight control is required for the rapid changes in power with time. Without proper thermal management, overheating will lead to cells degradation, malfunction or even catching fire.
Several modeling tools can help in the design process for guaranteeing a good designs. These can include:
Transient FEA for studies for the control methods,
CFD software for evaluation of the the air flow distribution and the resulting variation of temperature.
Overall mass and energy balance equations for sizing of cooling equipment
Sizing the cooling system with overall energy and mass balances
Providing the right capacity for BSS thermal control HVAC system will result in better performance for Storage system and a longer life for the batteries. Under sizing the HVAC cooling system can lead to overheating of batteries and system damage. Over sizing the HVAC cooling system can easily lead to large air temperature swings during operation cycles and short cycling of the cooling system.
HVAC equipment selection
Capacity ratings of HVAC system is based on a set of nominal parameters. The actual capacity of the HVAC system is lower than nominal rating of most energy storage applications because of the hotter outdoor temperatures, lower humidity and lower interior set point temperatures. The highest load for the storage system is heat generated from the batteries and therefore this is the most important factor to accurately predict.
Benefits of proper HVAC system selection for energy storage system
Batteries in storage systems generate heat like other electrical equipment, yet, manufacturer performance warranties ask for a lower temperature and a narrow optimum conditions for battery operation. Recently, with the worldwide movement for reducing greenhouse gas emissions emerging, including efforts like the Paris Agreement in 2015, many initiatives for reducing unnecessary energy consumption and using environmentally-friendly energy sources and consumer products like solar energy with Energy storage systems. For building energy management systems and energy storage systems, a heating, ventilation, and air-conditioning (HVAC) system optimum design and load reduction is also a major factor for increasing importance of HVAC system design and sizing.
HVAC System components
Power generation companies and residential companies are installing high capacity battery or energy storage systems. Also, other battery technologies, like lead acid batteries used in UPS (uninterruptible power supply) systems, can also release flammable levels of hydrogen during operation. This is an extra risk that need extra precautions.
Proper HVAC system design should provide components that guarantee optimum un-manned operation with components and that mitigate any operation risk. This can include:
Two stages for cooling
Humidity control for the battery room
Reverse airflow for improving heat dissipation
Explosion proof exhaust fans that should be tied to H2 sensors for automatic safety ventilation functions