Air-Cooled ESS Battery Cabinets Integrated with SunWell Inverters Deliver Stable Peak Shaving
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Project Year: 2026
Location: Poland
System Topology: 2 × 100kWh ESS battery cabinets in parallel
Cooling Method: Air-cooled integrated cabinet
Inverter: SunWell (external connection)
Application: Commercial & Industrial peak shaving + backup power
Project Background
In 2026, multiple C&I energy storage projects were commissioned across Poland to address rising electricity tariffs, grid instability, and demand charge pressure for commercial facilities. Among them, this site deployed two 100kWh high voltage ESS battery storage cabinets in parallel, forming a modular 200kWh C&I energy storage system.
The client required:
- Peak shaving during daytime production hours
- Backup power during grid interruptions
- Stable integration with existing PV and AC distribution
- A solution that is simple to install, easy to scale, and operationally reliable
System Architecture
This solution adopts an air-cooled all-in-one ESS cabinet paired with external SunWell inverters. The batteries operate on a high voltage DC bus, improving efficiency and reducing current losses compared with low-voltage systems.
Architecture Highlights
High voltage ESS battery clusters are inside each cabinet
Independent BMS per cabinet, coordinated in parallel
External inverter coupling for flexible AC integration
Standard air-cooling with intelligent thermal management
Plug-and-play parallel expansion
Why Air-Cooled ESS for This Site?
For medium-scale C&I projects (100–300kWh), air-cooled ESS battery storage provides a cost-effective and highly reliable solution without the complexity of liquid cooling.
Advantages realized on site:
| Feature | Practical Benefit |
|---|---|
| Air cooling structure | Lower maintenance, no liquid loop risk |
| Integrated cabinet design | Fast deployment and clean wiring |
| High voltage architecture | Higher efficiency, lower cable loss |
| Parallel capability | Easy future capacity expansion |
| External inverter design | Flexible compatibility with the existing AC system |
Installation & Commissioning
The two ESS battery cabinets were installed side-by-side and connected in parallel on the DC side, then interfaced with the SunWell inverter on the AC side.
Commissioning steps included:
- Parallel communication setup between BMS units
- High voltage DC bus configuration
- Inverter parameter matching for ESS operation mode
- Charge/discharge scheduling for peak shaving
- Backup mode verification during simulated grid outage
- The entire system was brought online smoothly with minimal integration effort.
Operational Results & Client Feedback
After several months of operation, the client reported:
- Stable daily peak shaving performance
- Noticeable reduction in electricity bills
- Seamless transition during grid power loss
- Consistent thermal performance from the air-cooled design
- Highly stable cooperation with SunWell inverter
- “The system runs very stably. Installation was straightforward, and performance has met our expectations for both cost savings and backup reliability.”
Technical Snapshot
| Parameter | Specification |
|---|---|
| Total Capacity | 200kWh (2 × 100kWh) |
| Battery Type | LiFePO4 ESS battery |
| System Voltage | High voltage ESS architecture |
| Cooling | Intelligent air cooling |
| Inverter | SunWell (external) |
| Application | Peak shaving + Backup |
| Expansion | Parallel scalable |
Why This High Voltage ESS Design Works for C&I
This Poland project demonstrates a repeatable model for medium-scale commercial energy storage:
- Avoid over-engineering with liquid cooling where unnecessary
- Use modular ESS battery cabinets for scalability
- Keep the inverter external for integration flexibility
- Leverage high voltage ESS for efficiency and performance
- It provides an optimal balance between CAPEX, operational reliability, and future expansion capability—a reference design for similar C&I scenarios across Europe.