YAMBOL, Bulgaria – MECC Solar, a manufacturer of liquid-cooled battery energy storage systems for commercial and industrial applications, has completed a parallel-connected energy storage installation in Yambol, Bulgaria. Four MECC AIO-261 cabinets operate as a single coordinated storage system, delivering a total rated output of 500kW and energy capacity of 1,045kWh. The deployment demonstrates how modular liquid-cooled storage cabinets can be combined to meet larger project requirements while preserving individual unit flexibility.
The installation links all four cabinets to a common AC busbar, supervised by a third-party energy management system. This architecture supports coordinated charge and discharge scheduling across all units, enabling operators to respond to electricity prices, production demand and on-site generation in real time. For project developers and engineering contractors across Europe, the case highlights a practical path from single-cabinet deployment to scalable commercial energy storage.
Core Highlights: Four AIO-261 Cabinets in a Unified Energy Storage System
Each MECC AIO-261 cabinet pairs a 125kW power conversion system with a 261kWh liquid-cooled battery bank. Combined, the four units provide 500kW of rated output and 1,045kWh of usable energy storage. The system is engineered for commercial and industrial sites where a single cabinet may be insufficient, but a full containerized solution is more capacity than required.
Parallel AC Coupling on a Common Busbar
The four cabinets are connected to the same AC busbar, forming one coherent energy storage system. Parallel connection on the AC side allows the units to operate as a single dispatchable asset while keeping each cabinet independently serviceable. This topology simplifies installation, reduces single points of failure and makes maintenance more straightforward for on-site engineering teams.
Third-Party EMS Coordination Across All Units
A third-party energy management system supervises the complete installation. The EMS controls charge and discharge schedules for all four units simultaneously, balancing state of charge across the battery bank and aligning operation with site objectives. Centralised control ensures the storage system responds consistently to grid signals, time-of-use tariffs and local generation output.
Technical Advantages of the AIO-261 Liquid-Cooled Storage Cabinet
The AIO-261 integrates power conversion and liquid-cooled battery storage in a single outdoor cabinet. Liquid cooling maintains stable temperatures across the battery cells, reducing thermal stress and extending service life. Stable thermal management also supports consistent performance during repeated high-rate charge and discharge cycles, which is essential for peak load applications.
Each cabinet is factory-assembled and tested before delivery, reducing on-site integration work for installers and contractors. The integrated PCS eliminates the need for separate inverter sourcing and wiring, lowering total system complexity. For distribution partners and EPC firms, this design shortens project timelines and simplifies procurement.
Modular Scalability Up to Ten Cabinets
The AC-side parallel architecture supports connection of up to ten MECC AIO-261 cabinets in a single system. This modular base lets project teams size storage capacity to match specific load profiles today, then expand capacity later by adding cabinets without redesigning the core installation. For growing industrial and commercial facilities, this flexibility protects the initial investment and supports phased deployment.
Target Application Scenarios for the Parallel Energy Storage System
The multi-cabinet configuration is suited to a range of commercial and industrial energy storage applications across global markets.
Peak Load Management and Demand Charge Reduction
By discharging during high-demand periods, the system reduces peak power drawn from the grid. Operators in industrial plants, commercial complexes and manufacturing sites can lower demand charges and stabilise monthly electricity costs. The coordinated EMS schedules discharge to align with peak tariff windows and site production needs.
Renewable Self-Consumption and Solar Integration
For facilities with on-site photovoltaic generation, the storage system captures surplus solar power during daylight hours. Stored energy is discharged when solar output falls or grid prices rise, improving self-consumption and reducing reliance on purchased electricity.
Flexible Operation in Response to Market Signals
Because the EMS can adjust each unit's schedule based on electricity prices and demand, the system supports time-shifting and market-driven operation. Operators can charge during low-cost periods and discharge during high-value windows, improving the economic return of the storage asset.
Market Value for Project Developers, EPCs and Distributors
For European project developers and engineering contractors, the Yambol installation offers a practical reference for commercial energy storage. The modular, AC-parallel design reduces the technical risk of larger deployments by building capacity from proven single-cabinet units rather than custom systems.
The AIO-261 enables distributors and integrators to offer a consistent, repeatable storage solution across projects of different sizes. Standardised cabinets simplify quoting, logistics and training, while the ability to scale from one to ten units supports customers as their energy requirements grow. Liquid cooling and factory testing also lower long-term maintenance burden for asset owners.
Company Outlook
MECC Solar continues to support flexible, scalable commercial energy storage through its AIO-261 liquid-cooled cabinet line. The parallel deployment in Bulgaria demonstrates the product's suitability for coordinated, multi-unit storage systems managed by third-party EMS platforms. As peak load management and renewable integration grow in importance across Europe and other regions, modular liquid-cooled storage will remain a core option for project teams.
MECC Solar remains focused on delivering reliable, well-supported energy storage hardware and project guidance for contractors, developers and distributors worldwide.
About MECC Solar
MECC Solar is a global manufacturer of photovoltaic and battery energy storage systems for commercial, industrial and microgrid applications. The company designs and supplies integrated solar and storage solutions to partners in over 50 countries, offering complete export support, OEM/ODM services and technical guidance for a wide range of project configurations.
Liquid Cooling 125KW 261kWh Lithium Battery Energy Storage Cabinet
The IP55 Protected All-in-One Solar Energy Storage Cabinet is a high-performance, integrated energy solution engineered for outdoor commercial, industrial, and utility-scale solar applications. It integrates a 125kW Power Conversion System (PCS), a 261kWh lithium iron phosphate (LiFePO4) battery bank, an advanced liquid cooling system, and a intelligent Battery Management System (BMS) into a single cabinet with IP55 weatherproof protection. Designed to withstand harsh outdoor environments while delivering efficient energy conversion and storage, it supports solar energy absorption, peak shaving, load shifting, grid auxiliary services, and emergency backup power. Ideal for utility-scale solar farms, industrial parks, large commercial complexes, and remote microgrids, it provides a reliable, space-saving, and low-maintenance solution for large-scale renewable energy integration.
