The National Renewable Energy Laboratory (NREL), in collaboration with Blue Frontier Inc., has unveiled a transformative technology poised to revolutionize commercial air conditioning and bolster grid stability. Their jointly developed Energy Storing and Efficient Air Conditioner (ESEAC) integrates cooling, humidity control, and energy storage into a single system, demonstrating the potential to cut peak air conditioning power demand by over 90% and reduce electricity bills for cooling by more than 45%. This innovation represents a significant leap forward in building energy management, offering a scalable solution to mitigate the escalating demand on electrical grids.

Unlike conventional vapor-compression refrigeration systems that simultaneously cool and dehumidify, often leading to energy waste through overcooling and reheating, ESEAC employs a distinct, more efficient approach. It separates dehumidification from active cooling through a liquid desiccant system that directly absorbs moisture from the air. Following this, ultra-efficient indirect evaporative air conditioning precisely cools the air. This method drastically reduces the energy required for dehumidification, directly translating into lower operating costs. A core feature of ESEAC is its integrated energy storage capability, which enables the system to operate without running compressors during expensive peak demand periods.

The ESEAC cycle involves three critical steps: charging, storage, and discharging. During the charging phase, a dilute salt-based liquid desiccant is separated into a high-concentration solution and pure water, consuming the majority of the system's electricity. These separated fluids are then stored, effectively decoupling energy input from cooling delivery. In the discharging phase, the stored concentrated desiccant and distilled water are utilized to cool and dehumidify air, requiring minimal electricity for pumps and fans, thus avoiding peak hour compressor use. Jason Woods, NREL senior engineer and co-inventor, highlighted, "This means the air conditioner can keep you comfortable all day but consumes the majority of its electricity when rates are low or renewable energy is available."

A year-long simulation conducted in Miami, Florida, on a 20-ton ESEAC system projected a 38% reduction in cooling-related electricity use, a staggering 93% decrease in peak demand, and a 45% cut in annual electricity costs. These figures translate to an estimated $165,000 in savings per unit over 15 years, underscoring the substantial economic benefits for commercial building operators.

Beyond individual building savings, ESEAC offers profound implications for grid infrastructure. By shifting energy consumption away from peak periods, the technology helps utilities flatten demand curves, reducing the need for costly grid storage solutions or peaking power plants. Achilles Karagiozis, director of NREL’s Building Technologies and Science Center, emphasized, “Air conditioning is a top driver of peak demand and a major reason for costly grid expansion. ESEAC stores energy when electricity is cheap and uses it during peak times—delivering energy storage benefits at a fraction of the cost of batteries.” The system's use of saltwater and pure water for energy storage is approximately 10 times less expensive than battery-based systems, offering a highly scalable and cost-effective approach to managing cooling loads.

With early financial backing from entities like Breakthrough Energy Ventures and Volo Earth, ESEAC systems are already being deployed across various commercial and institutional sites in the United States. Notable installations include U.S. Army Fort Benning, a Bank of America branch, an IMAX theater, commercial restaurants and grocery stores, and educational and healthcare campuses such as Barry University and Jackson Memorial Hospital. Matt Tilghman, CTO at Blue Frontier, confirmed, "Early performance data closely match our modeling results, confirming that ESEAC achieves significant energy savings and offers clear financial benefits for commercial buildings." The technology recently earned an R&D 100 Award, further validating its innovative design and potential impact. This new class of cooling technology, by separating dehumidification from active cooling and integrating cost-effective energy storage, is set to redefine energy efficiency and grid support in the commercial sector.