Dutch company for design, build, finance and operate aquifer thermal energy storage systems. The idea behind Aquifer Thermal Energy Storage is simple: store the cold or the heat when it is available and retrieve it for use when it is needed. During the summer, cool water from the cold well is pumped from the well to the building ventilation system for direct cooling. In cooling down the air, the water picks up thermal energy and becomes warmer. This warm water is returned to the hot well at a different location. In the winter, the flow is reversed. Warm water is pumped from the hot well and sent through the heating system to pre-heat building intake air. (In some cases, a heat pump could be added to provide more thermal energy to the air.) In transferring thermal energy to the air, water becomes cooler. This cooler water is returned to the cold well. The cycle will repeat itself every year.