BlueStream™ Hybrid Cooling Technology

Like fanning away sweat on a hot day, open cooling towers reduce the temperature of water heated in chillers, industrial processes, data centers and other high-heat practices. Through a “wet” process, the warm water is sprayed over the fill in a cooling tower to increase the contact area, and the heat is removed through evaporation.

A constant supply of water is needed to replace the water evaporated from the cooling tower, but in many regions, continuing droughts and increasing competition for this vital resource limit water availability. Additionally, some water is continuously bled from the system to reduce the buildup of undissolved solids as water is evaporated. This generates a large wastewater stream, often containing many additional water treatment chemicals.

We are testing a new approach with very promising results: the BlueStream™ hybrid cooling system. Used in conjunction with a traditional cooling tower, a hybrid cooling system offers a way to not only reduce environmental impact, but also lower operating costs and increase the resiliency of critical operations. The system offers “dry” cooling, using a thermosyphon process, in which refrigerant circulates naturally, with no need for a pump or compressor. Intelligent, web-connected
controls coordinate the operation of both the wet and dry system components and adjust in all weather and thermal load conditions for optimum efficiency, utilizing “wet” cooling when it’s hot and “dry” cooling when it’s not.

Best of all, because of the connection to building automation systems, building owners can maximize efficiency and have detailed operating information, which allows for better understanding of trends and helps forecast costs. Certainly there are some limitations. If it’s too hot outside or if the process temperatures aren’t warm enough, it’s inefficient to use dry cooling during these times.

Intelligent buildings make decisions automatically. In addition to responding to changing weather and system load conditions, the controller adjusts the fan speeds for the wet and dry units based on the Water-to-Energy Cost Equivalence Ratio (WECER) – the ratio of water costs to electricity costs for optimum system economic savings.