The new BlueStream hybrid cooling system from Johnson Controls is a solution designed to address water and energy challenges in facilities through more efficient cooling tower operations.
BlueStream features a new technology – thermosyphon hybrid cooling – to reduce water consumption in traditional cooling tower systems by 25 to 80 per cent compared to all-evaporative heat rejection systems. It also maintains peak process output and energy efficiency on hot summer days.
Open cooling towers reduce the temperature of water heated in chillers, industrial processes, data centres and other high-heat practices whereby 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, and 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.
The BlueStream system offers what Johnson refers to as “dry” cooling through a thermosyphon process in which refrigerant circulates naturally, with no need for a pump or compressor. 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.
“Water costs are becoming an increasingly larger component of a heat rejection system’s total operating cost,” said Clay Nesler, vice president, global energy and sustainability, Johnson Controls in a company release. “BlueStream offers a cost-effective way to reduce water use while simultaneously reducing operating costs in heat rejection systems.”
Johnson Controls worked with the Electric Power Research Institute to evaluate BlueStream in a range of cooling conditions in thermoelectric power plants. The project demonstrated Blue Stream’s ability to significantly reduce annual water use in plants while still maintaining peak plant output on the hottest summer days.
In addition, Johnson Controls tested two prototypes – the Energy Department’s National Renewable Energy Laboratory (NREL) in Golden, Colorado, and the Water Research Center in Cartersville, Georgia – to validate the dramatic reduction in water consumption provided by BlueStream. Johnson Controls partnered with NREL and Sandia National Laboratories to install BlueStream at NREL’s 1 MW data centre, where it is projected to save a million gallons of water each year.
BlueStream is an ideal technology for process cooling, data centres, power generation and year-round, base-loaded HVAC applications with water-cooled chillers. Initial analyses indicate a payback period of as low as 2.5 years, depending on the facility’s geographic location, utility costs and operating conditions.