140-180°F WATER STEAM EXHAUSTED IN COMBUSTION GAS = LOSS OF ENERGY HIGH EFFICIENCY HYBRID WATER HEATER For many years loyal Sioux customers asked Sioux to develop a direct-fired water heater designed specifically for use in the concrete industry, that would have the traditional Sioux high-quality, and other features needed for concrete production. In 2009 Sioux built its first direct-fired water heater which included a properly engineered combustion chamber and other features to obtain maximum efficiency. However, after extensive testing, it became obvious that the traditional direct fired design did not provide acceptable efficiency at higher water temperatures needed in the concrete industry. This is because at higher temperature, the heated water evaporates and passes out the stack with the combustion gasses, resulting in a huge loss of energy and unacceptable efficiency. So Sioux did not introduce this traditional direct-fired heater in 2009. At WOC 2012, Sioux introduced a revolutionary design that resulted in numerous benefits for concrete producers, utilizing a direct-fired section, plus two other sections. In this design, the media section ensures high overall efficiency by capturing remaining exhaust heat but the temperature of the water is low, so essentially none of the water turns to steam. The second section captures combustion gas heat in the bottom of the heater, and the third section (the coil section) allows water to be heated to the final temperature in the heating coil where none can evaporate, achieving a high temperature (up to 208 °F) without evaporation. Sioux Hybrid vs. Direct-Fired Water Heaters: Efficiency Comparison Sioux’s Hybrid Water Heater captures nearly all of the heat of combustion. High water temperature is reached in the coil rather than in the media section, eliminating significant losses due to steam escaping from the media section. In a typical direct-fired water heater, significant energy is lost when the water droplets turn to steam and exit the system with the exhaust gasses. Above is a photo of a ready-mix facility where a traditional direct-fired water heater is operating, showing the escaping steam.