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Project Info COMPLETE Project Title

Wet Bulb Chiller

Project Number ET15SCE7040 Organization SCE End-use HVAC Sector Commercial Project Year(s) 2013 - 2015
Description
Technology employs evaporative effect, in lieu of electrically-driven refrigerant compression, to chill water for HVAC cooling applications.
Project Results
Cooling loads constitute approximately 13% of the total demand for the United States, and in California, the hot dry summers drive cooling loads and peak demand throughout the season. Currently, the market is driven by compressor based systems, which are inherently limited in efficiency and constrain the electric infrastructure. In California, because the climate is hot and dry, there is potential to expand the market to incorporate evaporative cooling. Most ordinary evaporative systems, such as cooling towers, are limited to cooling to the ambient wet bulb, which limits their cooling capacity, and their applicability in chilled water cooling systems. The sub wet bulb evaporative chiller (SWEC) technology has a significant advantage over other evaporative technologies because of its ability to cool below the ambient wet bulb. Chilled water below the ambient wet-bulb could be utilized in a radiant floor or ceiling cooling system, or a fan coil system. In light commercial buildings, this type of cooling system could replace typical roof top units with air duct systems. Several unique designs exist that are considered sub wet bulb evaporative chillers, and this report focuses on one such design. The SWEC cools an outdoor air stream using an indirect evaporative cooling process. Part of this cooled, dry, outdoor air is delivered to the building as ventilation air; the rest is exhausted as part of the evaporative cooling process, which also chills a water supply used to cool the building. The SWEC design tested in this evaluation offers the following potential benefits: - Chilling of supply water to lower temperatures than conventional cooling towers - Cooling efficiencies higher than a conventional mechanical chiller - No introduction of humidity to the building  Ventilation air flow   The objective of this assessment is to evaluate the performance of the SWEC in the laboratory under a range of environmental conditions and operating modes. The supply water temperatures, system efficiency, and the water consumption required for cooling would be evaluated. The analysis provides insight to the potential for the SWEC to replace traditional compressor based systems, including the potential for peak demand and total energy savings. The SWEC was tested in an environmental control chamber in order to map its performance characteristics. The SWEC was instrumented such that the load, energy consumption, and water-use could be determined. Outdoor air conditions and return water temperature were held at a steady state. The performance of the SWEC chiller illustrates a large energy savings potential in hot, dry climates (daytime temperatures above 90°F with relative humidity
Project Report Document
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Industry
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