Indirect Evaporative Cooler

A National Renewable Energy Laboratory assessment of indirect evaporative coolers found that the technology reduced energy use while maintaining thermal comfort, but it can be difficult to find favorable economic payback. View full-size infographic. [PDF - 363 KB]

GPG Findings 035, September 2018, Small Circulator Pumps with Automated Control. OPPORTUNITY: How much energy can high performance circulator pumps save? 4.75TWh REPLACING 30 MILLION U.S. CIRCULATOR PUMPS WITH 50% HIGHER EFFICIENCY. TECHNOLOGY: How do highperformance circulator pumps with automated control work? < 2.5 HORSEPOWER PUMPS VARIABLE SPEED ELECTRONICALLY COMMUTED MOTORS ONBOARD CONTROL ALGORITHMS. M&V: Where did Measurement and Verification occur? NATIONAL RENEWABLE ENERGY LABORATORY (NREL) measured performance of two common pump applications at two buildings within the Denver Federal Center—a domestic hot water (DHW) system and an air handler unit (AHU). RESULTS: How did the small circulator pumps with automated control perform in M&V? 96% ENERGY SAVINGS for DHW pump, 60% savings for AHU pump. MORE OPERATIONAL VISIBILITY and reduced maintenance, no greasing of bearings or replacing pump seals. <6 YEAR PAYBACK @ 0.11/kWh GSA average utility rate and including annual maintenance savings. Payback and Savings Compared to Baseline Standard Pumps Higher flow rates combined with smaller pump sizes offered the best return on investment. DEPLOYMENT: Where does M&V recommend deploying small circulator pumps with automated control? END-OF-LIFE REPLACEMENT FOR CONSTANT-SPEED PUMPS Pumps used for DHW recirculation, small heating systems, small chilled water systems, solar hot water systems and small geothermal heat pump applications are all candidates for replacement. [PDF - 363 KB]


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Last Reviewed: 2019-12-02