With energy-consuming equipment, such as water heaters and refrigerators, we have good data on energy consumption and can set clear standards accordingly. In some product categories—clothes washers, for example—Energy Star standards were adopted because those standards provide a high enough threshold to represent just the very top segment of the product market (less than 10%). In other product categories—e.g., refrigerators and dishwashers—we set a higher threshold than ENERGY STAR: for example, exceeding those standards by 10% or 20%. With lighting and lighting control equipment, certain generic products qualify, such as compact fluorescent lamps and occupancy/daylighting controls, while in other categories only a subset of products qualify. In some cases, products that meet the energy efficiency requirements are excluded, because of evidence of poor performance or durability. Microturbines are included here because of the potential for cogeneration (combined heat and power) that they offer.
Climate Wizard, from the Australian company Seeley International and distributed in the U.S. by L&H Airco, is a refrigerant-free indirect evaporative air conditioner. The Climate Wizard uses fans with energy-efficient electronically commutated motors (ECM) to move air through a heat exchanger that contains both wet and dry channels. Heat is transferred across the membrane from the dry to the moist channel where it is vented into the atmosphere. The cool, dry, fresh air then passes into the building to provide cooling. Climate Wizard uses 6.6 gallons of water per hour for the 10 kW model (about 2.8 tons cooling); a 15 kW (4.3 tons) version is also available. Climate Wizard is used primarily in commercial applications and can be used to pre-cool air in conventional compression-cycle air conditioning systems. A residential unit is undergoing testing.
Evaporative coolers use far less electricity than conventional refrigerant-cycle air conditioners and they operate without the use of refrigerants, both features that make them attractive for green buildings. But their suitability is limited to drier climates, and most products use significant quantities of water.
Evaporative coolers use the latent heat of evaporation to cool air in areas of low humidity. The difference between the “dry bulb” and the “wet bulb” temperature indicates how much cooling is possible (with 100% humidity, the dry- and wet-bulb temperatures are the same). Most evaporative coolers are direct systems that bring moist cool air straight into the building. Indirect systems use an air-to-air heat exchanger to provide cool air without raising indoor humidity, and direct/indirect systems are two-stage coolers that can deliver air that is cooler than the wet-bulb temperature.
State-of-the-art modern residential and commercial evaporative coolers are more efficient and use less water than their “swamp cooler” predecessors, though it is difficult to get good, comparative performance information. There have been some efforts to develop a standardized measure of both cooling performance and energy efficiency with evaporative coolers, including an "Evaporative Cooler Efficiency Ratio" (ECER) that the California Energy Commission had proposed some years ago, but there is no such standard in place today. Cooling efficiency is often measured by the “saturation effectiveness," but this is only one measure of performance.
Products listed by GreenSpec must have saturation effectiveness of at least 80% under all operating conditions and a mechanism for effective cleaning with minimal water use (for example, a sump-dump system). When a uniform standard is developed for measuring and reporting evaporative cooler performance, GreenSpec will adopt that and set performance thresholds for listings.
EAc1: Optimize Energy Performance
EAc1.3: Optimize Energy Performance—HVAC
EAp2: Minimum Energy Performance
EAp2: Minimum Energy Efficiency Performance
EAp3: Fundamental Refrigerant Management
Ratings and Commentary