Residential Whole-House Evaporative Cooler Field Study

Evaporative coolers provide cooling without refrigerants and operate most efficiently in low-humidity conditions. To evaluate the feasibility of installing an indirect/direct evaporative cooler in lieu of a traditional split-system, refrigerant-based, central air conditioning system, the SDG&E Emerging Technologies group conducted a field study (“the Study”). The Study analyzed the annual energy consumption and water consumption following installation of indirect/direct evaporative cooling units at seven sites and provided a performance assessment of each system when operating at peak operating conditions. This report describes the unit’s system design and summarizes the energy and water consumption analysis and peak performance.

The Study sought to achieve the following objectives:

• Document installation procedures, including differences in installation procedures based on home vintage, layout, and location.
• Measure the energy and water consumption of the evaporative cooler and annualize usage using average meteorological year weather data.
• Determine if the system’s operation met occupant comfort with weather conditions present during the Study’s monitored period, including hot and humid weather.

The Study recruited residential homeowners in SDG&E’s service territory. The resulting sample consisted of seven installation sites, representing three of the most populous California Climate Zones in SDG&E’s service territory (CEC Climate Zone 7, 8, and 10). The selected sites represented a range of single-family home vintages, sizes, and designs, commonly found in the utility’s service territory.

The Study performed long-term monitoring of the evaporative cooler energy and water use, and the home’s thermal conditions after installation of the evaporative coolers at each site. To analyze how the evaporative cooler impacted the overall energy and water use in the home, the Study collected and analyzed the following over 12 months following installation:

• Evaporative cooler power consumption data.
• Evaporative cooler water consumption data.
• Weather data from temperature and humidity sensors.
• Temperature readings logged from three locations in the home.