Direct Solar Evaporative Cooling for Your Home

Direct evaporative cooling, most common in residential settings, uses an open circuit design and is most closely related to the primitive coolers long used in hot, low humidity climates. It quite simply and directly changes water to vapor. In other words, the warm dry air coming into the home is changed directly to cool moist air. That hot air passes through the moist pads within the evaporative cooler, forcing that water to evaporate resulting in cool moist air on the other side of the pad. This cool air is then shuttled, by way of electric blowers, directly into the home to cool the living space.

Water which is not evaporated as the warm air passes through the pads collects in a reservoir at the bottom of the cooler. From there it is recycled and sent back to the top and the process is repeated. Some water is inherently lost to evaporation, so a float valve is used (similar to that is found in a conventional toilet) to measure water depth. When the water dips below a set amount, the system knows to add more from the home's water supply. According to the Consumer Energy Center, an evaporative cooler will use anywhere from 3 to 15 gallons of water per day.

As with any evaporative cooler -- direct or indirect -- solar photovoltaic panels can be used to power the fans and blowers involved in the cooling process. Because evaporative cooling uses much less energy than traditional air conditioning, the electrical load for which the panels must compensate is not high, making solar panels a viable option for evaporative cooling even at today's relatively low panel efficiencies.

Indirect Evaporative Cooling / Direct Evaporative Solar Cooling / Two-Stage Evaporative Coolers