How To Build A Twelve-volt Swamp Cooler

How to build a twelve-volt swamp cooler

Evaporator coolers have been used for a long period of time.  They are energy efficient,  and produce no harmful byproducts or pollution. Modern swamp coolers are designed for operation at 120 volts AC.  There use in homes across America is primarily due to the fact that they use far less current than their counterpart the air-conditioner.  If one needs cooling in a remote area where line electricity is not available it is not practical to utilize a standard swamp cooler.  Generating AC current at 120 volts is inherently cost ineffective. If one is generating their own power it is far easier to create twelve volts DC stored in batteries.  Solar panels, a poor man's generator, or a wind generator, can be utilized to create twelve volts DC.  Each unit has it's own inherent benefits. All can be used at once to create a self-sufficient power structure. Most swamp coolers are constructed out of stamped sheet metal. It is a simple matter to remove the AC fan and the AC water pump and replace them with a twenty-four volt fan and a twelve-volt water pump. The use of a 24 Volt fan motor is highly recommended because a 12-volt motor consumes too much electricity. The torque of the twelve-volt motor generally found is so high that the current consumed is very inefficient. A twenty-four volt motor will not produce a high torque when operated at 12 volts and its power consumption is halved. Yet there still is enough torque produced to turn a fan blade at a rate, which will produce a very usable amount of airflow. A 12-volt boat bilge pump can be used for the water pump. Smaller bilge pumps pull only 3/4 of an amp dc and can still pump water at a high rate. Because the airflow is so much reduced in our unit it is imperative to take advantage of the lower temperatures at night. The unit needs to run 24 hours per day. By reducing the cooled structures temperatures at night to a low level much of this coolness is stored in the building and carried through to the next day. Since energy conservation is our goal a simple timing circuit, which operates at twelve volts, can be utilized to turn our boat bilge pump off and on at regular intervals. This will not only reduce the power consumed but also prolong the life of the pump itself. A period of 4 minutes off and 1 to 2 minutes on is enough to fully saturate the coolers pads . Water consumption is reduced and can actually be monitored. A slightly cooler airflow is created by limiting the amount of water the pads receive. The choice of your fan blade is critical for good operation. You must remove the large blower unit found in the cooler and replace it with a standard metal fan blade. Mount your 24-volt motor to the cooler chassis in an adequate fashion.  Aiming the blade downward to blow air into the structure. A venting assembly is recommended for good distribution of the airflow. The unit pictured below operates at 1.8 amps dc, 24 hours per day, keeps the trailer cooled to no more than 95 degrees Fahrenheit when out doors temperatures are as high as 125 degrees Fahrenheit. These measurements were taken with a high quality thermometer and recorded over several years. There is no question as to the accuracy here. Window coolers can be converted in a similar fashion but require the use of a double shaft 24 volt motor which utilizes twin auto blower blades.