Project Description:  Enclosed system for dramatically increasing AC efficiency in dry hot climate areas.

The system is designed to lower the ambient temperature entering the condenser on the AC unit.

The system is automated to only run when the AC is on and the outside ambient temperature reaches the set temperature. The system then shuts down once the ambient temperature drops to set degrees.

Advantages:

Ambient air passes through the mister and then through evaporation pads prior to entering the unit.  The misters provide the initial cooling effect then as the air passes through the evaporation pads they may add an additional cooling effect.  By using the evaporation pads no water droplets pass through to the condenser and the unit stays dry, negating the worry for scale build up on the condenser fins.  In addition because the system only engages when the AC is on and the temperature level is attained, the AC will run without the system running and dry the evaporation pads limiting the possibility of mold or mildew build up on the pads. The condenser unit stays dry so no worry about a galvanic reaction in units that have copper tubing and aluminum fins. The enclosure assures only air cooled by the misters and pads gets to the condenser.

The system is automated and only runs when the compressor is on and a set temperature is attained.

The temperature of the air hitting the condenser has a direct effect on the head pressure incurred by the compressor. By lowering the temperature the compressor requires less amps to effectively run the AC units, reducing the Kwh consumed and the cost of electricity.

 A filter is put in the water supply line to keep the misters from clogging up.

The system is non-evasive to the AC unit.  It is tied in using a circuit switch on the compressor run wire. Therefor it does not alter the function of the AC in any way (only the temp and humidity of the input air).  For safety sake you may want to contact the AC manufacture to insure this does not affect the unit’s warrantee.

Modifications: This system can be modified in many ways depending on the AC unit’s specifications.  Such modifications could include but not be limited mister orifice size, pad size, number of pads, power source or enclosure design. Regardless the uniqueness of this system is 

the automation, the enclosure and use of both misters and evaporation pads to control the ambient temperature as it enters the unit.

Considerations:

Every AC unit is different; you need to build this system based on the specifications of your AC unit. Makes sure the design is adequate to provide unrestricted air flow to the condenser.  This may require more and larger pads.  Also insure other hacks to increase the efficiency are in place to include clean HAVAC filters indoors, that the condenser is properly cleaned of any current obstructions, and indoor vents are properly adjusted. 

Comparison (hot dry Climate):

This system was developed in North Carolina, because of the moderate temperatures and natural high humidity as an ROI generator it is a total flop.  However in a dry hot climate it has a very high ROI.  Regardless of the ROI the reduction in the amount of strain on the compressor should extend the asset’s longevity.  I chose Phoenix to do a side by side comparison.

Operational and financial Metric

North Carolina

Phoenix,  Arizona

System Cost

 $                            475.00

 $                                                     475.00

Local electricity Rate

$0.1342 /Kwh

up to $0.4020 peak

Average outdoor temperature drop

15 degrees on hot days

20 to 30 degrees (dry air advantage)

Indoor vent temperature reduction

2 to 4 degrees cooler

6 to 8 degrees cooler

Annual system runtimes

200 hours

1500 hours

power shaved per hour

253 watts

414 to 506 watts

Cash saved from electrical bill

 $                                 6.80

$217

Payback period

70 years

2 to 3 years

This comparison does not include the inherent cost of municipal water and is only representative of the effects of climate on the system and not a guarantee of performance.

Beduan 110V normally closed solinoid valve with 1/4 inch disconnect    $         8.99 Solinoid is engaged and allows water to flow to the misters when both the compressor is running and the outside ambient temperature is met.
Kelotech Digital Tempeture controller AC 110V 10 amps    $       17.88 This control allows setting the temperature range so the misters run only when the settings are met.  I set this to engage at 90 degrees and disengage at 87 degrees. This insures that the misters only run when the ambient temperature  is above the design temperature of the AC for maximum efficiency.  It also allows the evaporation pad tp dry out when the ambient temperature is below  90 degrees and the AC is running (prevents and mold or mildew build up on the pad).
(2) waterproof toggle switch    $         6.99 Not really necessary to the system. I used these to be able to shut of the mister system off to collect amp load data during hot days by recording amps at the breaker box both when the system was running and when it was off.
Yetle waterproof electrical junction box ABS plastic 8x6x3    $       15.59 obvious necessity
Mister Kit 50 feet    $       25.67 Recommend .2mm orifice misters this allows small water particles that best cool the ambient air through evaporation as it eners the outside unit.
Wire Fence 1x2x24    $       35.83 see pictures. This is just material needed to build the evapration pad 
Dura Cool Evaporation Roll 29"x144"    $       58.09 I chose dura cool pads, they are inexpensive, permeable to allow air passage to the unit, easy to maintain and insure no water droplets reach the condensor and therefor alleviate the worry of scale build up.
Styrafoam insulation 2"x4'x8'    $       29.83 In expensive way to finish the enclosure and negate the effect of the sun beating down on outside unit
Hardware    $       28.00 Best guess as to the cost of wiring and conectors I used mostly items I had on hand
Total    $     258.81
Vevor outdoor Prvacy Screen 50"H  X 50'W   203.29 used to enclose the outdoor unit in conjunction with the styrafoam insulation
Digital Clock 24V   13.29 Not necessary to the system. I wired this to the 24 volt thermostat to record changing run times when the system was on or off.
Grand Total    $     475.39