I like the idea but the cooler needs to be small, to keep power usage low, and ALL the cooler output MUST go to the coil, any leakage will put humidity in the room. I guess you'd have to have the cooler kick on when the AC kicks on, otherwise same problem as above.

I didn't mean for the cooler to be indoors at all. Just to blow its output into the outdoor airstream of the heat pump to cool the compressor and condenser--I think I said evaporator before. I'm not into this stuff and don't recall which part of the unit is called which.
Nerdy

OK, plan B then. The condenser pulls air from many sides so doesn't seem the cooler would be very effective, plus unsightly. Keep thinking!

I guess it would be tough to duct properly, but I wonder if the outcome would he equivalent to a much higher seer unit. My stepson repaced his old unit with a new high seer Lennox. It is a monster and he needed a second unit for the second story of his house. I think a small swamp cooler wouldn't be much more obtrusive if I could come up with an attractive shroud around my condenser unit and interconnecting duct-work. The last time I used a whole house (abt. 4800 cfm) swamp cooler it was about the size of my stepson's condenser unit. I could probably get by with a 2400 cfm swamper.
Nerdy

I have also considered doing this on my ac unit. My plan is to fabricate an enclosure over the whole ac unit and duct the evap cooler into it. The evap unit I have is a small 2400 cfm window unit that pulls about 4amps on high. My plan is to run the unit at a slower speed all the time during the day to keep the condenser coils cool all the time. Depending on how it performs by cooling the coils or restricting the air I may put a relay on the condenser to switch the evap to high if needed while the condenser is running.

One problem I have is my ac unit is oversized already and I am afraid I am going to decrease my cycle times maybe causing the air inside the house not enough time to de-humidify. I think the installation would be most effective on a house with an undersized unit that runs almost constantly. I have a friend with this problem and after I do my install depending on my result may do his to see how it fares.

In order to capture savings, electrical usage, and temperature differences I am going to use a TED 5000 electrical monitor, which will provide useful graphs, cycle quantity and durations. I will also monitor inside, outside, and duct temperatures. I will do this before and after installation to have some comparison.

Any thoughts?

It sounds good but I'd really like to see some input from a mechanical engineer with HVAC experience. Something makes me think it won't work properly because the whole system is designed around certain temperature ranges, but it's just a gut feel.

One of the ideas i had was to use a car radiator between the two systems , the ac would be install on the side as a kicker to the swamp cooler and the radiator will be after the fan blower unit this will cool the air down and the air conditioner will have twice the coiling and save Electricity but you will still need water but not as much , in very very humid zones this will work , I m going to build a small unit , so to look at it from the side ,swamp cooler then the AC unit mounted on the side of a new duct box , the swamp unit configuration stays the same as it comes the only difference that you will blow the air from the swamp cooler then the radiator or coil then the AC unit then another blower as the final kicker , this works I am working on making a completed unit afterwards the patent on the idea . the trick is that the air passing across the radiator is reduced and colder then the swamp cooler ,the ac helps cool it even more then the final blower is the kicker for the BTU per square foot , this works ,i have tried this and it works , the final blower has to be twice the size of the blower on the swamp cooler, and don't forget to add 100 percent glycol to the radiator , don't worry if the radiator or coil gets wet that is the trick , it will work just like a economizer unit , but instead of just air coming in like a economizer unit there is the kicker of the swamp cooler and the coil

I believe the flow through my HP is from a fan that pulls air from all sides and exhausts it up. I think a swamp cooler with more air flow than the heat pump could be attached to the side nearest it and push air into the HP. The exhaust would take most of it up, but any excess would blow out of the other open sides. I'm no engineer but it looks like it would work on paper. Main problem is waste water. Salts in the water build up and are corrosive. My old swamp coolers always corroded out until they came up with plastic interior parts. A delux model constantly fed water in and used a float system to keep the reservoir full. Cost more but it worked.

if you put a ivory soap in the water they will stay clean , i epoxy the water basin strong as heck , the water id the problem I am looking at both electric waste and water , i worked for Verizon and every manufactures unit in America.the coil idea will take care of the heat .soon we can share my idea ,lets get together on this and see if we can make a change in the ozone layer huge corporations don't tell the leaks they have on unit i have seen thousand of pounds not reported

I tested this scheme with my 12 year old son for his science fair project 14 years ago. As an experimental temporary setup. Instead of using an EVAP cooler, we built cardboard duct perfectly sealed and encircling the outdoor condenser with a foot of clearance from the coils and an 8 foot long 3.5' x 3.5' opening tunnel leading to the unit. We measured compressor+fan current with clamp meter with the unit running steady without mist. Then used a pressure washer as an improvised evaporator to spray mist at the opening. Spray head was 2 feet outside the entry to the tunnel. The long tunnel was to minimize any spray water reaching the coils. The current dropped ~ 20% with the mist turned on. . At the same time, indoors, the delta T between return air duct and cold air exit duct went from 18 F deg to 21 F deg. So the factor for decrease in input energy for a specific cooling output was 18/21 x 0.8= 0.686 i.e. a 31.6% reduction in energy for the same amount of cooling. 3 ton heat pump. Gilbert AZ Early May. We did not subtract energy for the pressure washer pump because in a permanent installation, a media based the evap cooler would be used passively. i.e. no blower as the condenser fan will move the air. Circulating water pump energy is minimal. We did estimate the cost of evap water for this with normal run times and it was $2-3/mo. But the scheme is hugely dependent on low RH. I have that data but not in my head right now. You also have to ensure you direct the humid warm exit air of the outdoor condenser way form where the intake is or RH at the intake will suffer and efficiency will be lost accordingly. So if you have lots of room and condenser unit is our of sight so big ducting is not an eyesore. This can save a lot on A/C cost. But efficiency will drop greatly during our humid monsoon season. We never did implement a permanent set up, but the project may have helped to partly inspire my son to get a MS in mechanical engineering and he now does design work on gas turbines.