Billy Shafer RV Generator Question

John T

Well-known Member
Billy, I have a Genajunk (yeah I know lol but regardless it starts n runs n powers fine except !) 4700 Model 4.0 RV Generator I'm trying to make run a bit cooler especially if on a rare occasion if its like 90 degrees and I'm dry camping perhaps running the genset and AC maybe an hour or so before bedtime. Usually I would just move to a higher cooler elevation yayyyyyy. Best I can tell its engine end driven fan sucks cooling air in at a bottom center rectangular (perhaps 2 x 5 or so inches) open slot, then exhausts out one wide screen covered slot on the bottom on one side. It really throws a good strong air stream out that screen covered full width slot.

QUESTION What if I were to rig a 270 CFM side discharge fan on the bottom all ducted up to blow/force air into the suction intake slot ??? Do you think that would increase the compartment heat removal rate very significant??? I figure it shouldn't hurt !!!!!!!!!!!

FYI NO I don't know the CFM of the onboard engine driven fan system nor how many BTU's of heat that need to be removed nor
the cubic feet and insulation of the housing etc. etc. etc.
NO it came with the RV and for the most part works great and I'm NOT interested in changing at this time.
NO the AC is new and fine and NOT drawing excess current nor over taxing the gensets "electrical" capacity.

I ONLY wanna know if adding a 270 CFM fan similar to the one linked below to blow/force air into the bottom suction air intake might increase the heat discharge capacity to any significant degree ??????????????

Your thoughts are appreciated

John T PS in Engineering school Thermodynamics was NOT my best subject lol I do remember heat lost = heat gained. I need to extract more heat from the genset housing out to the environment to help AlGore and global warming LOL
Exhaust Fan
 
John
I did something like that on a dressing room trailer. Came down from the north to Texas. We added a fan to force in more air. It stopped the over heat problem we were having. The balance was off but we fixed that. The trailer was down here in July Texas heat. But it did run cooler. You may have to test it. To see which system works the best. But I think forcing in more air would work best.

Been raining for three days. We sure need it. Just wish it would stop so I could mow the grass. Had a heard of deer in the front yard water station this morning. Nice to walk out and watch them hanging out.
 
John, have you considered adding a misting device to your current setup?

As long as you have access to water, you can set up a gravity-fed system that releases droplets into the moving air stream or, better yet, add in a small 12v diaphragm pump that can force the water through a misting nozzle. The finer the droplets. the better the cooling effect.

When air temp is 90F, misting water that is 70F will have a dramatic cooling effect, and all without drawing much additional power.

I know you can get pumps as small as 1.1GPM, but you wouldn't need that much - maybe 1 quart per hour, maybe 2 quarts at most would be fine. Could have the excess recirculate back to the water tank. And being a diaphragm pump, you wouldn't even "have" to use clean water, so long as there's no solid debris in it. Granted, the cleaner the water, the better for the equipment.

Another idea would be to forego the diaphragm pump and have water drip onto a small piece of filter medium that is within the air flow. No extra power use at all.
 
Hello John T,

Billy must be occupied, so here it goes. Remember heat gained heat loss! Well it applies to air movement in a way. I think any extra air movement like you said is good. I would use the exhaust fan as an exhaust, then provide 40 to 60 % extra intake opening. 10 SQ. IN. fan size 4-6" extra opening. This would create a faster air movement, a better heat exchange the just pushing air in, and having the same exhaust opening. It may be easier to push the air in do that.
Then I would reverse the numbers. 40 to 60 % extra exhaust opening from the size of the fan. All this to create a bit of pressure beside extra volume. That's my guess, and I am sticking with it! Bully will chime in I'm sure. Stay kool.....

Guido.
 
Sorry but water and generators don't mix. Misting does work. But you don't want water being sucked into the gen section. Or getting
into the control boards. Can short out some very expensive parts.
 
A couple of things entered my head: The added amp load (1.7 amps) will load the generator at a little over 200 watts. That might just wash out the net gain in cooling.
I think increasing the intake port opening size, and redirecting the exhaust air farther away will produce desirable reduction in cooling. The cfm of the engine fan needs to be measured. if it is greater than the 270 cfm of the vent fan, it will add restriction on either push or pull air. (or do very little.
I also wonder if pushing air might push some engine heat out into the engine compartment (if indeed it does supply more than the engine fan)
I agree the mist idea has radical issues with electronics, and generators/engines. Jim
 
THANKS TO ALL The exhaust vent area seems plenty big, its all across one entire end and like 2 inches wide and the air really blows OUT strong there. There's no cutting or expanding any of the intake (or exhaust) vent area, there's engines and oil pans and shrouds and other stuff in the floor all over which leaves about the ONLY option of maybe forcing/stuffing a bit more cool outside air IN. PS the fan and air intake will NOT be placed in the same area or direction where the hot air is flowing OUT DUH. It doesn't appear the fan assembly (even if not running) and side discharge ducting offers much air flow restriction, so when running I'm "hoping" it will increase the air flow past and through the sheet metal engine shroud out the vent for added heat transfer ??? Sort of like a supercharger or blower stuffing/forcing more air IN lol

The genset is 30 amp, the AC draws maybe 12 amps max, and I don't run anything else in this rare situation, so I don't envision the 2 amp fan current will increase the heat load significantly.

Again, this is a RARE concern, its ONLY if its like 90 degrees dry camping and I cant move to higher elevations I might need to run the genset and AC for maybe an hour or so. There's absolutely NO problem otherwise and none if its say 80 degrees, its the 90 degrees in the sun where the temp limits (all new upgraded and working correct doing their intended job) might be reached after maybe 30 minutes of continuous operation. I already use the correct grade and viscosity of pure synthetic oil and don't run the carb too lean (too lean fuel = hotter operation). Otherwise I'm pretty well "fixed" for long term dry camping and never run out of stored battery DC energy having four solar panels (950 watts),,,,,,, A 50 amp MPPT Solar Charge Controller,,,,,,,Four Trojan 6 volt golf cart batteries (450 Amp Hours),,,A 2000/4000 Watt Pure Sine Wave Inverter,,,,,,,, and the Genset as a backup yayyyyyyyyyyyyyyyyy The limiting factor is fresh water storage, but I carry enough so we can camp a week before we need to move on to take on water and dump, but by then I'm ready to move anyway.


I figure the fan is worth a try, it may or may not help, but I don't think it will hurt. I enjoy tinkering anyway.

THANKS AGAIN TO ALL

John T
 
I think you will do fine. Buy just adding the fan. As long as the intake and exhaust ports are clear. If yours is like most I have worked on. You don't have much room to start with. The movie trailer I did didn't take much to fix the problem.
 
(quoted from post at 19:32:08 09/11/18) Sorry but water and generators don't mix. Misting does work. But you don't want water being sucked into the gen section. Or getting
into the control boards. Can short out some very expensive parts.

I don't like water around electricity either, but pure water/distilled, is not a conductor.

Dusty
 
(quoted from post at 09:49:07 09/12/18)
(quoted from post at 19:32:08 09/11/18) Sorry but water and generators don't mix. Misting does work. But you don't want water being sucked into the gen section. Or getting
into the control boards. Can short out some very expensive parts.

I don't like water around electricity either, but pure water/distilled, is not a conductor.

Dusty
s soon as that pure water hits those Dusty/dirty circuit boards and gen parts it won't be "pure" and non-conducting anymore.
 
(quoted from post at 15:49:39 09/12/18)
(quoted from post at 09:49:07 09/12/18)
(quoted from post at 19:32:08 09/11/18) Sorry but water and generators don't mix. Misting does work. But you don't want water being sucked into the gen section. Or getting
into the control boards. Can short out some very expensive parts.

I don't like water around electricity either, but pure water/distilled, is not a conductor.

Dusty
s soon as that pure water hits those Dusty/dirty circuit boards and gen parts it won't be "pure" and non-conducting anymore.

Very good point.

Dusty
 

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