How to - Window A/C in Dolphin

[waiter]

One of the questions presented was; "On my frig, the upper vent isn't on the roof, but is on the side. Could that existing vent be used for the A/C exit air?"

I promised to do an experiment on mine to see if the Window unit could work in these situations.

The theory was that the warm air from the frig would simply flow through the A/C unit when the A/C unit isn't running, and this isn't a problem when the A/C unit is running, as it is drawing air in from the lower Frig vent door.

To test this theory, I removed the Frig roof cover from my Dolphin, and sealed up the roof vent so the frig hot air could not escapee via that route. The only way for the frig to work, the frig air would need to flow into the A/C side vents, go thru the A/C condenser, and then exit out the back of the A/C and out the upper frig side vent. I put 4 warm water bottles in the freezer and plugged the frig into 110 volts.

After about 1 hour, it was cold in the freezer, AND, the upper cover for my A/C unit was warm.

I took a couple IR photos to show what the heat signature looked like. Outside Air temp was about 80.

The photo on the left shows the Frig air flow with the roof vent sealed. The vent temperature was about 90 deg f, and it was noticeably warm when I put my hand on it. This is the heat that the frig is generating.

The Photo in the middle was taken after the roof vent was put back to normal. The majority of the frig heat goes up to the roof vent.

The right photo shows a closer look at my normal roof vent.

CONCLUSION

I believe it would work, as long as there is a couple inches on the sides and top of the A/C unit so that the heat generated by the frig can flow through the A/C unit.

JOhn Mc

88 Dolphin 4 Auto

[acudoc]

very in depth good job. but.....the fridge works very differently when it is using propane. ie a flame.

supposed to be a chimney effect in the bottom out the top. my sunrader had the exit air on the side a fwe feet above the fridge.

i wonder??

the pics are really great. thnanks h

One of the questions presented was; "On my frig, the upper vent isn't on the roof, but is on the side. Could that existing vent be used for the A/C exit air?"

I promised to do an experiment on mine to see if the Window unit could work in these situations.

The theory was that the warm air from the frig would simply flow through the A/C unit when the A/C unit isn't running, and this isn't a problem when the A/C unit is running, as it is drawing air in from the lower Frig vent door.

To test this theory, I removed the Frig roof cover from my Dolphin, and sealed up the roof vent so the frig hot air could not escapee via that route. The only way for the frig to work, the frig air would need to flow into the A/C side vents, go thru the A/C condenser, and then exit out the back of the A/C and out the upper frig side vent. I put 4 warm water bottles in the freezer and plugged the frig into 110 volts.

After about 1 hour, it was cold in the freezer, AND, the upper cover for my A/C unit was warm.

I took a couple IR photos to show what the heat signature looked like. Outside Air temp was about 80.

The photo on the left shows the Frig air flow with the roof vent sealed. The vent temperature was about 90 deg f, and it was noticeably warm when I put my hand on it. This is the heat that the frig is generating.

The Photo in the middle was taken after the roof vent was put back to normal. The majority of the frig heat goes up to the roof vent.

The right photo shows a closer look at my normal roof vent.

CONCLUSION

I believe it would work, as long as there is a couple inches on the sides and top of the A/C unit so that the heat generated by the frig can flow through the A/C unit.

JOhn Mc

88 Dolphin 4 Auto

[waiter]

AcuDoc;

It should work. When your on LP, the flame provides heat for the Ammonia boiler, When your on electric (12 volts or 110 volts), there's a small heating element that provides heat to the Ammonia boiler tube . It doesn't work like your home frig that has a compressor, Evaporator, and condenser.

Airflow requirements for propane should be exactly the same as electric, heat is heat, doesn't make a difference where its coming from. I believe in the Dometic manual, they say that the LP provides about 110 watts of heat to the boiler while the Electric supplies about 130 watts. The key is, hot air rises, but there must be enough vent area (square inches) to allow air to flow up and past the refrigerators Ammonia heat exchanger (located behind the freezer).

This should work, but you must make sure there is enough free space around the A/C unit for it to draw in air from the plenium when its running.

John Mc

88 Dolphin 4 Auto

[acudoc]

Thanks John.

Did you see my question about the inverter?

Henry

AcuDoc;

It should work. When your on LP, the flame provides heat for the Ammonia boiler, When your on electric (12 volts or 110 volts), there's a small heating element that provides heat to the Ammonia boiler tube . It doesn't work like your home frig that has a compressor, Evaporator, and condenser.

Airflow requirements for propane should be exactly the same as electric, heat is heat, doesn't make a difference where its coming from. I believe in the Dometic manual, they say that the LP provides about 110 watts of heat to the boiler while the Electric supplies about 130 watts. The key is, hot air rises, but there must be enough vent area (square inches) to allow air to flow up and past the refrigerators Ammonia heat exchanger (located behind the freezer).

This should work, but you must make sure there is enough free space around the A/C unit for it to draw in air from the plenium when its running.

John Mc

88 Dolphin 4 Auto

[90toydolphin]

I've started the installation of a wall unit above the frig. The shelf and vertical came out by just twisting them by hand. the vertical was held to the top and bottom by the flat nails used to attach wood flush. Flat pieces of steel that are wavy, don't know another way to describe. The shelf came out the same way, was stapled through a horizontal 1X1 behind the back of the cupboard. It also twisted out by hand. The back of the cabinet i cut out with a carton opener, the bostisch type, took awhile but worked fine. the next step is to cut a hole to the outside for a vented cover. I'll wait until i get a cover then go for it. It seems solid enough to use a saber saw, I'll let you know how that works. Still nervous about it causing the thin fiberglass sheeting to crack away from the cut. I have two different brand 5000 watt window units and the outside measurements are almost identical, so it should be easily replaceable in the future. One insulation I saw here used a non opening vent, actually they said two covers mounted side by side. If i can find some that will work and look good i'll probably just drill alot of 1 inch holes behind them and let the exhaust a escape through the holes. If it doesn't allow enough air out i can always go back and use the other type and cut the complete hole. My thought is a lot of holes instead of a big hole would maintain more of the integrity of the outer wall. I'm converting the frig to strictly 110 AC so won't have much warm air competing with the air. Will post more as I go. I have taken picture of what I've done so far, not sure how to post them, so if wanted I can send via email to you. You can email me at randydavilla@gmail.com.

[90toydolphin]

question, i keep seeing things that are on the "yahoo site"? where is that? can i go there and look? i know, wrong area for this post )

[Dolphinite no longer here]

Go to toyota-campers@yahoogroups.com and join up. You'll be amazed at the wealth of knowledge there and the amount of active members that often get back to you with answers to questions within minutes!

John J

[acudoc]

there is also a link on the intro to this site.

Good luck on your install.

Henry

question, i keep seeing things that are on the "yahoo site"? where is that? can i go there and look? i know, wrong area for this post )

[90toydolphin]

a few posts back i talked about doing lots of holes instead of one big opening to keep some of the integrity of the wall. it didn't work, the unit cooled for awhile then gave up. made a few changes increasing the flow from the bottom, worked better and longer but finally quit. will be trying more things, will share if anything works short of cutting one big hole. need to make sure the air conditioner is working right too before doing too much more.

[90toydolphin]

I ended up creating three vertical cut outs, leaving some vertical wall for stability. My was is only 3/4 thick, half of what waiter's is. Buy doing so it is working fine. Will definitely have to do some divider between the cab and the coach to conserve the cool. I do live in a very warm area. With the unit sitting in the sun, no wind at all, the air couldn't keep up with the heat coming in from the cab. Was mid 90's outside with the sun shinning in through the windshield. I'm pretty confident that it will be just fine where we will be taking it and needing the air. If I had been in the shade I'm sure it would have been much more effective. All I have left to do is put on the vent cover outside and then I post a few pictures with a big YAHOO! Now we just need to pick a spot and go.

[waiter]

Wall Thickness:

My wall thickness is probably the same as yours, 3/4 inches.

The reason I bought long bolts (2 inches), I was going to add a wooden stiffener on the inside of the vent door cut out. As it turned out, instead of adding a piece of wood, I used the angle iron stuff on the top and bottom of the vent door frame.

The bolts go through from the outside to the inside: Door frame > Fiberglass > Foam > Plywood > Angle Iron > Washer > Lock washer > Nut.

This photo is taken from the inside, looking out. Your seeing the inside of the new vent door that I added. Near the top you can see the angle iron and the bolts (nuts) that are sticking through from the door frame (I know, the angle iron isn't level)

The more area you provide for you A/C exit air, the better you will be. I pop the vent door open to allow full/free air flow out the back of the A/C unit.

Windshield heat:

We have a thick curtain we made and clip it in place when parked to isolate the truck from the coach (privacy curtain). This also helps with heating (and cooling) the coach. (if its hot outside, leave the truck windows cracked a little to help cool the truck a little bit)

ALSO - We sometimes use this curtain when traveling because the trucks heater or A/C cannot keep the truck and the coach warm / cool. We clip the curtain on and the truck stays warm (or cool). We also notice the truck is a lot quieter when we're traveling with the curtain in place.

John Mc

88 Dolphin 4 Auto

[90toydolphin]

The job is done. I have a few pictures to show during the progress. Hopefully I can add the pictures and mix with a few words. Having read everything before, at least three times, and living through the project I imagine every install will take on it's own life. My only suggestion is have no fear and no dead line forcing you to do something you'll regret later.

This is the front vertical and it twisted out by hand. I just did it slowly so not to damage where it attaches. It was attached with metal, so could have cut it out with metal blade and a saber saw.

I was able to remove this shelf by just forcing it by had also. The shelf went back to a false back, closing in the flu for the frig, that i cut out with a heavy duty box knife.

This is the removed materials opening the back of the cabinet to the flu/chimney.

This horizontal was behind the back of the cabinet. I cut it in half and pulled from the staples that fastened it from the sides of the cabinet.

From the outside i drilled many many 4/4 inch holes, hoping that would be enough for the hot air to escape. As i mentioned earlier it didn't work. So i cut out sections, leaving two vertical areas to maintain some of the strength of the wall. This worked. As waiter did, he cut it all out and reinforced the hole with angle iron. I ended up using two flat vent covers painted to come close to matching the camper exterior similar to another install. can't remember the name ).

My unit ended up sticking out a little more than waiters, different over all depth of our cabinets. I was actually able to push it a little farther in, about 1.5 inches after this picture was taken.

That's it for now.

[90toydolphin]

btw, we will be adding a curtain between the cab and coach, needed for comfort and privacy as pointed out.

[waiter]

That looks pretty good.

Post a couple exterior photos when you get a chance.

Keep us posted on its performance.

John Mc

88 Dolphin 4 Auto

[Gulfstream Greg]

ALSO - I'm betting you won't need the fan, as long as there is a reasonable opening that the frig air can get through. Try it before you go to the trouble.

Personally I think even without the blockage created by the AC unit these refers need a ventilation fan at times to get that heat out. Don't forget about the CO2 that is generated by the refer. Blocking that airflow above the refer will cause some of that CO2 to possibly enter into the coach if you do not have really good sealing in place around that AC unit sticking inside. That includes the ability for CO2 to get inside the case of the AC itself. You all have a up to date CO detector right?

[waiter]

Greg;

Good point about CO (Carbon Monoxide). I installed some self adhesive foam around the front of the A/C unit. When I put the wooden front cover in place, it pressed against the foam to seal the joints between the A/C unit and the front cover.

ALSO - I would not recommend running the A/C unit with the Frig running on propane. Some (most) A/C units draw in a small amount of outside air. Well, in our case, the outside air is the Frig exhaust. NOTE - If you have 110 volts to run the A/C, switch the Frig over to 110 volts also.

I'm going to make a small warning sticker and place it on my A/C unit "

"Do not operate this Air conditioner if the Refrigerator is running on Propane"

EDIT NOTE - I edited my very first post to include this warning

As for the venting, I looked at various scenarios and have conducted testing to ensure my frig is getting adequate ventilation through its plenum.

I go back to my original calculations regarding exhaust area - Without doing any sizing calculations for the intake area to see what the velocity is for 130 watts of heat (Approximately 13 sq inches - 36 slots that are 3 inches wide and about 1/8 inch opening per slot), if we use the 20 degree temperature rise I seen using the thermal imager (worst case, air is flowing through the A/C unit with the top roof vent blocked), the air will expand (becomes less dense) by about 5 - 7%. This would mean that, ideally, the exhaust area needs to be about 5 - 7% larger than the intake area if we want the same air velocity at the exhaust as we have at the intake. Well, its not, When I block the roof vent, the intake and exhaust areas are equal (same door top and bottom). What this means, the Plenum is theoritically under a very slight positive pressure (I would bet that it would be micro inches of water)

In my case, I also have a roof vent, so I have more than enough exhaust area. In fact, I've added exhaust ventilation area because exhaust air not only flows thru the roof vent, but some of that air also flows through the A/C unit and exits out the top side vent (This can be seen in the Thermal Imager photos)

One of the missing pieces would be for someone who has a Frig that doesn't have a roof vent, but an upper side vent. and they will be doing this modification. If they had access to a thermal imager and could take a picture Before and After of the top vent, that would be very good exact temperature / air flow information that would (could) confirm my suspicion that even with the additional blockage of the air flowing through the A/C, there is still more than enough air flow to operate the frig.

John Mc

88 Dolphin 4 Auto

[Gulfstream Greg]

As for the venting, I looked at various scenarios and have conducted testing to ensure my frig is getting adequate ventilation through its plenum.

I go back to my original calculations regarding exhaust area - Without doing any sizing calculations for the intake area to see what the velocity is for 130 watts of heat (Approximately 13 sq inches - 36 slots that are 3 inches wide and about 1/8 inch opening per slot), if we use the 20 degree temperature rise I seen using the thermal imager (worst case, air is flowing through the A/C unit with the top roof vent blocked), the air will expand (becomes less dense) by about 5 - 7%. This would mean that, ideally, the exhaust area needs to be about 5 - 7% larger than the intake area if we want the same air velocity at the exhaust as we have at the intake. Well, its not, When I block the roof vent, the intake and exhaust areas are equal (same door top and bottom). What this means, the Plenum is theoritically under a very slight positive pressure (I would bet that it would be micro inches of water)

In my case, I also have a roof vent, so I have more than enough exhaust area. In fact, I've added exhaust ventilation area because exhaust air not only flows thru the roof vent, but some of that air also flows through the A/C unit and exits out the top side vent (This can be seen in the Thermal Imager photos)

One of the missing pieces would be for someone who has a Frig that doesn't have a roof vent, but an upper side vent. and they will be doing this modification. If they had access to a thermal imager and could take a picture Before and After of the top vent, that would be very good exact temperature / air flow information that would (could) confirm my suspicion that even with the additional blockage of the air flowing through the A/C, there is still more than enough air flow to operate the frig.

John Mc

88 Dolphin 4 Auto

Alright guess you can't mess with the proper calcs, but having now owned two of these rigs. the previous with a side vent and the present with a roof vent, and having installed exhaust fans at the top of the Plenum in both, my mechanical conclusion is that they made a difference especially at high altitude on hot days. One thing I believe that makes the difference is that heat in that Plenum chamber migrates into the refer (and the coach) even through the insulation, and if you can reduce that heat in the Plenum you in turn increase the efficiency of the refer. Also the refer gets more efficient when you can help cool down condenser. Anyhow for me I do see a difference being able to get that hot air to cycle out faster using a fan. The natural convection of hot air going out the top and cold replacing it from the bottom relies on the build up of heat in order to get that flow moving. I am not saying that your wrong and I am right, I am saying that for me it needs a kick in the butt to really get that heat out even with out a blockage, it makes my refer happier! For those interested in how these refers work go here http://www.rvmobile.com/Tech/Trouble/cooldoc.htm

[waiter]

.... it makes my refer happier!....

AND, if the frig is happy, the stuff inside (beer, pop, etc) is also happy

A small fan helping airflow will help improve the efficiency of the frig, just don't forget to turn it off. I would place the fan at the exit point, pushing air out.. :-)

AND - One of the side effects running the A/C, it will definitely increase airflow in the plenum. :-)

John Mc

88 Dolphin 4 Auto

[Guysakar]

Awesome thread. It is a little over my head though. I think I'm going to just opt for putting the AC unit in the passenger window (fabricate something to make it fit, etc...).

Question is, nobody has said how well the 5K BTU works?

Do you think a 5K BTU wall unit will work in Florida temps? If not, how about an 8K?

The roof unit that comes in these is around 8-9 K and I have heard people complain that they barely work well enough.

Any thoughts from someone who has a 5 or 8 K installed?

I will appreciate your feedback immensely. Thank you in advance.

[waiter]

5k, marginal for high temp, high humidity, during daylite. Ok for night. I used silver buble wrap in the windoiws, this helped a lot during day.

John

[5Toyota]

i did a pasenger window mount on my 78 minimax 5000 btu unit new 100 dollors had a guy make a metal table with a braket fit down over both sides of door with window down. then fitted around the outside of window and the A C a plate made of lexan and velcrowed on to the outside of the door. i stuck a small fan down on the floor behind the seats. worked very well daytime 75 inside 95 outside. at night very good my r v was 18 footer.

[5Toyota]

five thousand is about all that will fit in the window but if a guy built a stand i think it would be possible to use a larger unit. I live in a dry hot climate but water was pouring out of the back.

[paulnptld]

I think I've finally found the smallest available window mounted AC unit.

I'm going to yank my ancient rooftop AC unit and install this: http://www.amazon.com/Frigidaire-Window-Mounted-Conditioner-Full-Function-FFRL0633Q1/dp/B00IYQYN82/ref=dp_ob_title_hi

I have an efficient refrigerator that runs on 12v or 120, largely powered by solar panels and 2 deep cycle batteries. I'm going to use the existing vent on the RV for propane refrigerators and vent the AC unit that way.

Thoughts?

[Nam]

John MC and others in this thread have inspired me to move forward with this.

I am going to install this unit on my 1990 Itasca 21ft. This model has the least depth compared to any other units that I looked. http://www.homedepot.com/p/LG-Electronics-5-000-BTU-Window-Air-Conditioner-LW5012/203127491

Others in consideration is: http://www.homedepot.com/p/Frigidaire-5-000-BTU-Window-Air-Conditioner-FFRE0533Q1/205089536

This unit has remote control but it's 3" longer in depth. But it only draws 3.9Amp @120V

Once it's in, I may retrofit control with the wall mount unit thermostat. Will post progress as it goes.

[bicoastal eric]

Looking into doing this in my 1990 dolphin, any updates on its long term performance?

[linda s]

25 minutes ago, bicoastal eric said:

Looking into doing this in my 1990 dolphin, any updates on its long term performance?

They last as long as they would in your window at home. I have a Tiger Provan and the company used window AC's in the units. 1993 and it still gets cold.

Linda S

[jjrbus]

4 hours ago, bicoastal eric said:

Looking into doing this in my 1990 dolphin, any updates on its long term performance?

I put a 8000 btu in my 93 Sea Breeze and it is adequate in 95° very high humidity weather in FL. If you are looking for meat locker cold you may need a bigger AC unit.  Long term, I see no reason why it would not  last as long in an RV as a house.