My hot water project

[rhyary]

Just to be different I wanted to get a hot water on my Land Cruiser my own way, stealing ideas left and right.

After quite extensive research I selected this made in the USA heat exchanger

 

[rhyary]

This unit is 3" diameter and 8" long for heat exchange itself but with the extra sides it total almost a foot.

In the process I learned a lot about heat exchange properties and how the components are named.
Heat exchange components:
The Shell is the outside cylinder you can see. It is made of brass and very strong.
The sides are called Bonnets and they are held in place with bolts. The bonnet on this one are cast bronze.

The two plugs you see on the left are zinc. They are used as sacrificial metal. They get corroded and are replaceable. They protect the copper, bronze and brass from corrosion.

the two top ports are the shell side. They are 1" threaded NPT. Very large. More on that later.

The inside called the tube side. The many tubes inside are held with two brass brackets. The brass brackets on both sides (inside, you can't see it in the picture) hold the many copper tubes parallel to each other.

You can select 1, 2, and 4 passes configuration and you can select the distance the tubes are held together. On the right side the bonnet has two 3/4" threaded NPT ports which use to access the the copper tube inside.

The more passes and the closer the tubes together, the less gallon per minute (gpm) you can push thru it, but the more efficient it is.
so the narrow tube placement 4 passes can do 12GPM. The car is about 4 GPM from what I learned. Well withing the most efficient configuration of the heat exchanger.

The shell side is the hot liquid being used to heat up. In our case is the Engine coolant.
The tube side is the liquid being heated. In our case cold water.

So the shell liquid goes into the port closest to the tube ports (right in the picture) and comes out on the port on the left.

The silver looking metal band is not part of the heat exchange. more on that later

 

[rhyary]

The location was chosen by TrickyT and found to be ideal. Right on top of the passenger wheel well under the Slee relocated windshield washer bottle.

 

[rhyary]

The fittings:
The 1" and 3/4 inch were a problem. Initially I went with a 1" to 1/2" bushing and 3/4" to 1/2" bushing.
But I was afraid of clearance issues.

So I found a place on line that had 1" thread to 1/2" barb and 3/4" thread to 1/2" barb. Perfect!!!

 

[rhyary]

Next there was a mounting issue
The heat exchanger needs to be mounting to a wheel well that is not straight, or perpendicular to the port.
This heat exchanger allows removal of the feet. As you can see in the picture.

 

[rhyary]

At NAPA auto store I found this marvelous exhaust bracket/strap that was perfect for my need.
They were very kind to me and allowed me to open the 3" strap (nop, too small) and the 4" strap (nop too big).
So they went to the back and got the 3 1/2" strap (yap just right!)
I had an old RAV4 serpentine belt. I cut two pieces to wrap the H-E with and mounted the strap around it. It gave a good rubbery friction and some vibration insulation. You can see in the picture how there is a space between the strap and the H-E

 

[Trollhole]

I like it. What did the heat exchanger run you?

 

[rhyary]

The bracket had a metal block that had to go. It did not let the bolts protrude enough.
The bolts were SAE and my Landcruiser takes metrics
So I replaced the bolts with JIT M10 14mm 50 or 60mm long (you can't see in this picture)
I first used two nuts to secure the bracket to the H-E. Then used another two nuts on the wheel side of the wheel well to secure it to the truck.

 

[rhyary]

The heat exchanger ready for install.
I threaded the fittings as much as I could. I used thread sealer.
In this picture it was only threaded by hand.
But the problem with NPT is that it is a tapered thread and you can't thread it much more. I wish there was a way to trick the threads and thread it all the way in.
Everyone I asked in the plumbing stores said it can not be done. Meh!

 

[rhyary]

The windshield washer bottle removed from its relocation place to allow access.
Notice how the brake line is in the way. Carefully position the heat exchanger underneath it.

 

[rhyary]

Next position the H-E into location. the shell out port with the fitting installed has to go under the brake line, so it needs to be twisted toward the firewall, go under, then rotate back up.

In the picture you can see a problem. Well I didn't and it created a problem.
You can see the bolts and where holes need to be drilled.
The ports are pointing straight up. But when you tighten the bolts, it rotated the H-E and the ports were pointing forward creating interference with the bottle (the bottle in the picture is moved to the side). So you need to start with the ports pointing slightly toward the back so when tighten the strap down, the rotation will move the ports into the correct straight up orientations.

 

[rhyary]

Next connecting hoses.
The ports are 1/2" brass barb, but the LX450 is a 5/8" pipes.

5/8" is an odd size and I had to use two brass fittings.
I had to use [5/8" barb to 1/2" male thread] and a [1/2" barb to 1/2" female thread] (not shown in the picture)
Since I did not have it, I had to mount the half inch hose on the 5/8" pipe. I was not happy about it but it will be fixed shortly.

 

[rhyary]

In this messy picture you can see the fresh water in and out on the bonnet (pointing toward the engine) and the shell side coming from the truck coolant side.

 

[rhyary]

It was not clear what to do with the fresh water hoses.
I wanted quick connect but not mounted outside the truck.
I wanted 1/2" hose to match the rest of the hoses inside the car.

I got pressure washer quick connects from Lowe's, but the female quick connect came with 3/8" female thread. No where were I live I can find 3/8" male to 1/2" barb.

Ordered this on line from the fitting place.

 

[rhyary]

Next I did not want to have female ports unprotected. So I got quick connect male with female 3/8" and plugged them with a plug.
I drilled 3/16 hole in the plug.
I went to West Marine and had them crimped 1/16" stainless steel cable which I secured to the air canister and a M8 nut.
I marked the cold side blue (into the H-E) and the hot side red (out of the H-E)
To use, I just undo the quick connect and leave the plugs dangling

 

[rhyary]

Next was to design the out side portion. The fresh water side.
I first got a small pump 1.1GPM.
I used a motorcycle battery and tested the pump in the sink. It looked ok but was hiding a problem I later discovered.
I took it to the shower and used it to test for the least amount of mount of water I can use.
Using one gallon I was left soapy.
I tried two gallons, used less soap, and that worked.
But I discovered something interesting with the 1.1 GPM pump.
As long as you are under it, it worked. But when you try using the shower head horizontally, as one would showering outside, the pressure was not strong enough to have the water flow horizontally. With not enough pressure you end up spending too much water trying to wash the soap off.

 

[rhyary]

So I returned the 1.1gpm and got a 4.5gpm pump.
The fresh water hoses are 3/8" and the shower head I.D. is 1/4" so the GPM is restricted by the small I.D but the pressure is great. Exactly what I wanted use small amount of water and enough pressure for water to come horizontally.

 

[rhyary]

It was time to test the efficiency of the system.

I filled 2 gal of 40 degrees water into my metal NATO container
I run the LX450 to normal temperatures and left it idleing.

The first test was to meassure how many passes it takes to get from 40 to 120.
I had two 5 Gal containers and I switched source and destination until I got to 120 degrees:
The shower head is on a quick connect and has 1/4" I.D.
For this test I did not connect the shower head, hence open hose is at 3/8" I.D.

1st pass 40 to 80
2nd pass 60 to 90
3rd pass 90 to 100
4 pass 100 to 110
5 pass 110 to 120.

This was not a realistic test becuase I wouldn't care about passes. But it was interesting to know that the first pass was the most effective. Typically the water will come from the car and will start at a higher temperature. At least in the summer.

 

[rhyary]

Next it was time to test a more realistic scenario.
Using 2 Gal of 40 degrees water in 25 degree ambient air temp, how long it will take to heat up to 120 degrees?

So configured a loop and run the system.

2.5 minutes to 120
4 minutes to 130
5 minutes to 140.

I stopped at 140.

Also I discovered that at 25 degrees outside all the plastic hoses I used were stiff and unyielding. So I converted to silicon hoses which are not effected by temperature.

 

[rhyary]

Final notes:
It took me forever to come up with all the details. But now I can do this in 60 minutes and few phone calls.
So if there is interest and 10 people or more want to sign up, I can put together a package with all the pieces and save you all the sourcing work.

Yes I know everyone will ask for price but at this point I am just looking if there is an interest at any price. It is not cost effective doing it one-off.
But I hope in quantity of 10 plus it will make sense.