chinese diesel Water heater

[cadillackid]

the DTA360 even with the shutters closed cools down at idle if I have 2 inside heaters on high.. I dont like to idle it in a cool state so if I run the webasto also it keeps the engine temp up above 160 where im more comfortable.. setting the webast at 75c means the Tstat stays closed on the engine and the webasto cycles out so i dont waste heat in the radiator..



the no glow plugs arent an issue after the engine is running. at 0f with no start aids she starts hard.. vie done it but its a lot of cranking and chug-et-A-Chug-et-A which is hard on starter, batteries, engine.. so typically ill start the webasto up and let it warm the engine allowing it to light off pretty quick..



once its running it will stay running no issues..



this year i have a 16kw webasto (chinese) instead of a 12kw so ive increased my engine-off heating capabilities quite a bit.. I also added 200 Ah@12VDC more battery power so running another blower or 2 wont cause me issues with running down the batteries.. I have 400Ah of house batteries (AGM) and 200 Ah of starter batteries(AGM). this should give me lower temperatures at which I dont even need the engine when im running stopped as a mobile office


remember its a 7 window All-stock factory windows, factory walls, factory ceiling, factory doors.. high headroom 31 year old bus so it is not very efficient.. and again I like it TOASTY.. most people would probably bundle up a bit and turn the heat down..



your counter-flow is like my main flow.. my webasto is piped so that the output of it goes straight to the rear heater (my Jegs heater).. I have dual pumps.. one at the webasto itself and one at the rear heater (Davies-Craig pumps which are efficient and near silent).. so my cabin heater gets the heat first.. after that rear heater the water enters the main trunk headed forward where it passes by the feed for the Mid-heater, if i turn omn the mid heater its valve opens and that is a Large heater core.. so water will go through it and then back into the trunk line headed toward the webasto.. since that heater is so large that water is pretty well zapped so i wanted it to head back rather than go on toward the front.. any water that doesnt enter the mid heater heads forward passed the driver console and then under the hood.. (these are trunks so if the driver heater is off its valve is closed and the water goes by without entering) under the hood some water can flow through the step-well heaater and the rest gets returned back toward the webasto...



if I open the engine valves then some of the water can flow through the engine.. a small amount will unless I turn on the factory Booster pump which then sends more engine flow into the mix..



what I end up with is a reverse to front priority on heat from the webasto.. and a front to back priority on heat with the engine on..



normally the webasto is only on when im parked and in the back.. when the engine is on im usually driving and want most heat in front..



I do sometimes run the webasto on cold mornings driving just so I dont have to wait for heat.. i get it right quick..



the way I have it means I dont have counter-flow.. the only counter-flow occurs in individual heaters and not the whole system.

[Peterjk]

Thanks everyone.
I've now learned quite a bit on heating a bus without propane. Although the cooktop still might have to be, but that's a discussion for another time.


1. I'll be using coolant [not water] and the built in heat exchanger inside the Kuuma 6 gal tank to heat up water while the bus is running.

2. When the bus is stationary and eng not running, I'll be using the diesel heater to do the same. Heat coolant to heat up the Kuuma and thus water.

3. The existing coolant refill reservoir will be used to add additional coolant so this issue has been answered.

My last question to clear up is on the direction of the coolant flows. As I understand it from reading, from joeblack5 " With the webasto the flow is opposite."

First some notes first on my bus. Its a 10 window rear engine Thomas, with a cat 7.2L which holds 4 gals of coolant.
At the engine, there is a coolant shut off valve, which prevents the flow of coolant to the bus interior. I usually have it off, so no flow to the interior. It will need to be OK or open anytime were heating water in the bus.

[My observation side-note. At 4 gals of coolant, this is allot of coolant to first heat up, in order to heat up some water, just an observation]

Im attaching a hand drawn flow of coolant and where the devices might be installed. The flows indicated are with the engine running.

As I understand it from joeblack5, with the engine OFF, that flow is reversed.

Engine running picture:

Pictured flow, coming out of the engine, while its RUNNING, were going into the Kuuma 6 gal tank and exchanging heat there w the hot water line, then we come out and we go into the diesel heater, which is OFF while the engine is running, we then go to the front of the bus and the heater core, and come out and go back towards the rear and the engine radiator. [i didnt label the Kuuma, it is the square that shows the exchange with H2O]

Engine not running. No picture. But the flow is reversed, starting at the diesel heater, we go to the Kuuma tank to exchange heat with the water, then go to the engine....

[joeblack5]

Sorry , that I was a bit confusing.. I choose to have a reverse flow so that the heaters pump would see the lowest temperature possible and also to heat the engine up more efficient, at least on theory.

So if these reasons are less important to you then you can set it up in the same flow direction.

With your sketch in mind, our bus has the defroster in parallel with the engine connections. All my additions are in the loop that feeds the rear radiator.

For ck,
The point I was trying to make is that if you run higher electrical loads of the alternator then you will get a lot more heat out of the engine.

Johan

[Peterjk]

Aha! : )
re: Sorry , that I was a bit confusing.. I choose to have a reverse flow so that the heaters pump would see the lowest temperature possible and also to heat the engine up more efficient, at least on theory.


I thought it was a necessary design, NP.


So in my not so artistic diagram, in that case, I would place the diesel heater BEFORE the Kuuma, thus keeping the flow same as when the engine is running.

Just a side note. I plan on replacing the Kuuma's 110v ac temp probe heating element with a DC 32v 1000w element which will be powered by my solar diversion system.
Im not using alternator power at all.

[Rock-N-Ruth]

Originally Posted by Peterjk

RE: I like the idea of being able to use "free" heat from the engine or "free" excess solar when available, but have a fallback heat source.

Me too : )

So My electrrocacus Solar system [electrodacus.com] does precisely that , it can divert excess solar when available TO any destination, like a 36V heat element to heat water.

So why dont you just go with that you ask?
Because I'm still in the design stage of the plumbing build, and I am not sure, IF there will be enough "free" or "excess" solar, given 4 305w panels, two each in parallel, to give me enough hot water. That "diversion" method is designed when you have many more panels then a Schoolie can accommodate, as I am gleaning.

"Heating those 6 gallon / 22 liters from say 20C to 60C will require 22 * 40 * 1.16 = 1.02kWh of energy so around one hour from 4 panels when in full sun. According to speck about half of that energy will be lost in 24h if water heater is not powered." electrocacus boards

But given what I know now about diesel HEATER for air, not water, they are super reliable and IF they could be harnessed to provide near instant hot water in a reasonable time frame, then perhaps, coupling a diesel water heater, with a solar diversion system, would cover all the bases.

Questions.

What type of water tank can I go with, any suggestions ? A conventional 10 gallon 110v tank, then replace the heating element with a 36Vdc one ?
Could I then use the diesel WATER heater to heat the water going into the tank. Meaning, I get up in the morning, start the dieseI water heater, and wait till the water is hot enough, then shut it off. Could that scenario work? Then additional heating could be done with solar Diversion.

Ruth and I have 4k of solar and a huge LFP battery bank. We could heat our water with electricity if we wanted to. We dont. We would rather use that bounty of solar power to cool our bus on hot days and warm it on cold days.
Instead we use this: http://18L 4.76Gal Tankless Water He...XPBWJWRAMTDNCP

It is a fuel sipper and makes water hot enough for tea if we like. The price point is great.

[cadillackid]

All of the diesel heaters air and water have a pretty low efficiency rating as far as heat produced bs heat in the cabin.. an EGR cooler outfitted to the exhaust pipe could be used to heat coolant.. and the unit would still heat the air too.. of course in summer this model doesn’t work well