hydronic idea

[Markusbc]

I just had a thought and wanted to know if anyone has done that or has a opinion on it.

When using a diesel hydronic heater (webasto, Espar, Proheat) to reduce cycle intervals its good to have a buffer tank for the clycol/water mix, my thought is what about using a domestic water heater (11gal for example) as a buffer tank, it could also act as a heater for the system when connected to shore power.

Anyone got any thoughts on that?

[rffffffff]

I have thought of this. Great plan. Insulated and increased the water volume and you can plug it in for assistance. Only downside is the footprint on a skoolie but if you have a place to hide it I think it’s a perfect plan.

Insulated under bus mounted tank with a heating element added would be awesome too but way more work to fabricate it, and I don’t think water heaters should be mounted sideways and strapped underneath!

[Markusbc]

I have under bus storage compartments that would fit it pretty well.
Just have to deal with the expansion tank and the pressure release valve. I guess the expansion tank (probably a domestic home depot one) near the "buffer tank" and a pressure safety release valve on the highest point of the system somewhere in the engine bay close to the coolant over pressure release valve. It should not need to release pressure unless something goes seriously wrong.

[john61ct]

Best to go multi purpose, both fluid to fluid heat exchanger, aka calorifier / HWS for showers etc, and

insulated thermal mass storage / buffer tank.

If grid powered AC electric is in the mix, then a powerful heating element takes care of everything, even in arctic conditions.

DC elements are much less powerful, it's a rare rig that should feed that off stored energy. However, if you have "excess" panel output otherwise regularly, going to waste, diverting SC output to (pre)heating the hydronic fluid may well save fuel while off grid.

A simple manual switch rig is the way to go, trying to fully automate this idea adds too much complexity, reduces reliability.

[john61ct]

And of course waste engine heat should be utilized if that wasn't already obvious.

[Markusbc]

engine heat is included with a heat exchanger.
hot water is via a kummo, marine hot water with heat exchanger
excess panel output is done via diversion of the bms automatic and really simple. Electrodacus bms.

[john61ct]

Originally Posted by Markusbc

engine heat is included with a heat exchanger.
hot water is via a kummo, marine hot water with heat exchanger
excess panel output is done via diversion of the bms automatic and really simple. Electrodacus bms.

Yes Electrodacus is an excellent - and very rare - BMS ÷ SC that includes such functionality.

Weirdly restrictive on choices of panels allowed though?

[Markusbc]

To my knowledge it has to do with the type of solar charging. Pwm vs mppt. I believe for a 24v system it Is a 60 module panel

[rffffffff]

You can interface electrodacus to victim mppt controllers too. Not sure how exactly but I’m gonna find out when my batteries arrive.

[Markusbc]

Yes you can. The reason why I was thinking of using the electrodacus solar chargers is because of their ability for diversion and price. I am sure the victron unit has a diversion as well but I have not looked into that.

[john61ct]

Ideally the Victron SCs could be controlled / redirected by the diversion function on the electrodacus

[cadillackid]

if you use say an 11 Gallon hot water tank full of coolant as a buffer tank be sure to account for expansion.. if this tank is part of the Bus coolant system its entirely possible that the engine coolant expansion tank is not big enough to handle the amount of expansion / contraction required.. you may need to increase its size so that the coolant level isnt too low when the engine is cold.. and shoots it all over the ground when the system is Hot.



if your heating system is closed loop then you can run a standard hydronic heating system expansion tank in your closed loop system. depending on your total system volume a 2 or 5 gallon AmTrol tank would do the job. drop its pressure down to 2 or 3 PSI empty and it would work well in a bus with coolant as the Juice.

[TaliaDPerkins]

Err, "victim" mppt controller?

[LargeMargeInBaja]

Originally Posted by cadillackid

...account for expansion.. if this tank is part of the Bus coolant system its entirely possible that the engine coolant expansion tank is not big enough to handle the amount of expansion / contraction required.. you may need to increase its size so that the coolant level isnt too low when the engine is cold...

.
Like this?

[Markusbc]

On my build the two system are separate loops only connected with a heat exchanger that. Like cadillackid suggested I am thinking of using a standard domestic expansion tank. Thank you for the tip about reducing pressure. Still adding a second standard overflow and expansion tank on the highest point of the system for filling and monitoring levels.
I just added a arduino that will switch on pumps when i want to preheat the engine or the other way around if i want to heat the "house" loop with the engine and not fire the diesel heater or shore power. Arduino used to monitor temperature and switch pumps on accordingly.