Aqua heat systems

[Jim Blackwood]

With the hydronic (webasto) you don't have to limit yourself to either radiant floor heat or ducted heat, in fact a combination of both makes a very interesting option. The radiant heat will make the coach very comfortable and having switchable ducted heat would be great for the extra boost or OTR. Using diesel for the fuel source is very handy and not annoyingly loud. Routing the exhaust up to the roof should not be especially difficult either.

So far nobody has paid particular attention to speed control on the main heater core blower fan. (DL) This is a double ended DC motor that drives twin squirrel cages. Like all DC motors the speed is determined by the voltage, so a speed controller for it would be nothing more complex than  some type of voltage or current reducing device. The simplest would be a dropping resistor like on the blower fan in a car, but the most efficient would be a solid state controller which either reduces the voltage or chops it into pulses, both of which are now common and inexpensive. The PWM (pulse width modulation) controller is going to be the most energy efficient. I haven't looked at the amperage requirements but suitable controllers are listed on ebay in the $10-20 range.

Speaking of which, those can also be used on the condenser side of the OTR AC system to reduce power demands when stationary. Just find one that can use a thermocouple input to control output pulse width. And as I've mentioned before, those changes along with a household type sealed compressor can be used to convert the HVAC to shore use.

As for the hydronic plumbing, the system is not complex but needs to be considered in terms of circulation loops. You have 3 main loops to consider: 1) the burner loop, 2) the engine loop, and 3) the coach loop which btw includes the defroster loop (4). If you add radiant heat that is a fifth loop (5). Loop 1 feeds all the others which can be in series, parallel, or a combination of both. (Loops 3 and 4 are in parallel) Flow rates must be considered as well as a few other considerations.

It would be best not to allow unrestricted flow from loop 2 through loop 1 as this would bypass the main radiator.

Circulation through loop 1 should include at least one other loop at all times as otherwise you would dead-head the pump and could overheat the boiler, causing a safety shutdown.

Beyond that, other factors such as isolating the engine from the boiler while parked come into play. All this can be done without extensive modifications but some plumbing is required for an optimal system, which means draining the coolant.

It would also be possible to reverse flow through the HVAC system for heat-pump type operation but  I haven't really looked yet at how extensive the mods to do that might be. A typical heat pump uses shuttle valves and octopus plumbing where the DL uses TXVs so it really depends on the evap and condenser configurations, but at least in theory it should be possible.

Jim

[sledhead]

I had in floor heat ( hydronic ) in the M C I and when driving it was amazing . no noise and no blowing  of air just a warm floor . But it took a long time for the heat to come through the floor                    ( min. 1 hr ) and this was with 3 zones ( the complete floor of the coach ) and all heat loops at 7" apart with 1/2" pex heat link lines . I installed a forced air rad style heater as well that was 38 k out put and it helped to get the heat started .  All ran off the engine through a large heat exchanger and a pro heat boiler .
a very nice system but when camping and it was not that cold out most times I used cube heaters as it was instant heat and very easy to adjust .

On the featherlite I made my own boiler heating / water heater system from the same type of proheat boiler and it has been amazing but it heats the coach through under cabinet cozy heater box's of different sizes . It heats the coach up fast and is a lot easier to control the heat then in floor heat.
I have tenants that rent  and it took a long time for them to learn that you set the thermostat and LEAVE IT ALONE or you will be hot then cold . This is with a in floor natural gas heating boiler system

like said to have some options is nice when heating the coach and not just 1 heating source

dave   

[luvrbus]

I have electric floor heat controlled by the SliverLeaf,AquaHot with 3 zones and 8 heat exchangers, plus the heat pumps don't you know just what I need living in AZ