Hydronic vs. Non-Hydronic Heating. (Air & Water)

[moosevan]

Ok this is the circuit I have planned for my hydronic install. I would be grateful if those in the know could critique it.

I am planning a radiant floor as well. If possible I would make the floor loop last so that there is a buffer tank and the temperature difference isn't so great.

 

[Dannyboyski]

I am planning a radiant floor as well. If possible I would make the floor loop last so that there is a buffer tank and the temperature difference isn't so great.


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Good shout. Do you know what valve you intend to use on the underfloor loop?

 

[Coachgeo]

I am planning ... Sent from my SM-N950U1 using Tapatalk

looks like you need to edit your previous response...... cant tell where quotes stops and your comments start

 

[Joe917]

The idea behind the whole engine disconnect is In the summer time, when you want to run the D5 to make hot water, you don't also have to heat the engine mass as well!

You asked about engine on, valve closed, diesel heater off.

 

[Joe917]

Use a manual valve for the floor loop and all radiators and a thermostat to control cabin temps.
Get rid of the blower matrix and replace it with a radiator or two.
Take the vehicle blower matrix out of the camper loop.

 

[Dannyboyski]

Use a manual valve for the floor loop and all radiators and a thermostat to control cabin temps.
Get rid of the blower matrix and replace it with a radiator or two.
Take the vehicle blower matrix out of the camper loop.

Thanks Joe, appreciate your advice.
One detail I need to hammer out is the valve for the floor loop. Obviously I don't want 95c coolant (from the engine) in the underfloor loop... it needs to be a lot less. i am told underfloor valves can regulate the temps accordingly.
I'm concerned if I remove the matrix I will lose the ability to get the van warm in v cold weather.
Just figure if I can use the vehicle blower as its there anyway, why not? the cab area gets quite cold anyway because of all the glass. A bit of extra heat up front seems worth it. (and I appreciate your system won't lose the vehicle heater function, it was a silly question in hindsight)

Db

 

[nathane]

Two observations.
Don't use electric valves, they will fail at the wrong time, (they will fail, not might fail). An easily accessed manual valve is far better. Failure of one valve in your diagram could shut off the engine cooling loop.
You don't need 4 valves, just 1. Change your valves in the diagram to "T"s and add a single manual valve between the two loops. The single valve stops coolant circulating in one loop from circulating the other loop while allowing fluid to expand into the header tank. It does not matter which side you put the valve. you could put two valves (one between each T) for maintenance, but you only need to close one for operation.
That is our set up, the shut off valve is placed behind the driver's side front wheel.

Thanks Joe, good point. 4 is unnecessary overkill and failure prone, daft of me not to see.

 

[brianjwilson]

I haven’t used a hydronic system to take my opinion for what it’s worth. I spent a lot of time weighing options for building out my new sprinter. I like the concept of hydronic for the obvious reasons, but it seemed heavy, complex, and to use a fair amount more fuel and electricity than a heater alone.

In all of my other campers (propane fueled), I rarely used the water heater. Occasionally I would run it for short showers. Or just run it for a bit in the morning to have some warmer water for washing things. I use the furnace a lot though. It did not seem to make sense to be needlessly heater a bunch of water when I wouldn’t be using it much. As also stated, modern diesel fire right up well below freezing temps so preheating isn’t much of a concern. I also do not care to have air heat and water heat all tied into one system. If it fails, you use two separate functions.

SO I chose to install an espar d2, and I’ll be installing an isotemp slim square water heater. It is a 4 gallon water heater with a 110v heating element and a built in coolant heat exchanger. We tend to drive daily, so the coolant passing through will heat the water in the tank. 4 gallons of hot water should mix into enough for quick shower, hosing off kids at the beach etc and stay warm for a decent period of time. If needed I can run the water heater off of the inverter (not ideal but doable) or run the van (high idle option) and heat the water quicker, charge batteries etc whatever the case.

Meanwhile the espar d2 has been awesome. Programmable thermostat, sips fuel, low power draw. It will slow down to low heat and pump out steady warm air for hours. It’s light and small. I have mine ducted to an outlet in the front and the rear of the van and it is a very even consistent heat.

 

[Dannyboyski]

I disagree that hydronic is heavy. Do the sums, a 30m underfloor loop with 12mm HEP will contain 1.9 litres of water.. (surprisingly light). Granted you need a bit of 15 & 22m HEP to get the coolant to the inlet / outlet. which weighs marginally more.

Also the reason it uses more electricity is the fans & coolant pump. Many are trying to achieve a system that can handle milder temps without the fans, which brings the power usage more inline.

I imagine you will have plenty of hot with your isotemp square. Good luck with the install.

Anyway I may have hijacked this thread a little..... Apologies.

 

[part time nomad]

Alde heating! wet system runs on gas on mains electric, couple a heat exchanger to the engine and also a deisel webasto and you have 4 sources of heat & water using the same system.

 

[Joe917]

When you order your water tank I would suggest the smallest heater element available. This way your solar will be able to heat the water when you have excess power, too big an element will put an unacceptable load on the batteries.

 

[EMTacoma]

Quick question on this. We've been getting ready to overland in our 2001 7.3 Excursion. It struggles to start below 32F, and even with newer dual Odyssey batteries and newer glow plugs, it can be a bit of a chore to get it started. We don't want to be stranded, so we are considering the Espar hydronic D5 for engine preheating.

We also would like to have our kids (ages 1,3) stay in the back of the excursion on cold winter nights rather than in our rooftop tent.

If we hook up the Espar hydronic and have the truck in accessory mode with the rear heat turned on low, and the Espar circulating warm coolant, will the heat work? I realize there would be some draw on the battery with the blower fan running all night, and will check that prior to buying the Espar. I'd like to avoid installing additional blowers and coolant loops if possible, but haven't seen anyone using the existing vehicle ducting with the engine off.

The other option would be to purchase both an airtronic and hydronic to cover the interior heat and engine pre-heat, but I'd prefer to avoid the additional expense if possible.

 

[grizzlyj]

snipped

but haven't seen anyone using the existing vehicle ducting with the engine off.

I'm fairly sure that's a standard option with the likes of Espar so with the built in timer on the control panel you get a warm interior and a pre-heated engine. You could also run a loop around your batteries, or Arctic Cat do an under battery tray to link up to the hydronic circuit.

 

[Pinnacle Campers]

Quick question on this. We've been getting ready to overland in our 2001 7.3 Excursion. It struggles to start below 32F, and even with newer dual Odyssey batteries and newer glow plugs, it can be a bit of a chore to get it started. We don't want to be stranded, so we are considering the Espar hydronic D5 for engine preheating.

We also would like to have our kids (ages 1,3) stay in the back of the excursion on cold winter nights rather than in our rooftop tent.

If we hook up the Espar hydronic and have the truck in accessory mode with the rear heat turned on low, and the Espar circulating warm coolant, will the heat work? I realize there would be some draw on the battery with the blower fan running all night, and will check that prior to buying the Espar. I'd like to avoid installing additional blowers and coolant loops if possible, but haven't seen anyone using the existing vehicle ducting with the engine off.

The other option would be to purchase both an airtronic and hydronic to cover the interior heat and engine pre-heat, but I'd prefer to avoid the additional expense if possible.

I have a Espar hydronic only unit in my E350 van. I have the rear HVAC unit running off the "coach" batteries with a separate switch and thermostat. I can also run the front dash vents/controls with the key in acc position in engine preheat scenarios or to move more air/defrost windows without the engine running.
Having the separate airtronic/hydronic units would be nice for the redundancy with young kids around.

 

[EMTacoma]

I have a Espar hydronic only unit in my E350 van. I have the rear HVAC unit running off the "coach" batteries with a separate switch and thermostat. I can also run the front dash vents/controls with the key in acc position in engine preheat scenarios or to move more air/defrost windows without the engine running.
Having the separate airtronic/hydronic units would be nice for the redundancy with young kids around.

Excellent, that's exactly what I was looking for. I'll try running the vents for 12 hours or so in <32F temps to see what the drop in battery voltage would be. Then my first step will be to install a hydronic, and if that isn't sufficient, go for the airtronic also. The Excursion has a 44 gallon diesel tank, so I'm less concerned about the higher fuel consumption by pre-heating the engine overnight.

Do you have a write-up on how you hooked up the rear HVAC to the coach battery? That sounds like it might make sense to look into.