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In researching the appropriate size of glycol/water heat exchanger to use with my Espar B5E CS I'm not finding many resources and am curious if folks here have recommendations or experience on what configuration would work well to keep a shower running hot.

What I have found is:

My general system specs:
  • SEAFLO 3.0gpm 55psi pump prior to the heat exchanger.
  • 1.75gpm shower head mated with a thermostatic mixing valve.
  • Eberspacher / Espar B5E CS whose water/glycol pump specifies 'water delivery rate of >= 500 l/h' (~2.2gpm)
  • - 1/2" PEX throughout the system

I understand getting a specific scientific answer involves the flow rates and input temperatures on both sides of the heat exchanger, the heat exchanger surface area (plates being a poor proxy), and likely a few other variables. What I'm aiming for is an empirical recommendation, though if someone has the background and chops to do a calculation, more power to you! 馃挭 Thanks all.
 

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I have several of those links bookmarked as well 馃ぃ
This is what I based my purchase off of:
Rectangle Font Parallel Technology Screenshot


it's from one of the sportsmobile forum posts you linked. I think it's the same guy that sleuthed the 10 plate model number from the rixen system that you linked.
I chickened out a bit and up-sized mine to B3-23A 40 Plate Heat Exchanger with M8-1.25 Mounting Studs, 12" x 2.9", 0.92 m2 Total Surface Area. It seems to be of similar size to the one heatso sells, but more plates. And the reviews in the scintex page seem to indicate that their 30 plate is indeed good enough for showers, although they're implying that you run it off of your car's coolant loop rather than an espar so that may affect performance.
Unfortunately I just started my build so I can't report back yet how it works.

My Rixen's setup produces water the would be dangerously hot if it didn't have a tempering valve. I don't know the actual spec of the flash-plate exchanger, but if your data are correct, then...
Do you happen to know the part# of the plate heat exchanger or measurements of it - does it look like this one?
 

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This is about all I know about this subject - maybe this will help...
 

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2020 148wb AWD
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In researching the appropriate size of glycol/water heat exchanger to use with my Espar B5E CS I'm not finding many resources and am curious if folks here have recommendations or experience on what configuration would work well to keep a shower running hot.

What I have found is:

My general system specs:
  • SEAFLO 3.0gpm 55psi pump prior to the heat exchanger.
  • 1.75gpm shower head mated with a thermostatic mixing valve.
  • Eberspacher / Espar B5E CS whose water/glycol pump specifies 'water delivery rate of >= 500 l/h' (~2.2gpm)
  • - 1/2" PEX throughout the system

I understand getting a specific scientific answer involves the flow rates and input temperatures on both sides of the heat exchanger, the heat exchanger surface area (plates being a poor proxy), and likely a few other variables. What I'm aiming for is an empirical recommendation, though if someone has the background and chops to do a calculation, more power to you! 馃挭 Thanks all.

I have the heatso kit with the mixing valve, it works well. I have to use the mixing valve to not have too hot of water coming out. i don't really see a downside to just using that, since you will likely need a mixing valve anyway. there are review videos on the rixens kit, and it has been recommended to add a mixing valve to them.
 

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Yes, I'd call the mixing valve a must for anything being supplied an otherwise unregulated heat source from the engine, but it's never a bad idea to have a mixing valve in place somewhere at the end of the heat circuit either way. It also apparently adds a volume of water to your HW loop by being able to interject or add some cold water to the mix, increasing the overall volume available to you HOT while tempering it to a more safe and usable level.
 

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We have a Rixen system with two heat exchangers --> the first is a double wall exchange t: W=2" L= 7" 3/4 H= 4" 7/8 with a much needed mixing valve for main sink; the water directly from the exchanger is ~140 Def F so need to lower to about 110 Def F with mixing valve. Next in line is an air heat unit and then a single wall exchanger W= 1" 3/4 L= 7" 7/16 H= 4" 3/8 that is used for a shower with a shower mixing valve.

Double wall exchanger and air handler:
Audio equipment Computer hardware Trunk Electrical wiring Circuit component

Second single wall exchanger for shower:
Trunk Automotive tire Motor vehicle Automotive exterior Gas
 

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2016 Transit, 148", Medium Roof, 15-Passenger (originally), EcoBoost
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We have a Rixen system with two heat exchangers --> the first is a double wall exchange t: W=2" L= 7" 3/4 H= 4" 7/8 with a much needed mixing valve for main sink; the water directly from the exchanger is ~140 Def F so need to lower to about 110 Def F with mixing valve. Next in line is an air heat unit and then a single wall exchanger W= 1" 3/4 L= 7" 7/16 H= 4" 3/8 that is used for a shower with a shower mixing valve.

Double wall exchanger and air handler:
View attachment 166076
Second single wall exchanger for shower:
View attachment 166081
That rixen provides as much on demand water as your fresh water tanks allows, correct? It鈥檚 not heating water and storing right?
 

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That rixen provides as much on demand water as your fresh water tanks allows, correct? It鈥檚 not heating water and storing right?
Correct - the rixen system I installed is on demand, all water heated thru a heat exchanger. When started it takes <5 minutes for the exchanger to be hot enough for hot water. You do not need to run the water just wait until the exchanger is hot.
A heat exchanger system can also be used to pre-heat a tank of dedicated hot water by tying into the van heating system, as you drive the stored water is heated. Depending on the type of tank the water can stay hot for 1-2 days. There is a good youtube example video by Van Land (upfitter located in Northern CA) showing there undercarriage tank system.
 

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Not to highjack, but when I searched and found this discussion I thought one of you might have an answer鈥

I have a Rixen鈥檚 system with the 10 plate exchanger鈥 what have you found to be a good shower head flow rate (gpm) for an uninterrupted supply of hot water?

I think for my needs I鈥檇 rather try to find the appropriate flow rate rather than attempting a larger exchanger (cost, plumbing, space and such). I currently have a nice High Sierra 1.5gpm handheld with trickle valve鈥 it provides good pressure... and though inconsistent does provide a decent warm shower using the on/off trickle valve. I鈥檝e talked with a Tech at High Sierra and evidently the design of these already low flow heads don鈥檛 work well with common flow restrictors, which I鈥檝e tried without significantly changing the flow.

Bricor makes a 0.7, 1.0 and 1.25鈥 and High Sierra鈥檚 1.25鈥 but they are expensive, so I can鈥檛 play around with what works best.

Anyone have a flow rate that works best with this system?
 

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Well it depends... If you actually getting 1.5GPM at the shower head and the water temp rise is room temp to about 120deg it will be pushing a 10 plate heat exchanger to keep up (but it does depend on the rise in water temp i.e. how hot you want your shower to be). I believe a 10 plate exchange is rated at 20k BTUs. If you want 120 deg water and start with room temp I would suggest <1.5GPM. We are using <1.5GPM rated shower head with 50psi pump but I cannot remember the actual rating and no problem keeping water hot.
 

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In researching the appropriate size of glycol/water heat exchanger to use with my Espar B5E CS I'm not finding many resources and am curious if folks here have recommendations or experience on what configuration would work well to keep a shower running hot.

What I have found is:

My general system specs:
  • SEAFLO 3.0gpm 55psi pump prior to the heat exchanger.
  • 1.75gpm shower head mated with a thermostatic mixing valve.
  • Eberspacher / Espar B5E CS whose water/glycol pump specifies 'water delivery rate of >= 500 l/h' (~2.2gpm)
  • - 1/2" PEX throughout the system

I understand getting a specific scientific answer involves the flow rates and input temperatures on both sides of the heat exchanger, the heat exchanger surface area (plates being a poor proxy), and likely a few other variables. What I'm aiming for is an empirical recommendation, though if someone has the background and chops to do a calculation, more power to you! 馃挭 Thanks all.
The variability is why you should have a mixing valve after you heat your water.

I think the Rixen system uses the 10 plate heat exchanger because after that glycol goes through the 10 plate heat exchanger it flows to the air heater. If you are also using the hydronic system to heat the air in the van you don鈥檛 want to pull off all the heat before it goes to heat the air.

I have/installed the Rixen system and have a mixing valve, so I can adjust the water temp if I need to cool it down or heat it up. That said I will be insulating all my glycol tubing, the glycol tank, and the heat exchangers.

Here is a link to the Rixen mixing valve.
Here is a link for the Rixen Heat Exchanger.
Here is a link for the Rixen mounting bracket

As you progress in your build you will appreciate any device/component that comes with a mounting bracket and curse those that don't. Mounting the mixing valve using pex was a bit of a brain tease, but I solved it with two large hose clamps. Just did not feel comfortable with the pex holding up the mixing valve in a constant earthquake/van.
 

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We have a Rixen system with two heat exchangers --> the first is a double wall exchange t: W=2" L= 7" 3/4 H= 4" 7/8 with a much needed mixing valve for main sink; the water directly from the exchanger is ~140 Def F so need to lower to about 110 Def F with mixing valve. Next in line is an air heat unit and then a single wall exchanger W= 1" 3/4 L= 7" 7/16 H= 4" 3/8 that is used for a shower with a shower mixing valve.

Double wall exchanger and air handler:
View attachment 166076
Second single wall exchanger for shower:
View attachment 166081
Why the single wall for the recirculating shower? I thought the single wall was in tended for glycol to glycol/ engine heat to Rixen hydronic system.
 

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Why the single wall for the recirculating shower? I thought the single wall was in tended for glycol to glycol/ engine heat to Rixen hydronic system.
Correct typically used for engine loop. The shower water tank temperature rises during a recirculating shower, in addition we have a low GPM nozzle. After discussing the design with Jim Rixen, he said the single plate should work and it has worked fine. During a shower you do need to dial the temp down on the shower valve a bit e to help regulate the shower.
 

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The variability is why you should have a mixing valve after you heat your water.

I think the Rixen system uses the 10 plate heat exchanger because after that glycol goes through the 10 plate heat exchanger it flows to the air heater. If you are also using the hydronic system to heat the air in the van you don鈥檛 want to pull off all the heat before it goes to heat the air.

I have/installed the Rixen system and have a mixing valve, so I can adjust the water temp if I need to cool it down or heat it up. That said I will be insulating all my glycol tubing, the glycol tank, and the heat exchangers.

Here is a link to the Rixen mixing valve.
Here is a link for the Rixen Heat Exchanger.
Here is a link for the Rixen mounting bracket

As you progress in your build you will appreciate any device/component that comes with a mounting bracket and curse those that don't. Mounting the mixing valve using pex was a bit of a brain tease, but I solved it with two large hose clamps. Just did not feel comfortable with the pex holding up the mixing valve in a constant earthquake/van.
I'm looking at putting a Rixen system in our van for water heat and air. I will also have a heat exchanger for the recirculating shower.
With the rixen system can you control how hot the system heats the glycol?
Also what about valves that let you turn off different parts like one heat exchanger or the other or the air heater part? I know it would add a little complexity but it seams like it may be more efficiant that way and not create hot air when it is 80+ already in the van.
 

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I'm looking at putting a Rixen system in our van for water heat and air. I will also have a heat exchanger for the recirculating shower.
With the rixen system can you control how hot the system heats the glycol?
Also what about valves that let you turn off different parts like one heat exchanger or the other or the air heater part? I know it would add a little complexity but it seams like it may be more efficiant that way and not create hot air when it is 80+ already in the van.
Yes the Rixen system will tell you the input and output temperature (at furnace) of the glycol mix. On there website is a description of the values that are measured.
Regarding being able to turn off different parts of the system, that will require a 3 way valve. I have seen it on the forum for engine loop integration, but I cannot remember what thread - might need to do some searching. I assume by creating hot air you are referring to when you need to heat water; it will create radiant heat from the exchanger and coolant hoses and you want to minimize this? When just heating water I do notice some radiant heat from the cabinet the HW is installed in, overall it is not much but the drawer above the rixen install can get a little warm. Have not noticed it contributing to unwanted heat in the van.
 

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