Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
The Trithermogulator

Leave a Comment
Categories
- 80.9K THE MAIN WALL
- 2.5K A-C, Heat Pumps & Refrigeration
- 36 Biomass
- 394 Carbon Monoxide Awareness
- 2.6K Controls
- 1.4K Domestic Hot Water
- 3.7K Gas Heating
- 100 Geothermal
- 130 Indoor-Air Quality
- 2.3K Oil Heating
- 30 Pipe Deterioration
- 563 Plumbing
- 4.2K Radiant Heating
- 333 Solar
- 12.1K Strictly Steam
- 36 Water Quality
- 7 Industry Classes
- 51 Job Opportunities
- 7 Recall Announcements
Comments
Everyone always seem to think it's a bad idea, so I fleshed out an example that I hope is detailed enough to serve as reference for a useful discussion. This particular version relies on fixed synchronized flow rates and dual parallel ODR curves to control the storage and distribution of thermal energy to and from all parts of the system.
A common critique of this arrangement relates to a potential conflict in the supply temperatures required for the indirect tank and space heating system. An ODR curve that dips below the tank storage temperature would seem unwise, as surely this low temperature water would unproductively cool the DHW during a call for heat.
However, equal flow at the left and right of the trithermogulator results in 0 flow through the DHW storage tank heat exchanger, preventing space heating water temperatures from mingling with DHW storage. This can be readily accomplished if the boiler and system flows share a common range of acceptable fixed flows.
Thoughts???
trainer for Caleffi NA
The magic is in hydronics, and hydronics is in me
If no flow goes through the tank during a space heating call, how then does it serve as a buffer during space heating? That is the object we're shooting for: to provide buffer during space heating to prevent short cycling.
You can choose to do what you want, but you cannot choose the consequences.
I also typically wouldn't select this specific version of the Trithermogulator as being notably useful beyond the others, but I think this fixed flow version makes the analysis straight forward while being immediately relevant to JustinS.
If no flow goes through the tank during a space heating call, how then does it serve as a buffer during space heating?
Your question leads into Part 2.
Earlier I described the synchronized flow rates present while the boiler is responding to a space heating call. Once the ODR target is reached, the onboard controls obviously shut the burner down. At this point the boiler pump should also stop while the system waits for the boiler differential limit to kick the burner back on again.
Let's look in detail at this boiler standby phase of the heating cycle. There is no flow through the primary. The system loops are still on though. This implies that fluid is now being diverted up through the indirect tank's heat exchanger. The boiler has effectively handed off the work to the indirect while it waits in standby. The mix valve modulates the flow of energy from the thermal storage, acting to maintain the parallel ODR target curve temperatures delivered to the emitters.
@Ironman To answer your question, there is indeed flow through the tank during a space heating call, but not while the boiler is responding to it.
You can choose to do what you want, but you cannot choose the consequences.
JMHO.
Rob
I would just as well stay away from the type of zoning / micro zoning of those small loads.
Really folks radiant can be very simple, effective, and elegant in its simplicity. It seems more, and more some try to apply new hardware to some systems that can be very simple. These are tools in a designers tool box. It's not necessary to use them all.
Bottom line it goes back to the beginning of initial design.
Heat loss
Boiler sizing
Emitter selection
Piping
Control strategy
If zoning is desired design your zones as to not be below min. Modulation of selected boiler.
I'm not so sure a tank in a tank indirect would fare well as a hydraulic separator I think the mixing, and flows would not be consistent as with a regular hydraulic separator, or a buffer tank.
I'm not so sure a tank in a tank indirect would fare well as a hydraulic separator I think the mixing, and flows would not be consistent as with a regular hydraulic separator, or a buffer tank.
Can you think of example that might cause an issue? A problem I see is ensuring the flows in the primary and secondary remain truly equal, but I'm not sure if it's a significant issue.
You have an idea someone needs to make a tank with your desired tappings to do it.
The Trithermogulator uses two connections on the tank. It uses the tank as is. The tank does not need new tappings. A tee is put on the top connection and another tee is put on the bottom connection.
The smart multi energy has the hot going into the top.