Zones, Micro loading, Modulating boilers(jalcoplumb)

jalcoplumb_7

What is up with the whole zone thing with Mod/Con’s? I see so many folks zoning the crap out of systems to save money.

When you micro load any boiler and make it turn on and off a lot, you do not save money.

I hear it all the time from customers. "I can turn down the temperature to the rooms I am not using in order to save money." Not really. Maybe if you have electric baseboard heat you can.

I was just in a house before I deployed. It was all of 55,000 btu with three zones. On the mild days it was cycling like crazy. It had radiators.

OMG, how about a mod/con one zone w/ constant circulation and outdoor reset to boot. Oh yeah, not to mention a properly sized boiler. Not the 100,000 btu CI monster that was installed.

I was installing a stove, when the customer asked why the new boiler was cycling all the time. Did I forget to mention the heat anticipators were never set properly to boot?

Please tell me it bothers you too.

Joe

WaterHeaterGuy

I may have an agenda...

... but I don't mind at all. Then again I sell a buffer tank just for these types of applications

I do have to disagree with you about people doing it to save money, I find more people doing it for comfort. They want to have the abilty to control each and every damn room.

ALH_4

Control

IMO, there is a natural human tendency to over-control.

I still think for most homes, constant circulation with TRV/FVH's is the ideal system.

Steve Ebels_3

I think

In parts of Europe, I've heard that any room over 100 sq ft, or something like that, is required to have its own thermostat. Must be something to turning down the room(s) you're not using. Ya think?

Mike T., Swampeast MO

You've just stated perfectly (and only one reason) why I keep suggesting fully TRVd system with true constant circuation with mod-cons.

In normal operation the mod-con will see the ENTIRE structure as the load.

The user will see such a system as being independently zoned on a room-by-room basis; the mod-con however will see only a single "zone".

I've checked with nearly every manufacturer of mod-cons available in the U.S. and ALL can be used in a fully TRVd system without a wall thermostat. If the boiler has thermostat connections, merely jump them--do however use a warm-weather shutdown control as the "thermostat" if the boiler's controller does not have such built-in.

ALH_4

Comparison

Obviously, there is something to turning down each room. Cooler room = less delta-t across the wall = less heat loss.

Hypothetically, let's take relatively rectangular 2-story house with a Vitodens with constant circulation and TRV's on steel panel radiators and the RS control. (I pick on the Vitodens because it is designed specifically for this type of operation)

Compare that to the same house with another mod/con with a tN4 control, single pump, zone valves, and a thermostat in each room.

Compare that to a mod/con with a 3-way mixing valve on each zone with an indoor temperature sensor controlling each mixing valve.

Would there be a difference in fuel use for those scenarios?

It seems using a mixing valve for each zone would be the most efficient thermally, and may be the most comfortable, but each mixing valve requires a pump, increasing the electricity consumption dramatically.

The other two scenarios are much more difficult for me to compare based on energy efficiency. I know the simplicity of TRV/FHV's with constant circ is very appealing to me.

Mike T., Swampeast MO

In your hypothetical situation a Vitodens I honestly see no need for an RS-remote unless the panel rads were sized at above 180F supply temp.

Why?

Just think about it for a moment. Viessmann ONLY recommends the RS-remote for systems with low mass/volume emitters. Even without TRVs, the Vitodens does an amazingly good job of maintain space temperature without sensing space temperature. Such has been confirmed here publicly and privately to me as well. The only problems I've heard of (without TRVs) are daytime overheating in sun-drenched spaces and underheating in something like a back porch converted to "living" space and likely with poorly chosen/poorly designed emitters.

Think again. Why would Viessmann recommend the RS remote only for systems of low mass/volume when it can maintain space temperature without sensing space temperature?

Because the Vitodens is designed to learn and adapt to the mass/volume of the system to which it's attached! And NEVER forget that the Vitodens uses a radiant burner! Rely too much on convection and the programming logic will break down thus requiring feedback of actual room air temperature.

hr

micro zoning is here to stay, as it should

be.

It is one of the biggest selling features of hydronics!

And the forced air crowd is following suit. I see Arzel now offers zone dampers for high velocity 2" pipe systems!

Ultimate comfort, and fuel efficiency is a big driving and selling feature.

I think when we see those 1- 10 smart circs on the market we will once again look at new ways of micro zone control.

I think more buffer tanks should/ will appear. Watching more and more electric utilities offer off peak rates to residential customers sure parteners well with insulated buffer both for heating and chilled water cooling.

Imagine a 500 gallon storage heated or cooled with .05 per KW electric, possibly even driving a geo-thermal, then 1 watt circs moving that load around as zones call.

Or the ability to use multi fuels to warm that storage i.e. solar, wood, geo, gas, oil whatever is most cost efficient in your area at a given time.

Seeing all those 1000L and larger multi coiled storage vessels in Germany, some with 4" of insulation, sure got the gears spinning in my head

I spoke with a domestic stainless steel indirect tank manufacture today. They built a prototype dual coil indirect with a 1" FIP tap mid way up! Talk about an ideal solar/ boiler/ electric back up vessel.

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mike T., Swampeast MO

I can't disagree that micro-zoning is both here to stay and "as it should be".

For the life of me though I can't understand why anyone would micro-zone using anything but proportional flow control. Residentially that means TRVs/FHVs--commercially it's pneumatics.

Those "smart" circulators aren't going to come cheap and given their origin and what I understand about their operation they'll thrive driving a proportional flow system especially if it has multiple sources of heat input that will likely operate with quite different supply temps and/or reset curves. Instead of needing a "smart" circulator for each zone, you'll only need ONE for most residential systems.

I don't have "Siggy Software" but I know you've played with it Hot Rod. 5 will get me 10 you'll find that a perfect "paper" system driven by a mod-con can operate with fixed flow as long as you can accurately maintain a target temperature based on outdoor reset.

ALH_4

RS

I agree that technically it is unnecessary. Although, once nice thing about the RS is that is lets the user adjust the setback without having to mess with the boiler controls.

WaterHeaterGuy

> be.

>

> It is one of the biggest selling

> features of hydronics!

>

> And the forced air

> crowd is following suit. I see Arzel now offers

> zone dampers for high velocity 2" pipe

> systems!

>

> Ultimate comfort, and fuel efficiency

> is a big driving and selling feature.

>

> I think

> when we see those 1- 10 smart circs on the market

> we will once again look at new ways of micro zone

> control.

>

> I think more buffer tanks should/

> will appear. Watching more and more electric

> utilities offer off peak rates to residential

> customers sure parteners well with insulated

> buffer both for heating and chilled water

> cooling.

>

> Imagine a 500 gallon storage heated

> or cooled with .05 per KW electric, possibly even

> driving a geo-thermal, then 1 watt circs moving

> that load around as zones call.

>

> Or the ability

> to use multi fuels to warm that storage i.e.

> solar, wood, geo, gas, oil whatever is most cost

> efficient in your area at a given time.

>

> Seeing

> all those 1000L and larger multi coiled storage

> vessels in Germany, some with 4" of insulation,

> sure got the gears spinning in my head

>

> I

> spoke with a domestic stainless steel indirect

> tank manufacture today. They built a prototype

> dual coil indirect with a 1" FIP tap mid way up!

> Talk about an ideal solar/ boiler/ electric back

> up vessel.

>

> hot rod

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 144&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

ALH_4

Balance

I'm not sure what to think of small zones.

Where I could see a problem is if one small zone responds differently to the outdoor temperature than the rest of the house. For example, bonus rooms above unheated garages could call for heat when the rest of the house is fine.

It is an issue best cured with additional insulation rather than additional heat. These rooms should show up during the heat loss calculations. However, I would still insist on a room over an unheated garage being its own zone, just for insurance.

The way I see it, you can either balance the heat loads or unbalance the heating system. Micro-zoning causes issues when the heating system is unbalanced because of an unbalanced heat load.