Zoning

bigugh_4

comfort and second for efficiency. (why heat an area that is not used that much) the living room and kitchen are always occupied. but the kitchen can have a heat input (stove, D/W) of its own. It may be that It should be zoned seperately from the living room area even if they are connected ( efficieny). Baths, are the same thing. perhaps the visitor would like the main bath different than the master bath is.(comfort).

Brian

How many zones?

Hi Guys
One subject I've never seen on The Wall is number of zones either with radiant or rads.I've seen methods such as pumps or zone valves.I'm from the more the better school of thought.So let me set up an typical set-up and you can give number,method and reason.

TWO STORY HOUSE
Basement-open
Main Floor-Mud room
-2pc powder rm.
-Laundry
-Kitchen,living rm. (1room)
-Office
2ND Floor -3 bedrooms
-Master bedroom
-Master bathroom
-Main bathroom

I would zone in the following way:
Zone 1-Basement
Zone 2-Mud room,laundry,2pc(if at that area of house)
Zone 3-Kitchen,living rm (Tekmar 509 w/slab sensor)
Zone 4-Office
Zone 5,6,7-Bedrooms
Zone 8-Master bedroom
Zone 9-Master bath,main bath

I would use Wirsbo actuators with a single valve for the basement manifold.
Looking forward to your responses

Brian

bigugh_4

Zones are for

comfort and for efficiency. (why heat an area that is not used that much) the living room and kitchen are always occupied. but the kitchen can have a heat input (stove, D/W) of its own. It may be that It should be zoned seperately from the living room area even if they are connected ( efficieny). Baths, are the same thing. perhaps the visitor would like the main bath different than the master bath is.(comfort).

hr

pretty subjective

need to consider the owners use patterns. The beauty of radiant is every single loop could be a zone! I think this way, when I run the tube. I also consult with the owner concerning future use of the basement. If rooms will be partitioned later tube layout could be installed to handle this.

I ALWAYS sub zone bathrooms. Kitchen, dining areas are another "good zone" as you want the guests to enjoy warm toes while visiting.

Seems years of installation experience is the best help for designing real workable zones. Always quiz the owner to their lifestyle, ya never know what they may have in their mind

hot rod

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corey

micro zones

Just curious;
When you say "I ALWAYS sub zone bathrooms."
A single bathroom might be very small.
What methods do you use to prevent problems related to micro zoning?

Mike T., Swampeast MO

Don't forget that you can also zone with proportional two-way devices like TRVs (similar available for radiant panels). Combine this with constant circulation and you have total zoning as each device becomes its own "zone".

They essentially turn "micro-zoning" into a non-issue as when combined with constant circulation, if one zone needs heat, it is VERY safe assumed that most of the rest need some as well.

You can also do some really neat "tricks" when you've used TRVs and constant circulation.

Kitchens are often a vexing problem--not only do they have a highly variable occupancy loading, they often offer little in the way of space for an emission device--ANY device save the ceiling at least. I know this goes against convention but bear with me and I think you will see some real benefits:

1) When sizing for the kitchen radiation, INCLUDE a rather hefty occupancy loading--people, lighting, appliances--just like you do for cooling. Determine the supply temperature required in the reduced load kitchen at design temp. Size the REST of the radiation in the house to work with this temperature but NOT including any occupancy loading. This will effectively oversize the rest of the radiation compared to the kitchen.

2) When it comes time to set your reset curve, set a curve that is adequate to heat the kitchen WITHOUT the occupancy reduction. If necessary, adjust the kitchen radiation so that this temperature differential is in the 10°-15° range.

3) What you have done by this is to give some "headroom" to the reset curve. This allows the temperature in the rest of the spaces to be increased significantly more rapidly than otherwise possible.

Another neat thing you can do with such a system is to install small, "wild" radiant areas. You simply pipe them directly into the system with nothing but simple valves at supply/return to "set" the flow. You have to pay particular attention to your reset curve and use the heat transfer method most suited to achieve the desired surface temperature.

If you think that automatic setback with such a system is impossible, think again. Some mfgrs offer TRVs that can be installed with setback. While such does require wiring (usually telephone wire) it offers the possibility of some EXTREMELY sophisticated setback schemes that can quite easily be tied into other systems, like alarms or even telephone systems. They are absolutely fail safe because even at maximum setback and minimum valve setting they will still not freeze. Such is the sort of thing that an electric/electronics "tinkerer" has wet dreams over...

Some don't seem to encourage the use of TRVs because they view them as expensive. Granted, they are not the cheapest things in the world, but you must remember the things that they nearly eliminate: wall thermostats; zone valves/circulators; added piping; extremely sophisticated circuitry; check valves; buffers. When you consider this in a system with the number of zones you mention above, you should start seeing some SERIOUS cost savings--not only in materials, but in design and installation labor.

jose

Yeah but

Doesn't the material of what you're using for the floor have to be considered. (Tile or Wood)??????
They both heat and cool differently.

Mike T., Swampeast MO

The \"wild\" radiant

Yes, you have to carefully consider EVERYTHING when doing this. You strive to achieve the surface temperature required at outside design temperature using the supply temp supplied by the reset at that outdoor temp.

You adjust the supply/return valves you installed to achieve a reasonable delta-t at moderately cold outside temp. It may take a two or three adjustments to "nail" things just as you want as it takes a LONG time to achieve "maintenance", but once you have the setting, remove the valve handles.

This works very similarly to what is described in "Proportional Reset--An Under-utilized Control Strategy" by John Siegenthaler and available at his website, www.hydronicspros.com

I wouldn't use this in a space much larger than 60 square feet or so. Baths/laundries/big closets are the best candidates.

The "Rad Pad" available here at "Books & More" is very useful for designing such a system. Flow will probably be "below the scale" so you have to interpolate. The very low flow is why you have to have the valves to "set" your base flow.

In operation such a space will "ride the reset curve" and achieve a surprisingly constant temperature differential with the spaces surrounding. I have mine in baths and they are set to keep the baths 5° warmer than the rooms surrounding. Undisturbed, this differential is freakishly constant regardless of either the outside temp or the temp of the rooms surrounding.

The floor temp will not stay perfectly constant. In mine, it varies from "neutral" to the bare foot at warmer outside temps to about 85° at outside design (8°).

If you have an internal room with little/no loss save the ceiling and use heat transfer plates underneath, DO NOT INSULATE the plates!

Two of my baths run off the same litte reverse-return "manifold". They are nearly identical in size and have an identical amount of plates, same length of tube (3/8" copper), identical number of bends in the tube. Both are about 40 sq. ft. gross area with about 24 sq. ft. of heated area.

One of the baths is fully internal, the other has 8' of exposure with 2 good-sized windows. The plates on the exposed bath are carefully insulated with Styrofoam (both between and over the plates) and the internal has no insulation. Both achieve nearly identical results and surface temperatures.

While the layouts to these two rooms are about as identical as possible, there is a BIG difference in actual operation. The delta-t of the exposed bath is MUCH higher than that of the bath without exposure. This difference is one of the big reasons that my views on heat transfer via radiation are not quite what you read in texts...

Others here have used this scheme and report the same sort of success. You just have to pay careful attention to your numbers and select/tweak the heat transfer method best suited to your available water temperature.

--------------------------

Regarding the wood floors: Since I don't believe this should be attempted in large areas, you're generally left with small, "wet" areas like bath/laundry. I'm from the school that says wood flooring as the finished surface has ZERO business in such a space. It should though make no more difference to performance compared to any other radiant floor however.

You start with your heat loss, determine the surface temperature required to achieve this output at design and then choose a transfer method that most closely meets this temperature AT YOUR DESIGN RESET TEMPERATURE.