ZONING SYSTEMS

Michael Holigan: We're back at the High-Tech House where our geothermal heat pump system is being installed. In addition to the energy savings we've talked about, there are some other advantages worth mentioning. Both the indoor and outdoor part to this system operate very quietly and it greatly reduces the amount of humidity in your home. But we're adding something to this geothermal system that will add even more comfort and energy savings for the home owner - a zoning system inside the air duct.

Jerry Tartaglin (Enerzone): A zoning system take a single central heating and air conditioning system in your home and divides it into multiple zones of control using dampers located in each one of the ducts and a thermostat in each one of the zones, so you get tremendously better comfort control and at the same time you get the ability to set back areas of your home you're not using for energy savings.

M.H.: So we can add different rooms at different temperatures, say 80 degrees here and 70 degrees in the room next door?

J.T.: Absolutely. It's exactly like having a separate central heating and air conditioning system for each one of those rooms.

M.H.: But we don't have to pay that extra cost for those separate systems?

J.T.: That's right.

M.H.: Some people just use zoning to keep different family members comfortable in separate rooms of the house. But if saving energy is your goal, some studies say you can save as much as 30%. How do you actually install a damper system in a new home?

J.T.: Well, first of all we take a look at the floor plan of the house and decide how the home owner's going to be using that house. And then what we do is have the contractor design the system so a single duct goes to each one of the zones we're going to control. In this case, of course, a single duct is going to have a mechanical motor driven damper. Here's actually the motor. You can't really see the damper very well. It's installed in the duct right now, but this has the ability to shut the airflow to that zone on and off based on the demand.

M.H.: Well here's one that's not installed yet.

J.T.: Right.

M.H.: And there's our motor. How does the damper actually work inside?

J.T.: Well, this is what's called a large butterfly damper. The motor is on top. Here's the blade and I'm going to very carefully open it manually. Now if the thermostat in the zoning system said, "Hey, I'm too warm in this room, send me some cool air.", it would, of course, open this damper blade. Air flow would be allowed to pass until, of course, then the thermostat or the sensor said, "I've had enough. I'm cool enough.", in which case the zoning system will send a command to shut the damper.

M.H.: Normally with one heating and air conditioning system you're going to have one thermostat. And since you have several zones, how do you know what temperature it is in different rooms?

J.T.: Well, instead of just having one thermostat for that single heating and air conditioning unit, you're actually going to have multiple thermostats now. You may have two or three. You may have as many as five or six or more, one located in each zone that is being controlled by a damper. You'll have a thermostat like this or some other type in each area. If you don't want a thermostat on the wall, even one this attractive, we also have, which is becoming a very popular piece, a flush mount temperature sensor. This actually mounts in a hole in your sheet rock, pushes in and can be painted to match the wall, and so it's become a very popular part as people try to get more and more switches and other devices off the wall.

M.H.: Where does this send the signal back to?

J.T.: This always attaches back to the thermostat.

M.H.: Okay.

J.T.: The thermostat, in turn, always attaches back to the central zone control board.

M.H.: Okay. What if you're not building a new house? Let's say you already live in a home and you've got one room that always too hot or always too cold. Is there any way to go back and rezone that room yourself?

J.T.: Absolutely. Sometimes mechanical dampers like these will work for that application, but we actually have another system that's specifically designed for that application. This system was featured in Popular Science a few years ago and is a flexible retrofit damper. Many people in the northeast and also many people in the south have duct systems never designed for zoning and the cost of going back and trying to retrofit mechanical dampers is just prohibitive.

M.H.: Ah-huh.

J.T.: This damper, on the other hand, this is actually a piece of the inside lining of flexible duct, but it could be a rigid steel duct as well. It works equally well for either.

M.H.: It looks like a blood pressure....

J.T.: That's what it's often compared to as well as water wings. But in any case, to install it, it's simply a matter of folding it up like that, installing it into the duct system and popping it in place. This part is much less expensive than a mechanical damper, so a home owner can afford to put in 15 or 20...in fact, I think the record on one job is 37.

M.H.: After you get it in, what happens to it then?

J.T.: Well, there's a pneumatic...a small air compressor and switching assembly that comes with it that actually adds air to close. I'll demonstrate.

M.H.: If you've got all these thermostats and all these dampers, how do they speak to each other? How does that work?

J.T.: Well, the thermostats don't actually tie straight back to the dampers. They actually tie to one of our central zone control panels which actually serves as sort of a system traffic manager. And so what happens is, if only one thermostat is calling, the logic in the microprocessor on this board say, "Okay, dampers to all the other zones go ahead and close and let's just send air to this one zone.". It's all fully automatic. The user doesn't do anything here at the panel. All the control comes from the thermostat.

M.H.: What if you're using like only one room in the house, but you've got a zoning system for maybe 12 different zones, what happens with all the extra air that the unit's trying to push through?

J.T.: Michael, that's a very often asked question. This device is called a Barometric Relief Damper and it routes from the supply side of your air conditioning unit back to the return air side. So if only one room is calling, what happens is the pressure increases in the system and this door swings open based on how this weighted arm allows it to and so what happens is you start bypassing air from the supply back to the return air side. It's really not wasting air, you end up producing less, but colder or warmer air for that one room.

M.H.: Here on this unit behind us you can see where the air comes out of the top of the unit and it goes to all these ducts with the different zoning dampers on them, but in case they're shut off, it does come right back through here. Here's our Barometric Pressure Valve with a weight on it. It'll open back up and let the extra air come right back into the bottom of the unit again. You may not realize it, but your heating and air conditioning unit is responsible for about 75% of your energy costs. That makes it the most important appliance you'll put in your home. So incorporating innovations like geothermal heat pumps and zoning systems can be smart additions to your new house.

Jerry Tartaglino of Enerzone - 972-424-9808

Episode 48 1996 - 97 Season

| Geothermal Heat Pumps - Part 1 | Geothermal Heat Pumps - Part 2 | Attaching Ductwork | Zoning Systems | First Time Home Buyers |

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