Distribute Hit in house with Motorized Register?

Hi All,

I live in a Back Split house (bedrooms upstairs, living room
downstairs) and have one of those LCD thermostats on main floor. I am
not really happy with hit distribution in my house. I set the
temperature in a scheduled order to keep the temperature at nights at
23 (74) degree but regardless of that our bedrooms upstairs are always
to hot or too cold (depends on outside temperature). I think the
problem is cold/hit from outside first hit the main floor (that
thermostat is) and then bedrooms. Beside this problem I am wondering
if I can computerize the whole temperature control system. I am
thinking about someway to software-control temperature of each room.
So I can bring down bedrooms and bring up living room temperatures
during the days and backward during nights (or for instance turn off
hit for guest room if no one is there; no guest). For implementing
something like this I need two things:
1- Controllable Air Flow Register (Motorize)
2- Temperature sensor for each room (this part should be the easy
part, there are lots of digital single-wire sensor in market that even
can be chained)


Anyone knows anything about Motorize Register or any comment on my
idea? Anyone interested to do it as a team?


Thanks,

Homer

 

Let's say... Open/closed venting. (Not variable position control.)
How about a bunch of thermostats in parallel to the furnace.
The furnace runs until the last thermostat open cct's.
Each thermostat controls a motorized vent.
If every room comes up to temp, all flaps are closed, there's nothing
conducting in the parallel circuit and the furnace shuts down..

No software...


D from BC

 

There's a company in Beaverton, Oregon that produces a system that'll do
this for you.

But I've been trying to remember the name for the last ten minutes and
can't.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

Most central heating systems have "valves" for the duct work ususally
located near the furnace. These allow you to control the airflow to
various areas of the house. Close the upstairs a little and open the
downstairs a little.

 

Very smart thinking D. All I need is a motorized vent with thermostat.
I can even forget about linking them together and downsize the project
to replace old vents with new motorized ones. I then think of
something else for shutting down furnace is all vents are shut
(presure control switch or something like that).

Now here comes the big question: Is there anything like that in
market? anybody?

Homer

 

Yep. Search for 'motorized damper'. But these are for installation in
duct runs and may require chopping holes in walls and floors for a
retrofit. Motorized registers would seem to make a better option for a
retrofit.

 

I wonder how such a system would work if only a few rooms call for heat.
The furnace might not work well with the back pressure and reduced flow.
In fact, the heat exchanger may reach a high temperature. Most modern
furnaces have safety sensors to shut down in this case, but hey will
still treat this condition as a fault and may not even restart until
properly reset (usually following an inspection).

High back pressures might also cause 'closed' registers to whistle.

--
Paul Hovnanian mailto
------------------------------------------------------------------
Software Engineering is like looking for a black cat in a dark room.
Systems Engineering is like looking for a black cat in a dark room
in which there is no cat.
Knowledge Engineering is like looking for a black cat in a dark room
in which there is no cat and somebody yells, "I got it!"

 

Don't know what' available in the HVAC world. But
perhaps you could use the kind of mechanism found
in some greenhouses to open windows. AIUI they use
a cylinder that extends a piston when the gas inside
expands with heat. When the temp goes down, the gas
contracts and the piston retracts.

Ed

 

The company you are thinking of is at
http://www.homecomfortzones.com/product/default.htm
They use inflatable bladders to control each outlet and a RF linked
thermostat in each room. A central controller received each room temperature
and setpoint and adjusts the main heat/cool and bladders accordingly. The
duct bladders are blown backwards through the ducts to the central heater so
there is almost no installation hassle. Interesting system but I think they
want about $6000 for a typical system. Ouch!!

-bill

 

That's the one. I know a guy who does software work for them, and
they've interviewed me to do consulting but nothing came of it.

Neato idea, and the bladders are a clever way to avoid having to wire
the house for control (apparently the prototype systems used beach balls).

But I never looked at the price until now -- that's steep, isn't it?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

Ok, I did a little research on this a while back, and this is what I found.

First, you use either motorized dampers ($200+ each)or the 'balloon'
controls ($60 each, but you also need an air compressor and controls for
around $1000) for each zone you want. You have a separate thermostat
for each zone that turns on the system and activates the damper for that
zone.

Next, you have a little pressure regulator thingee that is basically a
weighted flapper that you put right next to the furnace, between the
output and the return air ducts. This keeps the pressure from being too
great and burning out your fan. Also, the recirculated air requires
less conditioning, possibly saving a buck or two.

Altogether, it can get pretty expensive and complicated.

Now, in my old two story house, all I did was buy a second thermostat
for upstairs, and wired it to a two position switch directly above it so
that I could either switch to the top thermostat at night, or the lower
thermostat during the day. Funny thing was, I almost always just left
it on the top one all day!

Charlie