Welcome to Smart HVAC
This is an open project. Please, fell free to edit any part of the text (just double-click). Add your notes, correct my mistakes.
Purpose: to bring heating/cooling of a residential house up to the 21st century level!
The first prototype is my own house located NW of Atlanta GA.
All results/solutions achieved in this project are public domain.
There is nothing wrong with my HVAC unit. It is 12 years old. It cools well, it heats well, and energy consumption seems to be reasonable. However, I have to heat/cool the whole house when one room would be more than appropriate in many situations. Moreover, I have to go a floor down at the midnight when I pretend to be courteous and my sweet wife feeels too cold/hot.
NOTE: The DIY-Zoning project http://diy-zoning.sourceforge.net/ is very close to our goals and it is in an advanced stage. I just signed in, said hello and found very nice guys ready to help. Highly recommended!
Stages:
1. Measure temperatures. The air temperature should be measured at least at 7 different places. I plan to use Dallas Semiconductor's DS18B20 connected to RS232 port of my PC through the IOM #142A board made by P.H. Anderson http://www.phanderson.com/iom142/iom142.html. I just received the card & it LOOKS GREAT! This (labor day) weekend was enough to get it working - see Com Reader. I will start by measuring temperature in various places of my office. That should show where is the best place in the room to place the sensor. Here are my first Speed And Accuracy Measurements.
2. Take over the thermostat job. IOM#142A comes with 4 relays. Those can be used to control HVAC vent (2 speeds), AC and the heater. NOTE: Vadim Tkachenko says this can cost me loss of the warranty/service on my furnance!
3. (Optional) Control ceiling fans. Problem: I wanted to use X-10 to control ceiling fans. Could not find affordable appliance modules that could be built into the ceiling fan itself or at least into the wall switch. COULD YOU ADVISE? (just doubleclick the page and enter your note here, please).
4. Control the Air Flow. It would be easy to buy 8 dampers and open/close the air flowing to each room. If I will not find air duct dumpers for a reasonable price (I consider $80+/damper shamelessly overpriced) I will have to build them. -- Yes, DIY-Zoning (see note above) might have solution! Got 7 futaba s3003 servo motors on ebay, and Pololu serial 8-servo (see Servo Controller for the list of choices).
5. User Interfaces. There will be Different Users and each of them deserves a good way to communicate with the system. Systems are judged mostly by their UIs -- see http://www.cooper.com/. Jerry Scharf got it right - see Jerry Scharf On User Interfaces. Currently I plan to use wireless X-10 remote control http://www.x10.com/automation/hr12a_s.html to send commands (device 1-7 will be zone, On means Temperature-Up and Off means Temperature-Down). Hopefully, I will figure out how to get 1 or to led's to each room to be able to confirm the command.
6. Software should be based on a good model of the house. It should recognize unusual responses to heating/cooling, find the cause (open window, local heater in the room, etc.) and adjust to it.