EcoRenovator - View Single Post - Arduino CO2 Sensor Controls PCM Fans in HRV

stevehull · 02-07-13, 07:02 AM

worldtrekker,

AC has a good sensor and it doesn't respond to humidity and temperature as do many CO2 sensors. All that said, we need to look at the total volume sampled (VERY small) inside a home that is not room to room ventilated as is in more typical (larger volume) houses. In this very specific scenario, you can have the CO2 values he has measured in the specific room he is in.

AC in in a very unusual house (700 ft2) and we need to keep that in mind.

I really like the Linear LTC1041 8 pin chip for doing exactly as you say. Proportional control for an HRV (or ERV) is clearly overkill. In keeping with ACs request that we focus on controlling the HRV, I would look at the following:

http://cds.linear.com/docs/en/datasheet/1041fa.pdf

VERY easy to hook up and only uA of current to drive it. I also like the ability to sense every few minutes to further reduce current. The inherent hysteresis eliminates the on off on "chatter" than a simple bang bang switch has. The 1041 is also cheap!

Steve

02-07-13, 07:02 AM	#25
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	worldtrekker, AC has a good sensor and it doesn't respond to humidity and temperature as do many CO2 sensors. All that said, we need to look at the total volume sampled (VERY small) inside a home that is not room to room ventilated as is in more typical (larger volume) houses. In this very specific scenario, you can have the CO2 values he has measured in the specific room he is in. AC in in a very unusual house (700 ft2) and we need to keep that in mind. I really like the Linear LTC1041 8 pin chip for doing exactly as you say. Proportional control for an HRV (or ERV) is clearly overkill. In keeping with ACs request that we focus on controlling the HRV, I would look at the following: http://cds.linear.com/docs/en/datasheet/1041fa.pdf VERY easy to hook up and only uA of current to drive it. I also like the ability to sense every few minutes to further reduce current. The inherent hysteresis eliminates the on off on "chatter" than a simple bang bang switch has. The 1041 is also cheap! Steve __________________ consulting on geothermal heating/cooling & rational energy use since 1990 Last edited by stevehull; 02-07-13 at 08:04 AM..