So, our air conditioner has been out since Monday. I don't think it's anything big; the repair person is coming today, and while any HVAC repair is not cheap, it shouldn't be too outrageously expensive. I think it just needs more coolant.
Anyhow, the lack of air conditioning has made it pretty hot in the house. I've opened the windows at night, to let the cool air in, and by morning the house is pretty cool. Yesterday morning it was 77; today it's 80. But this has made me realize that if we had a more efficient method of exchanging the air inside our house with the air outdoors, we could use a lot less energy for air conditioning.
Yes, there exist whole house fans, and that would help, but that's not all that I'm talking about. I think it would be useful to have an intelligent house with a hybrid HVAC system. Here's my idea.
You would provide a range of temperatures that you would consider acceptable indoor temperatures, let's say 68-80ºF, and an ideal temperature, let's say 78. Your house would shut all the windows and turn on the air conditioner, targeting your ideal temperature, when the outside temperature was too high to maintain the house within your range. Otherwise, the house would open windows, exchange the indoor air with outdoor air using your whole-house fan, close and shade windows on the side of the house where the sun is beating down, etc.
And the system could do the same sort of thing in the fall and winter: shut all the windows and turn on the heat at night, and then harness the warmth of the air outside during the day when it could.
If we had a system like that, I think we'd need to run the air conditioner only for a couple of hours during the day. But as it stands, even though it's 61º outside right now, the temperature in the house is 80, and if our air conditioning system were working, it would be running right now. What a waste!
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5 comments:
I believe smart houses like the ones you are suggesting already exist, but I'd be willing to bet that after you see the price tag, you wouldn't mind the heat as much.
That sounds really cool! But all that is stuff that you CAN do yourself, right? (With a whole-house fan and some indoor/outdoor thermometers. And some vigilance and willingness to run around opening and closing windows.)
Maybe having a "manual" house like yours is like having a stick shift instead of a hybrid: you can still save gas, but you have to use your brain more. :-)
Sarah, I imagine that you're right.
Laura, yes I could do some of that myself; however I don't think this house has a whole-house fan. Also I'm not home for most of the day during the week, which is why it would be nice for the house to do all the work for me.
I was thinking, I have no idea how to actually make the switches and electrical gadgetry necessary for this invention, but I know exactly how to program the "brains" of the operation. I even have a great idea for a heuristic algorithm! Any smart engineers out there want to help me?
Sounds like a great house to me. For a more passive approach, I've been coveting one of these houses since I read the article about them by NYTimes' David Pogue. Energy efficiency + laziness.
Did you know that a female mechanical engineer developed the mathematical analysis of "comfort" for the Carrier company?
http://anniversary.asme.org/pdf/Ingelsflat.pdf
In our climate, knowing the humidity is a key part of all that. We have an indoor-outdoor thermometer (from La Crosse Technology, FYI) that is crucial this time of year. We are much happier if the indoor humidity is closer to 40%, and over 50% is no good at all, so we use it to decide when to open the house.
The magic number for us seems to be a dewpoint of 50 deg F.
One technology that has not made it into houses is a heat exchanger for replacement air. (Outgoing air heats or cools the incoming air.) That way you can have a "tight" house but still get plenty of fresh air, even if it still needs to be "conditioned".
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