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From: STEINBERG@RUTGERS.ARPA
Newsgroups: net.physics
Subject: Re: Why don't thermostats work?
Message-ID: <16544@sri-arpa.UUCP>
Date: Wed, 8-Feb-84 13:19:24 EST
Article-I.D.: sri-arpa.16544
Posted: Wed Feb  8 13:19:24 1984
Date-Received: Sat, 11-Feb-84 05:49:35 EST
Lines: 18

From:  Lou 

>  Richard M King:
>	Assuming that the difference between the indoor and outdoor
>temperatures is large compared to the width of the hysteresis band, we
>observe that the temperature will fall at a constand rate within that band
>when the furnace is off, following which it will rise at a constant rate
>when the furnace is on.

Yes BUT:  The rates of rise and fall depend on the outside temperature.
When it is colder, the house cools faster and warms slower.  Thus when it
is colder outside the average temperature is indeed lower.  Also, since
there is some delay between the time the thermostat turns on and the time
the heat effectively reaches the room (due, e.g., to the heat capacity of
radiators), the bottom of the hysteresis band will be lower when it's colder.
However, these effects may be less significant than the other effects that
have been mentioned, such as radiation and evaporation.
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