Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site cubsvax.UUCP Path: utzoo!linus!philabs!cmcl2!rocky2!cubsvax!peters From: peters@cubsvax.UUCP Newsgroups: net.misc,net.physics Subject: Re: Why don't thermostats work? Message-ID: <167@cubsvax.UUCP> Date: Thu, 9-Feb-84 20:28:33 EST Article-I.D.: cubsvax.167 Posted: Thu Feb 9 20:28:33 1984 Date-Received: Sat, 11-Feb-84 05:42:47 EST References: <877@ihuxl.UUCP>, <194@heurikon.UUCP>, <164@cubsvax.UUCP>, <4312@amd70.UUCP> Organization: Columbia Univ Biology, New York City Lines: 27 Yes, industrial heating systems are inefficient, especially in the summer. In the winter, one bucks warm peripheral air with chilled air that is free; that is, it can be taken from outside, and usually has to be pre-heated a little in cold weather before being used. This isn't so bad. In the summer, however, one cools the periphery with expensive conditioned air, and then bucks this cooling effect with air which has been pre-heated at additional energy expense! (Conditioning of the warm air is necessary to get rid of the humidity.) Unfortunately, without this, there would be great temperature gradients as between an outside wall and the interior of the building. There are usually trade-offs between efficiency and performance, and this is an example. The inefficiency is compensated by the fact that heat-loss is proportional to surface area; the lower surface-to-volume ratios of large industrial buildings -- which is, after all, what causes the problem which the more complicated heating/cooling systems are supposed to fix -- also makes them inherently more energy efficient than small structures like houses. I believe (though I haven't seen data) that the heating bill for these large structures will be lower per square foot of floor space than for, say, a house, other things being equal. {philabs,cmcl2!rocky2}!cubsvax!peters Peter S. Shenkin Dept of Biol. Sci.; Columbia Univ.; New York, N. Y. 10027; 212-280-5517