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- From: howard.smith@spacebbs.com (Howard Smith)
- Newsgroups: sci.energy
- Subject: hot water
- Message-ID: <5016.1017.uupcb@spacebbs.com>
- Date: 23 Dec 92 08:46:00 GMT
- Distribution: world
- Organization: SPACE BBS - Menlo Park, CA - 10 Lines + 4gB - 415-323-4193
- Reply-To: howard.smith@spacebbs.com (Howard Smith)
- Lines: 38
-
- M> First, my home heating system is essentially a oil-fired hot water
- M> heater (except the hot water heats my house not a shower) and it is
- M> rated as 87% efficient. Higher efficiency is available. I see no
- M> reason why an oil fired hot water heater should be only 20-30%
- M> efficient.
-
- The problem with oil and gas water heaters is the flue. It has to have
- low thermal resistance to the water and also low resistance to the flow
- of the fumes and air up from the bottom of the flue. Much heat goes up
- the flue.
-
- Real inefficiency occurs when the heater reaches temperature and shuts
- off, leaving the heat from the pilot light and the water, back through
- the low thermal resistance, to pass up the flue by convection. The
- less hot water you use, the less efficient the system. Some sort of
- electric pilot light and automatic, insulated damper in the flue are
- needed to stop this loss.
-
- If the damper fails, you're in trouble.
-
- Electric heaters don't have these problems.
-
- The most efficient system for a large household is an active, roof-top
- mounted, solar heater with a large electric heater in loop for storage
- and standbye heating. All well insulated, of course.
-
- M> Second, while the electric heater is 100% efficient at converting
- M> the electricity you pay for into heat, the power plant is only about
- M> 40% efficient at generating the electricity and getting it to you.
-
- M> This is reflected in the higher price of electricity compared to oil.
-
- Yes, but you also have pay the man to bring the oil to your house.
-
- -Mike
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