Re: Continental vs British toilets

On Thu, 15 Sep 2005 21:23:24 GMT, Jonathan L Cunningham wrote:

> On Tue, 13 Sep 2005 18:04:59 -0500, Ric Locke <warlocke@xxxxxxxxxxxx>
> wrote:
>
>>On Tue, 13 Sep 2005 17:52:37 GMT, Jonathan L Cunningham wrote:
>>
>
>>> I wonder if it's noisy? I was trying to think today why heat
>>> pumps are not universally used instead of boilers. I'm guessing
>>> that noise is one of the issues for domestic use, but that the main
>>> factor would be capital cost, plus the cost of the energy to run
>>> the pump v. the cost of energy in fuel.
>>
>>One of the major issues is temperature differential. If you try to get the
>>difference between input and output of a standard Freon-based heat pump
>>over about 40 degrees F or 25 degrees C, you need *extremely* high
>>pressures and therefore low pumping efficiency, plus danger to the user and
>
> Also, the maximum theoretical[1] efficiency will depend on the ratio
> of the input and output temperatures: the bigger the rise, the less
> the theoretical efficiency.

Actually, there's something odd going on here. There is an electrical
equivalent, the Peltier Junction, which is a semiconductor heat pump. Put
current through it, and heat is forced from one side to the other. It's
reversible -- reversing the current direction reverses the heat flow.
They're currently used for cooling high-end microprocessors, and you can
buy a beer cooler with one inside for battery-powered (or solar-powered)
cool refreshment. At the moment they're too expensive for general use as
air conditioners and heaters, but the price has come down wonderfully in
recent years, and if the trend continues mechanical pumps may fall by the
wayside for that purpose.

The maximum reasonable temperature differential for a Peltier junction is
around 40 degrees Fahrenheit or 25 Celsius. Coincidence, what?

Regards,
Ric
.

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