Big Green: Heat pumps

[Joe Karten]

Metric ton or standard ton?

On Fri, Oct 31, 2008 at 7:14 AM, Barrie Moore <merlon at gn.apc.org> wrote:

>  It is still necessary in an area where you still accept British
> Imperialism for we Brits to teach you Americans how to speak English
> correctly.  British Thermal Units (BTU's) can lead to confusion when talking
> about power particularly where electricity is involved. We now use kiloWatts
> to rate diesel engines, boilers and electric motors. KiloWatts do not have a
> temperature, they are a measure of power. This is where  British Thermal
> Units can give a bum steer. Equally, over here, when you mention kiloWatts
> most people think you mean electricity.  Any debate which confuses heat with
> kiloWatts is going to lead to talking at cross purposes and utter confusion.
> Where you get your kiloWatts from is important because electricity is much
> more expensive per kiloWatt than one sourced from the ground or from
> burning. "Thermal" kiloWatts  are easy to obtain with electricity and we all
> like the convenience of our washing machines, electric power showers,
> dishwashers and kettles. Heat pumps are different and use the expensive
> electrical kiloWatts to alter the low grade "thermal" ones  into high grade
> thermal ones. COP's of more than 4:1 are possible if you do not have a huge
> temperature lift . Using the ground as an energy source avoids the confusion
> of high temperatures being the only source of energy (kiloWatts) and all you
> AC engineers already know how much energy can be obtained from a ton of ice.
>  So the correct term is GSHP  and your homework is to tell me how many
> kiloWatts in a tonne of ice ?
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-- 
Joe Karten, LEED AP, Green Star AP
mobile: 044.715.6181
www.greenbuildingworldwide.com
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