The Energy Star Efficiency Myth - Page 4

 Jesse Spencer wrote:

That's only true if you're using electrical resistance heating to keep your
home warm.

Grid electricity is generated from a variety of sources.  Most of these
sources use heat as an intermediate energy form, producing steam, which then
drives a turbine with drives a generator that producs the electricity.  This
process is not very efficient.  Count in transmission losses, and the
electrical energy delivered to your house compared to the heat energy we
started with in the generating plant is generally around 30%.

So, to keep things simple, let's say you heat your house with natural gas
(most people do here in Ontario, Canada).  If you burn the natural gas in a
good furnace, you get 90% of its available heat in your home.  If you burn
the same natural gas in a generating plant to produce electricity, then use
that electricity to heat your home with lightbulbs (or any other form of
electrical resistance heating), you get only 30% of the available heat in
that natural gas.

That 90% is 3 times better than the 30% you got with the lightbulb.  Not
coincidentally, heating your home with electrical energy generally turns out
quite a bit more expensive than burning natural gas.

If you were to use a ground source heat pump with a COP of 3, then your
electrically powered heating would be just as good as burning the natural
gas.

Regards,

Bert Menkveld

 

Bert Menkveld wrote:


I always find it so rather disappointing that it's no more efficient than that.

Graham

 On Sat, 3 Feb 2007 08:28:42 -0500, "Bert Menkveld"
<bertATreentronicsDOTcom> wrote:


You should be able to get COP of 4 for a geothermal unit.

I'we got an AIR to AIR heatpump that 3.xx* at 7c(I think) It's not as
efficient when temperatures drop bellow zero, but it's suposed to have
a COP of  2 with outside temperature of -10c

*Don,t remeber exactely, but it gives out 6300Kw and uses 1850Kw

--
SEE YA !!!
Trygve Lillefosse
AKA - Malawi, The Fisher King

 On Wed, 14 Feb 2007 19:47:04 +0100, Trygve Lillefosse


            That seems small, but I like the idea of a unit
that size, in fact, I would like to buy a one-way heat pump
that size, for heat only, a split unit could be built for just
a little more than a window air conditioner.

            I hope they are available, but maybe not, the
engineers are designing everything much more
complicated than needed.

Joe Fischer

 

Joe Fischer wrote:


It sounds good to me ! I reckon I could keep my house warm with that.

Graham