Efficiency of utilities

Google CHP and Microgeneration.
"hopefully" we'll see Hydrogen to the home in the next 10 or 20 years,
with
small home microgeneration based utilitys and DC power through your whole
house.

I vigorously disagree! Hydrogen has to be "made" (extracted, hydrolised,
etc), which uses as much energy as it releases (more, in fact) when it is
burned or reacted in a fuel cell.

It is really nothing more than a way of storing energy. It isn't a fuel in
its own right. And I'll tell you now, there's NO WAY anyone will invest in
a new distribution infrastructure to pipe hydrogen to everyone's home! Why
on earth would they, when we've already got gas piped to our homes?

The one good thing about hydrogen is that it can act a bit like a "common
currency". You can make it using almost any energy source. So it gives the
potential to drive cars using wind power, or tidal power, for instance. But
remember that alternative energy sources account for less than 5% of our
generated electricity, so there's no way alternative energy is going to make
big inroads in the short to medium term.

Like you, though, I'm really quite keen on microgeneration. So long as you
actually need the heat it captures (which is questionable, in summer), the
efficiency figures are startling.

AC power is really wasteful, esp as most of it we convert back to DC for
just about everything!

I don't think I understand why AC power is "really wasteful". Conversion
back to DC is trivial, and extremely efficient. Do explain why you think DC
around the home would be so much better. I can think of lots of reasons why
it would be worse! The main one being that it is very simple and efficient
to change its voltage (all you need is a transformer). If we move
electricity around in a high voltage, low current form, the low current
reduces resistive losses in the wiring, helping efficiency. Then we can
easily convert it to a low voltage (or straight to DC) at the point of use.

SteveT

Ambiguity alert!

I wrote the following very badly:

The main one being that it is very simple and efficient
to change its voltage (all you need is a transformer).

I'm referring, of course, to AC.

SteveT

Every time you use energy and converts it to another form, you lose, as
nobody has created the lossless conversion device yet. Like the perpetual
motion machine, it does not exist. Even the superconducting magnets at Cern
use power to keep them cold, as we now all unfortunately know!

Also, load may vary on the grid, but you keep on having to produce the
current. With gas, when its off, its off, assuming no leaks of course!
Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"larkim" wrote in message
...
I have a wife who is becoming obsessive about the use of electricity
and gas, and consequently is pushing up my requirement to know
something about these things.

One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

On a similar vein, there is the standby / mobile phone charges etc
arguments. If (as my physics teacher once said) energy cannot be
created or destroyed, just converted from one form to another, we must
be "using" the energy. If they heat up, we're using the heat, if they
buzz then isn't that sound energy converted into heat through the air
(?), if they have a small LED on them doesn't the light again convert
to heat energy (save for the part that disappears through the windows
as visible light). So aren't they equally "efficient" as an
electrical heater?

Matt

"CD" wrote in message
...
On Mon, 17 Nov 2008 15:13:52 +0000 (GMT), "Dave Plowman (News)"
wrote:


TRVs are one of the most cost effective things you can buy. As are
programmable thermostats.

My daughter lives in a managed block of flats, built in the 1920s. A couple
of years back there was a general refurbishment of the central heating
system, including replacing leaky and stuck radiator valves at the tenants'
expense - £25 per valve ISTR. I advised her to ask about TRVs, at least in
the bedrooms. She was quoted £100 per valve. Since the heating costs are
covered by an annual flat-rate (sorry) service charge, she did not take up
that offer. Reminds me of flats in the Soviet Union where heating was free
and people just opened the windows if it got too warm inside.


I do have a programmable stat & plan on getting TRVs. What I was
trying to put across was the fact that to use the rad in his room it
would mean heating the room downstairs. If I was to turn down a TRV in
that room the gas CH would still be churning away. Also one rad in the
system has to be TRV free.
At night the electric heater in the boy's room is the only heating
going off in the whole house.
I always wondered why gas CH systems don't have a method of heating
individual rooms (No doubt someone will now say such a system exists).

An electric heater in a single bedroom will be far cheaper to run than a gas
boiler running - as you say, churning away - against a house full of closed
TRVs (bar one). A gas boiler with an output of typically 15 or 20 kW needs
to be fully loaded and running continuously to achieve its design
efficiency - by definition it needs to be heating a lot of rooms. TRVs are
OK if they are mostly open most of the time, or if they are used to
distribute heat from an under-sized boiler to (many) selected rooms.
Otherwise boiler efficiency drops as heat demand and water flow are
restricted, leading to brief periods of burning between frequent cut-outs of
the water temperature 'stat, and you don't save as much as you think you are
going to. And it's not much use turning the gas down to reduce the heat
from of the boiler - again the efficiency falls away faster than the heat
output because the relationship of the flame to the heat exchanger body gets
b*ggered up.

TrevM

Every time you use energy and converts it to another form, you lose, as
nobody has created the lossless conversion device yet.

Hmmmm...... depends how you define 'lose'. The lost energy ends up as heat,
which may be the very thing you want.

SteveT

"TrevM" (delete) wrote in message
...
"CD" wrote in message
...
My daughter lives in a managed block of flats, built in the 1920s. A
couple of years back there was a general refurbishment of the central
heating system, including replacing leaky and stuck radiator valves at the
tenants' expense - £25 per valve ISTR. I advised her to ask about TRVs,
at least in the bedrooms. She was quoted £100 per valve. Since the
heating costs are covered by an annual flat-rate (sorry) service charge,
she did not take up that offer. Reminds me of flats in the Soviet Union
where heating was free and people just opened the windows if it got too
warm inside.

That's what happens in hospitals, schools, universities, and prisons. If you
walk along the edge of a flat roof you are hit by the heat coming up from
the windows.

Bill

The message
from "Bill Wright" contains these words:


"TrevM" (delete) wrote in message
...
"CD" wrote in message
...
My daughter lives in a managed block of flats, built in the 1920s. A
couple of years back there was a general refurbishment of the central
heating system, including replacing leaky and stuck radiator valves
at the
tenants' expense - £25 per valve ISTR. I advised her to ask about TRVs,
at least in the bedrooms. She was quoted £100 per valve. Since the
heating costs are covered by an annual flat-rate (sorry) service charge,
she did not take up that offer. Reminds me of flats in the Soviet Union
where heating was free and people just opened the windows if it got too
warm inside.

That's what happens in hospitals, schools, universities, and prisons.
If you
walk along the edge of a flat roof you are hit by the heat coming up from
the windows.

Electric heating _can_ be a lot cheaper than by gas, but you need to
invest in a heatpump based system. A heatpump can provide something like
3 to 4 KW of heating per 1KW of electrical power input. It's quite
common in The States, if the newsgroup alt.energy.homepower is anything
to go by (presumably on account of the much larger market in the related
air conditioning products).

Here, in the UK, heatpump technology seems to be totally ignored in the
home heating market. I don't know why, since the technology has been in
use for well over fifty years in fridges and freezers. I suspect, it has
a lot to do with our third world status as a technological manufacturing
country as much as anything.

It's a shame really, since the power stations are chucking away two
thirds of the fuel's energy as waste heat energy into the atmosphere and
heatpump technology seems to have a poetic justice to it in that it does
its bit to cancel the heat pollution caused by the PSUs.

--
Regards, John.

Please remove the "ohggcyht" before replying.
The address has been munged to reject Spam-bots.

In article ,
Johnny B Good wrote:
Electric heating _can_ be a lot cheaper than by gas, but you need to
invest in a heatpump based system. A heatpump can provide something like
3 to 4 KW of heating per 1KW of electrical power input. It's quite
common in The States, if the newsgroup alt.energy.homepower is anything
to go by (presumably on account of the much larger market in the related
air conditioning products).

But that isn't electric heating. The pump could equally as well be run by
gas, using some form of internal combustion engine.

--
*A fine is a tax for doing wrong. A tax is a fine for doing well*

Dave Plowman London SW
To e-mail, change noise into sound.

"Johnny B Good" wrote in message
.. .

Electric heating _can_ be a lot cheaper than by gas, but you need to
invest in a heatpump based system. A heatpump can provide something like
3 to 4 KW of heating per 1KW of electrical power input. It's quite
common in The States, if the newsgroup alt.energy.homepower is anything
to go by (presumably on account of the much larger market in the related
air conditioning products).

Here, in the UK, heatpump technology seems to be totally ignored in the
home heating market. I don't know why, since the technology has been in
use for well over fifty years in fridges and freezers. I suspect, it has
a lot to do with our third world status as a technological manufacturing
country as much as anything.

It's a shame really, since the power stations are chucking away two
thirds of the fuel's energy as waste heat energy into the atmosphere and
heatpump technology seems to have a poetic justice to it in that it does
its bit to cancel the heat pollution caused by the PSUs.

Installing heat pumps in homes won't save any energy or money as people will
use them in the summer to cool their houses rather than open a window and/or
swelter.

--
Max Demian

"Dave Plowman (News)" wrote in message
...
In article ,
Johnny B Good wrote:
Electric heating _can_ be a lot cheaper than by gas, but you need to
invest in a heatpump based system. A heatpump can provide something like
3 to 4 KW of heating per 1KW of electrical power input. It's quite
common in The States, if the newsgroup alt.energy.homepower is anything
to go by (presumably on account of the much larger market in the related
air conditioning products).

But that isn't electric heating. The pump could equally as well be run by
gas, using some form of internal combustion engine.

It's still electric. You might as well say that a petrol car doesn't run on
petrol because you could adapt it to run it on LPG or replace the engine
with a diesel one if you wanted.

--
Max Demian