Efficiency of utilities

"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.

--
*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.

OK assuming you make good use of the waste heat from the IC engine,
otherwise you'd be throwing away 75% or more of the energy from the gas,
thereby cancelling out the advantage of the heat pump system...

TrevM

In article ,
Max Demian wrote:
"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.

********. With a heat pump system it's not the electricity that does the
heating. Which is the main point of this discussion.

Oh - try running that car on electricity.

--
*If love is blind, why is lingerie so popular? *

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

In article ,
TrevM (delete) wrote:

"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.

OK assuming you make good use of the waste heat from the IC engine,
otherwise you'd be throwing away 75% or more of the energy from the gas,
thereby cancelling out the advantage of the heat pump system...

The sort of engine you'd use for a pump could be far more than 25%
efficient. And of course you could recover the waste heat from that
engine.

But you could run the pump from a watermill or windmill. Would the heating
then be provided by water or wind?

--
*Filthy stinking rich -- well, two out of three ain't bad

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

In article ,
TrevM (delete) wrote:
First, gas boilers have been around 70-75% efficient for the last 30
years at least. New condensing boilers (which recover some waste heat
from the flue gases by condensing out some of the water vapour) are
claimed to be around 90% efficient. What they usually fail to mention
is that those boiler efficiency figures are achievable only under
steady, flat-out, full-load operation - rarely seen in domestic use, in
my experience. If a boiler is crashing on and off every few minutes on
its water-temperature thermostat

Decent modern boilers modulate the burn and pump speed precisely to keep
them in condensing mode.

--
*I started out with nothing, and I still have most of it*

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

"Steve Thackery" wrote in message
...
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?


Who is to say that the gas pipes will not carry liquid hydrogen .
Yes, the infrastructure itself would be expensive to add in.


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.

Your point is valid, our renewable product is far too small, and generating
LH is really poor in terms of what you get. It has the benefits that
NaturalGas has (in that it can be nearly lossless and be easily stored) and
portability requirements that work well for everything from Car power to
Laptop power supplys! One of the big downsides of Renewables is that you
never know when your product will be there, and (as with any good Irish sod)
it probably wont be there when you want it. So I do view it as THE current
tech to benefit the population. It allows renewables to be there when we
want them (al be it, in a more wasteful way). I dont belive that hydrogen
is the carrier for energy that will solve the worlds power crisis, but it's
a excellent stopgap IF we can make it, store it, and transport it in an
efficent manner.

I have seen carbon recapture, and synthetic gasoline, and I think if we move
into fake conversion from energy into a polluting fuel when we could convert
from energy into a non-polluting energy carrier then it would be a big
shame.

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.


One thing I wonder is.. Why (when it's like 4c outside) do I have a fridge
in my house making heat to keep things cold :/
It's the simple things that we neglect :/.


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


I think it would be key to state that DC would only work IF we are talking
of microgeneration. Transmitting DC over long runs has huge losses because
it's not easy to step up and down. In my house the only AC product I have
is my fridge (and I am not even sure if it's AC). My washing machine
actually has a DC motor in it so I cant count it. Every lightbulb in my
house is a CFL (some may argue that not all CFL's can accept a DC source).
AC-DC conversion (with an output good enough to handle things like
computers or big televisions) is somewhere in the range of 80%-85% but
again, there are a LOT of companys who claim 95%~ levels. DC Supplys are
also MOST efficent when they are at their design peak for efficency, so if
your not using the product at it's peak point then you could fall foul of
that 80%, IF you had a fully control'd DC source then a lot of that loss
would be contained. If we could recover even half of our loss (in our home)
then I dont think anyone would say 10% waste getting removed is bad.

"Steve Thackery" wrote in message
...
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


When you turn on your electric heater you also increase the current in the
lekky line, this means that the resistance of the lekky line disspates more
power, so...
When you use your heater, you turn the lekky line into a larger heater ;P...
But yes, 100% of the power you use AT the heater is turned into heat.
For most people gas heating is cheaper.

Probably best to use something along the lines of Consumption(gas or
electricity) per BTU and then price them accordingly.

"Dave Plowman (News)" wrote in message
...
In article ,
TrevM (delete) wrote:

"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.

OK assuming you make good use of the waste heat from the IC engine,
otherwise you'd be throwing away 75% or more of the energy from the gas,
thereby cancelling out the advantage of the heat pump system...

The sort of engine you'd use for a pump could be far more than 25%
efficient.

40% for a turbine maybe...

And of course you could recover the waste heat from that
engine.

As I said...


But you could run the pump from a watermill or windmill. Would the heating
then be provided by water or wind?


Now you're talking! But there are very few watermills to go around, and the
wind is too intermittent in most places...

TrevM

"Dave Plowman (News)" wrote in message
...
In article ,
TrevM (delete) wrote:
First, gas boilers have been around 70-75% efficient for the last 30
years at least. New condensing boilers (which recover some waste heat
from the flue gases by condensing out some of the water vapour) are
claimed to be around 90% efficient. What they usually fail to mention
is that those boiler efficiency figures are achievable only under
steady, flat-out, full-load operation - rarely seen in domestic use, in
my experience. If a boiler is crashing on and off every few minutes on
its water-temperature thermostat

Decent modern boilers modulate the burn and pump speed precisely to keep
them in condensing mode.


Glad to hear it, but I bet they still need to be running at a high
proportion of maximum output to get high efficiency. Modulating boilers
were around in the '60s, but they seemed to fall from favour, for some
reason.

TrevM

"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.

--

I dont know of any American towns that use the heat from power stations to
warm their homes, but I am sure some exist.. (we dont call this heat pumps)
The biggest application I have heard of that uses this "tech" is in Germany.

In the USA "Heat-Pumps" are popular for COOLING but the heating units will
be located inside the home. "Heat-Pumps" are not popular in the UK because
we dont need to cool our homes. Heat-Pumps basically move the expanded gas
back outside to be compressed (where the heat is released).

Ground-Source Heat Pumps however are a different kettle of fish and many new
builds in the UK have in-floor based heat pumps added. I think that ground
sourc heat pumps are excellent, but you cant retro-fit it easily to
buildings in the UK. As I have family in the USA who build large housing
estates then I rekon they are still not using GSHP's as standard unless they
made a big change since last christmas .. Ground source heat pumps (as the
name suggest) get most of their power from the heat (or lack of heat) stored
in the ground, so much of the work normally done by the compressor has the
chance to be offloaded.

GSHP's are also excellent for pre-conditioning water.

A MUCH bigger problem however is the 400-500sqmetre ground space you ideally
need for this product!!
I have a fairly large UK garden (in my area) and I only have about 200 sq
metres :/

For my home to recover the cost of a GSHP heating system (assuming we could
get the whole thing for under 15k) it would probably take 30-40 years to pay
itself back (not counting loan cost, or savings/investment offsets).

"TrevM" (delete) wrote in message
...
"Dave Plowman (News)" wrote in message
...
In article ,
TrevM (delete) wrote:
"Dave Plowman (News)" wrote in message
...
In article ,
Johnny B Good wrote:
snip
But you could run the pump from a watermill or windmill. Would the
heating
then be provided by water or wind?

Now you're talking! But there are very few watermills to go around, and
the wind is too intermittent in most places...
TrevM


Sod the environmentalists, build the Seven Estuary hydroelectric Tidal
barrier,
it would produce 7 Gigawatts, 24/7
10% of the countries needs, and provide a first rate road bridge on top

a 2 Gigawatt Tidal barrier could also be build across the Mersey

Steve Terry