LETTERS
TALKING POINT
Limited potential
The reported VPhase voltage
reduction device (News, 19 May)
is similar to many domestic
embedded renewables technology
— good technical performance
but its potential may only be about
10 per cent realised.
Voltage reduction may indeed
save energy but, over time, for
only a small proportion of electricity
consumed. Most domestic
electricity performs heating and
work duties and these energies
will be expended regardless of
voltage, controlled by thermostats
(heating and cooling duties), or
motor speed, controlled by frequency
(domestic appliances).
Some duties may require more
time, but overall, the same energy
in kWh will be expended.
This leaves lighting and electronic
appliances. A 10 per cent
voltage reduction will reduce
incandescent light by 30 per cent
18
Where’s the saving?
You reported on the VPhase
energy consumption reducing
device (News, 19 May).
As the major power
consumers in the household
are likely to be heating and
lighting, a reduction in the
voltage will not produce energy
savings. Electric heating will
need to be on longer to
achieve the desired heat
output. Incandescent lighting
becomes more inefficient as
the voltage is reduced, wasting
even more energy as heat.
We do not expect the fridge
to get colder with a higher
supply voltage, but we are
interested in the energy
consumption to maintain the
target temperature. While
reducing energy consumption
is a laudable aim, I don’t think
this device will do as much as
your article suggests.
Mark Boult
Fillongley
and annoy householders, who will
simply select higher wattage
bulbs. The quantity of electronic
devices, TVs, computers, hi-fis,
will depend on the size and age of
the household.
The greatest gains from
VPhase will be in a house full of
teenagers and thumping music
and in these cases the head of
household may well wish to adjust
voltage to zero. Such households,
however, have a benefit that, with
full voltage, the heat given out by
the electronic appliances reduces
the cost of fossil fuel heating bills.
I suspect about 10–20 per cent
of energy savings will apply to
about 10 per cent of electricity
consumed, giving an overall
saving of 1–2 per cent before
subtraction of the 1 per cent
consumed by VPhase, and its
carbon footprint from procurement
of copper, Perspex, plastics, heavy
wiring connections and installation
activity. Regrettably, any savings
are only on the lowest-priced part
of one’s quarterly bill.
The device will need to withstand
temperatures of -10ºC to
+ 50ºC and be rigorously EMC
compliant to avoid interference
with possible electronic gas
meters, such as Lattice (‘Wireless
Watch’,10 March), especially if
switching 50 amp loads.
P H Field
St Albans
Price of knowledge
Is it just me, am I being thick,
short-sighted, naive or what? The
article ‘Bottling the big bang’
(Cover feature, 19 May) to me at
least, contained very little
enlightenment.
Paragraph after paragraph
described in a variety of different
ways that particle A was to be
smashed into particle B with the
consequence that something
might be learned from this
wonderful feat of engineering.
For those few mortals blessed
with the amazing intelligence of
Stephen Hawking, there will no
doubt be much information to
disseminate. Those of us with a
mere modicum of average nous
can only wonder, ‘What the
dickens is this all about?’
From an engineering
perspective, the construction of
this massive device is an
incredible feat bordering on being
a ‘wonder of the world’.
My simple logic, however, says
that if we find the answer to life,
the universe and everything,
then the human race will be
no better off than getting the
answer 42.
At a consumption of 230MW,
CERN’s LHC makes my
low-energy light bulb conversion
pale into insignificance. What
price knowledge, I ask?
I can just about hack the
spin-off benefits of space
exploration. Smashing particles
together, I don’t think so. Mr
Hawking’s debilitating motor
neurone disease would be a more
deserving cause of expenditure of
this magnitude.
Anthony Oliver
Norwich
Goodbye to cars
The MIRA project for ‘plug-in’
batteries (News, May 5) for electric
cars suggests an interesting
scenario.
If it were possible to design a
battery that was easily and quickly
exchanged and if car makers
adopted a common standard
(probably a forlorn hope), then we
could have a pool of battery units
available on a contract rental
basis at existing filling stations,
allowing an unlimited range for
electric cars.
No need for internal
combustion engines and hybrid
cars. Such an arrangement
appeared to work two centuries
ago with horses and stage
coaches.
Peter Bettridge
Stourport-on-Severn, Worcs
Flight of fancy?
Our Online leader article ‘Actually,
it is rocket science’ discussed
plans to convert an ESA ‘space
truck’ so that Europe can catch
up with the rest of the world
in the manned space flight stakes.
Here is a selection of your emails.
The greatest and most exciting
engineering achievements will
always be firmly on the ground so
they are visible and tangible.
It is almost impossible to get
enthused by EU (which is not a
nation) activity in space at a time
of economic uncertainty and
knowing that our own government
— the taxpayers — are broke.
Peter Field
What a brilliant idea, and what a
great opportunity for our
politicians. Sign them all up as
space crew. One small flight for a
politician, one great leap for the
rest of us...
Brian
After reading this article, I believe
it would be a great thing to have
some European space flights. We
in the US need some revamping of
this NASA thing, which has got
political as well as controversial
and mind-boggling. It is like the
federal government that supports
it — too big, fat and lazy. While
the EnGIneeR 2–15 JUNE 2008
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