|
1. How does solar water heating work?
A typical solar water heating system uses a
roof mounted collector, angled towards the south to capture heat from the sun.
About 1m2 of collector area is needed for each person in the household, with a
minimum size of around 2.5m2. The collector may be a flat panel, or a series
of vacuum tubes: in both cases it contains a heating fluid which is warmed by
the sun's rays, and then pumped through a heat exchange coil in the hot water
tank. As this coil warms up, it transfers the heat to the water in the tank.
An expansion vessel built into the system allows for any expansion or
contraction of the heating fluid as it warms and cools.
Any solar-based system will still need a
conventional water heater - powered by gas or electricity - to provide back
up. However, in hot weather solar energy should be sufficient to provide all
the hot water needed, and even on a cool day it will help to raise the
temperature of the water a little, meaning the conventional system doesn't
have to work as hard.
In some cases the conventional water heater
is used to heat a main water tank, with the solar heating system warming water
in a second tank which feeds into the main supply via a diverter valve. It
is simpler and more efficient, however, to have two heating coils in a single
tank. One is heated by solar energy, and the other by the conventional
heating source. The conventional heater takes over when a thermostat in the
tank warns that the water temperature has fallen.
2. Is the UK sunny enough?
While we love to complain about our weather,
in fact the UK has quite enough sunshine to make solar water heating
practical. It is estimated that we receive over a thousand kilowatt hours of
solar energy per square metre every year. Even if sunshine is diffused through
clouds, the energy can still be collected and used by a solar water heating
system.
Over a year, such a system will supply about
60% of the hot water requirements of an average house. During the summer a solar heating system can supply virtually all the
hot water needed, with water temperatures of 70-85 degrees C not uncommon. Even in
winter, the system can reduce water heating costs by around 20%.
3. What about fitting solar
water heating?
While commercial contractors will quote to
fit solar water heating, the costs can be high. A householder with some DIY
plumbing skills may want to consider fitting their own system. However, they
will not qualify for grants if they do their own installation.
The most difficult task is fixing the panel to the roof of the house. Flat
plate panels are bulky and can be heavy, and some assistance will probably be
needed. A scaffolding tower is recommended.
Some householders take the
opportunity to replace their old hot water cylinder with a more efficient,
better insulated one (and this will almost certainly be necessary if opting
for a two coil version).
4. Is Solar
Hot Water a good investment for me ?
The potential savings on
water heating bills are affected the most by the type of fuel you are using to
heat that water and the number of people in the home. If you are heating hot
water for two or more people and you heat water with electricity ,
LP gas or oil,
then you should take a look at solar water heating, it could be a great
investment.
5.
What is the "payback" on a solar hot water system?
The term "payback"
is a misconception.
Electric and gas water heaters do not have a payback! When you purchase a more
efficient refrigerator, the decision to buy comes not from how long the
savings generated will pay you back for your initial investment, but from
getting better service for a lower operating cost with
a better rate of return on your expenditure.
Solar water heating systems provide quality hot water at a lower cost
than heating with electricity or LP gas and add
equity value to your home when you come to sell it.
Solar collectors are typically
designed to last as long as your home with little or no maintenance. These
systems give a year ly
non-taxable return on your money - even for a two person household. It is
important to remember that hot water is a constant daily expense; other large
household appliances, like boilers, are seasonal expenses.
Hot water is typically
20% to 30% of the annual utility bill. If you are spending £800 per year on
energy then hot water usage for showers, dishwashing, and laundry is likely to
be costing £160-£240 annually.
Payback calculation
In this calculation assume that gas
prices, maintenance charges and fossil fuel savings grow by 7% per year.
1. Write down an estimate of how much
you pay for water heating this year. This is usually around 25% of you total
energy utility
costs. With an £800 annual bill this figure will be at least £200 a
year. Add your annual maintenance charge to get total annual fuel costs.
2. Increase fuel costs, maintenance
charges and fossil fuel savings at 7% / year.
3. Show cumulative savings from Year 1
to Year 10. Your total outlay for a solar water heating will usually have been
recovered in 10 years or less. Note : a 7% increase in fuel costs is probably
going to be a large under-estimate if recent energy price increases are any
indication of what may happen in the future.
4. You will obviously save a proportion
of your energy costs every year and this will grow as energy prices increase.
Beyond the payback period (which will probably be shorter than you think) your
solar water heating system will be providing
around 60% of annual water heating FREE. If you use underfloor heating there
will also be up to 30% recovery of your space heating costs as well.
We can guarantee
no increases in the cost of solar energy!
Put savings another way, the extra
mortgage loan on a typical £2500 solar heating system will be only
£125.00 per year (assuming interest rate at 5%). A new solar heating system can
save money, reduce pollution and add to the value of your home. Remember
: you buy appliances to do a job at the least cost. No-one expects a payback
from a refrigerator, washing machine or central heating boiler.
Don't forget that all solar savings are
essentially
non-taxable income, so £1.00 saved on your water heating cost is equivalent to £1.30
or more of your taxable income.
Grants News
For domestic customers
the UK Government's
Low Carbon Building Programme (LCBP) is
offering £400 grant on each professionally installed solar water heating
system. In Scotland the grant rate is 30% of the system price up to a maximum
of £4,000.
For business customers
the UK Government's
Enhanced Capital Allowance
(ECA)
scheme allows 100% of investment in solar and other renewable
energy systems in a single tax year to be reclaimed
6.
What about freezes and cloudy weather?
Both active and passive solar
water heating systems come with a 100% lifetime guarantee against freeze
damage. Solar
water heating systems are approved by the UK authorities.
Active solar systems often have
a conventional immersion
heater
element to heat water on the few days in the year when it
might be needed. All solar water heating systems deliver both higher
temperature water and more water volume than conventional water heaters.
7.
What about the appearance of a Solar Collector on your roof?
Today solar collectors are
typically integrated into the slope of the roof. This method of installation
gives the solar collector the appearance of a quality, opaque, glass skylight.
In most cases, since the piping is not seen, it actually improves the
appearance of the home because it looks like an elegant, expensive skylight. Installers
offer
a free solar site survey to determine the location of the solar collector, and
to verify that you will not have any collector shading problems.
8. What about the environmental benefits of going solar?
Any time you use solar
energy to offset the amount of fossil fuels that are burned, you contribute to
everyone's health and welfare. Operating a solar water heater instead of an
electric water heater saves burning fossil fuels and reduces carbon dioxide
emissions (a greenhouse gas) and sulphur dioxide (contributes to acid rain)
emissions. Multiply those emissions per household by all the homes in
the UK and the benefits -- and the air and water -- become even more clear.
Environmental Consciousness is a state that induces action through your belief
in leaving a better world for yourself and future generations.
9. Are
there easy payment deals to let me fit a solar water heating system?
All banks and lending
institutions will loan you money to put in a solar system. The good news is
that even for two people the equity value and savings will result in a net
positive income for the length of the loan and that equity value has been
proven to last over 30 to 40 years. Then the system will generate
non-taxable income each year. Solar hot water systems usually cost
£2,000 to
£4000
depending on the size and type of system you install. The money you
save on your monthly utilities is actually being used to purchase your own
water heating system.
There may also be various local
council or city-wide subsidy schemes; eg. Solar for London.
For
information, pricing and all other requirements contact
sales@energyenv.co.uk
|
