Frequently asked questions - Solar Heating The following questions have been taken from the SEI Greener homes application guide.
If any of the answers do not seem to cover the quiestions thoroughly enough, please feel free to get in touch!
Sizing and design How are your hot water requirements calculated and how is the solar water
heater sized? RVR Solar Systems are sized based
on the amount of hot water used in the home they are installed in. As a
rule of thumb, 60 litres of storage is a good amount per person per day. The
surface area of panel recommended per person is between 0.7 and 1
square metre with vacuum tube collectors, due to their high
efficiency. We would recommend between 1 and 1.5 square metres
per person with flat panel collectors A typical system would
consist of between 4.3 and 5 metres squared of collector (2 panels)
and a 300 litre hot water cylinder. This would cater for the hot water
needs of about 5 people. Is the solar system configured according to the
manufacturer�s specifications? Of course. All RVR Solar
Systems are configured according to the operating specifications of the
manufacturer. Our installation instructions and advice are provided after
close consultation with our suppliers regarding system pressure, safety
requirements and best practices. What percentage of your hot water requirement will be
covered by the solar water heater? Over the course of a year a
correctly sized systems will provide between 60 and 70% of water heating
needs in most situations. Water heating typically accounts for between 30%
and 40% of a household's annual
heating bill. By applying these figures to your own bill, you should be able to
get a better idea of the order of your savings. Is the location of the solar panels (orientation,
tilt, visual aspect) appropriate? For optimum efficiency, solar
panels should be mounted facing due south. However, the efficiency loss when panels are south-east or south-west facing
is only around 6%. Panels can be mounted as far as west or east,
however the efficiency loss at these headings is about 25%. Of course,
this can be countered simply by installing a larger surface area of panels. Solar collectors cannot be
faced north, as the sun is in
the south. The angle of mounting is typically determined by
the angle of your roof. However, panels can also be mounted on a flat roof
or on the ground. A good rule of thumb is that the optimum angle to use is
about the same as your latitude, or between 51 and 55 degrees for Ireland. However, any angle between 30 and 60 degrees is quite acceptable. Is there any disruption of the building structure required to install the
system? The structure of your building may be disrupted
only where running pipework is required, or a replacement hot water cylinder is
to be installed that is larger than your existing cylinder. In most cases,
there should be no or very little disruption. Removal of slate or tile is
not required on your roof, as panels are mounted by means of a hangar bolt
screwed directly through your roof, into the rafters. How is back-up heating going to be provided?
The basic principle of a
solar system system is to heat the water in your hot water
cylinder. Typically, RVR Solar Systems do this by use of a dual
coil cylinder.
Your existing system -
e.g. your gas or oil boiler / pellet burner continues to
heat the upper coil in this cylinder, while the solar system heats
the lower. In most cases, an immersion can also be used. Is the system regulated to bring the hot water to 60 degrees C at least once daily?
It is essential that stored hot
water is brought to 60 degrees C at least once daily in order to prevent the growth of
the a dangerous bacteria called legionella. This type of bacteria is a
problem in any situation where water is stored, not just solar systems. These bacteria can reproduce relatively quickly in lukewarm water which is
stored, however are unable to survive in cold or hot temperatures. During the summer months, a
correctly sized RVR
solar system can easily keep the temperature in your cylinder at 60 degrees
during the day -
overnight, there will only be a few degrees of temperature lost in your
cylinder. In wintertime
however, there is only enough sun to cater for about 15% of the water heating. When this happens, your existing boiler or immersion will bring the water in
your cylinder up to temperature. It is absolutely essential that you have
a means of water heating alongside your solar collectors! Equipment Are the solar panels and storage tank certified by a quality label and a CE
compliance label (see
front page)? Certainly. All our
collectors are CE marked. Our solar collector supplier, Calpak, is
certified under the Solar Keymark standard and all their collectors have had appropriate
testing by the Swiss SPF institute. Are all the flashing and fixing components for the
panels provided? Fixing components
differ according to mounting location. RVR supply both sloped roof
mounting brackets and flat roof uprights as accessories to
all our solar systems. Do all the materials used conform to the solar system
manufacturer�s specifications? Yes. Quality of materials
is essential. All piping systems and fittings supplied by RVR are suitable
for use in the high temperatures that our solar systems operate. Our
pre-insulated piping is UV resistant, as is the material used in the collectors
we supply. The bracketing systems we supply for roof mounting are made
from 304 grade stainless steel, to ensure a corrosion free mounting of your
collectors. Is the system protected against overheating, freezing
and excessive pressure? Overheating protection is
provided through the use of a high quality control system. However, a
backup safety device should always be installed in the form of a mixing /
blending valve on your hot water cylinder. This is essential to ensure
water never leaves the cylinder at a temperature higher than 50 degrees C. In this case, even if the appropriate controls fail, there is no risk of scalds or burns. In addition to these safety features, all pipework and
materials supplied by RVR are designed to accommodate the high temperatures
encountered in solar systems. The fluid used in our solar
collectors is a mix of water and 40% propylene glycol (food grade antifreeze). This will provide protection from freezing in temperatures as low as -23 degrees C. This will certainly cover Irish temperatures - The lowest
air temperature recorded in Ireland was -19. degrees C measured at Markree Castle, Co.
Sligo in 1881 while the lowest observed 20th century air temperature was -18.8 degrees C
recorded at Lullymore, Co. Kildare in 1979. All RVR Solar Systems are designed to use an
expansion vessel to cater for increased pressure, as our systems are
closed systems. As a result, there is no loss of thermal fluid at high pressure,
so there is no need to top up your solar system under normal operation. What is the performance rating of the solar collectors under expected
operating conditions? The performance rating of our collectors varies
according to model. Performance ratings are listed on all the pre-filled
greener homes scheme application forms throughout the site. Costs and payment What elements (equipment and labour) are covered by the quotation? Is there
additional cost? At present, RVR do not provide an installation
service. We can certainly put you in touch with an installer in your area,
with whom we would have an existing relationship. Exact equipment prices
and details are listed in detail on their respective pages. Prices listed
exclude VAT and do not cover the cost of installation. What is the range of annual savings under average conditions? As covered earlier, over the course of a year
a correctly sized systems will provide between 60 and 70% of water heating
needs in most situations. Water heating typically accounts for between 30%
and 40% of a household's annual
heating bill. By applying these figures to your own bill, you should be able to
get a better idea of the order of your savings. What are the financing options or payment terms? At present, RVR do not provide finance options
for our equipment. Payment terms are as covered under our normal terms of
sale. Installation and Commissioning Does the dealer offer delivery, installation, commissioning and after sales
service? RVR do not presently
perform installation or commissioning. However, we can certainly recommend
a qualified installer who can carry out installation. Our after sales
service is no different from the rest of the equipment we supply, and we can
happily provide technical advice about installation and proper running of your
system. Delivery nationwide is for a flat fee of just €15,
regardless of the size of your order. The following questions are
proposed by the SEI, however they are questions only an individual installer can
answer. As our equipment is already approved for use
under the greener homes scheme, you will naturally need an installer who is also
approved for the scheme. Any installer we recommend will have both
knowledge of our systems and will be SEI approved. - What is the training or accreditation of the installers involved in the
installation?
- Which trade associations do the installers belong to?
- Has the contractor installed a solar water heater in his house?
- How many systems has the dealer installed;are local references available?
- How much of the installation will be sub-contracted?
- Who is ultimately responsible for what segments of work?
- How long will the installation take?
- Who cleans up inside / outside?
- Who is responsible for commissioning the system?
Installation should generally take a day or less,
however in some cases there may be a longer period of work involved. What are the procedure and tests carried out when commissioning the system? Further information about the procedures involved in installation can be found
in our Technical section, in the pdf document titled "RVR Solar Systems Installation Instructions". After-sales services What is the manufacturer�s or supplier�s warranty for each component of the
system? All solar systems are required under european
directives to carry a minimum 5 years warranty. What guarantees / warranties are provided for the installation? RVR offer the same terms and conditions on solar
systems as on the rest of equipment we supply. Is an annual service contract available from the supplier? RVR do not provide an annual service contract at
present, however your installer may be happy to offer you one. Is full documentation, including the user�s manual, provided? Of course. Additional technical support is
also available from RVR at any time. All user manuals and downloadable
guides and instructions will be made available on RVR.ie as they are available,
and are supplied to the customer at no charge. How does the dealer provide emergency service work if required? We can certainly arrange for work to be carried
out in case of an emergency. With dedicated service technicians, you can
have peace of mind about your system. Also, with a network of contractors nationwide, we
are in an excellent position to recommend a local contractor should you prefer. Contact us Should you have any further questions or queries
not covered in this FAQ, please feel free to get in touch with us at
websales@rvr.ie.
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