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Solar Panels Types and
their Residential Uses
When choosing the solar panels type for your home, take into
account….
- the types of thermal panels:
1) Solar unglazed panels, 2) Solar flat-glazed panels and 3)
Solar evacuated tubes panels (and eventually in some very
special cases concentrating panels…)
- the uses intended for the residential solar panels: 1)
swimming pools heating 2) solar water heating (including their
uses in radiators, radiant floor or in other heating system) 3)
solar space heating and 4) solar air conditioning
- the price of the different types of panels
- the temperatures demanded by the applications and the
temperatures offered by the different type of panels
- the climate issue
We develop these topics below.
Best solar panel: the price issue
It doesn’t exist
a best type of solar panel. The best depends much
on climate and on the type of the intended residential solar
applications, and is also closely related with the price issue.
As we pass from 1) unglazed solar panels to 2) glazed solar
panels and on to 3) evacuated tubes panels the prices increase.
We can use evacuated tube solar panels in swimming pools
heating, but it would be too expensive. Evacuated tubes panels
are more efficient (30% or so) than unglazed panels but these
last collectors are much cheaper (1/5 – 1/10 of the cost of
evacuated panels), and with some extra unglazed surface we can
reach the same effectiveness of evacuated tub panels.
Similarly, we can also use evacuated tube panels in domestic
water heating, but in most cases the difference of efficiency
doesn’t justify the difference of price. Flat-glazed panels
usually present a better relation efficiency/price in spite of
recent developments in evacuated tube panels technology and
correlated increases of competitiveness.
Best solar panel:
the temperature demanded by the application
Different residential applications demand different temperatures
from the solar panels, which explain that each type of panel
dominates a particular range of applications:
- unglazed pool collectors dominate in low temperature
applications (0-25 °F/0-14ºC above ambient temperatures),
- flat plates panels dominate in the mid-range temperature
applications (25-125 °F /14- 50ºC above ambient temperatures)
- evacuated tubes panels dominate at upper temperatures (125+ °F
/ 50+ ºC above ambient temperatures).
The reason of these needs is rather obvious: whereas panels on
most pools operate within 10-20 °F above ambient temperatures,
residential solar panels for water heating, for instance,
operate in a wide range of temperatures above ambient in close
connection with season, climate and the particular applications.
That’s why in the first case unglazed solar panels are perfectly
suitable, but not in the last case, where it is needed a flat
glazed solar panel or even an evacuated tube panel…
Climate Impact on Solar Panels
Performance
Climate – expressed by solar irradiance, that is,
the amount of sunshine received on the collector – is an
important factor for determining the most suitable solar panel.
The basic rule is: the lower the amount of sun, the greater the
advantage of flat-glazed over flat-unglazed and of evacuated
tube over flat-glazed and unglazed panels.
In climates with many sunny days, glazed flat
panels may outperform evacuated tubes in many residential
applications. They are cheaper and in average and they have a
better relation performance/price.
In other words: while some applications in cold climates demand
evacuated tube panels (capable of generate higher temperatures),
these same application in mild and hot climates may only demand
flat-glazed panels or even unglazed panels.
Anyway the results vary according with the particularities of
local climates (namely with the number of cold and cloudy days)
and in the future with the variations on the prices of the solar
panels. Evacuated tube panels are becoming cheaper, and begin to
gain some of the segments of the market previously occupied by
the flat-plate panels.
Summary on the residential uses of the different types of
thermal solar
panels
Since choice depends greatly on 1) prices, 2) temperatures and
the 3) climate and uses intended for the solar panels, it is
possible to draw some rough conclusions about the most suitable
solar panels for the several solar applications:
Solar Unglazed panels
They are used in swimming pools and simple house space heating
(solar air heater panels with no heat storage, designed just to
heat a room or a small part of the house). Unglazed panels are
used in solar applications demanding low temperatures. They have
a wider range of particular applications in sunny climates,
where they can substitute more expensive panels.

Image credit:
EERE
Solar Air-Flat glazed panels
They are mainly used in solar space
heating, and may be tied to forced air systems. They have some
advantages over solar liquid-flat panels (they produce heat
earlier and later in the day than liquid systems, they do not
freeze and the consequences of eventual leaks are minimal) but
they are also less efficient than liquid collectors, and aren’t
as flexible in their applications.
Solar Liquid-flat glazed panels
These panels can be used in solar
domestic water heating systems and for central heating
(integrated in systems involving forced air systems, radiators
or radiant heating). They are a flexible, tested and competitive
option.
Evacuated tube panels
They share most of the applications of
flat glazed panels, mainly the more demanding applications
(those that demand higher temperatures); they are the most
powerful solution for more demanding applications: solar
cooling, demanding radiant heating systems. They aren’t as
common as solar flat glazed panels, but their presence are
increasing in cold and cloudy climates, due to their higher
average performance. A possible scenario is an increasing use of
evacuated tube panels technology in cold and cloudy climates,
while flat panels technology will maintain or even increase its
importance in sunnier climates.
Solar Electric panels
The production of solar electricity demand a special type of
collectors: the PV solar panels. See
Solar Electricity: Photovoltaic PV Systems
See also:
Basics of
solar systems
Domestic Solar Hot Water Systems
Solar Space Heating basics
Solar Space Heating in
radiators, radiant floor and air forced systems
Solar Cooling
Sizing Solar Systems
Solar Systems Orientation and
Location
Pros and Cons of Solar
Energy Panels
Costs and payback of
Solar Energy
Solar Panels Technology
Quotes and the
buying process
Market and Prices of Solar Hot
Water Systems
Market and Prices of Solar PV
Electricity
Manufacturers of Solar
Power Systems
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