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Solar Panel Types
Solar Electric and Solar Thermal
Panels
There are solar panels for...
1) solar electric productions and
2) solar domestic water-heating, or house air/space
heating and cooling
This page deals with solar thermal panels.
Solar Thermal Panels
Solar panels are – obviously – the key elements
of any solar heating or cooling system. It is they that gather
and transform the sun’s energy into heat, which is then
transferred to water or air or other fluid…
The uses of thermal solar panels in households
are mainly three:
- solar water-heating
- solar swimming pool heating
- solar space heating (or
cooling)
Types of solar thermal panels
There are two big types of solar collectors:
- flat-plate panels and
- evacuated-tube panels
We can also consider the concentrating type
panels, with a very little use on solar home applications.
Flat-plate solar panels
Flat-plate collectors are the most common type of
solar panels. They are basically an insulated metal box and a
dark-colored absorber plate. Most boxes are covered with a
“glazing”: a glass or plastic cover.
These collectors heat liquid or air at
temperatures less than 180°F.
Image Credit:
EERE
Besides the glazed type of solar flat-plate
panels, there are also other much cheaper unglazed panels, very
used in swimming pool heating and in very simple solutions of
home space heating ….
Liquid and air flat-plate panels
Solar flat panels can be liquid or air
flat-plate.
Liquid flat-plate collectors heat liquid as the
liquid flows in the system. The simplest systems use domestic
water, heated as it passes through the interior of the
collector.
Air flat-plate collectors are very similar to
liquid-plate collectors. They just use air instead of a liquid
medium. But since air is a worse conductor of heat, this type of
panels is less efficient and has a more limited range of
applications. They are mostly used on stand-alone space heating
solutions.
Evacuated-tube collectors
Evacuated tube panels are typically made of rows
of glass tubes, each of which contains a glass outer tube and an
attached metal absorber tube with a fin covered with a coating
(responsible for the absorbing and retaining of solar energy
heat). The name of these collectors is due to the fact that air
is “evacuated” from the space between the two glass tubes to
form a vacuum that eliminates heat loss.
These type of panels are increasingly
cost-competitive relatively to flat-plate panels, but are still
more expensive than these. Their advantage is on the much higher
temperatures they are able to generate (170–350°F/75º-176ºC are
common), making them particularly suitable for home applications
demanding high temperatures.
Image Credit:
EERE
Concentrating collectors – as the parabolic
troughs using mirrored surfaces to concentrate solar energy on
an absorber tube that contains a fluid – are able to produce yet
more high temperatures (300º C/570°F).
But they are scarcely used on residential
applications. They are expensive and involve a large set of
demanding requirements and configurations. They are used in
large projects and electrical generation. The true alternative
concerning solar panels for residential applications is between
flat-plate and evacuated solar panels.
The best choice: solar flat-plate panels or evacuated panels?
There is some polemic about which is the best solar panel: the
evacuated collectors or the flat-plate type? The truth is that
there isn’t exactly a best solar panel. It depends on several
factors, and mainly from the climate, uses and needed
temperatures.
Home applications that require temperatures below
200°F/93ºC use mostly flat-plate collectors; swimming pools
applications use unglazed flat-plate collectors. House
applications requiring temperatures above 200°F/93ºC use
evacuated-tube collectors.
See also:
Basics of
solar systems
Domestic Solar Hot Water Systems
Solar Electricity: Photovoltaic PV Systems
Solar Space Heating basics
Solar Space Heating in
radiators, radiant floor and air forced systems
Solar Cooling
Types of solar water
heating systems
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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