SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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1VII Further components of a solar system© target GmbH
Detailed sketch of a solar system
Source: Wagner & Co
2VII Further components of a solar system© target GmbH
Collector loop – rinsing, filling and ventilation
Source: Ambiente Italia
p
pump and safety group
collector
to the heat exchangerof the storage
ventilation
insulation
rinsing and filling
central ventilation
SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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3VII Further components of a solar system© target GmbH
Ventilation of large collector fields
Source: Solarpraxis
• lockable vent or hand vent in the collector field
• vent temperature resistant up to 170 °C
• centrifugal vent, adsorption or absorption ventas central vent in the cellar
• air collection tank
• moderating sections
4VII Further components of a solar system© target GmbH
Tubes – insulation for the exterior
Source: AEE, Aeroflex, Armacell, Sonnenkraft
Attention: temperatures up to 200 °C
Suitable insulating material: mineral fibrous insulating materialAeroflex-tubesArmaflex-tubes
external protection necessary!
SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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5VII Further components of a solar system© target GmbH
Tubes – insulation for the interior
Source: AEE
• insulation of mountings• insulation of valves• use of prefabricated
insulation jackets
• 100 % insulation• mechanical protection• labelling
6VII Further components of a solar system© target GmbH
Hydraulic in case of several storage tank
Source: AEE
store 1 store 2 store 3
cold water
hot water
store 4
supply withspace heat andtap water
colle
ctor
field
conventional heat producer
SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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7VII Further components of a solar system© target GmbH
Control
Source: AEE
T1 > (T2 + 7 K) —> P1 ON
heat exchanger = 5 K, primary losses = 2 K)
T3 > (T2 + 5 K) —> P2 ON
heat exchanger = 5 K)
speed control of P2, sothat T5 = 65 °C
speed control of P1, so
5-6 3-4 = const.
reduction of rotation speedof P1 and P2to a max. of 25 % of the nominal speed
T4
T5
T2
T6
colle
ctor
fieldT1
that and
8VII Further components of a solar system© target GmbH
Control through a radiation sensor
Source: AEE
T1E
T2
colle
ctor
field
• The radiation sensor can bea reasonable supplement forthe temperature measurement.
• P1 can then be operated throughthe radiation sensor (E).
• T3 is thus relevant for the charging of the storage tank through P2 (if P1 is in operation).
SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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9VII Further components of a solar system© target GmbH
Additional control functions
Source: M. Schnauss
• Rotation speed control
• Collector protection function
• Antifreeze function
• Data recording
• Error display
• Error diagnosis
• Remote monitoring
• Performance survey/control
• Input-Output-Control
10VII Further components of a solar system© target GmbH
Heat meter
Source: ZfU/HWK
A heat meter
displays,
• the heat amount the solar system has fed into the storage tank,
and does not display,
• whether the solar system has been working properly,• for how long the sun has been shining,• in what way the customers have been using the system.
SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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11VII Further components of a solar system© target GmbH
Most frequent deficiencies of solar thermal systemsafter 15–20 years
Source: Peuser, ZfS
Storage tank corrosionExpansion tank
Discolouration of the absorberControl
Storage tank leakageDiscolouration of the collector frame
Cracks in the collector frameAbsorber leakages
Ventilation problemsRoof leakages
Absorber corrosionCollector loop pump
Release of safety valveBreakage of glass
Pipelines at the exteriorInsulation at the exterior
Condensate in the collectorLeakage in collector loop
Examination of 113 solar thermal systems on public buildings between 1978 and 1983 (frequency in %)
12VII Further components of a solar system© target GmbH
Input-Output-Controller (I)
Source: R. Tepe
Why performance and function control?
• Malfunctions of a solar system are, due to the operation of the backup heating, often only discovered after a long time
(detection of the error by chance or in the framework of the next routine maintenance)
• A performance breakdown is leading to not foreseen additional costs.
SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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13VII Further components of a solar system© target GmbH
Input-Output-Controller (II)
Source: R. Tepe
Additional costs due to a performance breakdown
Period between breakdown and detection
Summer month
Half a year
Whole year
Small system Medium system Large system
Additional backup heating costs in €
14VII Further components of a solar system© target GmbH
Input-Output-Controller (III)
Source: R. Tepe, Grafik: Fa. RESOL, Hattingen
Principle of the Input-Output-Controller
Performance control through daily comparison
of measured output
and expected output
of the collector loop
SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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15VII Further components of a solar system© target GmbH
Input-Output-Controller (IV)
Source: R. Tepe
Characteristics of the Input-Output-Controller
• minor costs
• steady and automatic control
• high control precision
• easy to operate
• trouble indication on the device and/or as message to a mobile phone
• certification of the devices foreseen
• can be used without adaptation for different system variations
16VII Further components of a solar system© target GmbH
Input-Output-Controller (V)
Source: ISFH
Typical input-output-diagram
Daily
outp
ut
QKK [kWh/(m²·d)]
Daily irradiation HDay [kWh/(m²·d)]
measured value
expected value
malfunction
SOLARGE – Professional Training: Collective Solar Thermal Systems VII Further components of a solar system
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17VII Further components of a solar system© target GmbH
Input-Output-Controller (VI)
Source: RESOL
IO-Control module of the company RESOL
