Manual T*SOL basic 5.0 - Valentin Software

User Manual T*SOL 7 System Definition
Gdiff Diffuse solar irradiation striking a tilted surface
TCm Average temperature in the collector
TA Air temperature
fIAM Incident angle modifier
After deduction of optical losses (conversion factor and incident angle modifiers), a part of the absorbed
radiation is lost through heat transfer and radiation to the environment. These losses are described by
the heat transfer coefficient.
The heat transfer coefficient k states how much heat the collector releases into the environment per
square meter of active solar surface and temperature difference between the average collector
temperature and the environment in degrees Kelvin.
It is split into two parts, the simple and the quadratic part. The simple part ko (in W/m²/K) is multiplied by
the simple temperature difference, the quadratic part kq (in W/m²/K²) by its square. This gives rise to the
efficiency parabolae usually stated. Und? Relevance?
The specific heat capacity states the amount of heat per square meter of active solar surface that the
collector, including its heat transfer medium content, can store at a temperature increase of 1 Kelvin. It is
stated in Ws/m²K. This decides how quickly the collector reacts to the irradiation. The influence of this
value is only significant for relative small pipeline networks, as the capacity of the pipeline network
otherwise takes priority.
After leaving the dialog by clicking OK, the system schematic view is updated with the type of collector
selected.
The SRCC box indicates whether this collector has been tested according to the Solar Collector
Certification Program and that the simulation therefore uses different collector temperatures,
respectively.
7.3.1.2 Collector – Optical Losses
S ystem Definitions > Flat-Plate / Tube Collector > Losses / Optical Losses
Image: Calculation of optical collector losses of a
tube collector
The conversion and incident angle modifiers determine the optical losses, i.e. how much of the irradiated
energy is lost through reflection on glass and the absorber. The remainder is absorbed by the collector.
The conversion factor(in %) states amount absorbed with irradiation vertically to the collector surface
area.
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