Add guidance about temperature modeling to User Guide #2591
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| .. _temperature: | ||||||
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| Temperature models | ||||||
| ================== | ||||||
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| pvlib provides a variety of models for predicting the operating temperature | ||||||
| of a PV module from irradiance and weather inputs. These models range from | ||||||
| simple empirical equations requiring just a few multiplications to more complex | ||||||
| thermal balance models with numerical integration. | ||||||
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| Types of models | ||||||
| --------------- | ||||||
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| Temperature models predict one of two quantities: | ||||||
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| - *module temperature*: the temperature as measured at the back surface | ||||||
| of a PV module. Easy to measure, but usually a few degrees less | ||||||
| than the cell temperature which determines efficiency. | ||||||
| - *cell temperature*: the temperature of the PV cell itself. The relevant | ||||||
| temperature for PV modeling, but almost never measured directly. | ||||||
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| Cell temperature is typically thought to be slightly higher than module | ||||||
| temperature. | ||||||
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Shall we delete this? It seems to be covered in the point above that I commented on separately. It also reads a bit disjointed to me |
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| Temperature models estimate these quantities using inputs like incident | ||||||
| irradiance, ambient temperature, and wind speed. Each model also takes | ||||||
| a set of parameter values that represent how a PV module responds to | ||||||
| those inputs. Parameter values generally depend on both the PV | ||||||
| module technologies and the mounting conditions of the module. | ||||||
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| Another way to classify temperature models is whether they account for | ||||||
| the thermal inertia of a PV module. Temperature models are either: | ||||||
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| - *steady-state*: the module is assumed to have been at the specified operating | ||||||
| conditions for a sufficiently long time for its temperature to reach | ||||||
| equilibrium. | ||||||
| - *transient*: the module's thermal inertia is included in the model, | ||||||
| causing a lag in modeled temperature change following changes in the inputs. | ||||||
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| Other effects that temperature models may consider include the | ||||||
| photoconversion efficiency and radiative cooling. | ||||||
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| The temperature models currently available in pvlib are summarized in the | ||||||
| following table: | ||||||
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| +-------------------------------------------+--------+------------+--------------------------------------------------------------------+ | ||||||
| | Model | Type | Transient? | Inputs | | ||||||
| | | | +----------------+---------------------+------------+----------------+ | ||||||
| | | | | POA irradiance | Ambient temperature | Wind speed | Downwelling IR | | ||||||
|
There was a problem hiding this comment. Do you think "IR" is obvious or should we include a note defining the acronym? |
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| +===========================================+========+============+================+=====================+============+================+ | ||||||
| | :py:func:`~pvlib.temperature.faiman` | either | | ✓ | ✓ | ✓ | | | ||||||
| +-------------------------------------------+--------+------------+----------------+---------------------+------------+----------------+ | ||||||
| | :py:func:`~pvlib.temperature.faiman_rad` | either | | ✓ | ✓ | ✓ | ✓ | | ||||||
| +-------------------------------------------+--------+------------+----------------+---------------------+------------+----------------+ | ||||||
| | :py:func:`~pvlib.temperature.fuentes` | cell | ✓ | ✓ | ✓ | ✓ | | | ||||||
| +-------------------------------------------+--------+------------+----------------+---------------------+------------+----------------+ | ||||||
| | :py:func:`~pvlib.temperature.noct_sam` | cell | | ✓ | ✓ | ✓ | | | ||||||
| +-------------------------------------------+--------+------------+----------------+---------------------+------------+----------------+ | ||||||
| | :py:func:`~pvlib.temperature.pvsyst_cell` | cell | | ✓ | ✓ | ✓ | | | ||||||
| +-------------------------------------------+--------+------------+----------------+---------------------+------------+----------------+ | ||||||
| | :py:func:`~pvlib.temperature.ross` | cell | | ✓ | ✓ | | | | ||||||
| +-------------------------------------------+--------+------------+----------------+---------------------+------------+----------------+ | ||||||
| | :py:func:`~pvlib.temperature.sapm_cell` | cell | | ✓ | ✓ | ✓ | | | ||||||
| +-------------------------------------------+--------+------------+----------------+---------------------+------------+----------------+ | ||||||
| | :py:func:`~pvlib.temperature.sapm_module` | module | | ✓ | ✓ | ✓ | | | ||||||
| +-------------------------------------------+--------+------------+----------------+---------------------+------------+----------------+ | ||||||
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| Model parameters | ||||||
| ---------------- | ||||||
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| Some temperature model functions provide default values for their parameters, | ||||||
| and several additional sets of temperature model parameter values are | ||||||
| available in :py:data:`pvlib.temperature.TEMPERATURE_MODEL_PARAMETERS`. | ||||||
| However, these generic values may not be suitable for all modules and mounting | ||||||
| configurations. | ||||||
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| Module-specific values can be obtained via testing, for example following | ||||||
| the IEC 61853-2 standard. | ||||||
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| Currently, pvlib provides no functionality for fitting parameter values | ||||||
| using measured temperature. | ||||||
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There was a problem hiding this comment. I think we should at least mention the conversion capabilities in |
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| Other functions | ||||||
| --------------- | ||||||
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| pvlib also provides a few other functions for temperature modeling: | ||||||
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| - :py:func:`~pvlib.temperature.prilliman`: an "add-on" model that reprocesses | ||||||
| the output of a steady-state model to apply transient effects. | ||||||
| - :py:func:`~pvlib.temperature.sapm_cell_from_module`: a model for | ||||||
| estimating cell temperature from module temperature. | ||||||
| - :py:func:`~pvlib.temperature.generic_linear`: a generic linear model form, | ||||||
| equivalent to several conventional temperature models. | ||||||
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I prefer not to add this pseudo–/semi-quantification, in case anyone misunderstands and really extracts a quantitative difference here that they then overgeneralize. If it's less we can just say less, and if we want to explain a relation we can do that.