Questions regarding CSV input of hybrid heat pumps

[DorinevanderVlies]

Through issue #1556 importing hybrid heat pumps through a csv file was enabled, thanks!

I have some questions on how to properly use this new feature and how to interpret it.

• The node to which the technology is attached has a different name than the end node e.g. households_space_heater_hybrid_heatpump_air_water_electricity@buffer_space_heating_1.
  Do I have to use similar names (technology@buffer) if I want to import a hybrid heat pump through a CSV?
• The number of units for the technology is 1, instead of 576, which is the number of heat pumps. The capacity is still the same (4.9 for the electric part).
  Why is the number of units 1 and not the same as the hybrid heat pump? Is the capacity still 4.9*total number of heat pumps?
• The last column of the CSV is new and called export_key. I noticed that in a scenario without hybrid heat pumps this column is not required, in a scenario with hybrid heat pumps it is.
  Is that observation correct?
  When I fill this column am I correct to assume the formula to do so is "type@buffer"
• This question is not really related to the CSV input and might need to be a new issue. @grdw if you agree I will make it one: In real life the same hybrid heatpump supplies both the water and the space heating demand. So, the capacity of the heat pump has to be split between them. Right now it looks to me like the hybrid heat pump for space and water heating are two unrelated technologies.
  So the capacity which they represent in the model is bigger in the model than in real life, to me this seems undesirable. Is that indeed the case?

This is a LES containing nothing but hybrid heat pumps.

[grdw]

The node to which the technology is attached has a different name than the end node e.g. households_space_heater_hybrid_heatpump_air_water_electricity@buffer_space_heating_1. Do I have to use similar names (technology@buffer) if I want to import a hybrid heat pump through a CSV?
The last column of the CSV is new and called export_key. I noticed that in a scenario without hybrid heat pumps this column is not required, in a scenario with hybrid heat pumps it is.
Is that observation correct?

To explain. The export_key and the connection are meant to connect the 2 different components of the hybrid heat pump to the hybrid heat pump. To visualize it a little:

<node>
└── <buffer>
     └── <hhp>
          └── <hhp-part>

The CSV data is flat so there needs to be a "connection column" between the hhp and the hhp-part which is export_key <-> connection.

When I fill this column am I correct to assume the formula to do so is "type@buffer"

Yes.

The number of units for the technology is 1, instead of 576, which is the number of heat pumps. The capacity is still the same (4.9 for the electric part).
Why is the number of units 1 and not the same as the hybrid heat pump? Is the capacity still 4.9*total number of heat pumps?

This is a good question. I'm not sure if the number_of_units for a hhp part have any effect, but I can't say for sure. I need to investigate this.

This question is not really related to the CSV input and might need to be a new issue. @grdw if you agree I will make it one: In real life the same hybrid heatpump supplies both the water and the space heating demand. So, the capacity of the heat pump has to be split between them. Right now it looks to me like the hybrid heat pump for space and water heating are two unrelated technologies.

This seems like a good question for @ChaelKruip. It sounds allright to me, but than again I don't know why the initial approach was to have 2 separate technologies.