I am trying to make a model for a refrigeration cycle in excel with COPr as an output. For part of this I need lookup the entalpy which requires pressure AND temperature, so two inputs. I tried to do this with a HLOOKUP function, however when I got the the row-index-number I did not know what to do because this is not a fixed value.
How do I make the row-index number a variable in HLOOKUP (or VLOOKUP) so that it will look up the value of enthalpy for the combination of pressure and temperature that is given?
This is the table that I am using, this should clarify it a bit more:
The output that I want when pressure and temperature are provided:
In this case T=-10 C and P=3 Mpa, so I want a function that returns 176.3 for these inputs.