fix: return zero rates instead of NaN for zero-rate compressor timesteps (#1535)

docs: changelog entry for zero-rate NaN fix

Author: olelod

docs/drafts/next.draft.md

@@ -15,6 +15,7 @@ STP: "flare" column has been added to STP Export - for `FIXED` installations onl
 
 - Hardened compressor PH flash handling so invalid thermodynamic states are no longer used in compressor outlet calculations.
 - `LiquidRemover` now scales the outlet mass rate by the gas mass fraction when liquid is dropped, so the removed liquid mass is no longer carried by the gas stream downstream.
+- Compressor stage rate fields (`inlet_actual_rate`, `mass_rate`, `standard_rate`, etc.) now report `0.0` instead of `NaN` for zero-rate timesteps, so yearly resampling no longer forward-fills stale positive values into idle periods.
 
 ## Breaking changes
 

src/libecalc/domain/process/compressor/core/results.py

@@ -84,65 +84,57 @@ def create_empty(cls) -> CompressorTrainStageResultSingleTimeStep:
     def inlet_actual_rate_m3_per_hour(self) -> float:
         """Actual inlet rate in Am3/hour."""
         if self.inlet_stream is None:
-            return np.nan
-        else:
-            return self.inlet_stream.volumetric_rate_m3_per_hour
+            return 0.0
+        return self.inlet_stream.volumetric_rate_m3_per_hour
 
     @property
     def inlet_actual_rate_asv_corrected_m3_per_hour(self) -> float:
         """Actual inlet rate in Am3/hour, corrected for ASV."""
         if self.inlet_stream_including_asv is None:
-            return np.nan
-        else:
-            return self.inlet_stream_including_asv.volumetric_rate_m3_per_hour
+            return 0.0
+        return self.inlet_stream_including_asv.volumetric_rate_m3_per_hour
 
     @property
     def standard_rate_sm3_per_day(self) -> float:
         """Standard inlet rate in Sm3/day."""
         if self.inlet_stream is None:
-            return np.nan
-        else:
-            return self.inlet_stream.standard_rate_sm3_per_day
+            return 0.0
+        return self.inlet_stream.standard_rate_sm3_per_day
 
     @property
     def standard_rate_asv_corrected_sm3_per_day(self) -> float:
         """Standard inlet rate in Sm3/day, corrected for ASV."""
         if self.inlet_stream_including_asv is None:
-            return np.nan
-        else:
-            return self.inlet_stream_including_asv.standard_rate_sm3_per_day
+            return 0.0
+        return self.inlet_stream_including_asv.standard_rate_sm3_per_day
 
     @property
     def outlet_actual_rate_m3_per_hour(self) -> float:
         """Actual outlet rate in Am3/hour."""
         if self.outlet_stream is None:
-            return np.nan
-        else:
-            return self.outlet_stream.volumetric_rate_m3_per_hour
+            return 0.0
+        return self.outlet_stream.volumetric_rate_m3_per_hour
 
     @property
     def outlet_actual_rate_asv_corrected_m3_per_hour(self) -> float:
         """Actual outlet rate in Am3/hour, corrected for ASV."""
         if self.outlet_stream_including_asv is None:
-            return np.nan
-        else:
-            return self.outlet_stream_including_asv.volumetric_rate_m3_per_hour
+            return 0.0
+        return self.outlet_stream_including_asv.volumetric_rate_m3_per_hour
 
     @property
     def mass_rate_kg_per_hour(self) -> float:
         """Mass rate in kg/hour"""
         if self.inlet_stream is None:
-            return np.nan
-        else:
-            return self.inlet_stream.mass_rate_kg_per_h
+            return 0.0
+        return self.inlet_stream.mass_rate_kg_per_h
 
     @property
     def mass_rate_asv_corrected_kg_per_hour(self) -> float:
         """Mass rate in kg/hour, corrected for ASV."""
         if self.inlet_stream_including_asv is None:
-            return np.nan
-        else:
-            return self.inlet_stream_including_asv.mass_rate_kg_per_h
+            return 0.0
+        return self.inlet_stream_including_asv.mass_rate_kg_per_h
 
     @property
     def is_valid(self) -> bool: