Update calculation of IndoorCapillaryTemperature

Thanks to ginkage/MHI-AC-Ctrl-ESPHome#159

Author: hberntsen

esphome/components/MhiAcCtrl/MHI-AC-CTRL-operation-data.h

@@ -102,10 +102,14 @@ namespace operation_data {
     this->last_value * 0.327f - 11.4f) // only rough approximation
 
   /// a.k.a THI-R2
-  DEFINE_OPERATION_DATA_CLASS(IndoorCapillaryTemperature, 0x40, 0x81, uint8_t, uint8_t,
+  ///
+  /// Value uses renewed calculation of 2025-07-08, calculation needs to be confirmed.
+  /// Calculation from https://github.com/ginkage/MHI-AC-Ctrl-ESPHome/pull/159
+  /// Also see https://github.com/ginkage/MHI-AC-Ctrl-ESPHome/issues/145#issuecomment-3078841631
+  DEFINE_OPERATION_DATA_CLASS(IndoorCapillaryTemperature, 0x40, 0x81, uint8_t, float,
     mosi_frame[DB9] == 0x81 && (mosi_frame[DB6] & 0x80) == 0 && (mosi_frame[DB10] & 0x30) == 0x10,
     mosi_frame[DB11],
-    this->last_value) // formula for calculation not known
+    0.275f * this->last_value - 47.0f)
 
   /// a.k.a THI-R3
   DEFINE_OPERATION_DATA_CLASS(IndoorSuctionHeaderTemperature, 0xc0, 0x87, uint8_t, float,

esphome/example.yaml

@@ -170,6 +170,9 @@ sensor:
     # Calculation marked as 'to be confirmed' in mhi-ac-ctrl
     compressor_frequency:
       name: ${device_name} compressor frequency
+    # See https://github.com/ginkage/MHI-AC-Ctrl-ESPHome/issues/145#issuecomment-3078841631
+    indoor_capillary_temperature:
+      name: ${device_name} indoor capillary temperature
 
     # These two are marked as only a rough apprximation in mhi-ac-ctrl
     indoor_u_bend_temperature:
@@ -178,8 +181,6 @@ sensor:
       name: ${device_name} indoor suction header temperature
 
     # Formula for calculation not known for the following sensors:
-    indoor_capillary_temperature:
-      name: ${device_name} indoor capillary temperature
     outdoor_heat_exchanger_temperature_1:
       name: ${device_name} outdoor heat exchanger temperature 1
     compressor_discharge_pipe_super_heat_temperature: