Make thermomachines more thermodynamically sound (#18984)

Co-authored-by: Ilya246 <ilyukarno@gmail.com>

Content.Server/Atmos/Piping/Unary/Components/GasThermoMachineComponent.cs

@@ -12,9 +12,8 @@ namespace Content.Server.Atmos.Piping.Unary.Components
         public string InletName = "pipe";
 
         /// <summary>
-        ///     Current maximum temperature, calculated from <see cref="BaseHeatCapacity"/> and the quality of matter
-        ///     bins. The heat capacity effectively determines the rate at which the thermo machine can add or remove
-        ///     heat from a pipenet.
+        ///     Current electrical power consumption, in watts. Increasing power increases the ability of the
+        ///     thermomachine to heat or cool air.
         /// </summary>
         [ViewVariables(VVAccess.ReadWrite)]
         public float HeatCapacity = 10000;
@@ -30,12 +29,31 @@ namespace Content.Server.Atmos.Piping.Unary.Components
         [ViewVariables(VVAccess.ReadWrite)]
         public float TargetTemperature = Atmospherics.T20C;
 
-        [DataField("mode")]
-        public ThermoMachineMode Mode = ThermoMachineMode.Freezer;
+        /// <summary>
+        ///     Tolerance for temperature setpoint hysteresis.
+        /// </summary>
+        [ViewVariables(VVAccess.ReadOnly)]
+        public float TemperatureTolerance = 2f;
+
+        /// <summary>
+        ///     Implements setpoint hysteresis to prevent heater from rapidly cycling on and off at setpoint.
+        ///     If true, add Sign(Cp)*TemperatureTolerance to the temperature setpoint.
+        /// </summary>
+        [ViewVariables(VVAccess.ReadOnly)]
+        public bool HysteresisState = false;
+
+        /// <summary>
+        ///     Coefficient of performance. Output power / input power.
+        ///     Positive for heaters, negative for freezers.
+        /// </summary>
+        [DataField("coefficientOfPerformance")]
+        [ViewVariables(VVAccess.ReadWrite)]
+        public float Cp = 0.9f; // output power / input power, positive is heat
 
         /// <summary>
         ///     Current minimum temperature, calculated from <see cref="InitialMinTemperature"/> and <see
         ///     cref="MinTemperatureDelta"/>.
+        ///     Ignored if heater.
         /// </summary>
         [ViewVariables(VVAccess.ReadWrite)]
         public float MinTemperature;
@@ -43,6 +61,7 @@ namespace Content.Server.Atmos.Piping.Unary.Components
         /// <summary>
         ///     Current maximum temperature, calculated from <see cref="InitialMaxTemperature"/> and <see
         ///     cref="MaxTemperatureDelta"/>.
+        ///     Ignored if freezer.
         /// </summary>
         [ViewVariables(VVAccess.ReadWrite)]
         public float MaxTemperature;