Merge branch 'master' of https://github.com/space-wizards/space-stati…

…on-14 into upstream-merge-7

Content.Server/Atmos/EntitySystems/HeatExchangerSystem.cs

@@ -58,7 +58,20 @@ private void OnAtmosUpdate(EntityUid uid, HeatExchangerComponent comp, AtmosDevi
         // Positive dN flows from inlet to outlet
         var dt = (float)(_gameTiming.CurTime - device.LastProcess).TotalSeconds;
         var dP = inlet.Air.Pressure - outlet.Air.Pressure;
-        var dN = comp.G*dP*dt;
+
+        // What we want is dN/dt = G*dP (first-order constant-coefficient differential equation w.r.t. P).
+        // However, by approximating dN = G*dP*dt using Forward Euler dN can be larger than all of the gas
+        // available for sufficiently large dP. However, we know that dN cannot exceed:
+        //
+        //   dNMax = (n2T2/V2 - n1T1/V1)/(T2/V1 + T2/V2) = Δp/R/T2/(1/V1 + 1/V2)
+        //
+        // Because that is the amount of gas that needs to be transferred to equalize pressures [citation needed].
+        // So we just limit abs(dN) < abs(dNMax).
+        //
+        // Also, by factoring out dP we can avoid taking any abs().
+        // transferLimit below is equal to dNMax/dP
+        var transferLimit = 1/Atmospherics.R/outlet.Air.Temperature/(1/inlet.Air.Volume + 1/outlet.Air.Volume);
+        var dN = dP*Math.Min(comp.G*dt, transferLimit);
 
         GasMixture xfer;
         if (dN > 0)

Resources/Changelog/Changelog.yml

@@ -1,9 +1,4 @@
 Entries:
-- author: liltenhead
-  changes:
-  - {message: The economy behind timer electronics has crashed., type: Tweak}
-  id: 3984
-  time: '2023-06-13T08:09:18.0000000+00:00'
 - author: metalgearsloth
   changes:
   - {message: Add doorbumpopener to some stuff that should've had it (slimes)., type: Fix}
@@ -2983,3 +2978,8 @@ Entries:
   - {message: Composting produce into trays actually works now., type: Fix}
   id: 4483
   time: '2023-08-08T00:29:59.0000000+00:00'
+- author: Ilya246
+  changes:
+  - {message: Fix radiator transfer rate in high-pressure environments., type: Fix}
+  id: 4484
+  time: '2023-08-08T08:16:23.0000000+00:00'