From ceacacd4b8b78a2fff810c0c830d6a2553982743 Mon Sep 17 00:00:00 2001
From: Yalin <mailto.yalin.li@gmail.com>
Date: Fri, 12 Jul 2024 15:27:18 -0400
Subject: [PATCH] update with newer biosteam

---
 qsdsan/_sanunit.py                  |  5 +++
 qsdsan/sanunits/_heat_exchanging.py | 68 +++++++++++++++++++++--------
 2 files changed, 55 insertions(+), 18 deletions(-)

diff --git a/qsdsan/_sanunit.py b/qsdsan/_sanunit.py
index 30f0bdcf..2a9cbbb0 100644
--- a/qsdsan/_sanunit.py
+++ b/qsdsan/_sanunit.py
@@ -208,6 +208,11 @@ def __init__(self, ID='', ins=None, outs=(), thermo=None, init_with='WasteStream
         #: value.
         self.parallel: dict[str, int] = {}
 
+        #: Unit design decisions that must be solved to satisfy specifications.
+        #: While adding responses is optional, simulations benefit from responses
+        #: by being able to predict better guesses.
+        self.responses: set[bst.GenericResponse] = set()
+
         if not kwargs.get('skip_property_package_check'):
             self._assert_compatible_property_package()
             
diff --git a/qsdsan/sanunits/_heat_exchanging.py b/qsdsan/sanunits/_heat_exchanging.py
index d539d8b7..2c707d1e 100644
--- a/qsdsan/sanunits/_heat_exchanging.py
+++ b/qsdsan/sanunits/_heat_exchanging.py
@@ -106,16 +106,21 @@ class HXprocess(SanUnit, HXP):
     _N_ins = HXP._N_ins
     _N_outs = HXP._N_outs
 
-    def __init__(self, ID='', ins=None, outs=(), thermo=None,
-                 init_with='Stream', F_BM_default=None,
-                 *, U=None, dT=5., T_lim0=None, T_lim1=None,
-                 material="Carbon steel/carbon steel",
-                 heat_exchanger_type="Floating head",
-                 N_shells=2, ft=None,
-                 phase0=None,
-                 phase1=None,
-                 H_lim0=None,
-                 H_lim1=None):
+    def __init__(
+            self, ID='', ins=None, outs=(), thermo=None,
+            init_with='Stream', F_BM_default=None, *,
+            U=None, dT=5., T_lim0=None, T_lim1=None,
+            material="Carbon steel/carbon steel",
+            heat_exchanger_type="Floating head",
+            N_shells=2, ft=None, 
+            phase0=None,
+            phase1=None,
+            H_lim0=None,
+            H_lim1=None,
+            inner_fluid_pressure_drop=None,
+            outer_fluid_pressure_drop=None,
+            neglect_pressure_drop=True,
+        ):
         SanUnit.__init__(self, ID, ins, outs, thermo,
                          init_with=init_with, F_BM_default=F_BM_default)
 
@@ -155,6 +160,15 @@ def __init__(self, ID='', ins=None, outs=(), thermo=None,
         self.material = material
         self.heat_exchanger_type = heat_exchanger_type
         self.reset_streams_at_setup = False
+        
+        #: Optional[float] Pressure drop along the inner fluid.
+        self.inner_fluid_pressure_drop = inner_fluid_pressure_drop
+        
+        #: Optional[float] Pressure drop along the outer fluid.
+        self.outer_fluid_pressure_drop = outer_fluid_pressure_drop
+        
+        #: [bool] Whether to assume a negligible pressure drop.
+        self.neglect_pressure_drop = neglect_pressure_drop
 
 
 class HXutility(SanUnit, HXU):
@@ -176,6 +190,7 @@ class HXutility(SanUnit, HXU):
     
     line = HXU.line
     _graphics = HXU._graphics
+    
     _units = {'Area': 'ft^2',
               'Total tube length': 'ft',
               'Inner pipe weight': 'kg',
@@ -190,14 +205,22 @@ class HXutility(SanUnit, HXU):
                'Horizontal vessel diameter': (3, 21),
                'Vertical vessel length': (12, 40)}
     
-    def __init__(self, ID='', ins=None, outs=(), thermo=None,
-                 init_with='Stream', F_BM_default=None,
-                 include_construction=True,
-                 *, T=None, V=None, rigorous=False, U=None, H=None,
-                 heat_exchanger_type="Floating head",
-                 material="Carbon steel/carbon steel",
-                 N_shells=2, ft=None, heat_only=None, cool_only=None,
-                 heat_transfer_efficiency=None):
+    def __init__(
+            self, ID='', ins=None, outs=(), thermo=None,
+            init_with='Stream', F_BM_default=None,
+            include_construction=True,
+            T=None, V=None, rigorous=False, U=None, H=None,
+            heat_exchanger_type="Floating head",
+            material="Carbon steel/carbon steel",
+            N_shells=2,
+            ft=None,
+            heat_only=None,
+            cool_only=None,
+            heat_transfer_efficiency=None,
+            inner_fluid_pressure_drop=None,
+            outer_fluid_pressure_drop=None,
+            neglect_pressure_drop=True,
+            ):
             SanUnit.__init__(self, ID, ins, outs, thermo,
                              init_with=init_with, F_BM_default=F_BM_default,
                              include_construction=include_construction,)
@@ -226,6 +249,15 @@ def __init__(self, ID='', ins=None, outs=(), thermo=None,
             self.material = material
             self.heat_exchanger_type = heat_exchanger_type
 
+            #: Optional[float] Pressure drop along the inner fluid.
+            self.inner_fluid_pressure_drop = inner_fluid_pressure_drop
+            
+            #: Optional[float] Pressure drop along the outer fluid.
+            self.outer_fluid_pressure_drop = outer_fluid_pressure_drop
+            
+            #: [bool] Whether to assume a negligible pressure drop.
+            self.neglect_pressure_drop = neglect_pressure_drop
+
             #: [bool] User enforced heat transfer efficiency. A value less than 1
             #: means that a fraction of heat transferred is lost to the environment.
             #: If value is None, it defaults to the heat transfer efficiency of the