Inquiries about HXN errors

Hello, when I execute ```HXN```, the following error will be reported, which is caused by unit ```H102```, which is heating N2 under high pressure (Nitrogen is used to provide an inert environment for the glucose reaction). May I ask how to solve this error? Is it because ```N2.Cn.l.method = N2.Cn.g.method = "COOLPROP"``` (https://biosteam.readthedocs.io/en/latest/tutorial/Convergence.html#Importance-of-thermodynamic-property-package:~:text=N2.Cn.l.method%20%3D%20N2.Cn.g.method%20%3D%20%22COOLPROP%22%20%23%20You%20may%20need%20to%20%22pip%20install%20coolprop%22%20for%20this%0AN2.reset_free_energies()%20%23%20This%20is%20necessary%20to%20update%20enthalpy%20and%20entropy%20algorithms%20with%20new%20heat%20capacities%0Asys.reset_cache()) is not added?
Some of the code for H102 is as follows.
```
import biosteam as bst
bst.nbtutorial()
bst.settings.set_thermo(['nitrogen'])
nitrogen = bst.Stream(
ID='nitrogen',
total_flow=100,
units='kg/hr',
N2=1,
phase='g',
)
C101 = bst.units.IsothermalCompressor('C101', nitrogen, P=7000000)
H102 = bst.units.HXutility('H102', C101-0, T=200+273.15, rigorous=True)
HXN = bst.HeatExchangerNetwork('HXN', T_min_app = 10)
sys = bst.main_flowsheet.create_system('sys')
sys.simulate()

```
The error information is as follows.
```
File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_system.py:2631, in System.simulate(self, update_configuration, units, design_and_cost, **kwargs)
2611 def simulate(self, update_configuration: Optional[bool]=None, units=None,
2612 design_and_cost=None, **kwargs):
2613 """
2614 If system is dynamic, run the system dynamically. Otherwise, converge
2615 the path of unit operations to steady state. After running/converging
(...)
2629
2630 """
-> 2631 with self.flowsheet.temporary():
2632 specifications = self._specifications
2633 if specifications and not self._running_specifications:

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_flowsheet.py:38, in TemporaryFlowsheet.__exit__(self, type, exception, traceback)
36 def __exit__(self, type, exception, traceback):
37 main_flowsheet.set_flowsheet(self.original)
---> 38 if exception: raise exception

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_system.py:2687, in System.simulate(self, update_configuration, units, design_and_cost, **kwargs)
2681 outputs = self.simulate(
2682 update_configuration=True,
2683 design_and_cost=design_and_cost,
2684 **kwargs
2685 )
2686 else:
-> 2687 raise error
2688 else:
2689 if (not update_configuration # Avoid infinite loop
2690 and self._connections != [i.get_connection() for i in self.streams]):
2691 # Connections has been updated within simulation.

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_system.py:2675, in System.simulate(self, update_configuration, units, design_and_cost, **kwargs)
2673 try:
2674 outputs = self.converge(**kwargs)
-> 2675 if design_and_cost: self._summary()
2676 except Exception as error:
2677 if update_configuration: raise error # Avoid infinite loop

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_system.py:2390, in System._summary(self)
2388 f(i, i._summary)
2389 for i in self._facilities:
-> 2390 if isa(i, Unit): f(i, i.simulate)
2391 elif isa(i, System):
2392 f(i, i.converge)

File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\exceptions.py:94, in try_method_with_object_stamp(object, method, args)
92 raise StampedKeyError(message_with_object_stamp(object, repr(error.args[0])))
93 except Exception as error:
---> 94 raise_error_with_object_stamp(object, error)

File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\exceptions.py:84, in raise_error_with_object_stamp(object, error)
82 error.args = (message_with_object_stamp(object, msg), *args)
83 except: pass
---> 84 raise error

File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\exceptions.py:88, in try_method_with_object_stamp(object, method, args)
86 def try_method_with_object_stamp(object, method, args=()):
87 try:
---> 88 return method(*args)
89 except StampedKeyError as error:
90 raise StampedKeyError(message_with_object_stamp(object, error.args[0]))

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_unit.py:1097, in Unit.simulate(self, run, design_kwargs, cost_kwargs)
1095 self._load_stream_links()
1096 self.run()
-> 1097 self._summary(design_kwargs, cost_kwargs)

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_unit.py:975, in Unit._summary(self, design_kwargs, cost_kwargs, lca_kwargs)
973 if not self._skip_simulation_when_inlets_are_empty or not all([i.isempty() for i in self._ins]):
974 self._design(**design_kwargs) if design_kwargs else self._design()
--> 975 self._cost(**cost_kwargs) if cost_kwargs else self._cost()
976 self._lca(**lca_kwargs) if lca_kwargs else self._lca()
977 self._check_utilities()

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\facilities\hxn\_heat_exchanger_network.py:155, in HeatExchangerNetwork._cost(self)
150 hxs = [hu.unit for hu in hx_utils]
151 use_cached_network = (
152 sorted(hxs, key=lambda x: x.ID)
153 == sorted(self.original_heat_exchangers, key=lambda x: x.ID)
154 )
--> 155 with flowsheet.temporary(), bst.IgnoreDockingWarnings():
156 if use_cached_network:
157 hx_heat_utils_rearranged = [i.heat_utilities[0] for i in hxs]

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_flowsheet.py:38, in TemporaryFlowsheet.__exit__(self, type, exception, traceback)
36 def __exit__(self, type, exception, traceback):
37 main_flowsheet.set_flowsheet(self.original)
---> 38 if exception: raise exception

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\facilities\hxn\_heat_exchanger_network.py:155, in HeatExchangerNetwork._cost(self)
150 hxs = [hu.unit for hu in hx_utils]
151 use_cached_network = (
152 sorted(hxs, key=lambda x: x.ID)
153 == sorted(self.original_heat_exchangers, key=lambda x: x.ID)
154 )
--> 155 with flowsheet.temporary(), bst.IgnoreDockingWarnings():
156 if use_cached_network:
157 hx_heat_utils_rearranged = [i.heat_utilities[0] for i in hxs]

File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\network.py:270, in IgnoreDockingWarnings.__exit__(self, type, exception, traceback)
268 global DOCKING_WARNINGS
269 DOCKING_WARNINGS = self.original_value
--> 270 if exception: raise exception

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\facilities\hxn\_heat_exchanger_network.py:191, in HeatExchangerNetwork._cost(self)
186 self.HXN_flowsheet = HXN_F = bst.main_flowsheet
187 for i in HXN_F.registries: i.clear()
188 HXs_hot_side, HXs_cold_side, new_HX_utils, hxs, T_in_arr,\
189 T_out_arr, pinch_T_arr, C_flow_vector, hx_heat_utils_rearranged, streams_inlet, stream_HXs_dict,\
190 hot_indices, cold_indices = \
--> 191 synthesize_network(hx_utils, self.T_min_app, self.Qmin,
192 self.force_ideal_thermo, self.avoid_recycle)
193 new_HXs = HXs_hot_side + HXs_cold_side
194 self.cold_indices = cold_indices

File D:\anaconda\envs\zddd\lib\site-packages\biosteam\facilities\hxn\hxn_synthesis.py:541, in synthesize_network(hus, T_min_app, Qmin, force_ideal_thermo, avoid_recycle)
539 new_HX_util._run()
540 s_out = new_HX_util.outs[0]
--> 541 np.testing.assert_allclose(s_out.H, H_out_arr[cold], rtol=1e-2, atol=1.)
542 atol_T = 5. if 's' in hxs[cold].outs[0].phases else 0.001
543 np.testing.assert_allclose(s_out.T, T_out_arr[cold], rtol=5e-2, atol=atol_T)

[... skipping hidden 1 frame]

File D:\anaconda\envs\zddd\lib\contextlib.py:79, in ContextDecorator.__call__..inner(*args, **kwds)
76 @wraps(func)
77 def inner(*args, **kwds):
78 with self._recreate_cm():
---> 79 return func(*args, **kwds)

File D:\anaconda\envs\zddd\lib\site-packages\numpy\testing\_private\utils.py:797, in assert_array_compare(comparison, x, y, err_msg, verbose, header, precision, equal_nan, equal_inf, strict)
793 err_msg += '\n' + '\n'.join(remarks)
794 msg = build_err_msg([ox, oy], err_msg,
795 verbose=verbose, header=header,
796 names=('x', 'y'), precision=precision)
--> 797 raise AssertionError(msg)
798 except ValueError:
799 import traceback

AssertionError:
Not equal to tolerance rtol=0.01, atol=1

Mismatched elements: 1 / 1 (100%)
Max absolute difference: 584904.311
Max relative difference: 0.178
x: array(2693095.764976)
y: array(3278000.076034)

```