Changeset 4730 for palm

Timestamp:

Oct 7, 2020 10:48:51 AM (4 years ago)

Author:

suehring

Message:

Indoor model: bugfix - avoid divisions by zero

File:

• palm/trunk/SOURCE/indoor_model_mod.f90 (modified) (3 diffs)

palm/trunk/SOURCE/indoor_model_mod.f90

@@ -20 +20 @@
 ! Current revisions:
 ! -----------------
-! 
-! 
+!
+!
 ! Former revisions:
 ! -----------------
 ! $Id$
+! Bugfix - avoid divisions by zero
+! 
+! 4709 2020-09-28 19:20:00Z maronga
 ! Bugfix: avoid division by zero in case of zero window fraction (now also for vertical walls).
 ! Reactivated waste heat.
@@ -1408 +1411 @@
                                              near_facade_temperature, phi_hc_nd, buildings(nb)%theta_m_t_prev_h(fa) )
                 theta_air_10 = theta_air                                                !< temperature with 10 W/m2 of heating
-                phi_hc_nd_un = phi_hc_nd_10 * (theta_air_set - theta_air_0)                        &
-                                            / (theta_air_10  - theta_air_0)             !< Eq. (C.13)
+!
+!--             Avoid division by zero at first timestep where the denominator can become zero.
+                IF ( ABS( theta_air_10  - theta_air_0 ) < 1E-10_wp )  THEN
+                   phi_hc_nd_un = phi_hc_nd_10
+                ELSE
+                   phi_hc_nd_un = phi_hc_nd_10 * ( theta_air_set - theta_air_0 )                   &
+                                               / ( theta_air_10  - theta_air_0 )             !< Eq. (C.13)
+                ENDIF
 !
 !--             Step 3: with temperature ratio to determine the heating or cooling capacity.
@@ -1648 +1657 @@
 
                 theta_air_10 = theta_air !< Note the temperature with 10 W/m2 of heating
-
-                phi_hc_nd_un = phi_hc_nd_10 * ( theta_air_set - theta_air_0 )                      &
-                                            / ( theta_air_10  - theta_air_0 )            !< Eq. (C.13)
+!
+!--             Avoid division by zero at first timestep where the denominator can become zero.
+                IF ( ABS( theta_air_10  - theta_air_0 ) < 1E-10_wp )  THEN
+                   phi_hc_nd_un = phi_hc_nd_10
+                ELSE
+                   phi_hc_nd_un = phi_hc_nd_10 * ( theta_air_set - theta_air_0 )                   &
+                                               / ( theta_air_10  - theta_air_0 )             !< Eq. (C.13)
+                ENDIF
 !
 !--             Step 3: with temperature ratio to determine the heating or cooling capacity