Merge pull request #55 from pnnl/VAV_turndown

VAV Turndown verification item development

constrain/library/__init__.py

@@ -9,6 +9,7 @@
 from .heat_rejection_fan_var_flow_controls_cells import *
 from .hot_water_reset import *
 from .vav_static_pressure_sensor_location import *
+from .vav_minimum_turndown_during_reheat import *
 from .vav_turndown_during_reheat import *
 from .ventilation_fan_controls import *
 from .wlhp_loop_heat_rejection_controls import *
@@ -68,6 +69,7 @@
     # "optimum_start", # missing
     # "swh_restroom_outlet_maximum_temperature_controls", # missing
     "VAVStaticPressureSensorLocation",
+    "VAVMinimumTurndownDuringReheat",
     "VAVTurndownDuringReheat",
     "VentilationFanControl",
     "WLHPLoopHeatRejectionControl",

constrain/library/vav_minimum_turndown_during_reheat.py

@@ -0,0 +1,63 @@
+"""
+### Description
+When a VAV box is in reheat mode, the ratio of VAV airflow rate to VAV max airflow rate must not be greater than the min design turndown ratio
+
+### Code requirement
+
+- Code Name: ASHRAE 90.1
+- Code Year: 2016
+- Code Section: 6.5.2 Simultaneous Heating and Cooling Limitation
+- Code Subsection: 6.5.2.1 Zone Controls
+
+### Verification Approach
+- We aim to identify how VAV airflow rate varies when the VAV box is and isn't in reheat mode.
+
+### Verification logic
+```
+if reheat_coil_flag:
+  if V_dot_VAV_max == 0
+     Untested
+  if V_dot_VAV_max > 0.0 and V_dot_VAV / V_dot_VAV_max > VAV_min_turndown_design + turndown_tol
+     fail
+  else:
+     pass
+else
+    Untested
+```
+### Data requirements
+- reheat_coil_flag: VAV box reheat coil operation status
+- V_dot_VAV: actual VAV volume flow
+- V_dot_VAV_max: max VAV volume flow
+- VAV_min_turndown_design: design VAV box min turndown ratio
+- turndown_tol: VAV turndown tolerance
+
+"""
+
+from constrain.checklib import RuleCheckBase
+
+
+class VAVMinimumTurndownDuringReheat(RuleCheckBase):
+    points = [
+        "reheat_coil_flag",  # boolean
+        "V_dot_VAV",  # actual VAV volume flow
+        "V_dot_VAV_max",  # max VAV volume flow
+        "VAV_min_turndown_design",
+        "turndown_tol",
+    ]
+
+    def vav_turndown_check(self, data):
+        if data["reheat_coil_flag"]:
+            if data["V_dot_VAV_max"] == 0:
+                return "Untested"
+            elif (
+                data["V_dot_VAV"] / data["V_dot_VAV_max"]
+                > data["VAV_min_turndown_design"] + data["turndown_tol"]
+            ):
+                return False
+            else:
+                return True
+        else:
+            return "Untested"
+
+    def verify(self):
+        self.result = self.df.apply(lambda d: self.vav_turndown_check(d), axis=1)

schema/library.json

@@ -1559,31 +1559,59 @@
             "end"
         ]
     },
+    "VAVMinimumTurndownDuringReheat": {
+        "library_item_id": 68,
+        "description_brief": "When a VAV box is in reheat mode, the ratio of VAV airflow rate to VAV max airflow rate must not be greater than the min design turndown ratio",
+        "description_index": [
+            "Section 6.5.2.1 ASHRAE 90.1-2016"
+        ],
+        "description_datapoints": {
+            "reheat_coil_flag": "VAV box reheat coil operation status",
+            "V_dot_VAV": "VAV airflow rate",
+            "V_dot_VAV_max": "VAV max airflow rate",
+            "VAV_min_turndown_design": "design VAV box min turndown ratio",
+            "turndown_tol": "VAV turndown tolerance"
+        },
+        "description_verification_type": "rule-based",
+        "assertions_type": "pass",
+        "description_assertions": [
+            "if reheat_coil_flag:",
+            "  if V_dot_VAV_max == 0",
+            "     Untested",
+            "  if V_dot_VAV_max > 0.0 and V_dot_VAV / V_dot_VAV_max > VAV_min_turndown_design + turndown_tol",
+            "     fail",
+            "  else:",
+            "     pass",
+            "else",
+            "    Untested",
+            "end"
+        ]
+    },
     "VAVTurndownDuringReheat": {
-    "library_item_id": 68,
-    "description_brief": "When a VAV box is in reheat mode, the ratio of V_dot_VAV to V_dot_VAV_max should be higher than when it isn't in reheat mode",
-    "description_index": [
-       "Section 6.5.2.1 ASHRAE 90.1-2016"
-    ],
-    "description_datapoints": {
-       "reheat_coil_flag": "VAV box reheat coil operation status",
-       "V_dot_VAV": "VAV airflow rate",
-       "V_dot_VAV_max": "VAV max airflow rate"
-    },
-    "description_verification_type": "procedure-based",
-    "assertions_type": "pass",
-    "description_assertions": [
-       "if (reheat_coil_flag == False).all():", 
-       "    Untested",
-       "else: ",
-       "  V_dot_VAV_ratio = V_dot_VAV/V_dot_VAV_max",
-       "  mean_reheat_ratio = df.loc[self.df[`reheat_coil_flag`], `V_dot_VAV_ratio`].mean()",
-       "  mean_no_reheat_ratio = df.loc[~self.df[`reheat_coil_flag`], `V_dot_VAV_ratio`].mean()",
-       "  if mean_reheat_ratio < mean_no_reheat_ratio:",
-       "    pass",
-       "  else: ",
-       "    fail",
-       "end"
-    ]
+        "library_item_id": 69,
+        "description_brief": "When a VAV box is in reheat mode, the ratio of V_dot_VAV to V_dot_VAV_max should be higher than when it isn't in reheat mode",
+        "description_index": [
+            "Section 6.5.2.1 ASHRAE 90.1-2016"
+        ],
+        "description_datapoints": {
+            "reheat_coil_flag": "VAV box reheat coil operation status",
+            "V_dot_VAV": "VAV airflow rate",
+            "V_dot_VAV_max": "VAV max airflow rate"
+        },
+        "description_verification_type": "procedure-based",
+        "assertions_type": "pass",
+        "description_assertions": [
+            "if (reheat_coil_flag == False).all():",
+            "    Untested",
+            "else: ",
+            "  V_dot_VAV_ratio = V_dot_VAV/V_dot_VAV_max",
+            "  mean_reheat_ratio = df.loc[self.df[`reheat_coil_flag`], `V_dot_VAV_ratio`].mean()",
+            "  mean_no_reheat_ratio = df.loc[~self.df[`reheat_coil_flag`], `V_dot_VAV_ratio`].mean()",
+            "  if mean_reheat_ratio < mean_no_reheat_ratio:",
+            "    pass",
+            "  else: ",
+            "    fail",
+            "end"
+        ]
     }
 }

tests/test_vav_minimum_turndown_during_reheat.py

@@ -0,0 +1,150 @@
+import sys
+import unittest
+
+sys.path.append("./constrain")
+import datetime
+
+import pandas as pd
+from lib_unit_test_runner import *
+
+
+class TestVAVTurndown(unittest.TestCase):
+    def test_vav_turndown_untested(self):
+        points = [
+            "reheat_coil_flag",
+            "V_dot_VAV",
+            "V_dot_VAV_max",
+            "VAV_min_turndown_design",
+            "turndown_tol",
+        ]
+
+        timestamp = [
+            datetime(2024, 8, 1, 12, 0, 0),
+            datetime(2024, 8, 1, 13, 0, 0),
+        ]
+
+        data = [
+            [False, 0.005, 0.01, 0.3, 0.01],
+            [False, 0.005, 0.01, 0.3, 0.01],
+        ]
+
+        df = pd.DataFrame(data, columns=points, index=timestamp)
+
+        verification_obj = run_test_verification_with_data(
+            "VAVMinimumTurndownDuringReheat", df
+        )
+        results = list(verification_obj.result)
+        expected_results = [
+            "Untested",
+            "Untested",
+        ]
+
+        self.assertEqual(results, expected_results)
+        self.assertEqual(verification_obj.check_bool(), "Untested")
+
+    def test_vav_turndown_V_dot_max_zero_untested(self):
+        points = [
+            "reheat_coil_flag",
+            "V_dot_VAV",
+            "V_dot_VAV_max",
+            "VAV_min_turndown_design",
+            "turndown_tol",
+        ]
+
+        timestamp = [
+            datetime(2024, 8, 1, 12, 0, 0),
+            datetime(2024, 8, 1, 13, 0, 0),
+        ]
+
+        data = [
+            [True, 0.005, 0.0, 0.3, 0.01],
+            [True, 0.005, 0.0, 0.3, 0.01],
+        ]
+
+        df = pd.DataFrame(data, columns=points, index=timestamp)
+
+        verification_obj = run_test_verification_with_data(
+            "VAVMinimumTurndownDuringReheat", df
+        )
+        results = list(verification_obj.result)
+        expected_results = [
+            "Untested",
+            "Untested",
+        ]
+
+        self.assertEqual(results, expected_results)
+        self.assertEqual(verification_obj.check_bool(), "Untested")
+
+    def test_vav_turndown_pass(self):
+        points = [
+            "reheat_coil_flag",
+            "V_dot_VAV",
+            "V_dot_VAV_max",
+            "VAV_min_turndown_design",
+            "turndown_tol",
+        ]
+
+        timestamp = [
+            datetime(2024, 8, 1, 12, 0, 0),
+            datetime(2024, 8, 1, 13, 0, 0),
+        ]
+
+        data = [
+            [True, 0.005, 0.06, 0.3, 0.01],
+            [True, 0.005, 0.06, 0.3, 0.01],
+        ]
+
+        df = pd.DataFrame(data, columns=points, index=timestamp)
+
+        verification_obj = run_test_verification_with_data(
+            "VAVMinimumTurndownDuringReheat", df
+        )
+
+        results = pd.Series(list(verification_obj.result))
+        expected_results = pd.Series(
+            [
+                True,
+                True,
+            ]
+        )
+        self.assertTrue(results.equals(expected_results))
+
+        binary_result = verification_obj.check_bool()
+        self.assertTrue(binary_result)
+
+    def test_vav_turndown_fail(self):
+        points = [
+            "reheat_coil_flag",
+            "V_dot_VAV",
+            "V_dot_VAV_max",
+            "VAV_min_turndown_design",
+            "turndown_tol",
+        ]
+
+        timestamp = [
+            datetime(2024, 8, 1, 12, 0, 0),
+            datetime(2024, 8, 1, 13, 0, 0),
+        ]
+
+        data = [
+            [True, 0.005, 0.01, 0.3, 0.01],
+            [True, 0.005, 0.01, 0.3, 0.01],
+        ]
+
+        df = pd.DataFrame(data, columns=points, index=timestamp)
+
+        verification_obj = run_test_verification_with_data(
+            "VAVMinimumTurndownDuringReheat", df
+        )
+
+        results = pd.Series(list(verification_obj.result))
+        expected_results = pd.Series(
+            [
+                False,
+                False,
+            ]
+        )
+        self.assertTrue(results.equals(expected_results))
+
+        binary_result = verification_obj.check_bool()
+        self.assertFalse(binary_result)