TOC

1. Intro
2. TagModel
3. Structure
4. TimeZones
5. Units
6. Grids
7. Filters
8. Zinc
9. Json
10. Trio
11. Csv
12. Rest
13. Ops
14. Auth
15. VFDs
16. Networks
17. Energy
18. Zones
19. AHUs
20. VAVs
21. UnitaryEquips
22. Chillers
    1. Overview
    2. Chilled Water Plants
    3. Chillers
    4. Cooling Towers
    5. Heat Exchangers
23. Boilers
24. Tanks
25. ElecPanels
26. Lighting
27. Builds
28. Bacnet
29. ChangeLog
30. License

Chillers

Overview

A chilled water plant is composed of multiple pieces of equipment used to generate chilled water. The entire plant is modeled as an equip with its own plant-level points. Sub-equipment such as chillers and cooling towers are also modeled as equip contained by the plant via the equipRef tag.

The follow diagram shows the terminology used for logical flow of water through a plant:

Note that the terminology for sensors/setpoints are based on the perspective of the equipment. The condenser water leaving the chiller, is the condenser water entering the cooling tower.

Chilled Water Plants

We model the entire plant using the chilledWaterPlant tag. The plant is modeled as an equip and it will define its own plant level points:

Chilled water to/from AHUs

• chilled water leaving temp sensor
• chilled water leaving temp sp
• chilled water leaving flow sensor
• chilled water leaving pressure sensor
• chilled water entering temp sensor
• chilled water entering flow sensor
• chilled water entering pressure sensor
• chilled water delta temp sensor
• chilled water delta flow sensor
• chilled water delta pressure sensor
• chilled water delta pressure sp
• chilled water bypass valve cmd

Condenser water between Chillers/Cooling Towers

• condenser water delta pressure sensor
• condenser water bypass valve cmd

Note: not every combination of sp is listed, just most common setpoints.

We also define the following tags for pipework ands its associated equip and points:

• primaryLoop: pipework within the plant
• secondaryLoop: pipework from the plant to the building

Chillers

Chiller equips are marked with the chiller tag. Equip level tags:

• equipRef must reference parent chilledWaterPlant if associated with a plant
• waterCooled or airCooled
• absorption or if vapor compression: reciprocal, screw, or centrifugal
• coolingCapacity

Points associated with chiller equip:

Run/Status

• run cmd
• run sensor
• enable cmd
• load cmd
• load sensor
• efficiency sensor
• power sensor
• energy sensor

Chilled water to/from AHUs

• chilled water leaving temp sensor
• chilled water leaving temp sp
• chilled water leaving flow sensor
• chilled water leaving pressure sensor
• chilled water entering temp sensor
• chilled water entering flow sensor
• chilled water entering pressure sensor
• chilled water delta temp sensor
• chilled water delta flow sensor
• chilled water delta pressure sensor
• chilled water valve isolation cmd

Condenser water to/from cooling towers

• condenser water leaving temp sensor
• condenser water leaving flow sensor
• condenser water leaving pressure sensor
• condenser water entering temp sensor
• condenser water entering pressure sensor
• condenser water entering flow sensor
• condenser water valve isolation cmd

Misc Internal

• condenser cmd
• condenser refrig temp sensor
• condenser refrig pressure sensor
• evaporator refrig temp sensor
• evaporator refrig pressure sensor

Note: not every combination of sp is listed, just most common setpoints. Chillers share the same point modeling conventions as VFDs. Chillers which measure energy should model their points using the same conventions as elec meters or thermal meters.

Cooling Towers

Cooling towers equips are marked with the coolingTower tag. Equip level tags:

• equipRef must reference parent chilledWaterPlant if associated with a plant
• openLoop or closedLoop

Points associated with cooling tower equip:

• condenser water leaving temp sensor
• condenser water leaving temp sp
• condenser water leaving flow sensor
• condenser water leaving pressure sensor
• condenser water entering temp sensor
• condenser water entering pressure sensor
• condenser water entering flow sensor
• fan cmd
• fan sensor

Heat Exchangers

Heat exchangers are tagged with heatExchanger. Equip level tags:

• equipRef must reference parent chilledWaterPlant if associated with a plant

Points associated with heat exchanger equip:

• chilled water leaving temp sensor
• chilled water entering temp sensor
• condenser water leaving temp sensor
• condenser water entering flow sensor