I would like to open a working group to propose tags for Unitary Equipment.

Much of this work has been done but there is more to do to standardize and integrate typical unitary equipment into a standard model. These will include heat pumps, fan coils, and vav and fan-powered boxes.

I look forward to working with anyone interested!

Hi, we have been working on a number of heat pump systems and would like to offer up what we have developed so far. Hopefully, this will kickstart the process. Following is a summary of proposals and then ending with an entry similar to what you would find in the project-haystack.org documentation, minus the links. I tried to note the salient, new items in parentheses...

Summary

Suggested New Tags

• waterSource or airSource (similar to airCooled or waterCooled on a chiller)
• waterOutput? (don't really like this name to indicate water to water)
  • alternative tagging: waterToWater, waterToAir, airToAir to indicate source and output
• indirectCool or condWaterCool? (create a new tag for this)
• heatPumpMode (we use this like vavMode)
• compressor tag
• reversing tag

Questions

1. Are there other zone types out there?
2. source / output tagging above?
3. condenser water - we use these tags for the condenser water loop points and also use these for indirect cooling points. This is different than the Project Haystack definition, but I think that is because we have moved beyond the original Chiller Plant and AHU definitions. Thoughts?
4. For water to water heat pumps, we are thinking of treating it like a secondaryLoop with a heat pump in place of a heat exchanger. Without opening up the pandora's box of secondaryLoop questions, we propose tagging the output of a water to water heatPump as leaving water and entering water. Thoughts?

Heat Pumps

Overview

The heatPump tag is used to model heat pump assets. Heat Pumps should always be marked as equip.

Tags

Heat Pumps should be classified with the following type tags:

• waterSource or airSource (similar to airCooled or waterCooled on a chiller)
• waterOutput? (don't really like this name to indicate water to water)
• alternative tagging: waterToWater, waterToAir, airToAir to indicate source and output
• coolOnly or heatOnly, if applicable

The additional equip level tags are defined for Heat Pumps:

• hvac: always specified to mark as an HVAC asset
• chilledWaterPlantRef: plant supplying chilled water or condensing water, if applicable
• hotWaterPlantRef: reference plant supplying hot water
• steamPlantRef: reference plant supplying steam

Heating and Cooling Method

Heating method should define their heating method using one of the following tags:

• elecHeat
• hotWaterHeat
• steamHeat
• gasHeat

Cooling method should be defined using one of the following tags:

• indirectCool or condWaterCool? (create a new tag for this)

Constant vs Variable Volume

A heat pump should be tagged as either constantVolume or variableVolume based on its ability to adjust the volume of air flow. Typically this distinction is based on whether the fan is single speed or a VFD.

Zone Delivery

The following tags define the system used to deliver air or water to the zones:

• directZone: Heat Pump supplies air directly to the zone
• radiantZone: Water to Water Heat Pump supplies water to a radiant zone
• other zone types out there?

Sections

Most points for Heat Pumps are associated with one of the following sections of the unit:

• discharge: air exiting the unit to be supplied to the zones/terminal units
• return: air returning from the zone back into the unit
• outside: fresh, outside air entering the unit for air quality (dropped economizing for heat pump)
• cool: cooling mode (dropped elements/coils for mode)
• heat: heating mode (dropped elements/coils for mode)
• zone: conditioned space associated with the unit

Points

The following lists points commonly used with a Heat Pump:

Outside

• outside air temp sensor
• outside air humidity sensor
• outside air pressure sensor
• outside air flow sensor
• outside air flow sp
• outside air damper cmd

Discharge

• discharge air temp sensor
• discharge air pressure sensor
• discharge air flow sensor
• discharge air fan cmd
• discharge air fan sensor
• leaving water temp sensor
• entering water temp sensor

Return

• return air temp sensor

Conditioning

• cool stage cmd
• heat stage cmd
• filter sensor

Zone

• zone air temp sensor
• zone air temp effective sp
• zone air temp occ cooling sp
• zone air temp occ heating sp
• zone air temp unocc cooling sp
• zone air temp unocc heating sp
• zone air temp standby cooling sp
• zone air temp standby heating sp
• zone air co2 sensor
• zone air co2 sp

For water to water heat pumps, see radiant floor section for zone points.

Misc

• hot water coil entering temp sensor
• hot water coil leaving temp sensor
• condenser water entering temp sensor (we use condenser and water tags to indicate condensing water for things like indirect cooling)
• condenser water leaving temp sensor
• heatPumpMode sp (added similar to vavMode)
• occupied sensor
• compressor sensor (new tag for heat pump compressor)
• pump cmd (water to water heat pumps have a pump)
• pump sensor
• reversing valve cmd
• reversing valve sensor (reversing a new tag to indicate a valve that reverse flow)