Unmet Hours

Plant Loop Issues - Pump availability and heat pump water heater tank

asked 2018-02-23 14:30:55 -0600

jkneifel
121 ●3

updated 2018-02-23 15:16:34 -0600

__AmirRoth__

4446 ●5 ●17 http://bleedinggreenna...

I am trying to create the necessary plant loops for a DHW system with indirect solar thermal pre-heating with a heat pump water heater. I have been able to create both plant loops, but cannot find how to define availability managers. Is this still something that requires a measure that adds them using AvailabilityManager_DifferentialThermostat as discussed in "Fix 2410 - Implemented AvailabilityManagerAssignmentList and all missing AVMs" (https://github.com/NREL/OpenStudio/pu... Also, I am using the new Water Heater Heat Pump options in OS and there appears to be a disconnect between the Water Heater Heat Pump and Plant Loop. I have added the Water Heater Heat Pump as zone equipment, but the tank defined by the heat pump does not show up in My Model for me to drag and drop the tank onto the plant loop. I cannot drag and drop the water heater heat pump directly onto the plant loop either. Is there a work around for this issue and will it be addressed in the next release? Thanks.

answered 2018-02-26 08:51:26 -0600

jkneifel
121 ●3

I have found a temporary solution to this existing issue, but it requires manual edits to the OSM. This could also be done using a Measure.

(1) Add the HPWH to zone equipment (2) Add a water heater tank to the plant loop (3) open the OSM in text editor and delete the water heater tank object associated with the HP (4) change the nodes on the HP to connect to the water heater tank on the plant loop. (5) save and reopen in OS. This will lead to OS correctly matching the tank to the HP

As for the availability manager, you can manually add them to the OS file in a text editor. It requires... (1) creating the differential thermostat object (2) creating the availability manager list object (3) adding this list to the plant loop object

OS:AvailabilityManagerAssignmentList, {c37d0fc6-ae31-4e72-9740-0dbee26f38ba}, !- Handle Plant Loop AvailabilityManagerAssignmentList, !- Name {c37d0fc6-ae31-4e72-9740-0dbee26f38bb}; !- Availability Manager Name 1

OS:AvailabilityManager:DifferentialThermostat, {c37d0fc6-ae31-4e72-9740-0dbee26f38bb}, !- Handle Plant Loop Differential Thermostat, !- Name Node 41, !- Hot Node Node 40, !- Cold Node 10, !- Temperature Difference On Limit {deltaC} 3; !- Temperature Difference Off Limit {deltaC}