[Bldg-sim] WLHP Loop with Chilled Water and Geothermal Water Sources

[Xiaobing Liu]

Dan:
 
For your simulation, I think you can model it as a typical boiler and cooling tower system and then convert the heat rejection and heat addition loads of WLHP loop to the required energy use of the hot and cold water if you know the efficiency of the heat exchanger that isolates the WLHP loop from the hot/cold water. It may be a bit more challenging if you want to couple the chilled water system with the WLHP system. My initial thought is that you can create a dummy zone that is cooled by the chilled water system and has the internal load identical with the heat rejection load of the WLHP. You may have to run the simulation twice and manually input the internal load to the dummy zone. Why don't you use cooling tower to cool the WLHP water? Cooling tower should be cheaper to run than the chiller.
 
Regarding eQUEST using PVVT to represent air-side of WLHP (water-to-air heat pump), the reason is PVVT has more flexibility to model packaged DX coil unit. By specifying stages of cooling and heating capacity, minimum airflow ratio, and applying proper performance curves, PVVT can model either conventional heat pump with single stage compressor and constant speed fan, or more advanced heat pump with two-stage  compressor and variable speed fan. In addition, with PVVT, you can simulate a DOAS that heats and/or cools the OA with a water-to-air heat pump after OA is preconditioned with ERV.
 
Hope it helps,
 
Xiaobing

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org]On Behalf Of Dan Russell
Sent: Tuesday, September 16, 2008 11:43 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] WLHP Loop with Chilled Water and Geothermal Water Sources



I have a building that is predominantly VAV with UFAD using a boiler/chiller plant.  However, one portion of the building is residential which we would like to use WLHP's for.  I would like to use purchased hot water (geothermal at 110 deg from City) and the chilled water from the building plant to maintain the WLHP Loop between 60 and 90 deg.  

 

Any ideas on how to model this?

 

Also, I've been a bit confused on how eQuest uses PVVT systems to represent the air-side of WLHP systems.  Any references or resources anyone has that explains the theory behind this would be greatly appreciated.

 

Thanks,  

 

 Dan Russell, EIT 

 

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