[Bldg-sim] WLHP Wizard Options

[Xiaobing Liu]

For people who are currently using eQUEST 3.63:

Due to structural changes in eQUEST 3.63 installation, a new version of ClimateMaster add-on (version 2.01) is needed to install the heat pump library properly for eQUEST 3.63. A beta test version of ClimateMaster add-on 2.01 is available upon request. Please e-mail me If you want a copy of it.

Have a nice weekend,

Xiaobing

-----Original Message-----
From: Xiaobing Liu
Sent: Tuesday, May 05, 2009 11:11 AM
To: 'shaojieworld2006 at yahoo.com'; bldg-sim at lists.onebuilding.org bldg-sim at lists.onebuilding.org
Cc: 'steve.gates at doe2.com'; Jeff.Hirsch at DOE2.com
Subject: RE: [Bldg-sim] WLHP Wizard Options



Shaojie:



The difference between (single/multi-zone and simplified single zone) is actually the default type of air-side HVAC system used for simulating the air-side part of a water source heat pump unit. When "single/multi-zone" is selected, the default air-side HVAC system is PVVT; When "simplified single zone" is selected, the default air-side HVAC system is "Water Loop HP". When PVVT is used, it is capable of either serving one single zone or multi-zones with one water source heat pump unit. On the other hand, each "Water Loop HP" can only serve one single zone.



In most case, the difference in the simulation results is due to the different performance curves used for the two air-side HVAC systems. The cooling performance curves for  "Water Loop HP" are normalized (approximately) at 86F entering water temperature and 67F entering indoor wetbulb, while the heating  performance curves are normalized at 68F entering water temperature and 70F entering indoor drybulb, which is the ARI rating conditions for "Water Loop Heat Pump Application" of a water source heat pump unit. However, the cooling performance curves for "PVVT" are normalized at 77F entering water temperature and 67F entering indoor wetbulb, while the heating  performance curves are normalized at 32F entering water temperature and 70F entering indoor drybulb, which is the ARI rating condition for "Ground Loop Heat Pump Application" of a water source heat pump unit. Unfortunately, in current version of eQUEST, the default EIRs for cooling and heating are the same for both PVVT and "Water Loop HP". As a result, user has to check and modify the default EIRs (and capacities if it is specified by user)with the heat pump performance data at conditions consistent with the normalization points of the performance curves (with adjustment for fan power if it is calculated separately).



As an alternative, user can load all the consistent performance curves and data (e.g. EIRs and condenser pressure drop) by selecting heat pump from heat pump library, which is an add-on feature of eQUEST and can be download at http://www.climatemaster.com/index/equest for free after registration.



I also noticed that, if the "location set" is specified as "California (Title 24)" in eQUEST wizard when creating the simulation, an air-side economizer is added to the water source heat pump simulated with the PVVT system, but not for the "Water Loop HP". (It does not happen when "All eQUEST Locations" is selected for "location set". In this case, there is no air-side economizer for both PVVT and "Water Loop HP". ) It appears a bug and should be fixed. The easiest way to remove the air-side economizer from PVVT is to set the input entry of "Outside Air Control" to "Fixed Fraction" for all the heat pump units simulated with PVVT.



Sorry for the inconvenience, I believe these issues will be addressed in the new release of eQUEST.



Regards,



Xiaobing

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org]On Behalf Of eric wang
Sent: Monday, May 04, 2009 3:49 PM
To: bldg-sim at lists.onebuilding.org bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] WLHP Wizard Options


Hi,

I try to model WLHP and find there are two options (single/multi-zone and simplified single zone) in the SD wizard if I pick water loop as heat pump source. The two models give me different annual energy costs. If I choose the simplified single zone model, there are no cooling or heating sources under the air-side HVAC system tab. I am not sure what else makes the results different besides the heating/cooling performance curves and system types. Any suggestions are highly appreciated.


Thanks,

Shaojie




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