[Bldg-sim] eQuest modeling water-source heat pumps

[Brandon Nichols]

Hello Mike,
 
Whenever we need to add water source heat pumps to a project, we import
this .inp file code snippet:
 

$ *********************************************************
$ **                                                     **
$ **      HVAC Circulation Loops / Plant Equipment       **
$ **                                                     **
$ *********************************************************
 
$ ---------------------------------------------------------
$              Pumps
$ ---------------------------------------------------------
 
"WLHP Loop Pump" = PUMP
   NUMBER           = 1
   MOTOR-CLASS      = HI-EFF
   ..
"WLHP Blr (HWNatDrft) Pump" = PUMP
   MOTOR-CLASS      = HI-EFF
   ..
 
$ ---------------------------------------------------------
$              Circulation Loops
$ ---------------------------------------------------------
 
"WLHP Water Loop" = CIRCULATION-LOOP
   TYPE             = WLHP
   LOOP-OPERATION   = STANDBY
   DESIGN-HEAT-T    = 70
   DESIGN-COOL-T    = 85
   COOL-SETPT-CTRL  = FIXED
   LOOP-PUMP        = "WLHP Loop Pump"
   ..
 
$ ---------------------------------------------------------
$              Boilers
$ ---------------------------------------------------------
 
"WLHP Blr (HWNatDrft)" = BOILER
   TYPE             = HW-BOILER
   HEAT-INPUT-RATIO = 1.25
   HW-LOOP          = "WLHP Water Loop"
   HW-PUMP          = "WLHP Blr (HWNatDrft) Pump"
   ..
 
$ ---------------------------------------------------------
$              Heat Rejection
$ ---------------------------------------------------------
 
"WLHP Fluid Cooler" = HEAT-REJECTION
   TYPE             = FLUID-COOLER
   CAPACITY-CTRL    = ONE-SPEED-FAN
   CW-LOOP          = "WLHP Water Loop"
   ..
 

If you already have heat pump plant equipment defined, it may require
cutting (existing) and pasting (new) equipment directly from your .inp
file -- be sure of course to make a backup.  Is the campus he rejection
loop ultimately air cooled or ground source?  If air cooled then the
fluid cooler heat rejection should be reasonable.  If ground source, try
this code snippet instead for starters:
 

$ *********************************************************
$ **                                                     **
$ **      HVAC Circulation Loops / Plant Equipment       **
$ **                                                     **
$ *********************************************************
 
$ ---------------------------------------------------------
$              Pumps
$ ---------------------------------------------------------
 
"GSHP Loop Pump" = PUMP
   NUMBER           = 1
   MOTOR-CLASS      = HI-EFF
   ..
 
$ ---------------------------------------------------------
$              Circulation Loops
$ ---------------------------------------------------------
 
"GSHP Water Loop" = CIRCULATION-LOOP
   TYPE             = WLHP
   LOOP-OPERATION   = SUBHOUR-DEMAND
   DESIGN-HEAT-T    = 30
   DESIGN-COOL-T    = 110
   COOL-SETPT-CTRL  = FIXED
   MAX-ALARM-T      = 110
   MIN-ALARM-T      = 30
   LOOP-PUMP        = "GSHP Loop Pump"
   ..
 
$ ---------------------------------------------------------
$              Ground Loop Heat Exchangers
$ ---------------------------------------------------------
 
"GLHX (VertWell-CM)" = GROUND-LOOP-HX
   TYPE             = VERT-WELL-NEW
   CONFIGURATION    = "Rectangle-3x5"
   DEPTH            = 200
   SPACING          = 20
   PIPE-OUTSIDE-DIA = 1.05
   PIPE-INSIDE-DIA  = 0.859
   U-TUBE-LEG-SEP   = 3.9
   PIPE-COND        = 0.23
   FIELD-MULTIPLIER = 1
   GRND-DIFFUSIVITY = 0.0432208
   GRND-COND        = 1.68
   NUM-OF-YEARS     = 0
   GROUT-COND       = 0.85
   BOREHOLE-DIAM    = 6
   REF-GRND-ADJ     = 5
   FLUID            = WATER
   CIRCULATION-LOOP = "GSHP Water Loop"
   ..
 
 
Hope that helps...if not, verify your schedules against a known good
project.  Personally I change at the auto-generated schedules whenever
possible, here's a couple of posts on how to do that:
 
http://elcca-exchange.blogspot.com/search/label/Schedules
 
 
Brando
 
 
Brandon Nichols, PE, LEED(r) AP
Mechanical
HARGIS ENGINEERS

600 Stewart Street

Suite 1000

Seattle, WA 98101

www.hargis.biz

 

d | 206.436.0400  c | 206.228.8707

o | 206.448.3376  f  | 206.448.4450

 
 

  _____  

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Mike
Gutowski
Sent: Wednesday, January 02, 2008 3:15 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] eQuest modeling water-source heat pumps



Hello All,

 

My first post to bldg-sim, I have learned a great deal from your emails.

 

I am trying to wrap up an eQuest model of a school that is using water
source heat pumps (located in Georgia).  The building is connecting to a
campus condenser water loop, so there is no heat rejection system that
is actually part of the project, but I have to include something in
eQuest, which I have modeled as a cooling tower and variable speed pump.

 

I am running in to issues with no heating or cooling energy being
reported in the BEPS report, and 94% of hours outside throttling range.
I have tried several different types of HVAC systems (pkgd single zone,
water loop HP, pkgd var vol var temp) all with condenser type as "water
cooled" (except for water loop hp which doesn't allow you to pick a
condenser type).  I have set my circulation loop for condenser water to
loop type "condenser water" and also tried loop type "Water Loop HP"
which no success.  When I use "Water Loop HP" I get an error message
"Loop: WLHP water loop has no primary heating equipment."

 

On my HVAC systems "heating - coil capacity" display I have heat source
set to "heat pump" and zone heat source as "not installed"

 

Any ideas?  A bad combination of system type and heat rejection maybe? I
have tried all combinations that I can think of.

 

Thanks for taking a look,

 

Mike Gutowski, PE

BVM Engineering

 


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