[BLDG-SIM] ERV energy use in eQuest and economizers

[Brandon Nichols]

Karen,
 
What do you mean by floating hours -- system off?  Perhaps your
schedules are not assigned correctly.  
 
Here's a post with an enthalpy wheel I simulated recently that works as
expected...
 
http://elcca-exchange.blogspot.com/2007/08/equest-latent-heat-recovery.h
tml
 
Hope that helps!
 
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 at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Karen
Walkerman
Sent: Tuesday, September 11, 2007 6:41 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] ERV energy use in eQuest and economizers


Ok, so I have just noticed:

A comparison between the SS-M report of the baseline (no erv) and ERV
models shows that the ERV uses a little more fan energy for heating and
cooling modes (this seems reasonable) and then a HUGE amount more during
floating hours. 

This is what I have input (through a parametric run) for ERV's

   ERV-RECOVER-TYPE = ENTHALPY-WHEEL
   ERV-RUN-CTRL     = WHEN-MIN-OA
   ERV-CAP-CTRL     = MODULATE-HX
   ERV-FANS         = HVAC-SUPPLY/RETURN 
   ERV-FAN-EFF      = 0.9
   ERV-MOTOR-CLASS  = PREMIUM
   ERV-OA-KW/FLOW   = 8.5e-005
   ERV-FROST-CTRL   = USE-CAP-CTRL


ERV Model:

REPORT- SS-M Building HVAC Fan Elec Energy
WEATHER FILE- Burlington   VT TMY2 
------------------------------------------------------------------------
---------------------------------------------------------


         FAN ELECTRIC    FAN ELECTRIC    FAN ELECTRIC      FAN ELECTRIC
         ENERGY DURING   ENERGY DURING   ENERGY DURING     ENERGY DURING

            HEATING         COOLING      HEATING-COOLING     FLOATING
 MONTH      (KWH)            (KWH)            (KWH)            (KWH)




  JAN      2031.042           24.259             0.000        1134.069

  FEB      1699.503           24.384             0.000        1097.507

  MAR      1441.447           64.325             0.000        1964.537

  APR       632.728          129.451             0.000        3292.951

  MAY       174.217          444.731             0.000        4805.784

  JUN        58.014          617.355             0.000        4853.930

  JUL        16.702          868.591              0.000        4656.523

  AUG        11.749          860.175             0.000        4763.009

  SEP        73.569          408.324             0.000        5260.542

  OCT       256.301          198.773             0.000        4641.178

  NOV       899.911           41.370             0.000        2216.153

  DEC      1603.912           20.847             0.000        1417.681
         -------------   -------------   ---------------   -------------


  ANNUAL   8899.124         3702.583             0.000       40093.965


************************************************************************
******************

Baseline Model:

REPORT- SS-M Building HVAC Fan Elec Energy
WEATHER FILE- Burlington   VT TMY2 
------------------------------------------------------------------------
---------------------------------------------------------


         FAN ELECTRIC    FAN ELECTRIC    FAN ELECTRIC      FAN ELECTRIC
         ENERGY DURING   ENERGY DURING   ENERGY DURING     ENERGY DURING

            HEATING         COOLING      HEATING-COOLING     FLOATING
 MONTH      (KWH)            (KWH)            (KWH)            (KWH)




  JAN      1458.496           14.424             0.000           0.140

  FEB      1220.828           14.370             0.000           0.018

  MAR      1023.469           36.366             0.000           0.258

  APR       457.305           72.241             0.000            1.313

  MAY       144.202          235.738             0.000           0.450

  JUN        52.800          327.834             0.000           0.000

  JUL        16.527          467.251             0.000           0.000

  AUG        11.605          452.370             0.000           0.000

  SEP        63.427          214.222             0.000           0.069

  OCT       206.193          101.587              0.000           0.777

  NOV       633.372           23.710             0.000           1.893

  DEC      1101.974           13.247             0.000           0.000
         -------------   -------------   ---------------   -------------


  ANNUAL   6390.089         1973.342             0.000           4.919













On 9/11/07, Karen Walkerman < kwalkerman at gmail.com> wrote: 

	Ok, so there have been a couple post recently asking about
energy savings from ERV's in eQuest.  The concern is that there is some
reduction in cooling and heating energy use, but a significant increase
in fan energy use. 
	
	Here's my thought:  in the baseline case, the only energy
expended with respect to ventilation air is the energy required to heat
and cool the outdoor air, but the fan energy to move the ventilation air
through ductwork is not represented.  (If someone knows where to put
this number, or how to represent it, please let me know).  Any other
thoughts/suggestions out there? 
	
	I am trying to get to the bottom of this as well, because so
far, according to eQuest, installing an ERV has not made much sense.
	
	Also, is there a way to turn off the airside economizer?  I'm
modeling a building with heat pumps.  There is an ERV for ventilation,
but no economizer. 
	
	Thanks,
	~Karen~
	
	-- 
	Karen Walkerman
	Second Law Consulting
	802-238-0980
	kwalkerman at gmail.com 




-- 
Karen Walkerman
Second Law Consulting
802-238-0980
kwalkerman at gmail.com 


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