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.

<br><br>This is what I have input (through a parametric run) for ERV's<br><br>   ERV-RECOVER-TYPE = ENTHALPY-WHEEL<br>   ERV-RUN-CTRL     = WHEN-MIN-OA<br>   ERV-CAP-CTRL     = MODULATE-HX<br>   ERV-FANS         = HVAC-SUPPLY/RETURN

<br>   ERV-FAN-EFF      = 0.9<br>   ERV-MOTOR-CLASS  = PREMIUM<br>   ERV-OA-KW/FLOW   = 8.5e-005<br>   ERV-FROST-CTRL   = USE-CAP-CTRL<br><br><br>ERV Model:<br><br>REPORT- SS-M Building HVAC Fan Elec Energy                                                  WEATHER FILE- Burlington   VT TMY2

<br>---------------------------------------------------------------------------------------------------------------------------------<br><br><br>         FAN ELECTRIC    FAN ELECTRIC    FAN ELECTRIC      FAN ELECTRIC<br>         ENERGY DURING   ENERGY DURING   ENERGY DURING     ENERGY DURING

<br>            HEATING         COOLING      HEATING-COOLING     FLOATING<br> MONTH      (KWH)            (KWH)            (KWH)            (KWH)<br><br><br><br><br>  JAN      2031.042           24.259             0.000        

1134.069<br><br>  FEB      1699.503           24.384             0.000        1097.507<br><br>  MAR      1441.447           64.325             0.000        1964.537<br><br>  APR       632.728          129.451             

0.000        3292.951<br><br>  MAY       174.217          444.731             0.000        4805.784<br><br>  JUN        58.014          617.355             0.000        4853.930<br><br>  JUL        16.702          868.591

             0.000        4656.523<br><br>  AUG        11.749          860.175             0.000        4763.009<br><br>  SEP        73.569          408.324             0.000        5260.542<br><br>  OCT       256.301          

198.773             0.000        4641.178<br><br>  NOV       899.911           41.370             0.000        2216.153<br><br>  DEC      1603.912           20.847             0.000        1417.681<br>         -------------   -------------   ---------------   -------------

<br><br>  ANNUAL   8899.124         3702.583             0.000       40093.965<br><br><br>******************************************************************************************<br><br>Baseline Model:<br><br>REPORT- SS-M Building HVAC Fan Elec Energy                                                  WEATHER FILE- Burlington   VT TMY2

<br>---------------------------------------------------------------------------------------------------------------------------------<br><br><br>         FAN ELECTRIC    FAN ELECTRIC    FAN ELECTRIC      FAN ELECTRIC<br>         ENERGY DURING   ENERGY DURING   ENERGY DURING     ENERGY DURING

<br>            HEATING         COOLING      HEATING-COOLING     FLOATING<br> MONTH      (KWH)            (KWH)            (KWH)            (KWH)<br><br><br><br><br>  JAN      1458.496           14.424             0.000           

0.140<br><br>  FEB      1220.828           14.370             0.000           0.018<br><br>  MAR      1023.469           36.366             0.000           0.258<br><br>  APR       457.305           72.241             0.000

           1.313<br><br>  MAY       144.202          235.738             0.000           0.450<br><br>  JUN        52.800          327.834             0.000           0.000<br><br>  JUL        16.527          467.251             

0.000           0.000<br><br>  AUG        11.605          452.370             0.000           0.000<br><br>  SEP        63.427          214.222             0.000           0.069<br><br>  OCT       206.193          101.587

             0.000           0.777<br><br>  NOV       633.372           23.710             0.000           1.893<br><br>  DEC      1101.974           13.247             0.000           0.000<br>         -------------   -------------   ---------------   -------------

<br><br>  ANNUAL   6390.089         1973.342             0.000           4.919<br><br><br><br><br><br><br><br><br><br><br><br><br><div><span class="gmail_quote">On 9/11/07, <b class="gmail_sendername">Karen Walkerman</b> <

<a href="mailto:kwalkerman@gmail.com">kwalkerman@gmail.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><span class="e" id="q_114f4bdf5e6373b1_0">

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.

<br><br>Thanks,<br>~Karen~<br clear="all"><br>-- <br>Karen Walkerman<br>Second Law Consulting<br>802-238-0980<br><a href="mailto:kwalkerman@gmail.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">

kwalkerman@gmail.com</a>

</span></div></blockquote></div><br><br clear="all"><br>-- <br>Karen Walkerman<br>Second Law Consulting<br>802-238-0980<br><a href="mailto:kwalkerman@gmail.com">kwalkerman@gmail.com</a>