Hi Karen,<br><br>How are you?? Well, I trust. I will look at your calcs as soon as I can but I must go watch the PORTLAND TRAILBLAZERS (go BLAZERS!!) win! I hope!! The game is starting right now.<br><br>Sorry in advance to any/all Suns fans (just kidding). You know the Trailblazers are all we have here in Portland and we are FANS!<br>
<br>Carol!!<br><br><br><br><div class="gmail_quote">On Mon, Apr 26, 2010 at 2:07 PM, Karen Walkerman <span dir="ltr"><<a href="mailto:kwalkerman@gmail.com">kwalkerman@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div>Hello,<br></div><div><br></div><div>I have seen some discussion on how to separate fan power from EER on the various list-serves, but never seen an explicit description of exactly how to go about it. Below are my calculation methodologies and I'm hoping to generate some thumbs up/thumbs down discussion and clarification:</div>
<div><br></div><div>From ASHRAE 90.1 Users manual formula G-A:</div><div><br></div><div>EER = (Net Cooling [BTU/h]) / (Total Input Power [W])</div><div><br></div><div> = ((Gross Cooling - Supply Fan Power) [Btu/h]) / (Total Input Power [W])</div>
<div><br></div><div>Definitions</div><div><br></div><div>Total Input Power: Includes supply and condenser fan power, and condenser power</div><div><br></div><div>Supply Fan Power [btu h ] : this is the heat rejected by the fan to the supply air stream. If 100% of the fan power is eventually converted to heat, then this is 3,413 X Supply Fan KW.</div>
<div><br></div><div><br></div><div>To Calculate the EER, minus the fan, do the following:</div><div><br></div><div>Break Total Input Power into Supply Fan Power and condenser fan and compressor power</div><div><br>
</div><div>I'll use the following abbreviations for subsequent formulas to minimize typing:</div><div><br></div><div>GC : Gross Cooling [btu/h]</div><div>SPb: Supply Fan Power [btu/h]</div><div>SPw: Supply Fan Power [w]</div>
<div>CP: Compressor Power [w]</div><div><br></div><div>For an Appendix G baseline model, we have GC, SPb, SPw, and EER. So, from formula G-A, we solve for CP::</div><div><br></div><div>CP + SPw = (GC - SPb) / EER</div><div>
<br></div><div>CP = (GC - SPb) / EER - SPw</div><div><br></div><div>Now, we can determine the EER, excluding the fan power so:</div><div><br></div><div>Modified EER = GC / CP</div><div><br></div><div>A few things to discuss:</div>
<div><br></div><div>1. Is this really appropriate for systems where the fan power is calculated using the G.3.1.2.9 guidelines?</div><div><br></div><div>2. What is done when the requirements for cooling system efficiency is listed as a SEER instead of an EER? Is there an acceptable conversion factor for use in these calculations?</div>
<div><br></div><div>3. I this methodology what is intended? ASHRAE Appendix G, and even the User's Manual is extremely brief of this.</div><div><br></div><div>Thanks,</div><div><br></div><div>--</div><div>Karen</div>
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