Michael,<div><br></div><div>On a recent project I modeled this same situation. The way I was able to force the system to only operate during a call for cooling or heating was by defining a fan schedule with all hours set to 0. Per the DOE2.2 help documentation on fan schedules:</div>
<div>- <span style="FONT-FAMILY:Symbol"> </span>If the value is 0, the fans are off but may be turned on by
NIGHT-CYCLE-CTRL if zone temperatures warrant it. </div><div><br></div><div>Make sure to allow night cycle control (cycle on any). This basically defines all hours of the day to be "night" and the fan will cycle on to meet the load in the space. </div>
<div><br></div><div><p class="MsoNormal"><a name="_MailAutoSig"><span style="font-family:"Franklin Gothic Demi","sans-serif";color:#632423">Robby Oylear, </span></a><span style="font-size:10.0pt;font-family:"Franklin Gothic Demi","sans-serif";color:#632423">LEED AP</span><span style="font-family:"Franklin Gothic Demi","sans-serif";color:#632423"></span></p>
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<br><div class="gmail_quote">On Wed, Feb 1, 2012 at 10:00 AM, Chris Hadlock <span dir="ltr"><<a href="mailto:cjhadlock@gmail.com">cjhadlock@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Michael,<div><br></div><div>I would just run an hourly report for one of your heat pump systems and pick up hourly flow rate and fan energy. This way you can see how often your fans are running and whether they are cycling or running continuously. With heat pump systems, there are key words under the Fans tab (for a given system) that will indicate the control on the fans. One is night cycle control and the other is indoor fan mode (within the Flow Parameters tab). If your fans are not cycling, it is likely due to those two key words (or the fan schedule you have specified).</div>
<span class="HOEnZb"><font color="#888888">
<div><br></div></font></span><div><span class="HOEnZb"><font color="#888888">Chris</font></span><div><div class="h5"><br><br><div class="gmail_quote">On Wed, Feb 1, 2012 at 12:44 PM, Michael Mantai <span dir="ltr"><<a href="mailto:mmantai@systemworcx.com" target="_blank">mmantai@systemworcx.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
I'm modeling a 6-story hotel. Baseline is PTAC. I set up the baseline to<br>
have outside air at each PTAC with the fans running continuously. The<br>
Proposed Case is watersource heat pumps. Outside air is through dedicated<br>
units at the corridors. I've set (at least I am trying to set) the heat<br>
pump fans to cycle on the thermostat. I've set the heat pumps to 0 CFM<br>
outside air. When I run the two models, the ventilation fan energy is<br>
nearly identical. I expected to see some fan energy savings with the heat<br>
pump fans cycling. When I look at the detailed output report, the SS-C for<br>
the heat pumps seems like it is showing fans running continuously. I say<br>
this because the "hours floating" are less than the "hours fans on", and the<br>
"hours fans cycle on" is zero. This implies to me that the fans are running<br>
continuously. However, when I look at the reports that show fan energy<br>
consumption, the months with floating hours show significantly reduced fan<br>
energy, which to me implies that they are cycling. The total fan kW in the<br>
proposed model is about twice that of the baseline, so from that standpoint<br>
maybe the kWh being about the same is correct. I set up the PTAC units at<br>
.3 watts/CFM per ASHRAE. I set up the heat pumps fans with a static<br>
pressure input from the design drawings rather than input the fan motor<br>
sizes (used .2" w.g. Static).<br>
<br>
Also, my space cooling energy is higher in the proposed case than the<br>
baseline, even though the envelope is better, the watersource heat pumps<br>
have a lower EIR and the design lighting power density is 30% lower. I<br>
haven't dug into that yet because I'm still trying to verify my fan cycling<br>
is working.<br>
<br>
My questions are, can anyone explain how to interpret the SS-C reports in<br>
terms of fan cycling, or point me to which report I should look to really<br>
verify the fans are cycling? And anyone modeled a similar comparison, and<br>
if so, what type of results did you get with respect to cooling energy and<br>
fan power consumption? Seems like I should be seeing savings.<br>
<br>
<br>
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