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<TITLE>RE: [Equest-users] Not Meeting Heating Setpoint with Ground Source HeatPump</TITLE>
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<P><FONT SIZE=2>You may want to check your heating schedule. I find that Heat Pump systems have a hard time ramping up temperature quickly. If you set-back the temperature at night, the system probably has unmet heating load hours each morning when the system turns back on.<BR>
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In the past I have been able to make the unmet load hours go away on HP systems by modifying the heating schedule such that there is a several hour transition from my nighttime set back to my daytime set point.<BR>
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Nathan Miller<BR>
<BR>
Senior Energy Engineer/Mechanical Engineer<BR>
<BR>
direct: 206.788.4577<BR>
<BR>
fax: 206.285.7111<BR>
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-----Original Message-----<BR>
From: equest-users-bounces@lists.onebuilding.org [<A HREF="mailto:equest-users-bounces@lists.onebuilding.org">mailto:equest-users-bounces@lists.onebuilding.org</A>] On Behalf Of Doebber, Ian<BR>
Sent: Monday, August 11, 2008 4:17 PM<BR>
To: equest-users@lists.onebuilding.org<BR>
Subject: [Equest-users] Not Meeting Heating Setpoint with Ground Source HeatPump<BR>
<BR>
I am using the Package Single Zone (PSZ) air system to simulate a Ground Source Heat Pump.<BR>
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For Cooling, the Heat Pump Condenser Coil is specified as "Water Cooled" and linked the GSHP Water Loop.<BR>
<BR>
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For Heating, since there is no input for the Heat Pump Evaporator Coil, I'm assuming that Equest automatically uses the GSHP Water Loop.<BR>
<BR>
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Everything works great except that for many of the Heating Mode Hours, the system is not meeting the correct 70°F Setpoint Temperature.<BR>
<BR>
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The following HAS NOT worked :<BR>
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1. Increased "Heat Sizing Ratio" to 1.5 to oversize the Heating Capacity<BR>
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2. Added Electric Resistance as a "Zone Heat Source"<BR>
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<BR>
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The following HAS worked :<BR>
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1. Specifying "Electric" as a HP Supplemental Source<BR>
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There seems to be a control issue of either turning the Heat Pump off or not running it correctly to meet the Heating Load. I can maintain the Temperature by using Electric Supplemental Heat but I want the Ground Source Heat Pump to provide all the heating which it is capable of.<BR>
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Any thoughts. For instance, if I specify "Heat Pump" as my Supp Source, will this simply use the GSHP to provide the heating. Seems like an odd way of doing it.<BR>
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Regards,<BR>
<BR>
Ian Doebber<BR>
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