<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:10pt">Umesh:<br><br>The savings would depend on how well the existing pneumatic system has been calibrated and what the baseline sequence of operation is compared to the proposed sequence of operation. For example, there are pneumatic transducers for static and relative humidity which can be used for static pressure reset and enthalpy comparison. They are hard to calibrate and require cleaning and re-calibration at least annually. A DDC system will provide a more accurate static and enthalpy control. If you have the opportunity to observe the system in operation, you might be able to make some set-point adjustments and observe how the pneumatic controllers respond. This way you can model the baseline with a different throttling range than the proposed model.<br><br>You can factor
in the savings realized by removing the air compressor. It helps to monitor the air compressor for a bit to see how often it runs. Some that I have seen run continuously due to air leaks.<br><br>Paul Diglio<br><div><br></div><div style="font-family: times new roman,new york,times,serif; font-size: 10pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Umesh Atre <umesh@innovativedesign.net><br><b><span style="font-weight: bold;">To:</span></b> equest-users@lists.onebuilding.org<br><b><span style="font-weight: bold;">Sent:</span></b> Mon, May 9, 2011 8:46:34 AM<br><b><span style="font-weight: bold;">Subject:</span></b> [Equest-users] pneumatic to ddc savings?<br></font><br>
<div><span class="729253612-09052011"><font face="Calibri">We are working on a
school project where the clients wish to change their pneumatic controls to DDC.
It is a 20 year-old building.</font></span></div>
<div><span class="729253612-09052011"><font face="Calibri">Can anybody comment
on </font></span><span class="729253612-09052011"><font face="Calibri">what the
range of savings is? The existing system is a 2-pipe for most spaces, currently
being modified to a new 4-pipe.</font></span></div>
<div><span class="729253612-09052011"><font face="Calibri">Is it even possible to
quantify the savings, if any, using eQUEST? </font></span></div>
<div><span class="729253612-09052011"></span><span class="729253612-09052011"><font face="Calibri">Thanks,</font></span></div>
<div><span class="729253612-09052011"><font face="Calibri">Umesh</font></span></div></div></div>
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