<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:12pt">Hello John,<br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div><br>Thanks for your reply,<br><br><span>I can get service life of equipments from Chapter 36 OWNING and OPERATING COSTS in ASHRAE 2007 HANDBOOK or <a rel="nofollow" target="_blank" href="http://xp20.ashrae.org/publicdatabase/">http://xp20.ashrae.org/publicdatabase/</a>. But I am more interested to understand how the performance of HVAC systems changes during their life. HVAC equipment performance normally degrades with use and time, at a rate depending on the quality of maintenance and operations. Then for different
conditions of equipments (best, normal, and worst), maybe simple degradation rate can be used to indicate how the efficiency of equipments (such as boiler efficiency, chiller COP, fan efficiency, pump efficiency) degrades with time. Maybe there are some typical values from actual HVAC systems although </span><span>there should be very uncertain in
these degradation rates under actual conditions.</span><span> </span><br>1: Would you please let me know where I can find these degradation data for HVAC equipment performance? <br>2: Or maybe it is fair to say that HVAC equipment efficiency would remain similar to the initial one during their life (about 20 years) under good and constant maintenance? (I read some papers about how to calculate operating energy from HVAC systems in life cycle analysis. Most researchers assume that annual operating energy is a constant during the building life.) <br>3: Would you please give me some advice how to quantify or semi-quantify these performance change of HVAC equipment during their service life?<br><br>Thanks,<br><br>Jim Terrry <br><br> <br></div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font
size="2" face="Tahoma"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> John Aulbach <jra_sac@yahoo.com><br><b><span style="font-weight: bold;">To:</span></b> Jin Minming <jminming@yahoo.com>; bldg-sim@lists.onebuilding.org<br><b><span style="font-weight: bold;">Sent:</span></b> Tue, 16 February, 2010 5:38:06<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [Bldg-sim] How to estimate performance of HVAC system in life cycle analysis?<br></font><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div>Jim:</div>
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<div>I don't have the reference right in front of me, but I believe the ASHRAE HVAC Systems has a table for useful life. Also the California Energy Commission. But my references are at work. Reemail me at <a rel="nofollow" ymailto="mailto:jaulbach@ptrenergy.com" target="_blank" href="mailto:jaulbach@ptrenergy.com">jaulbach@ptrenergy.com</a> to emind me, and I shall look them up for you.</div>
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<div>John Aulbach<br></div>
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<b><span style="font-weight: bold;">From:</span></b> Jin Minming <jminming@yahoo.com><br><b><span style="font-weight: bold;">To:</span></b> bldg-sim@lists.onebuilding.org<br><b><span style="font-weight: bold;">Sent:</span></b> Mon, February 15, 2010 3:42:12 AM<br><b><span style="font-weight: bold;">Subject:</span></b> [Bldg-sim] How to estimate performance of HVAC system in life cycle analysis?<br></font><br>
<div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">Hello all,<br>
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<div><br>In life cycle analysis of buildings, it seems it is very hard to estimate long-term performance of HVAC systems (or other building components), for example, air handling units, chiller, or boilers. It makes sense that HVAC system will degrade with time, depending on many factors, like maintainence, wear-and-tear. The problem is how to quantify these change with time. Maybe some probabilstic or scenario methods can be used. Would you please tell me the common method to predict these performance change or where I can find some good references about this topic?<br><br>Thanks,<br><br>Jim Terrry <em></em><br></div></div><br></div></div></div><br></div></div></div><br>
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