[Bldg-sim] gains questions

Denis Bourgeois d.bourgeois at hotmail.com
Fri Nov 14 04:15:51 PST 2008

Chris, > Q1: I'm used to citing CIBSE as my preferred source of internal gains > info. However, the information is now a little dated and doesn't even > cover TFT screens. Is ASHRAE any better in this department? If not, is > there any reliable source that I can cite for modern desktops, laptops > and TFT screens?I'm replying with immediate access to the 2001 ASHRAE Fundamentals only - the current version is 2005 (so the information might also be slightly outdated). Chapter 29 (Nonresidential Cooling and Heating Load Calculation Procedures) [Chapter 30 in the 2005 version] cites studies from 1994 and 1999 for typical computer loads (Table 8 for typical computer equipment). I have found this study from 2002 more useful: http://repositories.cdlib.org/cgi/viewcontent.cgi?article=1567&context=lbnl It offers interesting comarisons between CRT versus LCD screens, monitor consumption as a function of display colors, PC activity, operating systems, etc. It is however based on data measured 6/7 years ago ... EnergyStar offers a calculator which could be of interest: http://www.energystar.gov/ia/business/bulk_purchasing/bpsavings_calc/Calc_monitors.xls These studies/tools are indeed useful (does anyone know of more recent studies ...?), but the data they're based on is likely outdated in many areas. If you're seriously interested in getting a detailed assessment, I wouldn't hesitate in purchasing a power analyzer/line meter ... Good knowledge of occupant mobility is also critical (field studies have shown that office workers can be absent from the offices/workstations between 25% and 50% of the time ... information not readily available). Finally, you should also check the ASHRAE RP 1093 project literature (e.g. http://repositories.tamu.edu/browse?value=Abushakra%2C+B.&type=author)> Q2: As temperature increases the human body gives off less `sensible > heat' and more latent heat. Can anybody cite any data regarding this > phenomenon? Again, there used to be a table in CIBSE guide A (1999) but > it was withdrawn in later versions. Table 1 in Chapter 29 of the ASHRAE Fundamentals (Nonresidential Cooling and Heating Load Calculation Procedures) contains sensible (radiant versus convective) versus latent heat (high versus low air velocity) for adult males and an 'adjusted' male/female/children distribution. That's a quick fix - that's a field in itself. Hope this helps,Denis Bourgeois> Chris> _______________________________________________> Bldg-sim mailing list> http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org> To unsubscribe from this mailing list send a blank message to BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG

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