Hi all, <br><br>Having some difficulty in an App. G model for a
6-floor 14,000 m2 GFA Hotel in zone 1B (Abu Dhabi). Assuming standard
design for each, should a proposed VAV system out-perform window AC units (the baseline)? <br><br>Proposed: <br>VAV with 2 Air-cooled centrifugal chillers, chiller COP = 3.1 (2.8 if condenser fan energy included)<br>Envelope - Better windows decrease heating demand by 8% rest of envelope is minimum required for compliance<br>
<br>Baseline: <br>System Packaged terminal heat pump, COP = 3.52<br><br>Using Energyplus v6.0 the results are;<br><br><span style="font-family: courier new,monospace;">Site Energy in End Uses BL Proposed COP5</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;"> MWh MWh MWh</span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;"> Space Cooling 747.5 1052.0 715.6 </span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;"> Heat Rejection 0.0 0.0 0.0 </span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;"> Space Heating 1.3 0.1 0.1 </span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;"> Pumps 0.0 60.0 60.0 </span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;"> Fans - Interior 42.2 137.7 137.7 </span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;"> Fans - Car park 0.0 0.0 0.0 </span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;"> Interior Lighting 530.5 530.5 530.5 </span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;"> Exterior Lighting 0.0 0.0 0.0 </span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;"> Service Water Heating 0.0 0.0 0.0 </span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;"> Receptacle/Process Equipment 146.3 146.3 146.3 </span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;"> Data Centre Equipment 0.0 0.0 0.0 </span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;"> Elevators and Escalators 0.0 0.0 0.0 </span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;"> Total Site Energy 1467.9 1926.6 1590.2</span><br>
<br>I have the energy for the baseline, the proposed with COP = 3.1, and then trying COP = 5. It seems that even if we drastically increase the COP of the chiller
plant in the proposed VAV system, we still can't get any energy savings. Is this realistic, an artifact of the simulation, or just an error on my part? <br>
<br>Any guidance would be appreciated, <br><br>Marcus<br>-- <br>Marcus Jones, LEED AP, M.Sc. <br>
<i>Freelance energy consultant</i><br><i>Vienna, Austria</i><br><br><br>