Hi, I am working on a office building of about 15,000sqm using AHU with underfloor system. The following are the HVAC baseline that I have input into the HAP software:
Chiller:
2 screw chiller sized equally
Chilled Water Supply = 6.7 deg C
Chilled Water Return = 13 deg C
Pumps:
Primary pumps only
CHW Pump Power = 349 kW / 1000L/s
CW Pump Power = 310 kW / 1000L/s
Heat Rejection - Cooling Tower:
Condenser Water Supply = 29 deg C
Condenser Water Return = 34.6 deg C
Variable Speed AHU with underfloor outlet (System 8):
Air flowrate = autosized with 1.15x for cooling
Power = 0.0021 kW per L/s
VAV Box opening = 50% minimum
// Are the above input correct?
Also, I was browsing through Appendix G and under G3.1.3.14, it states that the "Fans in parallel VAV fan-powered boxes ... shall be modeled with 0.74 W per L/s fan power", which is different from Table G3.1.2.9.
Can I understand when shall 0.74 W per L/s be used and when shall Table G3.1.2.9 be used?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
May 1, 2017 - 10:10 am
Sorry I don't have an SI version of the standard. When you do the conversions there are slight differences so I will deffer to someone who has that version of the standard.
G3.1.2.9 is used for the main air handler fans and the G3.1.3.14 fans are an additional allowance on top of it for the fan-powered boxes.
Yong Lee Low
ESD ConsultancyZEB-Technology Pte Ltd
179 thumbs up
May 30, 2017 - 5:24 am
Hi Marcus, thanks for the clarification earlier. Wanted to check further with you on the pump input.
In Appendix G (G3.1.3.10), it indicates that the baseline building design pump power shall be 349kW / 1000L/s (SI version).
In Budget System Description (Table 11.3.2A item e), it states that "Pump system power for each pumping system shall be the same as the proposed building design; if the proposed building has no chilled-water pumps the budget building design pump power shall be 349 kW/1000 L/s)."
From the above 2 extract from ASHRAE, which should be used as the design for the chilled water and condenser water pump reference?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
May 30, 2017 - 8:56 am
For the LEED Baseline you use Appendix G, not Section 11.