Hi all ?
I?m working on an ASHRAE baseline model with system #7 in eQuest. ASHRAE
requires the chilled water loop pump power of 19W/gpm. So I ran the model with
the default head and pump kW (left then blank) first, and found the gpm of the
pump from the report, then I calculated and input the kW of the pump. However,
after I ran the model again with this pump power, the pump gpm result was
changed in the report. Also, I got a warning that said the pump flow input is
lower than the actual flow. There is no input for a pump flow. So I don?t know
what happened inside eQuest.
Do you know what is wrong here? How to model the ASHRAE loop pump power
correctly in eQuest?
Thanks a lot!
Ying
I deal with this by adjusting the "pipe-head" of the loop until the
total specific design pump power = 19 W/gpm, while still letting
eQuest/DOE2 "autosize" the pumps.
I believe this W/gpm should be calculated as (sum of all pump power
for both "primary" and "secondary" pumps connected to a loop)/design
loop flow. In addition to the loop (secondary) pump, the ASHRAE baseline
includes primary pumps, in DOE-speak, a "CHW-PUMP" and "CW-PUMP" for
each chiller, which is not the way eQuest sets things up by default. And
only the "primary" pump on the CW loop.
Fred
Hi all ?
I?m working on an ASHRAE baseline model with system #7 in eQuest.
ASHRAE
requires the chilled water loop pump power of 19W/gpm. So I ran the
model with
the default head and pump kW (left then blank) first, and found the gpm
of the
pump from the report, then I calculated and input the kW of the pump.
However,
after I ran the model again with this pump power, the pump gpm result
was
changed in the report. Also, I got a warning that said the pump flow
input is
lower than the actual flow. There is no input for a pump flow. So I
don?t know
what happened inside eQuest.
Do you know what is wrong here? How to model the ASHRAE loop pump
power
correctly in eQuest?
Thanks a lot!
Ying
Set the mech efficiency then calc the required head needed as fred
stated.
Check out:
http://www.commercial.carrier.com/commercial/hvac/general/0,3055,CLI1_DI
V12_ETI10630,00.html#HAP49 for the calc.
Timothy Howe, MS, LEED(r) AP
Thanks! This works well. For setting up the pumps for water side systems that
serves more than 150,000 sf, my understanding is:
1. a loop (secondary) pump with VSD and a one speed(primary) pump for each
chiller;
2. a one speed conderser water loop pump, and one pump for each chiller, which
is the same pump in (1)
3. one VSD pump for each boiler, and no loop (secondary) pump
Is that correct?
Thanks in advance!
Ying
Thanks! This works well. For setting up the pumps for water side systems that
serves more than 150,000 sf, my understanding is:
1. a loop (secondary) pump with VSD and a one speed(primary) pump for each
chiller;
2. a one speed conderser water loop pump, and one pump for each chiller,
which is the same pump in (1)
3. one VSD pump for each boiler, and no loop (secondary) pump
Is that correct?
Thanks in advance!
Ying