Hi All,
In the ASHRAE-90.1-2004 it is menitioned that we have to
model chilled water pumps in baseline for 22W/gpm and hot water pumps
for 19W/gpm but there is no input in the software as W/gpm for the
pumps either we can enter gpm or watts seperatly then how can we
incorporate this for baseline?
In Page 182 G3.1.3.3 it is mentioned that hot water supply and return
temperature shall be 180 ansd 130F is this for boilers or Domestic hot
water heating system?
If in our proposed case DHW is electric type than can we show some
energy consumption difference for baseline DHW in terms of some
efficiency, insulation or temperature parameters or not ,or only if
our DHW is solar type than only savings can be claimed from
baselineDHW?
In Page G3.1.3.10 it is mentiond that chilled water oumos serving less
than 300TR shall be be modelled as primary/secondary system with
secondary pump riding the pump curve.I did'nt get what is meaning of
secondary pump riding the pump curve.
I shall be obliged if any one can give satisfactory answers to these
queries regarding ASHRAE.
Thanks
Sambhav.
Sambhav,
For baseline pump energy, you can adjust the mechanical efficiency of
the pump without affecting the autosized flow rate. In eQUEST, I adjust
the mechanical efficiency (usually reducing it to 0.52 +/-) to get
22W/gpm or 19W/gpm, as indicated in the PV-A report for pump power and
flow.
Sections G3.1.3.2 through G3.1.3.5 are for space heating hot water
systems. Domestic hot water requirements are found in Table G3.1, No.11
Service Hot-Water Systems.
A centrifugal pump "rides the pump curve" when it is a single-speed pump
(no VFD) but the system has at least some two-way valves to permit
variable loop flow. So, for example, in eQUEST you would model a
secondary pump riding the pump curve by setting the secondary CHW loop
pump capacity control to "One Speed Pump" and making sure some or all of
the CHW coil valves are "Two Way".
Regards,
William Bishop, PE, BEMP, LEED(r) AP
Hello All,
Another solution to the 19 or 33 W/GPM is to adjust the pipe head in the circulation loop. Just another way to do the same thing.
Regards,
Andrew Reilman, P.E.
Hello All,
I have a project with water loop heat pump system and district hot water as heating source. Different from regular configuration of boiler, I have trouble getting the district hot water loop into the water loop heat pump in DOE2.2. Does anyone have any idea how do I configure the loops?
Any suggestion is appreciated. Thank you,
David
David,
It looks like you will have to make a boiler to approximate the district hot water loop.
Some suggestions:
1. Make boiler efficiency equal to 1
2. Remove any auxiliary equipment and start-up/shut-down time
3. Assign a separate fuel meter to it with the associated district hot water cost per unit of energy (perhaps MMBTU, M=1,000) rate structure
This is similar to how you do this in TRACE as well, if anyone was wondering.
Alex Chapin, E.I.T., LEED AP BD+C
Date: Wed, 20 Oct 2010 14:29:46 -0700 (PDT)
From: Zhen Tian>
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Water loop heat pump with district heating in
DOE2.2
Message-ID: <629592.69162.qm at web32105.mail.mud.yahoo.com>
Content-Type: text/plain; charset="us-ascii"
Hello All,
I have a project with water loop heat pump system and district hot water as heating source. Different from regular configuration of boiler, I have trouble getting the district hot water loop into the water loop heat pump in DOE2.2. Does anyone have any idea how do I configure the loops?
Any suggestion is appreciated. Thank you,
David