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hi,
I've got a problem to model a water source heat
pump with heat rejection to a cooling tower
and a gas fired boiler as a backup for my
water loop.
Here is what I've already done :
first ( Jeff advice) I created a
heating/ventilating system ( AIR HVAC ) assigned to a fake
zone.
this is to model my make up air preheated, constant
volume, @ 55 F 100 % OA.
I created the water loop HP ( WATER HVAC ) with my
boiler and my cooling tower.
in reality I have an evap. cooling tower BUT I
considered an OPEN CT in powerdoe
Then my main HVAC system ( AIR HVAC) WATER LOOP HP
type.
in that system I assign my outside air coming from
my heating/ventilating system.
In my building as I have a bunch of heat pumps
I entered my total
cooling and heating capacity in my system level and
I entered for each zone
their own cooling and heating capacity depending on
the number of heat pumps
( my total zone capacities equals my system
capacities)
I also entered my total flow ( corresponding to the
recirculating and OA).
In my water loop (that as a 20 F delta T), I
want the boiler to turns on only when my water loop
temperature goes below 75 F, and my cooling tower
to reject heat when my water loop
goes above 80 F.
I entered the design GPM for my loop.
then comes the problem :
In my ouput
I almost don't have any heat rejection, and
very small cooling.
( My EIR seems ok 0.015 for CT, 0.24 for
HP)
I use a lot of electrical heat ( my heat pump meter
is EM1) and I have rooms that remains
under 60 F with a setpoint @ 72 F.
But I use an incredible high amount of gas in my
boiler..
plus I get these error message
the first message with the heat
and cooling capacity appears for all the zones !!
Powerdoe do not appreciate that my heat
pump heating capacity is higher than my cooling
capacity???
**WARNING**********************************************************************
HEATING-CAPACITY of
-5040000. is inconsistent with a
COOLING-CAPACITY of
4032000.in ZONE 2P-INT ZONE
**WARNING**********************************************************************
Pump: water source HP PUMP
has a total user-specified flow
of
485. gpm, but the loop flow is 3903.
gpm. **WARNING**********************************************************************
Pump: water source HP PUMP
has a user-specified head
of 57.
feet, but the loop head is 67.
feet. **CAUTION**********************************************************************
Plant equipment: OPEN CT
has a different
pressure drop on loop: HP LOOP
than the
other equipment. This is
unusual unless the loop
uses flow meters or other dynamic flow
control
devices to allocate the flow on an hourly basis
to
the active equipment. **WARNING**********************************************************************
Loop: HP LOOP
heating
capacity is smaller
than the secondary demand. Primary=
-2000000.
Secondary= -7089648. **WARNING**********************************************************************
Loop: HP LOOP
cooling
capacity is smaller
than the secondary demand. Primary=
4800000.
Secondary= 39062304. I must say that I am a little bit
lost...
Thanks,
Olivier Dosiere
Project engineer DMI - 450 lexington street Newton, MA 02466 617-527-1525 x 102 =====================================================You received this e-mail because you are subscribed to the BLDG-SIM@xxxxxxxx mailing list. To unsubscribe from this mailing list send a blank message to BLDG-SIM-UNSUBSCRIBE@xxxxxxxx |