I am having issues with the heat exchanger for a fluid cooler (closed
circuit cooling tower) in eQuest 3.64. I can run the simulation without the
heat exchanger, but get a series of the following message:
CURINV: No real root for CURVE:
1 0.449745 0.027043 -0.000444 -0.028325 0.000285 0.001570
which appears to be from the FluidCooler-FluidCap-fApp&WB performance
curve. This is likely due in part to operating the system at freezing
temperatures with the spray pump on.

If I add the heat exchanger so that I have a dry cooler for the winter
months (set the Wet Schedule to 60F), I get the following error:
***ERROR***********************************************************************
Heat-Exchanger: FluidCooler-DryHX has
inconsistent
input parameters for flow calculations
Mode SupTi DemTi DemTo
3 39.00 82.00 82.00
I allow everything for the heat exchanger to default as well as the
performance curves for the fluid cooler. The values for SupTi, DemTi and
DemTo will vary somewhat, but DemTi always equals DemTo, which I think may
be a problem.

The fluid cooler serves a heat pump loop that also serves as the condenser
water loop for a chiller. I'm trying to maintain the HP loop temperature
between 75 and 85F with additional heat provided by a boiler. I have
attached the .inp and .pd2 files if they may be of help.

Any help would be appreciated.

--
Ron Pecarina, PE, CEM, LEED-AP