annu777
Mechanical
- Apr 2, 2013
- 5
Having a chiller plant optimization;
we try to figure out the running the bases kW/Tr of the system in 10 years but sadly to say they can only archive a six months of trending output of chiller data; (delta temp of evaporator & condenser, pressure of ref. & etc), & for chilled water , condenser, & ct (kwh) & to used to determine the cooling load & the kW.
A. I am correct to used the output kWh of chilled water pump to determine the Tons of refrigeration as no other way to solve it,
solution like this way;
chilled water pump = 1600 kwh per day at each pump at 24 hrs running
= 66.7 kW per pump or 89.5 Hp if two pumps
at rated pumps, 2400 gpm, 154 feet, 150 hp
by applying affinity law of pumps,
Hp1/Hp2 = (N1^3/N2^3), if N=Q
150Hp/89.5Hp = (2400^3/Q2^3)
Q2=1872 gpm but two parallel pump so
how i can assume, let say 1872 x 2 x 60% = ?
if each pump
TR =500 x gpm x dT/12,000 (note: average deltaT of evap. from Chiller trending)
= 500 x 1872 x 7.56 /12,000
TR = 589 (in one pump)
TR = 1179 TR (in two pump)
or to assume at let say 1872 gpm x 2 x 60% = 2246 gpm
TR =500 x gpm x dT/12,000
= 500 x 2246 x 7.56 /12,000
TR = 707.6
which one is used, the direct adding of parallel pump or assuming the 60% of the total or the another way to determine the correct or accurate kW/TR of the chilled water pump.
The other ways to obtain the TR, water flow meter but not trending, lately they installed 7 not yet calibrated.
B. The chiller performance curve given by supplier of then they have value of PLR,
see attached file, in actual condition the chiller delta T of evaporator & condenser are less than dT = 10 F of design. Even in this case is still follow the performance curve of the rated? or there are 5% tolerable. Since the supplier not attend to give as simulation of the chiller performance curve base on actual delta T requested from us. I can't figure out exactly the variation of the performance of the curve respective to the delta T range. I assume that its no matter what its will be the same performance curve if its correct delta T..then in demand base control method according to hartman, can i used its to pilot the system as the data given, i can give the chilled water flow, condenser flow directly as chiller performance curve shown and by affinity law i can direct substitute to obtain kW or Hz equivalent in certain part load or there is problem as A. above situation for the parallel pumps.
C. chilled water system, the system was installed at PID method then try to convert in demand base method, the chilled water system was lots of problem in maintenance according to the client, they said there some cooling coil not fix, control valve are not fix, & balancing valve wide open, so the system not balance anymore. If i am correct for my analysis for this system to automate,
first thing to do is to calibrate the sensor instrument & fix the control valve & coil, then balance the chilled water system & automate.
we try to figure out the running the bases kW/Tr of the system in 10 years but sadly to say they can only archive a six months of trending output of chiller data; (delta temp of evaporator & condenser, pressure of ref. & etc), & for chilled water , condenser, & ct (kwh) & to used to determine the cooling load & the kW.
A. I am correct to used the output kWh of chilled water pump to determine the Tons of refrigeration as no other way to solve it,
solution like this way;
chilled water pump = 1600 kwh per day at each pump at 24 hrs running
= 66.7 kW per pump or 89.5 Hp if two pumps
at rated pumps, 2400 gpm, 154 feet, 150 hp
by applying affinity law of pumps,
Hp1/Hp2 = (N1^3/N2^3), if N=Q
150Hp/89.5Hp = (2400^3/Q2^3)
Q2=1872 gpm but two parallel pump so
how i can assume, let say 1872 x 2 x 60% = ?
if each pump
TR =500 x gpm x dT/12,000 (note: average deltaT of evap. from Chiller trending)
= 500 x 1872 x 7.56 /12,000
TR = 589 (in one pump)
TR = 1179 TR (in two pump)
or to assume at let say 1872 gpm x 2 x 60% = 2246 gpm
TR =500 x gpm x dT/12,000
= 500 x 2246 x 7.56 /12,000
TR = 707.6
which one is used, the direct adding of parallel pump or assuming the 60% of the total or the another way to determine the correct or accurate kW/TR of the chilled water pump.
The other ways to obtain the TR, water flow meter but not trending, lately they installed 7 not yet calibrated.
B. The chiller performance curve given by supplier of then they have value of PLR,
see attached file, in actual condition the chiller delta T of evaporator & condenser are less than dT = 10 F of design. Even in this case is still follow the performance curve of the rated? or there are 5% tolerable. Since the supplier not attend to give as simulation of the chiller performance curve base on actual delta T requested from us. I can't figure out exactly the variation of the performance of the curve respective to the delta T range. I assume that its no matter what its will be the same performance curve if its correct delta T..then in demand base control method according to hartman, can i used its to pilot the system as the data given, i can give the chilled water flow, condenser flow directly as chiller performance curve shown and by affinity law i can direct substitute to obtain kW or Hz equivalent in certain part load or there is problem as A. above situation for the parallel pumps.
C. chilled water system, the system was installed at PID method then try to convert in demand base method, the chilled water system was lots of problem in maintenance according to the client, they said there some cooling coil not fix, control valve are not fix, & balancing valve wide open, so the system not balance anymore. If i am correct for my analysis for this system to automate,
first thing to do is to calibrate the sensor instrument & fix the control valve & coil, then balance the chilled water system & automate.