PDA

View Full Version : will the fcu actuator stop the chilled water 100%?







moideen
01-04-2013, 06:15 AM
Dear guys, I have a question, will the actuator valve of the fan coil unit close the chilled water 100% completely? We have installed BTU meters (energy meter) for our new multistory buildings and trying to charge the consumption rate of the A/c. but recently so many tenants has raised complaints that energy bill is going high when the A/c is switched off. Then we inspected around 250 apartments. Around 50units are working properly. No meter is running when fcu is switched off. So we inspected defective valves, but it is closing but not 100%.water is leaking and meter is reading the rate. Meter has configured gpm*deltaT. Subsequent meeting with actuator supplier (siemens) says that this common thing. Any valve not closes properly 100%.please let me know what your comments?

Moideen-Dubai

install monkey
01-04-2013, 08:44 AM
2 port will allow flow through even if in closed position
3 port valves are more reliable as they divert back to the return, bypassing the fan coil

Tesla
01-04-2013, 10:01 AM
Hi Moideen
Can you give us the model numbers of the metering device and the valve. Is it going back to the BMS? if so it could be a case of simple modification to the code to stop counting "if FCU Fan = Off" But really wasting all that energy needs controlled better like IM above said. What is the water system in use? primary secondary vsd coupled??
In practice many (most) CHWVs leak a little after short time. The type of valve is important and there are many - ball with equalizing would be a good option.

moideen
01-04-2013, 10:16 AM
thanks tesla and install monkey,the model number will be update you........primary-secondary are coupled.

The Viking
01-04-2013, 02:07 PM
Had this on a site once and the answer then was that NO, 2 port valves does not fully close.
Our solution was to fit solenoid valves inline with the 2 port valves as this turned out to be the cheapest option.

Another solution might be to look in to the way your charges is calculated. Maybe if what you charge is based on a function of the true total running costs this error might have minimal impact? Something along the lines of monthly cost per apartment = ((total plant's annual running cost / total units used in the building) * units used annually in individual apartment) / 12
Just a thought...

:cool:

.

moideen
15-09-2013, 08:42 AM
Had this on a site once and the answer then was that NO, 2 port valves does not fully close.
Our solution was to fit solenoid valves inline with the 2 port valves as this turned out to be the cheapest option.

Another solution might be to look in to the way your charges is calculated. Maybe if what you charge is based on a function of the true total running costs this error might have minimal impact? Something along the lines of monthly cost per apartment = ((total plant's annual running cost / total units used in the building) * units used annually in individual apartment) / 12
Just a thought...

:cool:

.
Sorry for late replay and thanks your thoughts. It is better to explain with examples. I am also thinking the possibility of reconfigure the meter controller to limit the delta T and flow. Example: 6 ton capacity required gpm is 14.4, assume the flow is 3 when the actuator is closed and limit the delta T also is 2k.then can configure the result is 3*2=0 instead of result is 5.