Dear Experts,
Is it possible to get actual air flow (m3/h) of an AHU by refering to it's fan curve in a specific frequency by having actual kw of the fan?
It is a backward centrifuge fan with exact curvd in different frequency and power.
Actual power kw and actual RPM is displayed on VFD...
Hi dear Experts,
I have seen a differential pressure switch across a heat recovery wheel in some AHUs.
Could you please let me know the function of the DPS and how it should be adjusted.
Regards,
Dear Experts,
Could you please let me know what parameters should I consider to order a new G4 filter for AHU.
Unfortunately there is no data on the current installed G4 filter.
Any relationship bettween AHU air flow m3/h and filter air volume?
Regards,
Hi experts
A question has occupied my mind please clarify it for me:
As you may know pressure independent valves(PICV) have a dial on themselves to adjust maximum flow according to the load characteristic, it is in fact a balancing valve sitted inside the PICV
Now my question is that what...
Dear Experts,
I have a question regarding G4 filter (used in air handling unit)differential pressure switch adjustment please assist me;
As far as I know, each G4 filter has a initial pressure and final pressure that means if final pressure is reached
that filter should be replaced but the...
Dear Experts
Could you please let me know why some chemicals needs to be dosed to water heating and cooling close loop?
Is there a manual for understanding this subject from basic?
Regards,
Dear Experts,
Something in centrifugal pump or fan is vague for me so please correct my understanding:
In centrifugal pump or fan the vertical axis is the differential pressure across the pump or fan and horizontal axis is
flow and more flow means low pressure across the pump or fan and vice...
Dear Experts
In one of the Air handling units in our company cooling coil is used for dehumidification but although the cooling coil valve is 100% open and its temperature is lower than dewpoint but dehumidification is not done at all.
Could you please let me know what parameters should i check...
Dear Experts,
Could you please let me know what happens to a centrifugal pump if the load (e.g.fan coil or any other thing that take flow from the pump) connected to it is in two cases
less and higher than the pump specifications?
what is reaction of the pump in the two scenario?
Thanks,
Dear Experts
I have great experience of working on the plc. systems and different machines but not on HVAC system too much
As far as I know HVAC equipments such as chillers ,Air handling units and boilers have their own controller
that control function of them but I am curious to know how is...
Dear experts
In some projects I have seen fan coil units are used along with vav for rooms and also halls but vav can cope with heating and cooling load so, what is purpose of using fan coils with vav to do the job?
Is there any benefit of using fan coils?
Thanks
Dear Experts
The photo is related to one of AHUs on the riser. The problem is that only
This circuit has problem of pump cavitation on the riser and other ahu pumps are working fine
When pressure independent control valve is open more the cavitation sound
Willl be higher and vice versa so...
Dear Experts,
Could you please let me know how is "reset pressure setpoint " method implemented in chillers secondary loop?(in aspect of control algorithm)
And another question is that: How should the primary pump that supply chiller evaporator be controlled by VFD drive?(it should be control...
Dear Experts,
In a primary secondary chilled water system, we have problem of the chillers working when there is partial load on the secondary side,
and as you know loading chillers at low percent of load for long time can be harmful for the compressors so could you please let me know
how I...
Hi dear experts,
Dears i am very new to mechanic knowledge and my below question maybe seem very simple to answer but are very tough for me to get.🙂
Could you please let me know what pressure amount shold a close secondary loop of a chilled water be filled to? For instance a loop can be...
Dear experts,
I have seen some air handling units that their coil are equipped with freez protection pumps along with a check valve. These pumps not only run when the outside air temperature come below 5'c but also whenever coil control valve is opened. these pumps are designed at full flow of...
Hi dear experts
Could you please let me know how to get right diffrential pressure value in secondary loop of chilled water system supplying different terminal units?
A diffrential pressure transmitter has been installed in farthest unit and all units are equipped with pressure independent...
Dear Experts,
Could you please let me know how the air is even distributed in pharmaceutical halls? I mean suppose that one of zones of an Air Handling Unit is
a big hall that contains several diffusers with on VAV at first of Duct(VAV is controlling the whole flow to the main duct). I know in...
Dear Experts
I have been seeking to find standard control algorithm of AHUs for instance how control dampers or supply and return fan speed and so on but no success yet.
Could you please help me in this regard.
Any good book, document,any mecanichal drawing or flowchart
Your reply will be...
