Are VFD Centrifugal chillers suitable and/or worth their investment and additional maintenance costs for locations where the wet bulb changes are very less ?
HVAC68
We have an application with a standby motor in AHU.
Is it a standard practice to keep the belt "on" in the standby motor also, so that in case of airflow failure detected through the BMS, the standby motor takes over without the need for a technician to go and put the belt.
OR
Is it a...
Is it advisable to use side withdrawal type filters in AHUs. Some manufacturers recommend that front withdrawal type filters should be used. This would necessitate a mixing box or chamber before the filters so as to have access. Any thoughts on the negative aspects of having side withdrawal...
How is the performance of MCHX all aluminium condenser coil being promoted by a few manufacturers ? The question is specific to the corrosion resistance with respect to the traditional copper tube / aluminium fins. Are there any independent studies conducted ? other than the claims of the...
Is there a document that furnishes the test pressure that the refrigerant piping has to be subjected to in the case of a DX system using R22 refrigerant ?
HVAC68
Have never heard a question like this. But, has anybody used HDPE pipe for refrigerant lines ? If yes, can I have a feedback please. If no, why not ?
HVAC68
I have a 3.3KV auto transformer starter panel for a centrifugal chiller. The panel is a floor/pedestal mounted one, but there is no bottom plate. Cable entry is from top.
Does this meet the NEMA standards or is it mandatory to have a bottom plate ?
HVAC68
I have a direct expansion (DX) system, using R22 refrigerant. The AHU has been designed for 300KW and the air-cooled condensing unit has been designed for 214KW - reasons - probably, oversight ? I don't know.
These capacities are based on a saturated suction temperature of 6 deg C.
What...
Which process is better ? High Frequency Induction welding (HFIW), Fretz Moon (FM) or ERW ?
The specification calls for ERW pipes. However, the manufacturer is doing HFIW process for pipes from 50mm dia to 150mm dia and FM process for 15mm dia to 50mm.
Is there any inherent advantage or...
The traditional method of calculation of duct fitting (bends, elbows, etc.) is based on equivalent length calculation.
There is also another method wherein we use the velocity pressure and multiply the same with a coefficient (k).
(h/4005) square x k.
Needless to say, both produces different...
I have a cable tunnel which is 500m long and 2m x 2m cross-section. What's the air changes per hour to be considered for ventilation in normal mode and in smoke mode ?
HVAC68
Which Universities offer the post graduation in Refrigeration and Air-conditioning by Distance Learning method. I tried a google search, was not very helpful.
HVAC68
Hopefully, I am in the right forum to ask this question.
We are installing a 18" (450mm) dia pipe underground (to be buried under the apron of an airport) for carrying aviation fuel pipe. This involves 100% radiography and X-ray testing, etc.
There are some contractors who are able to do a...
We are designing an airport project. The terminal building has a height of around 20metres (65 feet). Should we install sprinklers ? I am applying more of logic than a code issue here and hence my question - With a height of 20metres, by the time the fire reaches the top and operates the...
