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  1. HVAC68

    Water curtain - Pipe sizing

    stookeyfpe - Our code says that the maximum size of a fire compartment in a basement car park area shall be 3000 sqm., beyond which we have to create another fire compartment. In a basement car park, it would be practically not possible to create a physical separation and hence the code allows...
  2. HVAC68

    Water curtain - Pipe sizing

    stookefype - We are providing automatic fire sprinkler in the basement. The water curtain is in addition to that, to primarily do a virtual fire separation/compartmentation based on the total basement area as per the codes. The code mandates 2 fire compartments based on the area. HVAC68
  3. HVAC68

    High Amps on Chiller Compressor Motor

    Both the condenser and cooler flow rates are down from the earlier numbers. Any reason why this is so ? Low suction ? High discharge ? HVAC68
  4. HVAC68

    RH and DB temperature

    Typically in a cooling coil, we do cooling and dehumidification, which means reduction of Dry Bulb and RH. However, if in the process of dehumidification, we end up over-cooling, then a sensible heat addition is done to bring back the temperature of air to the desired level. HVAC68
  5. HVAC68

    Water curtain - Pipe sizing

    Sorry my question was probably not clear enough. Due to time difference between the continent where I am in and where most of you are in, there could be some time lag in responding ! Coming back to the question : TravisMack - Yes, you are right. NFPA 13 indicates "Sprinklers in a water...
  6. HVAC68

    Water curtain - Pipe sizing

    Hi all, Can someone help me with the pipe sizing for water curtain ? HVAC68
  7. HVAC68

    design chiller delta T

    If it is not a big project, then the projected savings on account of lower pipe sizes, pumping, etc., may not be much and/or may not be favourable. However, this works well for large plants bordering on district cooling type of installations. HVAC68
  8. HVAC68

    How should I deal with this situation? I want to do better!

    Great position to be in ! I see lots of opportunities if you get free time. Learn ! Ask your supervisor or your colleagues and pick up some old orders / drawings / challenges. Be an optimist and utilise this time to the fullest advantage to equip yourselves for tough times ahead ! HVAC68
  9. HVAC68

    AHU Outside Air getting sucked in

    Where is the AHU sucking outside air from, if the outside air damper is closed ? Is the return air ducted to the AHU or is it free return into the AHU room ? HVAC68
  10. HVAC68

    VFD Centrifugal chillers - suitable for locations with very little wet bulb changes

    Thanks for the inputs. Was busy with a few things and hence couldn't log on earlier. This is a new installation. Another issue that has come up is the restart time required, since this is a critical data centre installation. Eventhough there is redundancy available in the form of a standby...
  11. HVAC68

    VRF vs. Chilled water system

    Questions. 1. How's the fresh air being taken care ? 2. What capacity are we talking about ? 3. Do you also have other areas like accommodation, dining, etc., attached to the school ? If yes, a chilled water solution would be better. 4. Several indoor units would require interference and...
  12. HVAC68

    VFD Centrifugal chillers - suitable for locations with very little wet bulb changes

    Thanks for the responses. This is a 24-hour application - a data centre to be precise. The internal loads are more or less constant. The external loads vary considerably thanks to the outside temperature variations. 2 schools of thought. One pitching in for VFD regardless of whatever the...
  13. HVAC68

    VFD Centrifugal chillers - suitable for locations with very little wet bulb changes

    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
  14. HVAC68

    Standby motor in AHU

    The customer wants what he wants. Period. Having said that, we feel that it is our duty to tell the customer the pros and cons of both. Again, with limited knowledge on the subject, customer is not buying the argument unless backed up with "standards"or "codes"and hence my request in this...
  15. HVAC68

    Standby motor in AHU

    Thanks. Does any code talk about standard practice of allowing the belts to run on the idle motor as well. I understand the need to additional torque and oversizing the motor to take care of this. My question is the other way round. If something is not a standard practice, then, customer...
  16. HVAC68

    Standby motor in AHU

    Thanks for the response. There is a scheduled weekly change-over through BMS from duty to standby motor. This is a 24-hour application and hence in case there is a breakdown in the night, there may not be operatives available for changing the belts. This is the reason they want the belts...
  17. HVAC68

    Standby motor in AHU

    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...
  18. HVAC68

    Side withdrawal bag filters in AHUs

    Thanks SAK9 and ChasBean1 HVAC68
  19. HVAC68

    Side withdrawal bag filters in AHUs

    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...
  20. HVAC68

    HAP software help

    Use the F1 (help) button at any point in the HAP software and it will give enough help for one to understand. HVAC68
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