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  1. EnergyProfessional

    Video series on engineering life

    Will you still make regular videos, or shorts only? Looks like only the Friday video is a regular video now. Whatever is in the shorts likely is valuable (didn't watch, and wont), but an 8 minute video in interviewing may make more sense instead of 8 1-minute videos. I won't participate in...
  2. EnergyProfessional

    HEAD PUMP - MAXIMUM OPERATING PRESSURE

    Figure 4 is a pump curve, not a system curve. Google should explain the difference. I don't think the fact that a pump needs to create pressure in a system needs to be defended.
  3. EnergyProfessional

    PICV valve and it's impact on fan coil

    Correct. you want to make sure you maintain a specific DAT (or a small range). For cooling this is important to make the air cold enough (to dehumidfy, unless you are in Arizona or so). For heating you want to avoid stratification unless you have very low ceiling or floor diffusers. but you...
  4. EnergyProfessional

    PICV valve and it's impact on fan coil

    Does the FCU have a variable speed motor (e.g. ECM)? Do you have discharge air temperature sensor? If you have that, or can add it you could do this: - cooling: control fan and valve to have DAT at 55F or below. Increase airflow if more cooling is needed, while keep opening the cooling valve...
  5. EnergyProfessional

    HEAD PUMP - MAXIMUM OPERATING PRESSURE

    You lost me slightly before "A pump creates flow, not pressure". I like to see the system that allows flow at no pressure differential. The point of no pressure change refers to no change in pressure due to pump operation. Pressure will change with temperature and height, but this is different...
  6. EnergyProfessional

    PICV valve and it's impact on fan coil

    Too cold or too warm? Do you have actual temperatures? I ride my bike in summer with short pants and t-shirt and sweat, and others also riding, but with long pants and jacket. Apparently they still feel cold at 90°F, while I feel warm. Without actually measured objective data you know nothing...
  7. EnergyProfessional

    HEAD PUMP - MAXIMUM OPERATING PRESSURE

    The expansion tank is there to accept expanded volume (from thermal expansion). The point of no pressure change also works without ET if you don't heat (or chill) the water. If it wasn't for a boiler or other means of heating the water, you didn't need an expansion tank, the pump and hydraulic...
  8. EnergyProfessional

    PICV valve and it's impact on fan coil

    Sounds like you have a modulating actuator and the PICV have a preset for the flow. Each of the numbers represents a flowrate (I wish they would write that on, but yo have to look that up int he spec sheet). Also sounds like your FCU is just on/off. So when heat is needed, the fan starts and the...
  9. EnergyProfessional

    HEAD PUMP - MAXIMUM OPERATING PRESSURE

    I think discussing all the wrong options (expansion tank not at point of no pressure change) is moot. If the ET is at the wrong location, things will be wrong. Expansion tank should be at the correct location in relation to the pump. Period. Maybe review the book and the website I posted...
  10. EnergyProfessional

    PICV valve and it's impact on fan coil

    Based on what are you controlling the valve? discharge air temperature? By dial, I suppose you mean one of those that get field-adjusted by limiting actuator travel. So you have a 0.5 gpm, 1 gpm and 1.5 gpm setting etc. that dial would set the maximum flow (or actuator travel. Up to that...
  11. EnergyProfessional

    HEAD PUMP - MAXIMUM OPERATING PRESSURE

    You install auto vents at the highest point regardless of expansion tank location. You also install a separate air/dirt separator. You also set the pressure so that at the highest location it is above atmospheric pressure. If you have 0 psi at the highest level, you did not design/set up the...
  12. EnergyProfessional

    HEAD PUMP - MAXIMUM OPERATING PRESSURE

    The expansion tank pressure will be set to whatever the static pressure is at the suction side of the pump (which will depend on the pump elevation in the system). I cannot think of a reason to not have it near the suction side of the pump. You typically have an isolation valve and a strainer...
  13. EnergyProfessional

    HEAD PUMP - MAXIMUM OPERATING PRESSURE

    Expansion tank and fill-station should be as close to pump suction (point of no pressure change) as possible. a lot of funny things happen if you put it elsewhere. among others, the membrane may wear out due to pressure changes of pump operation. Read this...
  14. EnergyProfessional

    HVAC Equipment Lead Times

    It is what it is and whatever lead time they told you at time of design, could be much different when you actually order and that can be much different from when it actually happens. And you only need one thing missing and the entire project is not functional. So I just design a usual and then...
  15. EnergyProfessional

    Chemical Engineer, MBA

    If you want to do it, don't wait too long. Many people do it without experience, so you can do it while starting work. The older and more settled you get, the harder school will be. More time conflicts etc. You should consider your reasons. Love for learning? Career? then decide what type of...
  16. EnergyProfessional

    Renewable solar companies: No PE on staff

    Do you know of specifics that their design or work is bad? 500MW is something the utility, or the network company would be involved and oversees the interconnection. They make sure that no problem will transfer into their grid. they also may be part-owner of the project. Is there a legal...
  17. EnergyProfessional

    filters in AHU

    Filter manufacturer will give a maximum pressure. Above that, the filter may collapse. then you obviously have a problem. So your alarm should be a bit below that value. For VAV AHU, it is hard to measure how dirty the filter is just by looking at dP. Every once a while a mechanic just has to...
  18. EnergyProfessional

    HEAD PUMP - MAXIMUM OPERATING PRESSURE

    at any time at any height the pressure needs to be above atmosphere (or the de-aerators will aerate...). Pumps off, or at full speed. Pressure on discharge of the pump will be static pressure plus the dead head pressure of the pump. Or static pressure only when the pump is off. This could apply...
  19. EnergyProfessional

    ASHRAE Conditions for Global Warming

    FWIW, you made me curious and I contacted our JHA. Our energy code lists 87°F DB and 75°F WB as ambient design temperature. Larger equipment typically means less efficiency. So I assumed those are maximum design temperature to avoid oversizing. But they stated I can use higher temperatures and...
  20. EnergyProfessional

    Video series on engineering life

    I don't recall if you already covered this. Advising young engineers that start their career and want to learn technical skills would be good. Like a young engineer could start at a firm where there are no knowledgeable (in that field) senior engineers or for some reason they don't provide good...

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