Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  1. engair

    R Value for standard rubber

    I am looking for R Values for standard rubber. I am wanting to find a rubber that can hold up to my requirements in compression, but my boss also wants me to be able to make a claim to its R value. I am googled out, so any assitance would be greatly appreciated.
  2. engair

    a question about make up air unit

    RTU is right. A simple heat pipe system would work pretty well for you.
  3. engair

    DX Split Hot Gas Reheat

    Careful of trying to install mod reheat on the system if it isn't R-22. Some of the components you need for 410A aren't ready yet.
  4. engair

    Coil Energy Recovery Loops

    Maurice is right, engery recovery is the first thing I see VE'd out most the time
  5. engair

    Coil Energy Recovery Loops

    Why pump fluid? Just use a heat pipe, and it does all the work itself.
  6. engair

    Need help explaining use of ASHRAE Design Condition Charts

    Ha! I had no idea they used to make enthalpy wheels from asbestos! That is a fun fact. Gold star for you maurice.
  7. engair

    Need help explaining use of ASHRAE Design Condition Charts

    Correction I did not read well enough and jumped the gun with my response. You want 75/50%RH in Portland you are going to be looking at a unit with dehumidification and reheat. You are in a moist enviroment and will need to get the dew point of your outside air to 55 to be able to reach 50%RH at...
  8. engair

    Need help explaining use of ASHRAE Design Condition Charts

    You are in Portland, and you will be cooling outside air. Even though you are only going to 75 you will probably be seeing some dehumidification.
  9. engair

    Outside Air Damper Leakage Solutions

    I have had lots of experience with low - leak dampers. You can get them from several companies in any size you want. I have seen lots of Ruskin and Tamco personally and they seal really tight and nice. How that affects your sick building syndrome worries I dont know, but the dampers will seal up...
  10. engair

    Oil burner AHU system design

    I would say call up a vendor for direct fired units in Canada. Those guys deal with that kind of design and worse everyday.
  11. engair

    250' Condensing unit piping

    not the refridg, its the oil in the refridg. There is mineral (and POE depending on the refridg) in the refridg. The oil will always try to migrate towards the coldest point. The longer the line length the harder it is for the compressor to pull the oil back to the compressor. If it is...
  12. engair

    What percentage of a building electrical usage is HVAC?

    But willard how can you be sure if you dont taste it also?
  13. engair

    R22 - 407 gas change

    R-22 is being discontinued as a refridgerant, and in larger applications a direct drop in has not yet been approved. My understanding is they needed to charge the system and were not able to purchase R-22. No matter the reason it was probably just a mistake. There are alot of them get made and...
  14. engair

    250' Condensing unit piping

    Adjusting the charge in the line is standard for split systems. Dropped performance only occurs in the sense of line loss in temperature. The real problem with it is the migration of oil in the refridg because it will go to the coldest point, and you can slug a compressor.
  15. engair

    R22 - 407 gas change

    hoorain, your response was mostly right but you didnt finish it. 407C is not a drop in refridg for R-22 as explained above. They would need a new system as the condenser will be undersized, and the compressors will not work properly with 407C. You are right about all of the components they will...
  16. engair

    Filters downstream of steam dispersion

    for a dri-steem in our equipment 36" is the absolute minimum
  17. engair

    Filters downstream of steam dispersion

    Is it a humidifier or steam dispersion coil? Those are two different things.
  18. engair

    250' Condensing unit piping

    Well in general oil return on long line lengths IS a problem, thats why companies dont like to do them. I am very interested in this oil recovery function though. The only way I can imagine that working is for the unit to turn off.
  19. engair

    VAV system min outside air control

    trashcanman is correct. If you are in economy mode you should be bringing in 100% outside air, but the system should only be in economy mode when the O/A temperature suits the needs of the space.
  20. engair

    Filters downstream of steam dispersion

    24" is standard practice. If I understand your steam dispersion coil there isnt steam in the air stream so mold should not be a factor.

Part and Inventory Search

Back
Top