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Recent content by walkes

  1. walkes

    AHU heat gain due to supply fan motor

    It seems reasonable, you have a high static pressure, so your bhp per cfm is a little higher and the associate temperature rise matches that. The entire motor load is included, but the heat may not be realized immediately, as some of the heat gain will be due to friction through the duct. At...
  2. walkes

    RTU in training room

    Use a small HRV to ventilate the training room and condition it with ductless split units. If you are putting some air in from RTU-1, you run the risk of poor temperature control or duelling thermostats.
  3. walkes

    HAP: Air Tempering Unit with vent reclaim (direct exhaust)

    Check to see if your return air and outside air temperature are similar. If they are then there will be no benefit in cooling mode. The exhaust is assumed to match either the ventilation load or the sum of the zone direct exhaust volumes.
  4. walkes

    Solar Assisted A/C

    I have reviewed building installations from the 60s that used absorption chilling machines. One was designed around its own source of natural gas that was used for the electric generator and the steam boiler, the steam was in turn used for the absorption chiller. The whole building essentially...
  5. walkes

    When does Boiler room ventilation to cool room become too excessive based on air changes per hour?

    Is this a process boiler application or heating boiler? If the latter does the load drop when the out door air temperature is warmer? Can you use a reduced load for the jacket losses from the boiler? Can you insulate the boiler jacket more to reduce losses?
  6. walkes

    Reheat on GSHP

    The condenser water reheat coils can work well, for sub-zoning or better temperature control with dehumidification. Taking the water right after the heat pump can be used to reheat or recool the air depending on what mode the heat pump is running in. Since you are not using additional energy...
  7. walkes

    Fan Law - Belt Drive vs Direct Drive

    The only savings you should see are due to belt/drive losses.
  8. walkes

    Plenum Return - Return Airflow Path (Walled Room vs Open Office)

    You should likely review ASHRAE 62 and determine if transfering the air reduces the classification of the space. If it is a concern, another option may be to provide a return fan ducted from the south offices to the north plenum, avoiding tranfer through the open office. If you had a...
  9. walkes

    Plenum Return - Return Airflow Path (Walled Room vs Open Office)

    No return; then limited airflow when the door is closed and potential whistling through cracks (depending on the available static pressure from the fan). We put acoustically lined transfer elbows at high level with a grille on the outside wall (to the open office)
  10. walkes

    Bulk Tender Pricing By Equipment Suppliers

    Thanks 11241, I think you nailed it. I may try using the line item in the bid forms for those specific "widgets".
  11. walkes

    Bulk Tender Pricing By Equipment Suppliers

    What is your experience with bulk pricing of tender packages by HVAC equipment suppliers? The supplier can provide equipment considered equal to that specified, some of the products may be more expensive, some less expensive, but they give the contractors one lump number for everything such...
  12. walkes

    Heat pump fan coil in a small closet

    There are other models of heat pumps that are designed for closets or corner installations for condos/apartments. An example can be found at http://www.skymarkinternational.com/images/resources/166.pdf (I have no knowledge of this manufacturer, but the units are pretty common)
  13. walkes

    New mechanical engineer in MEP field......

    You can also get equipment design information from the McQuay website. They have a number of different design manuals that can be downloaded. A key item would be the Honeywell Engineering Manual of Automatic Controls for Buildings. Ask a local rep for a copy or you may be able to download a...
  14. walkes

    Don't know what the heck I am doing!!!

    Too bad, I was in the neighborhood at Holiday Hills last summer. Usually, the ahu's are selected to provide a 55°F discharge air temperature to provide a 75°F 50% RH condition in the space. Has the space changed over the years? Are they leaving the door open? Is the coil in the AHU dirty...
  15. walkes

    Pizza oven venting

    You can try an alternate pizza oven manufacturer as well, just to get an idea how some should be installed.
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