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Recent content by sloyal

  1. sloyal

    VRF Performance on 100o DB summer 32o Winter 780WB

    I'm using 2 pipe heat recovery systems all over northern climes. much easier installation. Ball valves allow isolation of single head during service w/o dumping all the rfrg... longer line lengths & primarily soft copper preinsulated linesets. Integration of analog sensors (motion, Humidity...
  2. sloyal

    VRF Performance on 100o DB summer 32o Winter 780WB

    What kind of WSHP? Boiler/Chiller? A cooling tower @78dFwb is going to use a ton of power to chill water. An air cooled chiller is also gonna be taxed. A geothermal system is going to gobble it up easily, but with a design of 32dF winter, I'd be concerned about the "recovery time" for the ground...
  3. sloyal

    calculation of a 100% outside air cooling load

    Here's my 2 cents... BTUH = 4.5 x cfm x Delta H H=psych chart enthalpy McQuay & Trane as well as others have downloadable Charts that should give Enthalpy conditions, I prefer the straight edge on a paper graph (calcs for the files) My design conditions are 89db/73wb Enthalpy = 36.5 indoor...
  4. sloyal

    dryer vent pipe length

    Watch your velocity... Dryer vent is sized to convey the lint, not on a pressure drop of the air. Flex is a no-no for anything other than connecting. As with kitchen exh systems, the grease/lint needs motivation or the duct fills up. The lint will build up & issues will arise, not the least...
  5. sloyal

    Clothes Dryer Exhaust Vent

    I've seen this done before, it's a costly project. First the shaft must be lined. NO SHEETROCK! I've seen sheetmetal duct & Mylar (wallpapered) used for the linings. Our local code official required sprinklers as well. Next the dryer connections must not face each other so that one blows into...
  6. sloyal

    Duct Losses vs Static Pressure

    Great post IMOK2! I'm printing a copy to hand out to a few I work with. Not to pick nits with your example.. "return duct with a design pressure drop of 0.05 wg you determine that the total equivilent length(TEL) is 95-104 ft that is = to a pressure drop of 0.05"... supply duct, the design is...
  7. sloyal

    Duct Losses vs Static Pressure

    Now you've gone & done it... TSP & ESP, That is the question! TSP stands for Total Static Pressure. ESP stands for External Static Pressure. Problems arise in asking "External to What?" Some Mfgrs regard it as external to the AHU/System, others say external to the blower. I've found it...
  8. sloyal

    Duct Losses vs Static Pressure

    Let's step back a bit... Your previous post said you had 10 outlets, correct? Are you hoping to deliver similar amounts of air to each diffuser? Are there any balancing dampers on any of these branch ducts, or was this originally designed to deliver measured amounts based on the varying duct...
  9. sloyal

    Duct Losses vs Static Pressure

    Are you totalling the entire systems static losses? As with pumping water, the system static losses will be the total of the worst case run. This is usually the longest run, but not always, some shorter runs may have higher restriction fittings, etc... Upsizing the duct, minimizing flex duct...
  10. sloyal

    Autocad R14 doesnt reconize "MBUTTONPAN"

    It's been awhile since I've used 14, but if you poke around Tools/Options/System, you might have an option of pointing device. In some cases you can reprogram the mouse buttons for specific purposes. It might give you the option if you reload your mouse driver as well. I prefer the 3rd button...
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