Recent content by rifter1

That is one of the puzzles I'm trying to solve. a) An existing R-22, 5 ton residential unit is replaced. b) The new R-410a system does not cool as well at high temperatures. c) Why. It seems to keep happening. I have plotted 30 published extended performance data from a single manufacturer...

The "extended performance" data published by manufacturers is apparently linear. In the back of Manual S they show a linear equation to recreate performance data tables. When you plot the actual published performance data on a graph, it is also - apparently - linear. However DuPont published...

Yes I still have that on my desktop I haven't had time to look at the solution yet, believe it or not. After 12 hours a day I draw the line. I think in autumn or winter I will have time. I'll get to it. I'll let you know.

Precisely. It's very easy with a chart. How do you do it with formulas. I'm still working on that.

(B) I'm trying to take 107F (dry bulb) 72 wet bulb air and cool it to 75F dry bulb, and determine what the new wet bulb would be.

I know I'm missing something simple. In order to find Pswb I need to know Twb. But I don't know Twb, that's what I'm trying to solve for...

Ah. OK looks easy... Pswb = saturation vapor pressure at Twb, Pa Patm = atm pressure, in Pa Pv = vapor pressure, in Pa Twb = wet bulb temp, in K T = dry bulb temp, in K Pswb - Pv = B1(Twb - T) where B1 = {1006.9254(Pswb - Patm)(1 + 0.15577[Pv/Patm])}/(0.62194 hfg1) ; [for 255.38 <= T <=...

Manual J publishes design dry and wet bulb data for each city. So, for instance: Phoenix, AZ would be 107 db, and 71 wb for outdoor air. However, I want to calculate what the wet bulb would be if I took the published conditions and changed the dry bulb to indoor air temperature of, for...

In a 3 phase wye configuration of loads (let's say electric resistance heaters since I have a photo of one of those)... http://members.cox.net/rifter1/images/3pshDiag.jpg voltage is 480V. now, just the way 3 phase works, the potential at the centerpoint in the diagram is zero to ground...