• (Edited )

i’ll kick it off.
#6 is Total Heat Loss (through material):
q [BTU/Hr] = U [BTU/Hr-ft^2 deg F] x A [ft^2] x Td [deg F]

q = total heat loss

U = overall coefficient of heat transmission

A = area

Td = temperature differential (inside to outside etcetera)

• (Edited )

#5 is definition of “1 ton” of AC (which is basically a metric thing i think).

#7. Definition of U Value (?) for a Wall Section (?)
U [BTU/Hr-ft^2-degF] = 1 / Rt [BTU/Hr-ft^2-degF]
Rt = resistance total

AKA: U = 1 / Sum of R Values

• (Edited )

what do i call #3? Rate of Sensible Heat or Gain due to Infiltration or Ventilation (?):
q(u) [BTU/Hr] = V [CFM] x 1.08 x delta T [degF]
q(u) or “q sub u” = heat loss
V = volumetric flow rate of air (in cubic feet per minute). this is empirically rested and is provided as a given value.
1.08 = is a constant

• # 8: Coefficient of Heat Transmission
Uo [BTU/Hr-Ft^2-degF] = (Uw x Aw) + (Uop x Aop) / Ao
all U are in BTU/Hr-Ft^2-degF and all A are in Ft^2
Uo = overall coefficient of heat transmission (overall)
Uw/Aw = coefficient of heat transmission or area for window
Uo/Aop = coefficient of heat transmission or area for “opaque wall” (?)
Ao = area of total wall

• #9:
same as 8 but for an (opaque) roof and a skylight?
Uo [BTU/Hr-Ft^2-degF] = (Ur x At) + (Us x As) / Ao
definitions as above except r = roof and s = skylight

• (Edited )

#4 Definiton of Kilowatt-Hour (metric thing):
1 kWh = 3,400 BTU/Hr

• #10. Definition of R Value (or Resistance) (?)
R [Hr-Ft^2-degF/BTU] = x [inches] / k [constant]
R = Resistance or the hours needed for 1 BTU to pass a given thickness at a temp change of 1 degree Fahrenheit.
x = material thickness
note that “C” is Comsuctsnce which is basically k but for a specific material (leaving out the thickness. so R = 1/C and C = 1/R

• anyone able to proof that and help with #’s 1, 2, and 11...?!

• looks like i just need help with three before i can summarize this for everyone. any takers for 1, 2 and 11?

THANKS

• Jonathan,

These are helpful explanations.  Did you find any specific example problems to practice using these?

Thanks,