Can anyone explain how to use these formulas, from the NCARB formulas available while testing- or point me towards an online resource?
BTU/year= peak heat loss x (full-load hours/year)
Heat Required= [(BTU/h)/temperature differential] x 24hours x DD degrees F
I've tried and failed to find them in my books (MEEB 9th edition, HCL 3rd edition, Ballast). Maybe my books are too old!
I never did get an answer for these formulas before my test, but here are names for some other reference formulas to help others locate relevant resources:
Zonal Cavity Calculation/ Average Maintained Illumination Level:
Footcandles= (lamp lumens x lamps per fixture x number of fixtures x CU x LLF) / area in SF
Heat Loss through Air Infiltration (also, it appears that rearranging the formula can be used to calculate CFM required for cooling in MEEB section "Psychrometrics and Refrigeration"):
BTU/h = cfm x 1.08 x deltaT
Heat Flow through Envelope aka Heat Loss through Transmission through walls, windows, doors and roofs:
BTU/h = U x A x difference in T between indoors and outdoors
Heat loss through Envelope (one formula for wall, one formula for roof, but they work the same):
U total wall = [(U x A for window) + (U x A for opaque wall )]/ A total
There's several acoustical formulas for sound absorption that appear to be a series that build one upon the other. The first helps you find the sound absorption of a particular material in a space (a = SAC x S). The second helps you find total sound absorption in the room by adding the absorption of the different surfaces. The third relates that to the reverberation time.
For questions like that, NCARB would probably give you a geographic location and info about heat loss thru building. You can look up in Graphic Standards the Heating Degree Day by location, which is how you find the BTUs you need. It's based on the difference between the outdoor temp and the indoor temp. Every day, every degree is added up. Colder climates need heat for more hours/year and thus need more BTUs.
Hope this helps!
Rebekka O'Melia, R.A., NCARB, B. Arch, M. Ed, NOMA, Step UP ARE 5.0 Courses
Please sign in to leave a comment.