Manual N Flashcards
You are asked to cool a room in a pump house that contains 10, 20hp pump motors that are inside the space to be conditioned. What is the total sensible load of the pump motors in btu?
585,000btu/h
Pg. 413 Manual N
What is the recommended indoor relative humidity and dry bulb temperature in a museum rare book vault?
70-72 DB 45 degrees RH
Pg. 493 Manual N
The exhaust rate for a sports locker room in educational occupancies is________.
.50cfm/sqft
Pg. 479 Manual N
According to ACCA Manual N, what is the summer design conditions in Greensboro, North Carolina?
90DB, 74WB
Pg. 255 Manual N
What is the heat gain for the lights in a room when twenty fluorescent fixtures with standard ballasts and 2-48in T-12 Fluorescent bulbs per fixture are in the room?
6279.92
20 Fixtures x 92Watts/fixture = 1840Watts
1840W x 3.413 = 6279.92btu
Pg. 407 Manual N
Per Manual N, a large store has 235 occupants, how many btu/h of latent heat will the occupants generate?
76,375btu/h
325btu/h latent heat per hour x 235people = 76375
Pg. 410
Manual N
A building used for light industrial assembly in Asheville, NC has a roof deck that sits on structural steel with a suspended ceiling below. The roof deck consists of 1.5in thick wood with R-3 insulation board and a suspended ceiling below with R-19 insulation located on the ceiling tile. What is the heat loss for this assembly on a design winter day if the roof measures 250ft by 40ft and the indoor temperature is to be maintained at 70⁰?
19,980btu/h HTM = U-value x (ΔT) HTM = .037 x (70 - 16) HTM = .037 x 54 HTM = 1.998 BTUH = HTM x Area BTUH = 1.998 x (250 x 40) BTUH = 1.998 x 10,000ft² BTUH = 19,980 Pg. 361 & 335 Manual N
A commercial wall is constructed of 8in block with filled cells, it has steel studs on the inside with R-13 cavity insulation, stucco finish on the outside and gypsum board on the inside. The building is located in Asheville, NC and the wall faces east and is 500ft². The building is used for an office so what is the heat loss on this wall on a design winter day?
2,403btu/h HTM = U-value x (ΔT) HTM = .089 x (70 - 16) HTM = .089 x 54 HTM = 4.806 BTUH = HTM x Area BTUH = 4.806 x 500ft² BTUH = 2,403 Pg. 255, 335, 339 Manual N
A furniture store in Greensboro, NC has 1/8in thick clear, double pane, fixed sash glass in a metal frame with a thermal break. The glass is ten feet tall by 40ft long and has a 10ft horizontal projection mounted 2ft above the glass. What is the total heat loss on the glass?
12,852btu/h Heat Loss HTM = U-value x (ΔT) Design temp = 19 Default indoor = 70 HTM = .63 x (70 - 19) HTM = .63 x 51 HTM = 32.13 BTUH = HTM x Area BTUH = 32.13 x (10 x 40) BTUH = 32.13 x 400 BTUH = 12,852 Pg. 255, 297 Manual N
A warehouse that is 50f by 75ft is made of 12in thick open cell concrete block with no interior or exterior finish and has no insulation, with a ceiling height of 12ft. What is the heating load for the walls only if the indoor temperature is to be maintained at 60⁰ in Asheville, NC if the net wall area is 33,750ft²?
867,240btu/h HTM = U-value x (ΔT) HTM = .584 x (60 - 16) HTM = .584 x 44 HTM = 25.696 BTUH = HTM x Area BTUH = 25.696 x 33,750ft² BTUH = 867,240 Pg. 255, 335, 336 Manual N
What is the heat gain in btu/h for a dark colored commercial roof sitting on structural framing with a suspended ceiling below dead airspace if the roof deck is made of 1.5in wood with R-20 insulation board and R-13 on the suspended ceiling. The roof is 65ft by 65ft in Wilmington, NC on a summer design day with an indoor temperature of 75⁰
2,981btu/h HTM = U-value x CLTD CLTD = 36⁰ Assuming it's mid day 3pm Adjusted for dark roof CLTD = (Table CLTD x Color Factor) + (summer design temp - 95) + (75 - indoor design temperature) + Daily Range Adjustment Adjusted CLTD = (36 x 1.2(Dark Roof)) + (91 -95) + (75 - 75) No daily range adjustment due to it being Medium Adjusted CLTD = 43.2 + (-4) + 0 Adjusted CLTD = 39.2 HTM = .018 x 39.2 HTM = .7056 BTUH = HTM x Area BTUH = .7056 x (65 x 65) BTUH = .7056 x 4225 BTUH = 2981 Pg. 255, 362, 380 Manual N
