Engineering, 28.05.2021 22:00 dhruvi62
The roof of a house has three layers: (1) 2 inch thick pine, (2) 4 inches of fiberglass insulation and (3) 0.1 inch thick Asphalt shingles. Calculate the rate of flow of heat (BTU/hour) through the roof. The temperature inside the house is 700F and the temperature outside is 300F. The R/inch for pine is 1.28, the R/inch for fiberglass is 3.0 and the R/inch for Shingles is 4.0. Take the area of the roof to be 500 square feet. The Unit of R is mixed: ft2 . 0F. h/BTU
Answers: 2
Engineering, 04.07.2019 18:10
Which of the following components of a pid controlled accumulates the error over time and responds to system error after the error has been accumulated? a)- proportional b)- derivative c)- integral d)- on/off.
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Engineering, 04.07.2019 18:10
Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.
Answers: 3
Engineering, 04.07.2019 19:10
10 kg of co2 is initially contained at 400 kpa and 300 k. the gas constant for carbon dioxide is 189 j/lkg k) and has a specific heat ratio, k, of 1.289. isentropic expansion then occurs until the pressure is 200 kpa. a) determine the initial volume of co2 in m. b) determine the final temperature in k. c) determine the work done by the system during the expansion kl.
Answers: 2
Engineering, 04.07.2019 19:10
Air inially occupying a volume of 1 m2 at 100 kpa, 27 c undergoes three internally reversible processes in series. process 1-2 compression to 500 kpa during which pv constant process 2-3 adiabatic expanslon to 100 kpa process 3-1: constant-pressure expansion to 100 kpa (a) calculate the change of entropy for each of the three processes. (b) calculate the heat and work involved in each process. (c) is this cycle a power cycle or refrigeration cycle?
Answers: 3
The roof of a house has three layers: (1) 2 inch thick pine, (2) 4 inches of fiberglass insulation a...
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