Engineering, 05.03.2021 02:00 Nathaliasmiles

A building with an internal volume of 400 m3is to be heated by a 30-kW electric resistance heater placed in the duct inside the building. Initially, the air in the building is at 14°C, and the local atmospheric pressure is 95 kPa. The building is losing heat to the surroundings at a steady rate of 450 kJ/min. Air is forced to flow through the duct and the heater steadily by a 250-W fan, and it experiences a temperature rise of 5°C each time it passes through the duct, which may be assumed to be adiabatic. Determine the average mass flow rate of air through the duct.

Answers: 2

Show answers

Another question on Engineering

Engineering, 04.07.2019 18:10

Hydraulic fluid with a sg. of 0.78 is flowing through a 1.5 in. i.d. pipe at 58 gal/min. the fluid has an absolute viscosity of 11.8 x 105 lbf-sec/ft2. is the flow laminar, turbulent or within the critical range? give both a numerical reynolds number and a term answer.

Answers: 3

Answer

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

Answer

Engineering, 04.07.2019 19:10

What is the major difference between thermoplastics and thermosetting plastics from the polymerization structure point of view?

Answers: 2

Answer

Engineering, 04.07.2019 19:20

Air at a pressure of 1atm and a temperature of 40 c is in parallel flow over the top surface of a flat plate that is heated to a uniform temperature of 120 c. the plate has a length of 0.40m (in the flow direction) and a width of 0.15m. the reynolds number based on the plate length is 50, 000. what is the rate of heat transfer from the plate to the air? if the free stream velocity of the air is doubled and the pressure is increased to 10 atm what is the rate of heat transfer?

Answers: 2

Answer

You know the right answer?

A building with an internal volume of 400 m3is to be heated by a 30-kW electric resistance heater pl...

Questions