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3 years ago

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In a movie theater in winter, 510 people, each generation sensible heat at a rate of 80 W, are watching a movie. The heat losses

through the walls, windows, and the roof are estimated to be 130,000 Btu/h. Determine the contribution of people to the heating of the building. The average rate of heat generation from people in a movie theater in sensible form is 80 W per person.

1 answer:

Harrizon [31]3 years ago

6 0

Answer:

$139213.68\ \text{Btu/h}$

Explanation:

Number of people = 510

Heat generated per person with respect to time = 80 W

$1\ \text{W}=3.4121\ \text{Btu/h}$

Heat generated by 510 people is

$\dot{Q}=510\times 80\times 3.4121$

$\Rightarrow \dot{Q}=139213.68\ \text{Btu/h}$

The contribution of people to the heating of the building is $139213.68\ \text{Btu/h}$

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ii). fuel consumption = 0.4947 kg/hr

Explanation:

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and at 70% compression, 30% of the swept volume remains

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$1.594=\frac{v_{c}+0.7v_{s}}{v_{c}+0.3v_{s}}$

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$0.2218v_{s} = 0.594v_{c}$

$v_{c}=0.3734 v_{s}$

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$Q_{supply}=\frac{W_{net}}{\eta _{act}}$

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2 years ago

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Answer:

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From the question; the equations of the velocities profile in the system are:

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The above boundary condition can now be written as :

At y= 0; u =0 ----- (a)

At y = h; u =0 -----(b)

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where ;

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Replacing the boundary condition (b) in equation (1); we have:

$u = u_{max}(Ay^2+By+C) \\ \\ 0 = u_{max}(A*h^2+B*h+C) \\ \\ 0 = Ah^2 +Bh + C \\ \\ 0 = Ah^2 +Bh + 0 \\ \\ Bh = - Ah^2 \\ \\ B = - Ah \ \ \ \ \ --- (d)$

Replacing the boundary condition (c) in equation (1); we have:

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replacing $A = -\frac{4}{h^2}$ for A in (d); we get:

$B = - ( -\frac{4}{h^2})h$ $B = \frac{4}{h}$

replacing the values of A, B and C into the velocity profile expression; we have:

$u = u_{max}(Ay^2+By+C) \\ \\ u = u_{max} (-\frac{4}{h^2}y^2+\frac{4}{h}y)$

To determine the volume flow rate; we have:

$Q = AV \\ \\ Q= \int\limits^h_0 (u.bdy)$

Replacing $u_{max} (-\frac{4}{h^2}y^2+\frac{4}{h}y) \ for \ u$

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$\frac{Q}{b} = u_{max}(\frac{2h}{3}) \\ \\ \frac{Q}{b} = \frac{2}{3} u_{max} h$

Thus; the volume flow rate per unit depth is:

$\frac{Q}{b} = \frac{2}{3} u_{max} h$

Consider the discharge ;

Q = VA

where :

A = bh

Q = Vbh

$\frac{Q}{b}= Vh$

Also; $\frac{Q}{b} = \frac{2}{3} u_{max} h$

Then;

$\frac{2}{3} u_{max} h = Vh \\ \\ \frac{V}{u_{max}}=\frac{2}{3}$

Thus; the ratio is : $\frac{V}{u_{max}}=\frac{2}{3}$

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3 years ago