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It is desired to freeze 10,000 loaves of bread each weighing 0.75 kg from an initial room temperature of 18°C to a final temperature of -18°C. The bread-freezing operation is to be carried out in an air-blast freezing tunnel. It is found that the fan motors are rated at a total of 80 horsepower and measurements suggest that they are operating at around 90% of their rating, under which conditions their manufacturer’s data claims a motor efficiency of 86%. If 1 ton of refrigeration is 3.52 kW, estimate the maximum refrigeration load imposed by this freezing installation assuming that fans and motors are all within the freezing tunnel insulation and the heat-loss rate from the tunnel to the ambient air has been found to be 6.3 kW. Extraction rate from freezing bread (maximum) = 104 kW

Correct Answer: 46 tons of refrigeration
Extraction rate from freezing bread (maximum) = 104 kW Fan rated horsepower = 80 Now 0.746 kW = 1 horsepower and the motor is operating at 90% of rating, And so (fan + motor) power = (80 x 0.9) x 0.746 = 53.7 kW With motors + fans in tunnel Heat load from fans + motors = 53.7 kW Heat load from ambient = 6.3 kW Total heat load = (104 + 53.7 + 6.3) kW = 164 kW = 46 tons of refrigeration.

A company paid tk.500000 in merit raises to employees whose performances were rated A, B, or C. Each employee rated A received twice the amount of the rated C.each employee rated B received 150% of the amount of the raise thst was paid to each employee rated C. if 50 workers were rated A,100rated B and 150 were rated C, how much was the raise paid to each employee rated B?

A thief steals half the total number of loaves of bread plus 1/2 loaf from a bakery. A second thief steals half the remaining number of loaves plus 1/2 loaf and so on. After the 5th thief has stolen there are no more loaves left in the bakery. What was the total number of loaves did the bakery have at the beginning ?

Refer to Q4 and estimate the maximum refrigeration load imposed by this freezing installation assuming the fans but not their motors are in the tunnel.

A fan running at a speed of 280 rpm circulates 105 m3/s of air in a mine. If the power input to the motor for driving the fan is recorded to be 75 kW, with the combined efficiency of fan and motor at 70%. If the fan pressure is to be increased by 200 Pa by changing the fan speed. the fan speed in rpm will become

The ABC company has released their Android app. And 80 people have rated the app on a scale of 5 stars. Out of the total people 15 people rated it with 1 star, 20 people rated it with 2 stars, 30 people rated it with 3 stars, 10 people rated it with 4 stars and 5 people rated it with 5 stars. What will be the final prediction if we take the average of individual predictions?

On 1st January, 2004, 'A' took a mine on lease for 10 years. The rate of profession fee is 50 paise per tonne and the minimum fare is Rs. 8,000 per annum. Short working amount has the right to be recovered till 31st December, 2008. Production was as follows-
2004 ⇔ 3,000 ton, 2005 ⇔ 10,000 ton, 2006 ⇔ 20,000 ton, 2007 ⇔ 28,000 ton, 2008 ⇔ 14,200 ton.
The amount to be given to the landlord for the year 2006 is

The fan drift pressure readings and fan quantities are measured to be 500 Pa and 65 m3/s respectively at the time when NVP aids fan pressure. On reversal, the fan delivers a quantity of 50 m3/s while acting against NVP with fan drift pressure of 600 Pa. Assuming that the NVP remains constant in both cases the total resistance of the mine in Ns2/m8 will be

A mine ventilation system consists of two splits A and B with resistances of 0.8 Ns2m-8 and 3.2 Ns2m-8, respectively as shown in figure. Trunk airways have resistance of 0.2 Ns2m-8. The main mine fan is generating pressure of 500 Pa.
Mine Ventilation mcq question image
The flows in the two splits are equalized by placing a booster fan in split B. Assume that the fan pressure does not change after installation of the booster fan. The size of the booster fan in Pa is

A fan running at a speed of 280 rpm circulates 105 m3/s of air in a mine. If the power input to the motor for driving the fan is recorded to be 75 kW, with the combined efficiency of fan and motor at 70%. the fan pressure in Pa is

Hotel Aditya has 10 single AC rooms, 5 double AC rooms and 18 non AC rooms. The fixed monthly rent of hotel is 150,000. The per day maintenance cost is Rs. 100 for double AC room, Rs. 75 for single AC room and Rs. 40 for non AC room. The per day charges are Rs. 600 for double AC room, Rs. 400 for single AC room and Rs. 250 for non AC room. In April 2003, the occupancy rate of non AC room was 50%, 70% of single AC room and 40% of double AC rooms. Find the profit/loss % for that particular month.