A classroom that normally contains 40 people is to be air-conditioned with window air-conditioning units of 5 KW cooling capacity. A person at rest may be assumed to dissipate heat at a rate of about 360 KJ/hr. There are 10 light bulbs in the room, each with a rating of 100 watts. The rate of heat transfer to the classroom through the walls and the windows is estimated to be 15,000 KJ/hr. If the room air is to be maintained at a constant temperature of 21°C, determine the number of window air-conditioning units required.

A classroom that normally contains 40 people is to be air-conditioned with window air-conditioning units of 5 KW cooling capacity. A person at rest may be assumed to dissipate heat at a rate of about 360 KJ/hr. There are 10 light bulbs in the room, each with a rating of 100 watts. The rate of heat transfer to the classroom through the walls and the windows is estimated to be 15,000 KJ/hr. If the room air is to be maintained at a constant temperature of 21°C, determine the number of window air-conditioning units required.

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter1: Heat, Temperature, And Pressure

Section: Chapter Questions

Problem 6RQ: One British thermal unit will raise the temperature of _____ 1b of water _____F.

See similar textbooks

Similar questions

One British thermal unit will raise the temperature of _____ 1b of water _____F.
Describe heat transfer by conduction.
A metal spoon and a wooden spoon are left overnight in a room. Why do we feel colder when we touch the metal spoon than when we touch the wooden one? a. Since metals usually have a lower heat capacity than non-metals, the metal spoon loose more heat to the room and consequently has a lower temperature b. Metals release heat faster than non-metals because of their higher thermal conductivity c. This is merely psychological since we are conditioned to think of metals as “cold” d. Metals absorb heat faster than non-metals because of their higher thermal conductivity
Q1: If a calorimeter is not assumed to be adiabatic, how would one calculate the heat transfer? Guide Questions: What are the parameters to be considered and the equations to be used? What law of thermodynamics does this transfer of heat to the surroundings touch? Is an adiabatic system automatically considered as a closed system? Please help me understand by also attaching a reference/book/journal article. This would help me in my essay. Thank you.
A particular frost-free refrigerator uses about 745 kWh of electrical energy per year. Express this amount of energy in unit cal.
Half a liter of liquid is being heated in a closed container to prepare food. Initial temp is 25C and desired temperature is 85C. How much energy is needed to raise the temperature of this amount of water as described? Specific heat of water is given as 4.18 kJ/(kg.K)
energy can be conserved when your home heating/cooling system works less during the heating and cooling seasons. in fact/ a one degree celsius difference in your thermostat setting can reduce energy consumption by up to 5%
b. The ceiling of a certain room in a student's dormitory has an area of 200 ftť. It contains insulation such that its R-value is 30. If the room is maintained at 22°C and the attic has a temperature of 50°C. How many Joules of heat flows through the ceiling into the room in 1 day?
A solar panel is mounted on the roof of a house. Fig. 4.1 shows a section through part of the solar, panel. 4 sunlight trapped air copper pipe, painted black water glass sheet insulating metal backing sheet, painted black material Fig. 4.1 A pump makes water flow through the copper pipes. The water is heated by passing through the solar panel. (a) Select and explain three features of the solar panel that maximise, the final temperature of the water.
(d) The rate of heat generated, Btu/min
Answer question 2 based on the results of question 1. You have a natural gas furnace in your home that used 78,500 cubic feet of natural gas for heating last winter. Your neighbor has a furnace that burns heating oil, and used 516 gallons of heating oil last winter. You can convert the natural gas and heating oil consumption data into Btu to determine which home used more energy for heating. Natural gas BTU: 1,028 Btu per cubic foot Oil BTU: 138,590 Btu per gallon Natural Gas BTU= 80698000 Btu Oil BTU = 71512440 Btu The home that used a natural gas furnace used more energy for heating. 2. You need a new furnace for your home, and you are comparing systems that use natural gas and heating oil. One factor to consider is the cost of fuel. You can compare the price of the fuels on an equal basis by dividing the price per unit of the fuels by the Btu content per unit of the fuels to get a price per million Btu. Assume Natural gas price = $10.50 per thousand cubic…
1. The pressure in the substance drastically decrease from 354 to 21 POUNDS PER SQUARE INCHES (PSI), the heat energy of the open system reduces 555BTU/LB, and the volume increases from 1 to 10FT^3/LB. a.) Determine the work per LB. Units:BTU/LB b.) Determine the work in HP (Horse Power) for 10LB per min. (1HP = 42.4BTU/MIN) Units: HP