The temperature controller for a clothes dryer consists of a bimetallic switch mounted on an electrical heater attached to a wall-mounted insulation pad.
The switch is set to on at 70°C, the maximum dryer air temperature. To operate the dryer at a lower air temperature, sufficient power is supplied to the heater such that the switch reaches 70°C
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Fundamentals of Heat and Mass Transfer
- Which of the three air-conditioning possible systems listed below should be used to maintain the indoor temperature of a house at 20°C while resulting in a daily lower operating cost when the outdoor temperature is -2°C. Based on the construction of the house you estimate that under the given indoor and outdoor temperatures the rate of heat loss to the surroundings is 17 kJ/s. Which system would you recommend as a feasible alternative? Support your answer for each one of the cases below with convincing computations that show which one of the systems is requires the minimum electrical power while being in compliance with the first and second law of thermodynamics. a. Electrical heating b. A heat pump with COPHP = 3.0 c. A heat pump with COP = 14.0arrow_forwardAnswer this ASAP,thx Furnace walls are lined with 3 layers of firebrick with a thickness of 6 in (k=0.95 Btu/h.ft.°F), insulating brick (k-0.4 Btu/h.ft.°F) and common brick (k=0.8 Btu /h.ft.°F) Firebrick inlet temperature, T₁ = 1800°F, maximum insulating brick temperature, T₂ = 1720°F and T3 = 280°F. 1. Calculate the thickness of the insulating brick layer. 2. If the common brick is 9 in., calculate the exit temperature.arrow_forwardHello Sir,Good Morning.I have a question in my homework related thermodynamics lesson. The following below is my question. Please advice. Thank you. Regards,Irfan An air conditioning system is used to keep the house at 65°F when the outside temperature is 85°F. The house gets heat through the walls and windows at a rate of 810 Btu/min, and the rate of heat generation inside the house from occupants, lights, and equipment is 120 Btu/min. Determine the minimum power input required for this air conditioning system.arrow_forward
- Consider a heat transfer situation. Heat flows from the hot item or area to the cold item or area. Describe this in terms of spontaneity.arrow_forwardA cooling system is necessary for computers for a number of reasons. So, what precisely are the various cooling techniques?arrow_forwardEstimate how much collector area and storage capacity would be required for an active solar hot-water system designed to supply the total needs for two four-person families, one living in Manchester, New Hampshire, where the latitude is 44+°N, and the other in Albuquerque, New Mexico, at 35+°N. The heat capacity of water is about 4,200 J/kg°C, and the hot-water supply temperature in both houses is 75°C (140°F). State and justify all additional assumptions made.arrow_forward
- Calculate the cooling load for the refrigerated space considering internal temperatures of 2oC, -18oC and -18oC, respectively. And the external temperature is given as 35 degree, and - 10 degree celcius. draw one T-S diagram accounts for the entire system. Note: Refrigerant R410-A to be usedarrow_forwardDefine Dander-Thermal Plantsarrow_forwardHeat is produced by computers while they run. Do you have any questions concerning computer cooling systems?arrow_forward
- A thermoelectric device cools a small refrigerator and discards heat to the surroundings at 25°C. The maximum electric power for which the device is designed is 100 W. The heat load of the refrigerator( that is, the heat leaking through the walls that must be removed by the thermoelectric device) is 500 W. What is the minimum temperature that can be maintained in the refrigerator?A.10.6 °CB. -15.6 °CC. 0°CD. -24.7 °Carrow_forwardWhat are the different Heat pump circuits? Explain any one of them with the help of neat sketcharrow_forwardQUESTION 21 A domestic refrigerator with inner dimensions of 0.7 m by 0.7 m at the base and height 1 m was designed to maintain a set temperature of 6 °C. The bodies consist of two 10-mm-thick layers of Aluminium (k = 225 W/mK) separated by a 30 mm polyurethane insulation (k=0.028 W/mK). If the average convection heat transfer coefficient at the inner and outer surfaces are 11.6 W/m2K and 14.5 W/m2K respectively, calculate: the resistance(R) for the inner fluid thermal layer in K/W to 4 decimal places. harrow_forward
- Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning