A freezer is to convert 1.67 kg of water at 28.8°C to 1.67 kg of ice at - 4.8°C. If the coefficient of performance of the freezer is 2.38, how much heat is delivered outside the freezer? The specific heat capacity of: (a) water is 4190 J/(kg-K) and (b) ice is 2100 J/(kg.K); and the latent heat of fusion for water is 3.34××10 J/kg. 5 326.1 kJ 482.0 kJ O 776.1 kJ O 1102 kJ

The figure belows shows three components of an air-conditioning system, where T3 = 95°F and m3 = 1.5 lb/s. Refrigerant 134a flows through a throttling valve and a heat exchanger while air flows through a fan and the same heat exchanger. Data for steady-state operation are given on the figure. There is no significant heat transfer between any of the components and the surroundings. Kinetic and potential energy effects are negligible. Saturated liquid R-134a T3, m3 m₁ = i Throttling valve lb/s 4 P4= 60 lbf/in.² Air T₁ = 535°R Cp=0.240 Btu/lb-ºR Fan wwwwww T₂=528°R +2 5 Wey = -0.2 hp Saturated vapor Ps= P4 Modeling air as an ideal gas with constant cp = 0.240 Btu/lb. °R, determine the mass flow rate of the air, in lb/s. -Heat exchanger

(a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 59.3°C and a cold reservoir temperature of -12.7°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 x 10' ) of work (10.0 kw · h) is put into it? kcal (c) Assume the cost of this work input is 10c/kW · h. Also assume that the cost of direct production of heat by burning natural gas is 85.0c per therm (a common unit of energy for natural gas), wher a therm equals 1.055 x 108 J. Compare the cost of producing the same amount of heat by each method. cost of heat pump cost of natural gas Additional Materials OReading

The rate of heat leaking into a house from the warmer outdoors is given by A(TH – TC) where TC and TH denote the indoor and outdoor temperatures, respectively, and A is a constant. If the outdoor temperature is 32°C, what will be the ratio of the power required to maintain an indoor temperature of 21°C to that required to maintain an indoor temperature of 25°. Assume the air conditioning system operates at its maximum possible coefficient of performance.

Solar PV systems have large potential to produce large amounts of electricity in desert regions such as in Oman. It is proposed to build a very large solar PV system in the Al Sharqiya Desert to supply all of Oman's electricity needs which is about 28 x 10° kW-hr per year. If the average annual solar insolation in the Al Sharqiya Desert is 2400 kW-hr/m² per year, and assuming a solar cell efficiency of 20% and a system efficiency of 65%, A. What total PV area is required? B. If AI Sharqiya Desert has an area of 1.25 x 1010 m², what percentage of the desert will have to be covered with solar PV?

(a) How much heat transfer occurs to the environment by an electrical power station that uses 1.25×1014 J of heat transfer into the engine with an efficiency of 42.0%? (b) What is the ratio of heat transfer to the environment to work output?  (c) How much work is done?

Suppose a woman does 650 J of work and 9250 J of heat is transferred from her into the environment in the process. What is the change in her internal energy, in joules, assuming she does not consume any food? AU= What is her percent efficiency? n (%) = ||