A flow-through electric water heater has a 22 kW electric heater inside an insulated 2.0-cm-diameter pipe so that water flowing through the pipe will have good thermal contact with the heater. Assume that all the heat energy is transferred to the water. Suppose the inlet water temperature is 12° C and the flow rate is 8.0 L/min (about that of a standard shower head).

Steam 90°C 10. A shell-and-tube process heater is to be selected to heat water (Cp = 4190 J/kg-°C) from 20°C to 90°C by steam flowing on the shell side. The heat transfer load of the heater is 600 kW. If the inner diameter of the tubes is 1 cm and the velocity of water is not to exceed 3 m/s, determine how many tubes need to be used in the heat exchanger. 20°C Water

A centrifugal pump compresses 3000 liters/min of water from 98 kPa to 300 kPa. The inlet and outlet temperatures are 25°C. The inlet and discharge piping are on the same level, but the diameter of the inlet piping is 15 cm, whereas that of the discharge piping is 10 cm. Determine the pump power in kilowatts.

A compressor is fed with superheated steam at 300°C and 20 bar. The compressor inlet speed is 20 m/s and the internal diameter is 0.1 m. The discharge tube, after the compressor, with a smaller diameter is 170 m/s. Compressor output is superheated steam at 300°C and 20 bar. The heat loss from the compressor to the surroundings is 5 kW. Determine the work generated by the compressor in hp.

Define the energy equation of a uniformflow system reduces to that of a closed system when all the inlets and exits are closed.

3. Nitrogen gas @ 90° F (MW=28) goes through a compressor, increasing its pressure from 10 psi to 65 psi. The temperature remained constant throughout. Determine the work in Hp for a steady flow process; AKE=0, APE=0; mass flow rate of nitrogen is 2 Ibm/min.

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Water is pumped from a lake to a storage tank 15 m above at a rate of 70 L/s while consuming 15.4 kW of electric power, as shown in Figure 4 below. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine a) the overall efficiency of the pump-motor unit and; b) the pressure difference between the inlet and the exit of the pump. Storage tank 15 m Pump Figure 4

A refrigerated compartment is maintained at a temperature of -5°C. Heat from the surroundings, at 25°C, leaks into the compartment at a rate of 1.2 kW. Find the compressor power required to maintain the temperature difference for the following scenarios:

In rural housing the water source is obtained through groundwater pumped upwards. Suppose the groundwater source has a depth of 60 m from the surface. The water will be lifted as far as 5 m above ground level with a pump. The diameter of the pipe inlet is 10 cm and the outlet is 15 cm.By ignoring the interaction of heat with the environment and heat due to friction, determine the input work (Watt) required by the pump for the water to flow stable at a rate of 15 liters / s. (Water type mass 1000 kg / m ^ 3).  (Application of the 1st Law of Thermodynamics to open systems)