ES3B5 University of Warwick Thermodynamics Steam Plant Driven Homework A steam plant driven by solar thermal energy is used to operate an industrial refrig

ES3B5 University of Warwick Thermodynamics Steam Plant Driven Homework A steam plant driven by solar thermal energy is used to operate an industrial refrigeration system (Freezer) for food storage. The steam turbine is coupled to a mechanical compressor of the refrigeration system through a shaft with a coupling mechanical efficiency of 85%. The steam leaving the boiler is superheated at a pressure of 1.55 MP and it exhausts from the turbine at pressure of 7.38 kPa: the full steam cycle (simple Rankine cycle) is shown on the p-h diagram for Water including relevant points (Figure 1). The estimated steam mass flow rate is 1800 kg/h. The industrial refrigeration system uses the vapour compression cycle with Ammonia refrigerant and operates at a condensing temperature of 40oC and an evaporating temperature of -20oC.

a)Sketch the basic block diagram of the full combined steam plant and refrigeration system (properly label key components and both energy flows and flow streams of each sub-system).

b)By using exclusively the p-h diagram for Water (Figure 1), complete Table 1. Enter N/A for any value that cannot be extracted from the diagram provided

Point Number

1

2

3

4

5

6

Dryness

(%)

Pressure

(MPa)

Temperature (oC)

Specific Entropy

(kJ/kg K)

Specific Enthalpy

(kJ/kg)

c)What is the net power output of the steam plant and its efficiency?

d)Evaluate the power of the compressor of the refrigeration system and the Ammonia refrigerant mass flow rate considering a specific enthalpy across the compressor ΔHcompressor= 400 kJ/kg.

e).By considering the combined steam plant and refrigeration system as a heat driven refrigeration system with 1100 kJ/kg cooling effect, estimate the cooling power and the overall system COP (Coefficient of Performance). What do you think about the proposed heat driven refrigeration system?