An ideal vapour refrigeration cycle uses RF-134a as the working fluid and consists of the following steps:

(i)        Saturated vapour at 20 psia is compressed adiabatically and reversibly to a pressure of 120 psia. [The compressor]

(ii)       The vapour is cooled and condensed at constant pressure, leaving the condenser as a saturated liquid. [The condenser]

(iii)      The saturated liquid is expanded through a throttling valve to a pressure of 20 psia. [The throttling valve]

(iv)      The liquid-vapour mixture leaving the throttling valve is heated at constant pressure until it is 100% saturated vapour. [The evaporator]

The flow rate of refrigerant in this cycle is 0.1 kg s^-1.   For this cycle do the following:

(a)        Plot the cycle on the attached P-h chart for RF-134a.                                  

(b)       Calculate the power input to the compressor in kW.                                     

(c)        Calculate the heat transferred to the environment in the condenser in kW.  

(d)       Calculate the coefficient of performance (as a refrigerator) for the cycle.     (5marks)

Total = 20 marks

Note: Use the attached P-H chart for R-134a as your data source.

            1 kg = 2.21 lbm

            1 J = 9.48*10^-4 Btu

            1 bar = 10⁵ Pa = 14.5 psia

In detail explain, what are the challenges/competition facing the Oil & Gas industry over the next 10 years and whether it has a future?

Differentiate the advantages of centrifugal filtration and centrifugal decantation.

Liquid air is available (79 mol% of nitrogen and 21 mol% of oxygen) and it is required to obtain a fraction whose oxygen content is 90% (mol), for which part of the mixture evaporates to the atmospheric pressure. Determine the fraction of evaporated mixture, taking as the average value of relative volatility 4.12

i.The current density of a fuel cell is 0.61 A cm-2. Assume the water generated remains in the liquid phase and no water is ejected from the stack during operation, calculate the time required for 1 mg cm-2 liquid water to accumulate in a fuel cell.

ii.Explain the process that determine water dynamics in a polymer electrolyte fuel cell. Use a diagram to help explain the different processes, where water is generated and the direction and mechanism by which it is transported

A pond 2 m in diameter is to be filled with water by a flow that varies linearly with the level of the pond so that it reaches the maximum value of 217 lt/h when the pond is empty and is zero when the level reaches 2 m. Calculate: a) Time it takes to reach the level of 1 m. b) Time it takes to fill up completely. Discuss this last result.

. Limestone containing 85.5 % CaCO3, 6% MgCO3, 2.5% Fe2O3 and 1.5% SiO2 and rest water is calcined (thermally decomposed) in hot air to vaporize H2O and separate CO2 from the carbonates The CaO and MgO are created by the reaction leave in the solid calcine, along with hematite and silica. How many kilograms of calcine will be produced per metric ton of limestone?

   CaCO3 → CaO + CO2                                                            MgCO3 → MgO + CO2

. Limestone containing 85.1 % CaCO3, 6% MgCO3, 2.5% Fe2O3 and 1.5% SiO2 and rest water is calcined (thermally decomposed) in hot air to vaporize H2O and separate CO2 from the carbonates The CaO and MgO are created by the reaction leave in the solid calcine, along with hematite and silica. How many kilograms of calcine will be produced per metric ton of limestone?

   CaCO3 → CaO + CO2                                                            MgCO3 → MgO + CO2

We mentioned earlier in the course that energy technologies in developing countries often have much lower efficacies than those in developed countries. Let’s look at one example, lighting via kerosene lamps, which are common in developing countries but about 150x less effective than incandescent lightbulbs at turning energy into useful light. If a family wanted just one tenth of the light provided by the 75 W lightbulb, they’d need to consume 15x as much power, or 1125 W. If a family ran 1125 W worth of kerosene lamps for just 2 hours each day, how much CO₂ would this emit? You may assume that kerosene produces the same emissions as gasoline.

4. The thickness of each part is 0.500”. The allowable stress of the material is 15,000 psi. The joint efficiency is 1.0 and the inside diameter is 60”. Calculate the maximum pressure for each part: a) 2:1 Ellipsoidal Head: __________ psi b) Torispherical Head: __________ psi c) Hemispherical Head: __________ psi d) Cylinder: __________ psi e) Sphere: __________ psi
5. State which shape is the best for containing pressure and which shape is the worst for containing pressure

Business information on styrene, such as major producers, trends in worldwide production capacity, recent industry news, new projects, typical plant capacities, and historic and current prices, and technology developments. Please include at least two recent business sources and one recent research / technology development article, with recent meaning, say, 2017–2020.

1- Assume that you are going to build up a model for a system where unit operation and unit processes are carried out. Explain the various steps involved in the process of model building for the system you have chosen.

Carman kozeny equation lead from darcy weisbach equation