Chemical Process Utilities Heat Transfer Media and Solar Energy Prof.Shishir Sinha Department of Chemical Engineering

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Questions and Answers

What is the production capacity of the Megha Solar Plant CSP Project in Anantapur, Andhra Pradesh?

25 MW electricity
75 KW electricity
100 MW electricity (correct)
50 KW electricity

What is the main advantage of utilizing molten salts as high-temperature fluids (HTFs) in power tower systems?

Low viscosity
Low thermal stability
Ability for thermal energy storage (correct)
High vapor pressure

What temperature range are molten salts generally stable at?

Over 800°C
Around 500°C (correct)
Between 200-300°C
Below 100°C

Why is it important to consider the stability of piping and container materials in relation to molten salts handling?

To maintain the stability of the molten salts (A) Signup and view all the answers

What property of molten salts makes them comparable to water at high temperatures?

Low viscosity (A) Signup and view all the answers

What is the main advantage of using water/steam as both Heat Transfer Fluid (HTF) and working fluid in solar thermal systems?

It simplifies the system and leads to improved efficiency (C) Signup and view all the answers

Why is the scarcity of water a concern when using water/steam as the Heat Transfer Fluid (HTF) in desert regions for CSP plants?

As these plants are located in deserts where water is scarce (B) Signup and view all the answers

Which type of single fluid solar thermal system uses water/steam as the Heat Transfer Fluid (HTF) according to the text?

Direct steam generating (DSG) parabolic troughs (D) Signup and view all the answers

What is the main problem associated with using water/steam as the Heat Transfer Fluid (HTF) in CSP plants located in deserts?

Scarcity of water (A) Signup and view all the answers

What is carried to the turbine to produce electricity in a solar thermal system using water/steam as the working fluid?

Energy from the working fluid (D) Signup and view all the answers

Why are high temperature steam corrosion issues reported in the literature concerning water/steam HTF?

To illustrate challenges with particular alloys (A) Signup and view all the answers

What is a main disadvantage of using liquid sodium as a thermal energy storage medium?

High combustibility when in contact with water (B) Signup and view all the answers

Why was the liquid sodium test plant decommissioned in 1986?

Sodium fire (B) Signup and view all the answers

What is the approximate viscosity of liquid sodium?

0.00021 Pa s (B) Signup and view all the answers

Which material is mentioned as highly compatible to be used as piping/container materials with liquid sodium?

SiC (ceramics) (D) Signup and view all the answers

Compared to solar salt, what is a disadvantage of liquid sodium?

Higher combustibility (C) Signup and view all the answers

What is a unique feature of the Na-K eutectic mixture mentioned in the text?

Liquid at room temperature (A) Signup and view all the answers

Why are Helium or hydrogen typically used as the working fluid in a Stirling engine?

Because of their high heat conductivity and low molecular masses for faster heat transfer (D) Signup and view all the answers

Which material showed good corrosion resistance with almost zero weight loss after 1000 h immersion at temperatures up to 750 oC?

SiC (C) Signup and view all the answers

Why are high strength expensive materials needed in the cylinder of a Stirling engine?

To withstand large thermal stresses resulting from high temperature differences (C) Signup and view all the answers

What is the corrosion rate of the Na (22.2%)-K(77.8%) mixture at 600 oC?

0.87 μm/year (B) Signup and view all the answers

Which binary mixture of liquid metals is being investigated for use as Heat Transfer Fluids (HTFs) in CSP systems?

Cd–Bi (C) Signup and view all the answers

What makes fast changes in power output difficult to achieve in a Stirling cycle?

The warm-up time required (B) Signup and view all the answers

What is the Stability temperature of Na-K (77.8%)-Li (22.2%) mixture?

785 oC (B) Signup and view all the answers

Why is dissipation of waste heat particularly complex in a Stirling engine?

Because coolant temperature must be kept low for maximum thermal efficiency (C) Signup and view all the answers

Which material is NOT mentioned in the text as having promising corrosion resistance properties with piping/container alloys?

Liquid Ca–Cu (B) Signup and view all the answers

Why does a Stirling engine require a warm-up time before it can start functioning efficiently?

To reach the optimal temperature for operation (A) Signup and view all the answers

What is a significant drawback of Stirling engines for automotive applications?

Inability to provide fast changes in power output (C) Signup and view all the answers

What is the Viscosity of Na (22.2%)-K(77.8%) mixture at 600 oC?

0.00018 PA-s (D) Signup and view all the answers

Flashcards

Megha Solar Plant Capacity

100 MW of electricity production capacity.

Advantage of Molten Salts as HTF

Offers thermal energy storage capabilities.