एक ज्वारीय बैराज ऊर्जा प्रणाली (Tidal barrage energy system) को आर्थिक रूप से व्यवहार्य बनाने के लिए आवश्यक न्यूनतम विशिष्ट ज्वारीय सीमा (Tidal range) कितनी है?

Which of the following is an example of phase change materials for latent heat thermal energy storage?

Consider the following statements regarding Evacuated Tube Collectors (ETCs): A. They contain a vacuum between two layers of glass tubes, which significantly reduces convective and conductive heat loss. B. They can operate efficiently even under overcast or cold conditions. C. Water always flows and heats directly inside the inner glass tubes without any copper heat pipes. D. They are generally less efficient than flat-plate collectors. Which of the above statements are correct?