Which inefficiency in the Newcomen engine did Watt’s separate condenser resolve?

💡 Explanation:

The Newcomen engine used cold water injected directly into the cylinder to condense the steam and create a vacuum. This process required the cylinder to be alternately cooled (for condensation) and then reheated (by the incoming steam for the next stroke), which wasted a significant amount of heat. Watt's separate condenser allowed the working cylinder to remain hot while the separate vessel remained cold to condense the steam, thereby eliminating the massive cyclical heat loss and drastically improving the engine's fuel efficiency.