Why is there always some waste heat in a heat engine?

Only part of the energy absorbed as heat can be converted to work. The reason is, that the heat, as it flows in, brings along entropy, which must somehow be disposed of before the cycle can start over. To get rid of the entropy, every heat engine must dump some waste heat into its environment.

Why do machines generate heat?

All computers require electricity to function, and some computer components require more electricity than others. As electricity passes across circuits and through wires, it meets a natural degree of resistance. This resistance, like the friction of two hands rapidly rubbing together, creates heat.

What is the biggest source of waste heat energy?

The largest proportions of total waste heat are from power stations and vehicle engines. The largest single sources are power stations and industrial plants such as oil refineries and steelmaking plants.

What are the potential causes of waste heat generation?

Waste heat is released as by-product of various processes in different forms such as: combustion gases discharged to the atmosphere; heated water released into environment; heated products exiting industrial processes, and heat transfer from hot equipment surfaces.

Why is waste heat a problem?

Waste heat is everywhere. Every time an engine runs, a machine clunks away, or any work is done by anything, heat is generated. The problem is not so much that waste heat directly warms the atmosphere — the heat we throw into the air accounts for just 1 percent of climate change. Instead, the problem is one of wastage.

Why are heat engines not 100 efficient?

A heat engine is considered to be 100\% efficient if only all the heat is converted into useful work or mechanical energy. Since heat engines cannot convert all the heat energy into mechanical energy, their efficiency can never be 100\%.

How hot is too hot for a PC?

Above 80 degrees C (176 degrees F) is too hot and could cause damage to your computer if you run it for a sustained period. Beyond this, you should shut down your PC and let it completely cool down.

Is it OK for your PC to get hot?

Most computers get warm after a while, and some can get quite hot. This is normal: it is simply part of the way that the computer cools itself. If you have a desktop computer which feels hot to the touch, it may have insufficient cooling.

Does waste heat cause global warming?

All these clearly suggest that the current global warming is a direct result of the huge amount of waste heat discharged into the climate system from human activities, implying that the residual heat or waste heat is the main contributor to the current global warming or climate change.

What is a waste heat source?

Sources of waste heat include for example hot combustion gases discharged to the atmosphere, heated water released into environment, heated products exiting industrial processes, and heat transfer from hot equipment surfaces.

What happens to waste heat?

Waste heat is the unused heat given to the surrounding environment (in the form of thermal energy) by a heat engine in a thermodynamic process in which it converts heat to useful work. Waste heat is often dissipated into the atmosphere, or large bodies of water like rivers, lakes and even the ocean.

Why is it impossible to create a 100 efficient machine?

Explanation: No machine is free from the effects of gravity, and even with wonderful lubrication, friction always exists. The energy a machine produces is always less than the energy put into it (energy input). That is why 100\% efficiency in machines shall not be possible.

Why do machines lose energy when they move?

In summary, any machine that has parts that contact one another can never perfectly transfer and transform energy because friction forces will take some of that energy and transform it into heat energy, and be lost because that heat is not used to perform work. Q: Why do machines waste energy? Write your answer…

How is waste heat produced in a power plant?

The second law of thermodynamics states that waste heat must be produced when converting a temperature difference into mechanical energy (which is often turned into electrical energy in power plants ).

Why do some processes give off waste heat and others don’t?

All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility (or in thermodynamics lexicon a lower exergy or higher entropy) than the original energy source.

What is the definition of waste heat in physics?

Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility (or in thermodynamics lexicon a lower exergy or higher entropy) than the original energy source.