Question: Why 100 Efficient Engine Is Not Possible?

Under what conditions would an ideal heat engine be 100% efficient?

Expansion and compression is possible without friction and conduction proof cylinder wall.

Energy input is done at constant temperature, in which ever way it is possible..

Which is the most efficient cycle?

Carnot cycleThe most efficient heat engine cycle is the Carnot cycle, consisting of two isothermal processes and two adiabatic processes. The Carnot cycle can be thought of as the most efficient heat engine cycle allowed by physical laws.

How can I improve the thermal efficiency of my house?

Ten steps to improve energy efficiency at homeInsulate your loft. Poorly insulated roofs and walls can be a major cause of energy wastage. … Upgrade your boiler. … Hang thick curtains and insulate your doors. … Watch your energy consumption. … Switch to a cheaper energy tariff. … Use a water-saving showerhead. … Fit double glazing. … Invest in an eco kettle.More items…•

How do you increase thermal efficiency?

Run the engine fuel-lean, that is, use excess air. It is well known that fuel-lean running improves the efficiency. … Higher compression ratio. … We need new cycles put into practical use. … Run the engine at optimum conditions, meaning low friction (modest engine speed) and low pumping work (air throttle more open).

How do we calculate efficiency?

The work efficiency formula is efficiency = output / input, and you can multiply the result by 100 to get work efficiency as a percentage. This is used across different methods of measuring energy and work, whether it’s energy production or machine efficiency.

Why is friction irreversible?

Because the energy lost through friction is hard to get back. … This spent energy cannot be easily collected and be put back to the original bulk kinetic energy. Thus, the energy loss process of friction is considered an irreversible process.

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

It is must for all the cyclic heat engines to produce waste heat (reject heat). … So to complete the cycle the gas rejects the heat (heat absorbed by it to raise the internal energy in first step) to the sink. So that’s the reason heat engines reject the waste heat.

What is the most efficient engine?

Wärtsilä 31Fuel efficiency The new Wärtsilä 31 is the most fuel-efficient four-stroke engine currently available on the market. The diesel version of the engine consumes on average 8–10g/kWh less fuel compared with the closest competitor across its entire load range. At its optimum point this number can go as low as 165g/kWh.

Is 100 percent efficiency possible?

Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work). The output work is always less than the input work because some of the input work is used to overcome friction. Therefore, efficiency is always less than 100 percent.

Why is a perfect heat engine Impossible?

It is impossible to construct a perfect heat engine. … Since it absorbs heat, its entropy is increased. If it increases its entropy enough, it will ensure that the entire system has a net increase in entropy.

Is Carnot engine 100 efficient?

Efficiency is 100% when T1 is infinity or T2 is zero. Since we cannot reach absolute zero temperature so these conditions cannot be achieved.

Why is Carnot efficiency maximum?

A Carnot engine operating between two given temperatures has the greatest possible efficiency of any heat engine operating between these two temperatures. Furthermore, all engines employing only reversible processes have this same maximum efficiency when operating between the same given temperatures.

Can we consider heat engine 100 efficient Why?

100 percent efficient engine is not possible. In reality, heat engines are inefficient systems. The input is not equivalent to the output of the system. This is because engine efficiency is reduced by friction.

What is Carnot efficiency?

Carnot efficiency is the maximum efficiency that a heat engine may have operating between the two temperatures (Figure 2-7). Figure 2-7. Carnot process efficiency. The Carnot efficiency has little practical value. It is a maximum theoretical efficiency of a hypothetical engine.

What is the formula for thermal efficiency?

quantities are heat-equivalent values. So, for a boiler that produces 210 kW (or 700,000 BTU/h) output for each 300 kW (or 1,000,000 BTU/h) heat-equivalent input, its thermal efficiency is 210/300 = 0.70, or 70%. This means that 30% of the energy is lost to the environment.

What are the two factors of thermal efficiency?

Answer Expert Verified. In theory, the factors that affect thermal efficiency (the performance of an engine or the work it has done in relation to the value of heat supplied to it) are the heat input and the heat output.

What are the 1st 2nd and 3rd laws of thermodynamics?

The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. … The third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature approaches absolute zero.

Is it possible for a heat engine to operate without?

It is not possible for a engine to operate without rejecting any waste heat to a low temperature reservior. … It violates the second law of thermodynamics, the operation of a heat engine a low temperature sink as well as a high temperature source.

Can you design an engine of 100% efficiency?

Or, it is not possible to design a heat engine that has an efficiency of 1.00 or 100%. The efficiency of a heat engine can be 100% only if all the heat energy gets converted into work (or mechanical energy). … In other words, it will never be possible to design a heat engine having 100 per cent efficiency.

Is Carnot cycle reversible?

The Carnot heat-engine cycle described is a totally reversible cycle. That is all the processes that compose it can be reversed, in which case it becomes the Carnot refrigeration cycle.

How do you increase Carnot efficiency?

The more effective way of increasing efficiency of Carnot engine is toA. Increase higher temperature.Decrease higher temperature.Increase lower temperature.Decrease lower temperature.