# Harnessing Energy in an Engine: The Secrets of Thermodynamics

• Dreebs
In summary, when designing a climate control system for a cabaret, the main goal is to extract excess moisture from the air. This requires producing a cold surface, which inevitably requires electricity or an equivalent source of ordered energy. This process pumps heat from the cold surface to the hotter surroundings, consuming ordered energy and raising the temperature of the surrounding air. This is why the device will become hotter than the original outside air.
Dreebs

## Homework Statement

You're in Paris, working on your first novel and short on cash. The owner of the cabaret downstairs has offered to take care of your rent if you'll help her design a climate control system for the place. It gets too hot and damp in the summer, and too cold and dry in the winter. You're up to the challenge, so you begin to make plans for the new system. You start by considering the summer, when the cabaret air and the outside air are normally at the same temperature and the air in both places is moist and hot. It's hard to have a good time when you're dripping wet, so your system's first goal is to extract the excess moisture from the cabaret air. It does this by creating a cold surface and passing the cabaret air across that surface. Some of the moisture will then condense and run down a drain as liquid water. Why will producing that cold surface inevitably require electricity (or an equivalent source of ordered energy) and why will something become hotter than the original outside air?
Select one:
a. You will have to extract thermal energy from the cold surface, convert that thermal energy into work, and use electricity to get rid of the work. Friction will eventually convert the work into thermal energy and produce hot surfaces.
b. You will have to pump heat from the cold surface to the hotter surroundings, a process that requires the consumption of ordered energy. The pumped heat, as well as the electrical energy that becomes disordered, must go somewhere and it will raise the temperature of its destination.
c. You will have to extract thermal energy from the cold surface, convert that thermal energy into electrical energy, and convey that electrical energy to the power company. When that electricity arrives at the power company, the power company will convert it into thermal energy again by operating an electric space heater.
d. You will have to extract thermal energy from the cold surface, convert that thermal energy into entropy, and use electricity to get rid of that entropy. The entropy will be converted into heat that will flow into the outside air, increasing the temperature of that air.

N/A

## The Attempt at a Solution

A, because it is a device that converts thermal energy into ordered energy as heat flows from hot object to cold object.

A is incorrect. Please describe in more detail how you carry out the process, perhaps using a thermodynamic cycle involving an ideal gas.

Chestermiller said:
A is incorrect. Please describe in more detail how you carry out the process, perhaps using a thermodynamic cycle involving an ideal gas.
If not A, then D because the device wouldn't turn thermal energy into electrical energy. And I don't believe it's B because the device isn't pumping the cold air through the area, it is merely trying to reduce the moisture in the air. Or am I misunderstanding?

Dreebs said:
If not A, then D because the device wouldn't turn thermal energy into electrical energy. And I don't believe it's B because the device isn't pumping the cold air through the area, it is merely trying to reduce the moisture in the air. Or am I misunderstanding?
Any more guesses?

Dreebs
Chestermiller said:
Any more guesses?
B? Because in order to pump heat from a cold surface to hotter surroundings electrical energy is required, which in turn will raise the temperature of the surrounding air?

Dreebs said:
B? Because in order to pump heat from a cold surface to hotter surroundings electrical energy is required, which in turn will raise the temperature of the surrounding air?
Correct.

## 1. What is thermodynamics and how does it relate to engine energy?

Thermodynamics is the study of the relationships between heat, energy, and work. In the context of engines, thermodynamics helps us understand how energy is converted into usable forms, such as mechanical work. By understanding the principles of thermodynamics, we can optimize engine design and performance.

## 2. How does an engine harness energy?

An engine uses the principles of thermodynamics to convert chemical energy from fuel into mechanical work. This is accomplished through a series of controlled explosions, also known as combustion, in the engine's cylinders. The resulting force from the combustion is used to power the engine and perform work.

## 3. What is the role of temperature in engine energy?

Temperature plays a crucial role in engine energy as it is directly related to the efficiency of the engine. In thermodynamics, the efficiency of a system is defined as the ratio of work output to the energy input. Higher temperatures allow for more efficient conversion of energy into work, making it a key factor in engine performance.

## 4. How do engineers optimize engine energy?

Engineers use the principles of thermodynamics to optimize engine design and performance. This can include using materials that can withstand high temperatures, improving combustion efficiency, and reducing energy losses through heat transfer. Additionally, advancements in technology, such as turbocharging and hybrid systems, have also helped to improve engine energy efficiency.

## 5. What are some challenges in harnessing energy in engines?

One of the main challenges in harnessing energy in engines is managing heat transfer. As engines operate, they produce a significant amount of heat, which can lead to energy losses and decreased efficiency. This is why engine cooling systems are crucial in maintaining optimal temperatures. Additionally, finding sustainable and renewable fuels to power engines is also a challenge in today's world.

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