# How is it possible to use only 1000 W to transfer 10,000 BTU/h?

#### maudzked

Summary
How can one machine only consume 3,600,000 joules of electrical energy to transfer 10,550,560 joules of heat energy without broke the laws of thermodynamics?
Hi,

I was reading a newspaper article on the energy efficiency of commonly used air conditioners in homes. Then a doubt arose when the article informed me that there are air conditioners that have an energy efficiency of 10 BTU/watt. That means a classic 10,000 BTU/h air conditioning machine will consume only 1,000 watt of electrical power during that amount of time.

Using joule as unit for both, this means that in 1 hour the machine will only consume 3,600,000 joules of electrical energy to transfer 10,550,560 joules of "heat energy" from my room to the outside.

I noticed that the machine is not creating heat from the electrical energy, but transferring the energy using electrical energy. But I am still in doubt about how is it possible. How can I get a zero-sum from that? How is this possible without violating the laws of thermodynamics?

Sorry for english mistakes and thank you for trying to help me to think about this question.

Related General Engineering News on Phys.org

#### hutchphd

Yes it is possible. Please see
Remember the temperatures are always absolute (Kelvin or Rankin)

#### russ_watters

Mentor
I was reading a newspaper article on the energy efficiency of commonly used air conditioners in homes. Then a doubt arose when the article informed me that there are air conditioners that have an energy efficiency of 10 BTU/watt. That means a classic 10,000 BTU/h air conditioning machine will consume only 1,000 watt of electrical power during that amount of time.

Using joule as unit for both, this means that in 1 hour the machine will only consume 3,600,000 joules of electrical energy to transfer 10,550,560 joules of "heat energy" from my room to the outside.

I noticed that the machine is not creating heat from the electrical energy, but transferring the energy using electrical energy. But I am still in doubt about how is it possible. How can I get a zero-sum from that? How is this possible without violating the laws of thermodynamics?
How much work does it take to pick up a bucket of water and move it 10m to your left? What if it is a bucket of ice - does it take more energy to move it? So is the energy required to move heat well connected to the amount of heat you are moving?

### Want to reply to this thread?

"How is it possible to use only 1000 W to transfer 10,000 BTU/h?"

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving