Understanding the Discrepancy in Horsepower Ratings for Air Conditioning Units

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Discussion Overview

The discussion revolves around the discrepancies in horsepower ratings for air conditioning units, specifically comparing manufacturer claims with calculated cooling outputs. Participants explore the relationship between horsepower, cooling capacity, and energy input/output in the context of air conditioning systems.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant notes that manufacturers like Carrier and Panasonic list their air conditioning units with horsepower ratings that do not align with calculated cooling outputs based on BTU conversions.
  • Another participant clarifies that the 1.5 horsepower rating refers to input mechanical work rather than cooling output.
  • A link to the Coefficient of Performance is shared, suggesting a deeper exploration of the efficiency of the systems.
  • There is a question about whether the cooling output can be expressed in watts, given that the input is stated as 1.5 horsepower.
  • One participant asserts that power can be expressed in various units, including watts, horsepower, BTU/hr, and tons.
  • A concern is raised about the law of conservation of energy, questioning how an output of 4.7 horsepower can result from an input of 1.5 horsepower.
  • Another participant counters that the input electrical energy is not the only energy input, implying that other factors may contribute to the output.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of horsepower ratings, the relationship between input and output energy, and the implications for energy conservation. No consensus is reached on the reasons behind the discrepancies in horsepower ratings.

Contextual Notes

Participants reference various units of measurement and their conversions, but the discussion remains unresolved regarding the implications of these discrepancies and the definitions of input versus output energy in air conditioning systems.

riezer
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A manufacturer like Carrier or Panasonic listed their 1 Horsepower Aircon as having 9,500 KJ/h and 1.5 Horsepower Aircon as 13,000 KJ/h. But it doesn't tally with the BTU conversion.

1 ton refrigeration = 12000 Btu/Hour = 12,661 kJ/Hour = 3.517 kW

now 1 watt = 0.00134102209 horsepower therefore 3.517 kW = 4.7 Horsepower!

But the Carrier/Panasonic manufacturer listed 1.5 Horsepower Aircon has having 13,000 KJ/hour which is equivalent to 12000 Btu/Hour or 1 ton. Yet calculation of this data show 4.7 Horsepower. Why did Carrier/Panasonic, etc. listed them as 1.5 Horsepower Aircon?

I've been searching in net for this for hours but can't find the reason. Anyone got any idea why?
 
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1.5 hp is the input mechanical work, not the cooling output.
 
russ_watters said:
1.5 hp is the input mechanical work, not the cooling output.

You mean 3517 Watts (equivalent to 4.7 Hp) is the cooling output? Can you use watts as cooling output (the input being 1.5 hp as you mentioned)?
 
Yep. And power is power - you can use watts, horsepower, btu/hr, tons etc.
 
If the input is 1.5 HP (1200 watts) and the output is 4.7 HP (3517 watts). Doesn't it violate law of conservation of energy because the output is greater than the input?
 
No. The input electrical energy isn't the only energy input. Please read Chris's link...
 

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