reverse cycle air conditioning heating is more efficient??

An airconditioner (like a fridge), is what's called a 'heat pump'. In the reverse cycle mode, it moves heat energy from outside to inside. That's why the external evaporator gets cold. So you get more heat energy out of it, than the electrical energy you put into it. At least that's what I was told. :-)

Bob

No, the reverse cycle air conditioning is up to 250-300% more efficient but more like on average around 200 - 250%

Well I believe another term for the refrigerative A/C might be a HEAT PUMP! When heating it is actually transfering heat from the outside of you house to the inside, when cooling transfering heat from the inside to the outside....hmmm....ever wondered why the output ratings of the A/Cs is higher than the input power consumption? Using electrical energy to move heat. The little fan heater on the other hand is converting the electrical energy to heat.

James

"APR"

"Trevor Wilson" wrote

Nope. You'd be wrong. Almost all heaters are pretty damned close to 100% efficient. Modern air cons can be up to 500% efficient.

****** I just can't believe that you have single handedly solved the worlds energy problems for all eternity!!!!!!

500% efficient!!!

The mind boggles!!!

Wota wanker!!!!!!!!!!!

Brian Goldsmith.

Badly explained but sorta .

**Nope. Energy still needs to be expended to heat or cool. There's no such thing as a free lunch. **How do YOU explain the equivalent of 5kW of heating capacity from 1kW of electrical input? The air condictioning industry calls it EER (Energy Efficiency Ratio) or COP (Coefficient Of Performance).

--
Trevor Wilson
www.rageaudio.com.au

In fact with reverse cycle the energy consumed in pumping heat from one place to another needn't approach anywhere near the amount of heat moved .. Std laws of physics and that's not marketing .

"Phil in Melbourne"

** The "heat pump" technique works for water heaters too:

What a * warm * idea !

....... Phil

The rest of the world calls it 'marketing', except for scientists, who call it 'a physical impossibility'.

**Yeah, I thought about that one too. I also looked at Solar hot water, heating, until I got the quotation. My average hot water bill is around $18.00/quarter. At that rate, it would take around 75 years to payback the cost. I figure with a $18.00/quarter hot water bill, I'll leave well enough alone. My figuring is this: At the old place I had an outdoor 210 Litre off peak system. It cost around $70.00/quarter. I now have an indoor, 420 Litre off peak system and my bill is less than $20.00/quarter. I figure the efficiencies from being indoors and the fact that there is less surface area to radiate heat from puts me well ahead.

--
Trevor Wilson
www.rageaudio.com.au

Quantum Energy are another Australian company doing hot water systems using heat pumps instead of rooftop panels.

I always thought it would be neat to have a combination heat pump/rooftop panel system, but I haven't seen one of these yet.

**Not really. It was a scientist who invented air conditioning.

--
Trevor Wilson
www.rageaudio.com.au

Maybe you should go back to school and learn something about thermodynamics.

Er NO. Efficiency is power out divided by power in. You forgot the power in contributed by the sun in your calculation!

See, now you remember :-)

MrT.

Along the same lines... is the heat exchanger of reverse cycle more efficient than standard "blow air over a gas heaterl" central heating?

(And for that matter why are the central heating inlets at floor level rather than towards the ceiling where the hot air would be?)

**Of course, but the cost of gas heating may well work out lower. Or not. **Inlets? Do they have inlets (We Sydney-ites don't have central heating)?

--
Trevor Wilson
www.rageaudio.com.au

I would, but Im too busy building my perpetual motion machine using thermodynamics :)

I kinda remember doing thermodynamics, albeit, i am struggling. Heat pump is a marketing thing according to thermodynamics.

However, a 'heat pump' is more efficient than an element because as well as creating heat from using electricity is is also 'moving heat' from as a side affect of that process, therefore making it more efficient than a plain electric element heater.

If one thinks these devices are 500% efficient, then go do the math. Energy is not free (basic physics) and there is still going to be energy lost. If one was comparing the effeciency compared to a wood heater, then the RELATIVE difference may well be 500%. Please people, it's all basic physics, if you wish to make outlandish claims them plese put it into context so it is then beleiveable.

BTW. IF one was saying 500% percent relative to the power used then a reverse cycle aircon would be returning power to the grid. IE, the aircon would cost nothing to run.