Duh... Now that I think about it, I'm sure the reason a heat pump can be so efficient is because if the compressor is inside, most of the electricity it uses is also converted to heat inside the house on top of what it brings in from the outside...
Hmmm, Would you kindly explain what PF is? And what is reactive component?
Hi, Of course. Even with poor PF, if the light output(Lumen) is higher for the power consumed compared to old incandescent bulbs.
And of course, you're wrong. As someone explained very well earlier, a heat pump is efficient because it's MOVING heat, rather than generating it. Modern heat pumps can generate more heat for the same Kwh than resistance heaters, even when the outside temp drop into the teens. BTW, the compresors in the ones I've seen are outside.
On a head to head competitive basis, where one could buy either, who knows which would win, or if both would survive? Some people say they save money, but others are not convinced, especially considering the up front cost of the CFL. Some say they last longer, but it has been my experience that they have a greater failure rate than incandescents.
At any rate, I have purchased enough incandescent bulbs to last me a life time, and it didn't cost much more than buying one full set of bulbs for the house. Also, if an incandescent breaks, I don't have a health issue with mercury.
But most important of all is that I bow my back against any government rule that tells me how I have to live.
Bob-tx
A lot of this assumes the Kill-a-Watt Gizmo knows what the hell it's doing. I'm not so sure anymore. I know a lot of people on here have used them. I borrowed one from a friend and used it to measure my old vs new fridge last year. So, on a recent trip to Costco, when I saw they had the EZ model for $26, I bought one.
The EZ model lets you enter your cost of electricity per KWH and can then display the cost of electricity used per day, month, year, etc. Upon trying to enter the cost of my electricity, I discovered the "set" key just didn't work at all. So, I took it back and exchanged it. This one, the "set" key works, but the "up" key doesn't. But until I take it back, I figured I'd try it out a bit. I put it on the cat water fountain, which uses a small 2.5W plug-in transformer. It's been on there for 5 days and still reads 0.00$ used per year. It also doesn't register any current or watts either. The transformer is small, rated at onely 2.5W. Just checked it for PF and it shows 1.0
Apparently, this draws so little current it can't measure it. But after having 2 bad units in a row, and this thing being made in China, I'm beginning to wonder about how accurate or reliable it really is.
They save 75% on electricity, its a easily proven fact, they last years I have 50 , many run on photocell and after 2 years 2 failures. HD has a 7 yr warranty and top color rendition rating at www.popmechanicsma= g.com If you live where AC is used you will really benifit during AC season, Incandesants are actualy electric heaters only outputting about 6% of the energy consumed as light you actualy see, the rest is heat, so run
11, 100w incandesants and you run a 1000w electric heater, and you then run the AC longer to remove that extra 1000w heat. You do and will see a lower electric bill, every place ive been in Ive cut costs 50% overall by just using Cfls. HDs soft white and good and cheap, near 1$ a bulb. Mercury, because so much electricity is generated by coal is it stated using a cfl reduces Mercury air emissions 2-3 times that over burning incandesants over a bulbs lifetime, Airborn Mercury is what poisons water, and fish. That thermostat you threw away has 10,000x more mercury in it.
e quoted text -
You probably have defective units, I measure power supplies of as little as 4w with the old unit ok. [ I didnt try 2.5w]
I understand what they do, and I said I knew nothing about how efficient they were at doing it (for the sake of argument, not taking anyone's word as correct on that). My point was that even if one happened to be very inefficient at moving heat, it would be, at worst, atill be functioning as a pretty good radiant heater (as does almost anything else that uses electricity).
Briefly, in AC circuits, if you have non-resistive loads, then the current waveform and the voltage waveform may be out of sync. The upshot is that some of the current flowing in the circuit doesn't perform any work, it is just "circulating". The power factor is the ratio of the work the given current is actually doing to the work it could do if voltage and current were in sync.
The reason this matters is that our electrical distribution system (both inside and outside the home) aren't built from superconductors. So anytime current flows, there is some loss from the resistance of the wires. Thus the "circulating" current doesn't do any work, but it does cause some losses.
In the case of compact flourescents, here's the upshot: A reasonable estimate of the power factor of a CFL is 0.5. And CFLs are about 4 times as efficient lighting wise as incandescent bulbs. So if you replace an incandescent with an equivalently sized CFL, you'll be using 1/4 the power for lighting. However, the current in the circuit will only drop by 1/2, so the distribution losses won't decrease quite as much you might think. But overall it is a huge win. [Unless you live in a heating-only climate and use electric resistive heating, in which case you have much bigger efficiency problems than your lighting.]
One important implication of all this, though, is that when sizing branch circuits for CFLs, after adding up the power of the CFLs, you need to correct by the power factor to determine the current draw. For example, if you have a 15 amp branch circuit, maxed out with 18
100W incandescent bulbs on it, and you want more light, you can safely convert to CFLs with a power factor of 0.5 and use 18 50W CFLs (200W equivalent), doubling your light output. But if you were to use 18 100W CFLs (400W equivalent), then you would be drawing 30 amps on the circuit, and you'll have a big problem.Cheers, Wayne
It is not; ALL electricity coming into a house is turned into something; all of which ends up as heat. Even if it starts off as light or sound or a TV picture etc. it is all absorbed by the house, it's furnishings and the people in it! (Well Ok a little light escapes through the indows!) We have a bathroom that is almost entirely heated by the six 40 watt bulbs (240 watts) above the vanity mirror. When additional heat is needed (cold weather) the 500 watt electric baseboard with it's thermostat cuts in. Doesn't matter where the electrically made heat comes from, it's all 100% efficient. A few homes here are using (air) heat pumps; but gather that at lower temps, well below freezing for long intervals they don't pump enough heat from the cold air and the auxiliary electric heaters then cut in. So there are long periods when the heat pump is not very effective. (Or efficient!).
Yeah. We had a phone-in programme recently with a temporary host replacing the usual one, who was 'Ooing and Ahing' about various crackpot ideas that people were phoning in to save electricity. Some were laughable.
The host obviously had no idea about the physics involved. And was 'jumping on any band wagon' on the basis that if it was being touted it must be good idea!
Really worrying; it was like some of the debates about oil versus, gas versus electric heating being 'better'. When it all comes down to matter of cost of fuel, cost of installing and maintaining the heating equipment etc. etc.
The latest 'thing' here is wood pellet stoves! But all they can burn of course is pellets! Great some people say and in house about the size of this one, having bought and installed a $1000 stove, with vent, they burn about one bag per day at a cost of say $5 per bag. And there have been some shortages of pellets while the opening of a proposed pellet making plant is now on hold! And the pellets have to be bought and driven home in a gas using vehicle; a pallet of bags of pellets is not a lightweight matter! Try saying a "pallets of pellets" quickly three times!
Hmm; one bag a day is roughly $150 per month and there is other heat in any house from lights, cooking, hot water, TV on, maybe small heater in bathroom etc. etc. so their light bill is say $100. ($150 + $100 =3D $250).
That brings their total energy bill to more than my total for this all electric now 39 year old and therefore not that well insulated by today's standards, house.
Nothing magic about; you make heat by some (several) means. That costs money and/or effort, the heat escapes from the house, depending how fast is function of the structure.
Gas, except expensive propane, not vailable here.
Stay warm!
Stan,
Please cite a reference for your statement that heat pumps are less efficient that incandescent bulbs or resistance heat??
For > "Air conditioners and heat pumps are heat engines like the refrigerator.
They make good use of the high quality and flexibility of electric energy in that they can use one unit of electric energy to transfer more than one unit of energy from a cold area to a hot area. For example, an electric resistance heater using one kilowatt-hour of electric energy can transfer only 1 kWh of energy to heat your house at 100% efficiency. But 1 kWh of energy used in an electric heat pump could "pump" 3 kWh of energy from the cooler outside environment into your house for heating. The ratio of the energy transferred to the electric energy used in the process is called its coefficient of performance (CP). A typical CP for a commercial heat pump is between 3 and 4 units transferred per unit of electric energy supplied."
Simply stated this says that for one kilowatt of electricity consumed a heat pump can provide between three and four kilowatts of heat. Put another way, from a heating standpoint heat pumps are from 300% to 400% efficient. I believe that this author is somewhat conservative and modern CP's are more like 4 to 6.
EJ in NJ
The heat pump is OUTSIDE. You'd have to stand there to get any radiant heat from it. And anything that uses electricity is NOT necessarily a pretty good radiant heater or even a radiant heater at all. The common electric water heater being one good example, which heats via conduction.
My mistake, but ideally if you were using the heat pump for heating only, you could make the system more efficient by putting the pump inside. Probably too much of a noise issue for most people though.
An electric water heater heats the water by induction, but when the water is not being used most of that heat eventually radiates out into the home. It's not an effective radiant heater, but still an efficient one when you're not carrying that heat away for other uses.
Power factor is real power (watts) divided by apparent power (volt-amps for linear loads). You can't have a power factor over 1.
If you connect an "ideal" capacitor (no resistance) to a watt-hour meter it will register zero, just like an ideal inductor. Like an inductor, a capacitor takes energy from the source twice per cycle and returns the same energy to the source twice per cycle.
As you said above, mechanical watt-hour meters mechanically integrate the volts times amps continuously. For an ideal cap or inductor that is negative twice per cycle. I assume a Kill-o-watt meter measures volts and amps in very short intervals and multiplies. It then integrates the readings for watts and watt-hours.
Power factor does not measure efficiency.
Would make not a wit of differemce because the motor/compressor is a sealed unit. Heat loss in the motor is directly transfered to the refrigerant.
Not induction, conduction.
Most water heaters are located in an unfinished basement or garage. How much of the heat that escapes from the water heater do you think will go towards heating the living space? With concrete all around that's at ground temp, even in the case of a basement, I'd say it's going to be not much. Which makes it very inefficient.
Even if the water heater is in the living space, typically it's in a utility closet with an outside wall and frequently also contains a furnace, which is sucking in combustion air. Bye bye to most of the heat from the water heater there too.
Actualy most of the lost energy goes up the chimney in regular Ng tanks. Thats why most are no better than 60 EF.
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