how quickly can a furnace raise house temp 20F?

[ransley]

Whats an EE degree, is that something you just avoided. Here everyone goes for Bachelors, Masters, and Doctorates.

[Eric in North TX]

Depends, Mine is a 96% efficient model, computer controlled. The exhaust is so cool they use PVC to plumb it. I can't see how an undersized one running 24-7 at max capacity could top mine cycling as intended. I've got a 5 ton heating and cooling about 2k fairly well insulated sq ft. My only complaint is; it is a bit noisy on the intake side.

[ransley]

At Zero, what do you do, offer coupons on your undersized crap. Walmart elect heat !!!! Yea and you sell 95% efficent WH tanks you moron, they dont EXIST, mr Bubbatardcrapolaasbrainsimanimbicileretard, and more

[Zootal]

So, me make sure I understand. According to what others are saying, the rate at which heat will transfer from a solid to a fluid is not just dependant on the difference in temp between the solid and fluid (delta T), but is also dependant on the speed at which the fluid flows past the solid? IOW, if the liquid is moving, heat transfers slower, and the faster the fluid moves, the slower the heat transfers, even if it means the fluid is coolder then it would be if it was moving slower. Therefore, the solid will be hotter and fluid colder if the fluid is moving? Is this decrease in efficiency linear on the speed of the fluid?

[hallerb]

ransley ransley ransley high efficency furnaces are sized to maintain

70 degrees at zero degrees outside, unless the homeowner lives somewhere colder like alaska.......

the furnaces are ost efficent sized this way

[KLS]

The OP (that would be me) had a furnace DIE last weekend. The house temp dropped 20F as a result. I don't believe that installing various other heating devices would have been the cost-effective solution to my essential problem of not having central heat.

Those of you who have been paying attention will be jubilant to know that my repaired furnace now is back to raising the house temp 5 degrees in an hour, as it used to. Whew!

[ransley]

Of course, I meant Bubbas heat world

[Bubba]

I guess ransley, you have awoken out of your 3 day drunken stuper. Too bad you dont have a clue how to size equipment. Its quite apparent with your retarded banter. ransley the f*ck nut. Go back to your bottle at the trailer. Your sister is waiting. Bubba

[Bubba]

An EE is something way way out of your league. It is usually one step above a garbage collector. As for the other degrees, you couldnt afford them. Remember, you are too cheap. You dont even take showers because it cost to much to heat water. Bubba

[Bubba]

I guess the suspense is just going to have to kill you till you figure it out. Meanwhile, just use that big boulder to bash your head in. Bubba

[clare]

That's why I installed a 2 stage furnace. So far it has not been cold enough long enough to require the furnace to run on the high BTU setting (only had it 6? years now)

[Bubba]

Still cant seem to grasp reality, eh ransley? I guess when you live in cinderella world, everything is different. Bubba

[makolber]

x-no-archive:

CORRECT

NOT CORRECT

Mark

[makolber]

x-no-archive:

Zoot, I think the basic fact that you are missing is that HEAT and TEMPERATURE are not the same thing.

Consider a candle flame has a very high temperature but not a lot of heat.

A ton of water at 90 deg F has a low temperature compared to the candle flame but the water has a lot more heat.

If you slow the airflow down through a furnace, the TEMPERATURE of the air will go up but the total amount of heat will go down a little.

If you speed up the airflow the temperature will go down, but the total amount of heat will go up.

Heat and temeprature are not the same thing.

Bubba, yes I'm an EE.

Mark

[Zootal]

Oh, no, I'm not missing it at all. Let's consider a simple example. Say we have a heating element with some heat source applied to one side of it (gas flame), and air flowing over the other end of this element. The question is, how can I get the maximal amount of energy to pass from the element to the air? The assumption is that the temperature of the house is dependant on 1) how much energy is passing from flame through element into air flowing past it and 2) how much energy is escaping through doors, windows, walls, etc. What we are interested is how much energy we are putting into the house, not how efficient the house is.

Let's first look at the side of the element in proximity to the flame. Assume that the gas flame is constant so that a constant amount of energy is available. How much of this energy is going into the element, and how much is going up the chimney? Simple physics tells us that the amount of energy that goes into the element is dependant on the difference between the temperature of the flame and the temperature of the element. If they are both the exact same temp, then all of the energy from the gas flame is going to go up the chimney and get vented outside. If the temp of the element is

10 degress lower then the flame, the a certain constant amount of energy is passing into the element. If it is 20 degrees colder, even more energy is passing into it and again this is a constant amount(we'll get to what is going on at the other end of the element in a bit).

The assumptions are that 1) The amount of energy going into the element is dependent on the difference between the temperature of the elemen and the temperature of the flame and 2) the energy going into the element is being dissapated at the other end and is going into the house.

Does it stand to reason therefore, that the lower the temperature of the element, the more energy is going from flame into the element, and therefore the more energy goes from the element into the house, and that the difference between the temp of the flame, which we assume for now is constant, and the temperature of the element, is a measure of the amount of energy going into the house?

I need agreement on this before I can go any further, otherwise I'm wasting my time and yours :)

[makolber]

x-no-archive:

Yes I think we agree about that ( if I understand you correctly).

And the more airflow over the element from the blower, the __cooler__ it will be, and the __cooler__ the air will be and __more__ heat energy will be taken from the element and less will go up the chimmy.

That is what the other guys were saying, more air through the blower, = lower air temperature.

Bottom line:

more air through the blower = lower vent temperature but a little better efficency in the furnace.

It seems backwards that the air temperature is lower when the heat energy is higher but it is correct and goes back to the difference between temperature and heat energy. Mark

[Zootal]

That's not exactly what they were saying - they were saying the more air through the blower, the colder the house will be. I'm saying the more air through the blower, the warmer the house will be.

So riddle me this - if more airflow over the element means the element is cooler, then that means more energy is going into the house. So how can the house be colder if this is the case? Where did the energy go?

[Bubba]

Holly shit! You and trader would get along great. I cant believe how far you have stretched your simple question. Bubba

[Zootal]

LOL! I had to, to make my point :)

[clare]

What are your qualifications for claiming this is not true?