Have you guys seen these?
#43
RE: Have you guys seen these?
well im in no way an expert, but high-school physics has taught me that heat dissapation into the atmosphere occurs at an exponential rate (^-1 tho), wheras heat from a furnace would be encourred into your house at a linear rate. In other words, the bigger the difference between outside + you, the faster your house cools off/warms up to outside temperature. However, the furnace works on a more linear scale, as it can heat up your house x amount of degrees in an hour, regardless of the current temp of your house. (this is of course disregarding the already-existing atmospheric loss) however without exact, or even approximate figures on the data, I cant really say which method would be more efficient.
#44
RE: Have you guys seen these?
Heat loss is non-linear in dT because of buoyancy-driven stuff like air going up a chimney & in/out the cracks between windows etc. More non-linearity for radiant heat at night especially when the sky is clear. So what? Just do the experiment.
If you want to do an experiment, you'll want to record how often & how long the heat runs. It would be a little easier if you had gas heat & you simply didn't use any other gas appliances during the 'test'. Then read the meter. It's more difficult to get thru normal life without using any other electric devices.
If you don't want to do the experiment, one way to figure it out is to pretendthe heat loss is linear in dT (Tin - Tout). Say the outside temperature is 20F & the inside is 70F. The dT is 50F. Shut OFF your heat all night long - completely shut it off. How cold does the house get? Say 50F? Average during the night is say 60F for a dT of 40F. So your house lost 40/50 or 80% of the heat that you would have used. You still have to heat it back up, but during the time it was cool, it was losing less heat.
If your house is so well insulated (and/or has large thermal mass) that it only drops to 65F overnight, then it's very little advantage. In that case it's probably still worth it to set it down to 50 (or whatever) when you're gone for a couple days or more.
If you want to do an experiment, you'll want to record how often & how long the heat runs. It would be a little easier if you had gas heat & you simply didn't use any other gas appliances during the 'test'. Then read the meter. It's more difficult to get thru normal life without using any other electric devices.
If you don't want to do the experiment, one way to figure it out is to pretendthe heat loss is linear in dT (Tin - Tout). Say the outside temperature is 20F & the inside is 70F. The dT is 50F. Shut OFF your heat all night long - completely shut it off. How cold does the house get? Say 50F? Average during the night is say 60F for a dT of 40F. So your house lost 40/50 or 80% of the heat that you would have used. You still have to heat it back up, but during the time it was cool, it was losing less heat.
If your house is so well insulated (and/or has large thermal mass) that it only drops to 65F overnight, then it's very little advantage. In that case it's probably still worth it to set it down to 50 (or whatever) when you're gone for a couple days or more.
#46
RE: Have you guys seen these?
mclaren ..... no
others .... good ideas ..... for SN's case, electric is essentially 100% efficient (97-99% in reality, but who cares about that). When an electric heater energizes, the heater uses it's full potential (of the stage if multi-staged) which means that the heat output is 3.143 BTU's per hour per Watt. Unlike a boiler, there are no efficiencies to complicate the review. In the cae of electric forced unit heaters with local controls, you are best to just minimize its use (ie. - turn the temp down to 60-65 when nobody is using the room).
In the other case, where you have a boiler, you shouldn't turn the setback temp too low because the recharge time is too long ..... also, you don't want the water in the system too cool too much. Baseboards don't give out nearly as much heat as forced air, but they give the heat more uniformly and have thermal capacitance for when the system shuts down due to the heat in the water. If your boiler produces enough heat that it cycles on only 50% of the time on the coldest days, you can turn down the boiler water setpoint temperature. This will save energy by reducing thermal losses and also makes the boiler heat the water to a lower temperature on recharge.
Hardly any homes have multi-stage boilers so if there are any specific questions regarding them, PM me.
others .... good ideas ..... for SN's case, electric is essentially 100% efficient (97-99% in reality, but who cares about that). When an electric heater energizes, the heater uses it's full potential (of the stage if multi-staged) which means that the heat output is 3.143 BTU's per hour per Watt. Unlike a boiler, there are no efficiencies to complicate the review. In the cae of electric forced unit heaters with local controls, you are best to just minimize its use (ie. - turn the temp down to 60-65 when nobody is using the room).
In the other case, where you have a boiler, you shouldn't turn the setback temp too low because the recharge time is too long ..... also, you don't want the water in the system too cool too much. Baseboards don't give out nearly as much heat as forced air, but they give the heat more uniformly and have thermal capacitance for when the system shuts down due to the heat in the water. If your boiler produces enough heat that it cycles on only 50% of the time on the coldest days, you can turn down the boiler water setpoint temperature. This will save energy by reducing thermal losses and also makes the boiler heat the water to a lower temperature on recharge.
Hardly any homes have multi-stage boilers so if there are any specific questions regarding them, PM me.
#47
RE: Have you guys seen these?
ORIGINAL: sir_nasty
I'm switching all the lights in my house over to the CFL's (Compact Florescent Lights) simply because they are massivly cheaper to use...
Check out this spreadsheet comparison about them that I just found.... it's AMAZING....
http://www.productdose.com/article.php?article_id=1142
I'm switching all the lights in my house over to the CFL's (Compact Florescent Lights) simply because they are massivly cheaper to use...
Check out this spreadsheet comparison about them that I just found.... it's AMAZING....
http://www.productdose.com/article.php?article_id=1142
The first one has yet to burn out.
Anyways, a small tidbit of advice...when you buy them at WalMart, make sure you open the box and check all the bulbs. Me and my wife bought a box of 8 once and 4 of them were broken[:@]. Since I didn't check them at the store I didn't know if they were already broken when we bought them or if they broke in my trunk on the way home due to my mad driving skillz....
#48
RE: Have you guys seen these?
This looks promising: http://www.autocar.co.uk/News/NewsAr...Accord/225926/
#49
RE: Have you guys seen these?
Here are the atmosphere'sgases and their concentrations:
Here are measurements of atmospheric CO2 concentration asobserved by techniciansatprobably the most importantobservation stationin the world (with the last few years of data selected by a box):
An enlargementof the data in the boxthat clearly shows the historical yearly cycle of CO2 concentration (the relatively straightline that cuts through the middle of the data is a running average, I believe):
Notice that the reported CO2 concentration in the first table - 0.0360% (360 ppm) - is now out of date.That datasuggests that the table was published in about 1995. The current concentration is about 383 ppm and will likely rise further in the future. (Of course there is no way that we can predict that with scientificcertainty, however. As I said, it's all a matter of faith.)
Here are measurements of atmospheric CO2 concentration asobserved by techniciansatprobably the most importantobservation stationin the world (with the last few years of data selected by a box):
An enlargementof the data in the boxthat clearly shows the historical yearly cycle of CO2 concentration (the relatively straightline that cuts through the middle of the data is a running average, I believe):
Notice that the reported CO2 concentration in the first table - 0.0360% (360 ppm) - is now out of date.That datasuggests that the table was published in about 1995. The current concentration is about 383 ppm and will likely rise further in the future. (Of course there is no way that we can predict that with scientificcertainty, however. As I said, it's all a matter of faith.)
#50
RE: Have you guys seen these?
The thing about that chart that I found interesting is that if you look at the link from one of my first posts it shows co2 content over a couple million years, and according to that chart we actually had a higher CO2 content about 125,000 years ago. That's what I was wondering about