Monday, June 16, 2014

BTU

Anybody who ever bought a small window AC unit knows about the abbreviation BTU. On the box, it is written the amount of BTU the unit can handle. I've got an older 100 dollars unit that has a stated capacity of 5000 BTU and a a newer one of 120 dollars of 5000 BTU as well. With a P3 Kill A Watt power consumption meter, they each show a consumption of about 450 W, with the thermostat on continuously.

(When i first wrote this i used an ammeter than was showing 2.70 Amps, when multiplied with 120 V (grid voltage) was resulting less. But the trick is to wait until the units built pressure and consumption increases, which i didn't do with the ammeter).

Never knew what BTU was until recently. It is an abbreviation for British Thermal Unit. It is a non-standard unit for measuring energy.

The boxes are labeled with the amount of BTU. Without specifying the time interval, which in hour case is per hour, it has no meaning. It should be BTU/h, or BTU per hour, as BTU is a unit of measuring energy and BTU/h is a unit of measuring power, for which there is already a standard unit, the Watt. There are conversion formulas between the two.

From Wikipedia, i brought here the sub-chapter that talks about conversion between BTU/h and Watts.

http://en.wikipedia.org/wiki/British_thermal_unit#As_a_unit_of_power

"When used as a unit of power for heating and cooling systems, BTU per hour (BTU/h) is the correct unit, though this is often abbreviated to just "BTU"

1 watt is approximately 3.41214 BTU/h[10]

1000 BTU/h is approximately 293.071 W

1 horsepower is approximately 2544 BTU/h"

Thus for a unit of 5000 BTU/h, if written correctly, the equivalent of power in watts would be 1465.355 watts.

But there is a (there are actually several) problems.

On the Wikipedia page about air conditioning it says

http://en.wikipedia.org/wiki/Air_conditioning#Seasonal_energy_efficiency_ratio

"For example, a 5000 BTU/h air-conditioning unit, with a SEER of 10, would consume 5000/10 = 500 Watts of power on average."

Please note that here is used, correctly, BTU/h.

But according to the conversion formulas from the other Wikipedia page

5000 BTU/h divided by 3.41214 = 1465 W

That is how much a 5000 BTU/h AC  unit should draw from the grid. Instead, it draws a little over 400 W.

Forgetting about the coincidences of using the acronym SEERS that also has a meaning in English, and the fact that pronunciation is similar with the word Sears, who also sells those type of units, among others.

Don't get me wrong. They really feel like they output 5000 BTU, not 1500 BTU as it results from multiplying the measured power, 450 with 3.42, the BTU/watt ratio. I don't believe it's a case of false advertisement.

Then anybody can tell me where the mistake is?

I personally think there is no mistake, the AC, as its cousin, the heat pump are truly over unity devices (output more energy than input). Which they manufacture, sell  and even advertise like that and use for decades without the Universe being thorn apart or something.

Proposed experiment. Feed both ends of an AC unit like this into a Sterling engine that has an efficiency of about 50%. At a consumption of 450 W you would have 10000 BTU entering the Sterling engine (adding both cold and hot output, that for a small compact AC is lost) and hook a generator to it and see if you can get in the end more than 450 (input) watts.

Tuesday, June 10, 2014

A Theory on Alcoholism

The presence of Alcohol Dehydrogenase (ADH) at high levels in the human body triggered by the consumption of alcoholic beverages insures, as a side effect, protection against many types of alcohols including methanol and glycols because it helps metabolizing all those alcohols.

This is the reason ethanol is often used in emergencies as antidote for methanol or glycol accidental ingestions.

Heavy drinkers exhibit a continuous production of high level of dehydrogenase (definition framed here) for years or decades, production triggered in human body only by the consumption of ethanol.

Ethanol is as toxic to humans as methanol but by raising the production of dehydrogenase, the human body can metabolize it.

In the same time ingestion of alcohols other than ethanol generally does not trigger production by the human body of enough of the protecting ADH, thus their very toxic effect.

Both situations are due to genetic factors accumulated by human and other species throughout evolution.




Throughout the whole period of heavy drinking the human body does not need its immune system for fighting against methanol producing bacteria that live in the gut because the methanol produced by those is also metabolized by the ADH of which production is triggered by the ethanol from drinking (and maybe permanently reallocates those resources for producing dehydrogenase for metabolizing both ethanol and methanol and other alcohols produced by the bacteria in the gut or coming from a polluted environment).

It is possible that the immune system by not being used to fight that type of bacteria for so long looses the capacity of fighting it.

That's why they probably can not stop, because of the terrible hangovers given among other things by the methanol produced by those bacteria without the presence of ADH "normally" triggered by drinking alcoholic beverages, bacteria that their immune system abandoned fighting or forgot recognizing.

Maybe the solution could be as simple as vaccination against those so the immune system start recognizing them again.

ADH is always present in healthy individuals in amounts that insure protection against the amounts of all types of alcohols normally present in food. Although only ethanol raises ADH production, the other alcohols present in food or generated by other alcohols production microorganism are always reasonably proportional. Probably ethanol is most common and that's why the human body uses it as trigger in raising ADH production.

By overstimulating the production of ADH with heavy alcohol consumption it is also possible that the production mechanism to be depleted by overuse and/(or more likely) the triggering amount necessary for starting production to become permantely raised so the normal amounts present in food or generated by ethanol or other alcohols producing microorganism living in the gut do not trigger its production before (relatively low) toxic levels are being built, giving hangovers. In this case due to lack of further knowledge, all i can say is it can be imagined a lifelong treatment that may include ADH or other medication that can stimulate the production of it at normal levels.