2012/05/27

The Complex World of Humidity and Temperature

During sunlight hours (minimal cloud) the water vapour in the air will absorb long wave IR (Green House Effect) from the sun and from the ground.
This will be radiated back in all directions.
The solar radiation will therefore be modified such that the wavelengths absorbed by the water vapour will be reduced depending on the effectiveness of the green house effect.
 However the same wavelengths radiated upwards will be more effectively "reflected" back down.

At night the solar input stops and the only radiation hitting the earth is that from GHGs So more water vapour = better "reflector"

Is this visible in the data previously used below.
Firstly data is limited and to get sensible results each point needs significantly more than one result to be significant.

Night time readings cannot include cloud coverage as this is not measured when dark
The former plots used either average or min/max values. The min max tend to plot one off anomalies. In the plots below 1st and 3rd quartile results have been used to improve this.

First a whole year all possible times with up to 9% opaque cloud cover

http://www.nrel.gov/midc/srrl_bms/

not sure why humidity so high!
Now in sequence 2 months at a time a couple of hours and up to 9% opaque cloud cover
Now for some night responses 2 months at a time
Conclusion?

  • Well minimum temperature shows a increase with increasing water vapour (positive slope) over coldest period but turns to negative slope during warmer months
  • The max temp during the night shows little change with water vapour.



2012/05/24

IARC-JAXA Sea Ice Extent is back online

The plots beow are from IARC-JAXA data, now with new satellite integrated to previous AMSRE data.

No suprises yet - the data continues to show exess area inthe early part of the year followed by a rapid decline beginning around beginning of May.

2012/05/20

Nuclear Power Data

Useful book:
http://www-pub.iaea.org/books/IAEABooks/8954/Nuclear-Power-Reactors-in-the-World-2012-Edition

Age of Nuclear Stations:

Compare this to 2009 and it can be seen that some are being decommissioned but the glut at 28 years old are still running (maybe a few bankruptcies in a few years time??!):


Perhaps shown clearer here:


It seems that decommissioning starts at about 33 years but presumably life cannot safely be extended much beyond 40 years.

Just how good is their availability:


Cetainly better than Wind but still not good at 78%

Wind and the price of electricity in UK

From a post at wuwt  (EU violates Aarhus Convention in ‘20% renewable energy by 2020’ program) :

Mark Duchamp, Executive Director of EPAW, points that Mr. Swords initiated his recourse one and a half years ago, as it was already obvious that the European Commission was imposing an enormously costly and ineffective policy to EU Members States without properly investigating the pros and cons. “It is high time that Brussels be held accountable for the hundreds of billions that have been squandered without a reality check on policy effectiveness” says Mark. “To spend so much money, a positive has to be proven. – It hasn’t.”
He [Pat Swords] continues: “Electricity costs are soaring to implement these dysfunctional policies, which have by-passed proper and legally-required technical, economic and environmental assessments. Not only is the landscape being scarred as thousands of wind farms are being installed, but people in the vicinity are suffering health impacts from low frequency noise, while birdlife and other wildlife is also adversely impacted. It is long overdue that a STOP was put to this type of illegal and dysfunctional policy development and project planning.”

So just how has windpower affected the UK electricity prices. Presumably if Swords is correct then the price of electricity will have increased at a greater rate than the fuel used to generate it. With words like "soaring" used these differences must be substantial.

Looking at data from http://www.decc.gov.uk/assets/decc/statistics/source/prices/qep213.xls you get this graph.



Interesting! Less of a soaring price than gas or coal
So is this just another distortion from the watts crowd?

If windpower were a driving factor then perhaps the energy cost will appear as a bigger budget item in the countries with higher windpower generation.
So let's have a look at germany:
compared to UK
compared to Denmark

So with UK having the lowest penetration of windpower of the three it also has the biggest Utilities cost (this of course includes a number of utilities not just electricity.


How about Cradle to grave costs. Here is the build / working breakdown of costs over 20 years:
Project: Single wind turbine (800kw)
Location: Balloo Wood, Bangor, Co. Down, Northern Ireland
Turbine: 800kw Enercon E48
Dimensions: 56m hub height, 24m blade length, 80m overall height
NGR: 350760E 379503N (lat 54.6411N, long 5.6656W)
Status: Operational


build £        889,650.00 install
planning etc £        434,583.00 install
maintenance0.0055perkwh
maintenance/year for delivered 280kwh £             562.49 per year
routine expenses £         30,000.00 per year
rating1000kwh
load factor28%
deliverd energy280kwh
Balancing Cost £               0.014 per kWh
Short term Reserve £               0.007 per kWh
total install cost= £     1,324,233.00
install cost/delivered kwh £           4,729.40
conventional backup costs/year £         51,544.08 per 280 kWh/year
running cost/year £         82,106.57 per 280 kWh/year
over n years25
total install over 25 yrs £     1,324,233.00
running cost over 25 yrs £     2,052,664.13
total cost over 25 yrs £     3,376,897.13
decomissioning cost (guess=.5*build) £        444,825.00
total cradle to grave cost £     3,821,722.13
energy generated over 25 yrs61362000kWh
cost per kwh over 25 yrs £               0.062 per kWh


most data from
http://silverford.com/blog/?p=1689/
This seems a reasonable figure but the decommissioning costs are pure guess work. The life time of most wind turbines is believed to be 25 years. The warranty period is 12years for this turbine.

A closer look at Germany/france:
For example:

Germany 2012 Note price Note Double peak

Germany 2012 Note price note single peak at peak volume

 PV electricity produced in Germany
check PV produced on Germany on daily basis from 2010


How about nuclear??




2012/05/01

A cool body can transfer measurable heat to a hotter body

So much non-science about transfer of energy between different temperature objects.
So many state that it is impossible for a cool object to heat a hotter object.

But both bodies emit radiation corresponding to their temperatures. Each body obviously does not know of the existence of the other before it releases its radiation.
The cold body obviously receives radiation from the hot body and therefore warms
The hot body obviously receives radiation from the cold body and therefore cools slower than if the cold body were at 0K.

Specification for a thermal imaging camera

http://www.flir.com/cs/emea/en/view/?id=41964

Imaging Performance
IR resolution 640 x 480 pixels
Spectral range 7.5 – 13 ┬Ám
Image frequency 30 Hz
Focus Automatic or manual
Focal Plane Array (FPA) Uncoooled microbolometer
Measurement
Temperature range -40°C to +500°C (optional up to +2000°C)
Environmental specifications
Operating temperature range -15 °C to +50 °C

This thermal imaging camera will operate at +50°C ambient This means the imagaging device (a micro bolometer array) is at at least 50°C since it is uncooled.
How can it measure -40°C when it is at 50°C?

How does a microbolometer work:
http://www.laserfocusworld.com/articles/print/volume-48/issue-04/features/microbolometer-arrays-enable-uncooled-infrared-camera.html

Modern microbolometers measure temperature changes caused by IR absorption in individual pixels, which are thermally isolated and assembled into focal-plane arrays (FPAs).
Each pixel in an array is a very low-mass IR-absorbing structure supported by thin legs, which limit heat conduction to the underlying substrate, as shown in Fig. 1. The lower the mass of the illuminated pixel, the less IR energy is needed to increase its temperature a given amount, and the more sensitive it is.


FIGURE 1. One pixel in a microbolometer array. An infrared-absorbing surface is elevated above the substrate and thermally isolated from adjacent pixels. Low mass increases the temperature change from heat absorption. Read-out circuits typically are in the base layer, which may be coated with a reflective material to reflect transmitted IR and increase absorption of the pixel.

Two classes of IR-absorbing materials are used in microbolometers. Pyroelectric or ferroelectric crystals generate electrical signals that are directly proportional to the temperature increase caused by IR absorption; the most common material now in use is barium-strontium titanate. Other materials act as thermistors, in which the electrical resistance changes with temperature. As in the original 19th century bolometer, measuring the resistance of a microbolometer pixel measures the incident IR intensity. The leading materials today are the semiconductors amorphous silicon and vanadium oxide (often abbreviated VOx), which are compatible with the standard semiconductor processing technology used to fabricate the read-out circuits that generate images.

 The sensitivity depends on how much the resistance or other electrical signal changes with temperature, and this depends on the absorbing material. The pixel response time also is important; absorbers should collect heat quickly and hold it long enough for measurement, then dissipate it before the next frame is recorded. A typical rule of thumb is that the time response should be no longer than one-third of the interval per frame, about 10 ms for a 3 Hz frame rate. Response time and performance also depend on the read-out integrated circuit (ROIC), which collects temperature data from all pixels for each frame. Noise usually is measured as noise-equivalent temperature difference (NETD), with lower being better, and 50 mK a desirable target.
=================

So there we have it the receiver plate is heated by the IR

Heat from the bolometer will be radiated away in all directions there can be NO imaging of the object from this radiation leaving the bolometer. Radiation leaves the bolometer before it knows where it will land so will be equal from all parts of the bolometer even if it eventually lands on a cooler object beyond the lens.

Unless you postulate negative energy rays (cold rays - this would be a new concept on me!) from the cold object that can be FOCUSED onto the bolometer then I cannot understand how statements suggesting that cold cannot heat warm can be a feature of the explaination of a bolometer’s operation.

If you assume normal physics applies then the thermal imaging camera can be understood.
Point the camera at 100°C the bolometer receives radiation focused on it and its temperature raises above its ambient.
Point the camera at 0K the bolometer receives no radiation so will stay at its ambient.
Point the camera at -20°C the bolometer receives radiation focused on it and its temperature will rise but too a lower value than in the 100°C case.
A -20°C object will therefore produce an image in the bolometer’s output

An Iceberg at night by IR 

.
Note that thermal imaging to give exact temperatures is not simple the emissivity of the object under inspection affects the temperature calculated. Also a IR reflective surface may actually show a temperature of a reflected object rather than the reflector

Point a microbolometer array through a germanium lens (i.e. a thermal imaging camera) that focuses objects at -273 to +1500C onto parts of the array.
at -273C the bolometer sees no source of heat so it will be at say 20C this being the temperature of the bolometer when it is warmed by camera ambient within and losing heat at 20C
at -20C the bolometer sees both focused IR from the object and the energy from the 20C local camera ambient. The temperature 20C is the same as before (within reason) so the rate of loss of heat will be the same as when -273C is focused. When the bolometer radiates it does not know the temperature of its destination. The bolometer is now receiving more energy than when -273C is focused. The bolometer therefore heats a fraction to say 20.1C
Hopefully you can see where this is going.
The microbolometer temperature is modified by temperatures above -273C - the IR is focussed by the germanium lens onto each part of the array. The temperature of the bolometer is then converted to a video signal. This can therefore show a difference between the bolometer with focussed ir from an object at -20c and the bolometer at -273C DESPITE the fact the array is at 20C.
The lense does not focus cold rays!
The stuff on my blog shows photos/videos taken with a room temperature microbolometer array. This includes sky photos showing temperatures down to -40C (the camera limit) together in the same frame as a temperature of  -1. All measured to an accuracy of +-2C with a sensitivity of 0.03C
(note that as ambient changes the array is calibrated by viewing a isothermal plate rather than the image required)
If cold objects did not add energy to a warm object then this sort of camera would not work. (note that it does not cause warming it slows cooling.) There are no cool rays to focus onto the array so it has to be IR.
The difference between bolometers and thermopiles is large. bolometers are used for arrays as these can be processed like silicon semiconductors. But in essence the physics is similar.a sensor temperature is modified by the IR falling on it (from any thing above -273C) and this is referenced to a measured internal temperature.
I agree that the accuracy of the PIR is not good about 5w/sqm at 300W/sqm i.e. about 2% but saying this negates any measurements seems over the top.

Transmission properties of germanium used in IR camera lenses.
 

Some stuff from the BBs
thefordprefect says:


Your comment is awaiting moderation.



2013/03/26 at 6:53 AM

Joseph E Postma says: 2013/03/25 at 7:21 PM

When these devices detect “cool”, it is a LACK of signal that they detect, a “negative voltage”.

———–

Look at the drawing for a bolometer. There is an IR absober. It has IR only focussed on it (the camera lens is made from germanium – which is opaque to visible light – I have added the transmission property to the post indexed above). The IR absober temperature is measured and the this value is output to the video processor.

Can you please explain what you mean by “detect cool” I keep stressing there are no cool rays there is only Thermal radiation (between 2u and 15um) that can get through the lens. This thermal energy adds to the energy from the ambient conditions and changes the temperature of the IR absorber – a -273C temperature adds no energy, a -20C adds more and the absorber warms above the temperature that would have occurred at -273C. a source of 1500C (within the range of the cameras calibrated sensitivity) adds even more energy so the absorber is warmer still.

Whatever the temperature of the object that is focussed on the absorber (above -273C) energy is added to it and its temperature rises (it is not that -273C cools the object because that would require cooling rays to be focussed)

And I LOVE this one on science of doom page
http://scienceofdoom.com/roadmap/back-radiation/#comment-13825
:

JWR


The chicken wire has emissivity eps as is indicated.

Please read the article before asking questions.



As concerns your second question, you should read Claes Johnson.

I will tell it to you in simple language.

There are two kind of radiations, the informative one, and the heavy artillery , radiation which carries calories.

The information radiation is used in

infrared camera’s, IR remote thermometers,pyrgeometers and indeed two plates telling each other which one is the warmest.

It is two way traffic.

In case of the two plates the information radiation is a traffic light, and enables nature to obey the second law andto send the second heavy artillery with calories from the warmer plate to the colder one!



Therefore in the paper I insist that SB is always written for a pair, with two temperatures. In fact also emission from temperature T to temperature zero K is a pair, q=sigma*(T^4-zerok^4) which is usually written in abreviated form since zeroK^4=0!.

If this matter interests you, go to the blogs of Johnson, where you can read historical phrases by Planckton and by Einstein that indeed they were not happy with the quanta!