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Glucose Photosynthesis

by ovacs
Tags: glucose, photosynthesis
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Jun17-14, 02:44 PM
P: 19
Can this photo synthesis be done by technical means or is it only happen in plants?

6CO2 + 6H2O(gas) + sun radiation = C6 H12 O6(Glucose) + 6O2

Revers: (cellular respiration)
C6 H12 O6(Glucose) + 6O2 = 6CO2 + 6H2O(gas) + caloric energy (deltaG)

deltaG = -2880 kJ per mole Glucose
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Mike H
Jun18-14, 08:01 AM
P: 485
Insofar as I am aware, there is no significant literature on non-biological carbon fixation via photochemical means - there is a good amount in various reconstituted/cell-free systems, of course, and certainly there is plenty of fully 'artificial' research into particular aspects of the photosynthetic machinery (e.g., people looking at organometallic complexes as catalysts for water oxidation), but not the entire overall reaction.

If you take a look at photosynthesis and biological carbon fixation, you'll see that while it is easy to write the overall reaction, it masks the fact that nature accomplishes this with a variety of proteins and protein complexes - it's not just having to find a 'technical' substitute for one or two proteins that do it all.
Jun18-14, 08:24 AM
P: 19
Serious: we work on a technical conception which applies sun radiation and air as in my introduction indicated. After unusal high heat rates measured, there was the guessing, if it could be a photosynthetic process developing that extra energy. However, we try to identify the cause of that magic results. Any interest to join in into this adventure as accompaning our experiments??

Mike H
Jun18-14, 09:57 AM
P: 485
Glucose Photosynthesis

Photosynthesis is about the conversion of solar energy to biologically available chemical energy - it is not some additional source of energy in addition to solar energy.

I am not certain you are claiming this given your phrasing, but if you think you are getting more energy out of this process than you are putting in, you have a problem with the laws of thermodynamics. If you are not, then you will almost assuredly have to explain further what you are doing in detail if you expect any useful feedback.
Jun18-14, 10:25 AM
P: 19
I fully agree with your explanations. What i am talking about is a latent heat storage, having an exceptional capacity of 1000kJ/kg of the storage material compared to about 300kJ/kg of ordinary PCM. Our PMC is charged with sun radiation and air passed through. It is discharged with moisture air. Any idea what could be the cause of the large difference, except wrong meaurements? The air outlet temperature of the storage is approx. 10C higher than the inlet and the operation range so far tested is between 1 and 15C of the ambient air.
Jun18-14, 10:26 AM
P: 19
PCM = phase change material
Mike H
Jun21-14, 11:24 AM
P: 485
Quote Quote by ovacs View Post
I fully agree with your explanations. What i am talking about is a latent heat storage, having an exceptional capacity of 1000kJ/kg of the storage material compared to about 300kJ/kg of ordinary PCM. Our PMC is charged with sun radiation and air passed through. It is discharged with moisture air. Any idea what could be the cause of the large difference, except wrong meaurements? The air outlet temperature of the storage is approx. 10C higher than the inlet and the operation range so far tested is between 1 and 15C of the ambient air.
Obvious questions (been swamped at work lately) -

1.) Is this 1000 kJ/kg PCM the same substance as the 300 kJ/kg PCM but 'charged with sun radiation and air passed through', or is it a different substance?

2.) Is the air that is used for charging the same as is used for discharging? I am not sure what 'moisture air' is here.

3.) Probably the most obvious - are you comparing a 'charged' PCM sample fresh from being exposed to sun (and heat) to a 'cold' off-the-shelf PCM sample, and it's just the fact the 'charged' PCM has been getting warmed up and is re-equilibrating to ambient temperature? You need to 'charge' the PCM, let it cool down to ambient temperature, and then compare that to a 'cold' off-the-shelf PCM sample.

Hope this helps.
Jun22-14, 12:21 PM
P: 19
1) Same substance: animal fat consisting of hydroxy acids (C8-C41) and dihydroxy alcohols (C14-C36)
2) Same air for charging and discharging but higher % moisture for later as there is no sun heating.
3) There is no heat energy produced from PCM due to temperature difference but from phase change of moisture: water steam of the air condensed. However, the amount of energy is multiple higher than this phase change and common adsorption energy. Therefore again, could there be involved a photosynthetic reaction with respiration if we consider some fat molecules as proteins capable for this cycle (Krebs)?
Mike H
Jun24-14, 10:55 AM
P: 485
I'll be honest - I find myself with more questions than answers, and I'm feeling like there's a lot that should have been done well before this point in the experimental conception and design.

Regarding the animal fat - is it all from the same 'batch', or are you comparing across samples that possibly have different proportions of hydroxy acids and dihydroxy alcohols?

How are you actually testing these samples? Your supply air (which should be the same air you ideally use for any charging procedure, IMO) should have a consistent moisture/oil content and pressure (with some modest fluctuations). I don't see how heating from the sun could affect it, as the laboratory should be at a fairly consistent temperature.

Speaking of which, what is the 'charging' procedure in detail? If it's not reproducible/consistent, that's a problem as well.

I am still not sure if you understood my earlier question clearly - if you run these tests at, say, 298 K, is everything at 298 K when you start? That is, if you take a freshly 'charged' sample that has been exposed to the sun for some period of time and is now, say, 310 K, you need to let that sample cool down to 298 K before you start.

Also, photosynthesis or the Krebs cycle (not the same thing) doesn't make very much sense given the composition of these samples. However, lipids and fats are known to be sensitive to ultraviolet and visible light, and are often stored in dark-colored containers to protect them from photochemical degradation. That is a far more likely scenario, presuming it's not one of the issues I raise above.
Jun24-14, 02:12 PM
P: 19
Thanks for your response. I may send a drawing about the set up of the experiment. But for now: It is always the same fat, which is on a substrat of saw dust. During a sunny day, the fat covered substrat is warmed up from the sun's radiation, which consiquently heats up the air passing the saw dust bed. This is called charging the PCM but it is in fact a drying process as the warm air is moistured from water evaporated from the fat covered saw dust.
During night, when there is no heat furnished to the bed of saw dust, the air moved through gets heated up as it is dried from the saw dust (condensation and also adsorption energy is set free*).
Except sun radiation during day time, there is no difference of the set up and the operation of the experiment: same ambient air, same PCM bed, same flow direction of air, same flow amount of air, not even a stop between charging and discharging is applied, it switches by it self from one to the other mode...
Regarding the temperature of the 'sample' or PCM, it always takes the temperature of the passing air with a unkown difference, otherwise it could not transfer heat in and out to the passing air.
* these energies are measured as the temperature differences between in- and out-flow, but as said, much higher than could be expected compared to ordinary PCM materials
Mike H
Jun25-14, 11:51 AM
P: 485
So you have a layer of lipid on a layer of sawdust, all of which is exposed to the environment? Is this material directly exposed to the air and sunlight, or is it in some sort of container? Is there any effort to measure the day's irradiance? I think you need to control for possible variables far more carefully than what is described here, especially if you expect to convince anyone of the claimed latent heat measurement. You might want to take a look at this article for further information on PCM testing and design for various applications, if you haven't already done so.

Honestly, I'm going to bow out of this thread, as it seems to be going down a rabbit hole I'm not all that interested in going down. Given that you've got fat and sawdust exposed to sunlight, I'd be looking at regular photochemistry as a contributing factor (presuming more careful consideration and experimental design don't do the trick) - not purely chemical mimicry of photosynthesis and cellular respiration.

Good luck.
Jun26-14, 01:12 AM
P: 19
Thanks Mike to go down the hole so far.
There is no need to push a sientific explanation about the measured figures we have observed.
From an engineering point of view, we can work well with the results found.
Compared to the potential competitor who also works with water and whose numbers are far of scope by giving 1000times higher values than realistic: 30kJ/g instead 30kJ/kg as enthalpy per mass of heat storage material. See abstracts and publication below.

Adsorption/desorption of water vapour on raw Saudi bentonite (RB) is proposed as a heat energy storage. This is most readily achieved by adsorption and desorption of water vapour on RB at different temperatures as a function of time. The RB subjected to preheating temperature of 200 C, before subjecting to the adsorption process carried out. The IR spectra of RB before adsorption of water vapour at 298 and 313 K were studied. The adsorbed and desorbed water vapour from bentonite surfaces at 298 and 313 K was determined at different time. The adsorptive capacities of RB sample at 298 and 313 K were 0.0097 and 0.0141 mol/g of dry RB, respectively, after 72 h. The desorbed amounts are 0.0085 and 0.01 mol H2O/g of RB at 298 and 313 K, respectively after 72 h. A kinetic models of second order of the adsorption and desorption of water vapour fitted well the experimental data. Application of Vant Hoffs law at two temperatures (298 and 313 K) yields the adsorption and desorption enthalpy. The adsorption enthalpy (stored energy) of RB increased with increasing contact time up to 5 h. At this time the maximum enthalpy was about 30 kJ/g dry bentonite, at which the clay has lost all the energy that could be released due to adsorption of water vapours. Then it shows a decrease in sorption energy when the time increases. On the other hand, the desorption enthalpy increases gradually with the increase of the time up to 72 h then become constant, maximum enthalpy was 14.99 kJ/g. The rate of water vapour adsorption was found to be very high so that the extracted energy from the bentonite surface would not be a problem in any practical utilization of this system.

Energy storage;
Raw Saudi bentonite;
Enthalpy of adsorption: kinetic, adsorption and desorption

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