Wednesday, May 10, 2017

Time that Home Appliances are made available in DC, too.

This Post is somewhat  a  sequel to  my earlier one in Novemeber 2016.

I made certain improvements for better data collection and utilization of electricity generated from my 2 KW roof top PV panels.

1) Extended the connection to Ground Floor with a change over switch and requested the tenents to use solar energy from morning  8 am to 5 pm everyday.  This had improved the average generation from 6.5 kwh per day 8.5 kwh  due to live consumption.

2) I attached a separate energy meter and measured the actual consumption. I wanted to know whether what is being generated is fully utilized or lost something due to inefficiency.

This is where I had a shock to find that only just about 55 %-60% of the generation is accounted in useful work. A closer watch helped me to understand that 25 to 30 % is lost in the MPPT inverter which goes on converting DC to AC  or AC to DC back and forth.

My search through internet revealed that each time  when this conversion takes place, there is a loss of 12 %. To put it simply  1) Solar to Inverter ( DC to AC)- 12% 2) Inverter to Battery ( AC to DC) -12% and  again Battery to Inverter ( DC to AC) another 12% ie  about 36% . This may vary with type of electical load, time of utilization, temperature etc.

Just see the values I recorded recently below :

What is shown in the red color is the consumption by the inverter for every kwh (or units) it deliverd. This is pretty constant showing that we are losing  0.41 kwh for every kwh used.  That is HUGE !!

What I understand is that, it is inevitable if we continue to use  230V AC home appliances. Best way  to reduce this loss is, to use appliances that run on Direct Current (DC).

Incidentally the DC appliance needs lesser energy compared to AC appliance to do the same job. For example  a 60 watt, AC ceiling  fan  can be replaced by  27 watts DC ceiling fan. This is attributed to better torque delivery by DC machines.
  
An interesting study at NIIT Trichy,  published in Dec 2016, showed that to operate a home wet grinder of same capacity, the DC motor needed lesser energy as compared to conventional AC motor.  This in turn reduced the number of Solar panels from 12 to 6 !!   They found similar trend with a dough making machine also.  IIT ( Madras) too taking efforts to promote the concept of Direct Current utiliztion in micro grids  to reduce the conversion losses.   

For a wider acceptance of solar roof top electricity generation, thus, the home appliances need to be made available by the OEMs ( Original Equipment Manufacturers). This also reduces the size of solar panels and overall investment to a great extent. This should dawn on the Policy Makers.

Now, Government  should step in - like they did to promote LED bulbs- through some subsidies or tax incentives to develop and promote DC appliances including refrigerators and air conditioners. This will pave way to decentralize energy generation towards self sustaining economic model.
  
I am sure in a few years this will become a reality and hence  I can do More with my investment than what I originally thought !!

Tuesday, April 11, 2017

Beware of Photoshop(ed) ADs

So much of confusion is created in the consumers' mind with the modern technological tools and many make believe stories are created everyday.

I came across this comparative photos 'Before & After' as part of anecdotal claim to make your teeth white and prevention of yellowing.



While I have no opinion about the product per se, what prompted me to write this post was they are trying to convince the reader using a digital manipulation technique.
It is very easy to see  both the pictures are identical  except for the color of the teeth. Compare the areas of red line on the left with that of right. 

If the product has taken some time to work ( ~ one month, if I recollect correctly) they cannot be identical with respect to light, angle of picture shot etc. 

Those who practice digital art know that it is very easy to change colors with a click of your mouse. It is no magic that the yellow becomes white or even any other color you wish.

Many whatsapp photos are also sent viral by this digital image manipulation. You can see a five headed cobra  or a big temple on a high rise boulder sitting in the lake etc. Whenever you see some unbelievable picture, look for smudge marks around the areas or color patch-up. These may not be visible in a smaller resolution pictures. If we magnify the same in picture editor it will show up. 

I only hope this manipulators don't have time to read this kind of posts. Otherwise in future they become smarter even to get trapped like this :))

Tuesday, January 3, 2017

BHIM vis a vis the Prepaid Cards

Since yesterday I have been trying to configure my BHIM app  in my Calling Lenovo tablet but all in vain.

Though claimed to be simple in operation with simple one line UPI address for cashless transaction my experience has not been satisfactory. I am suppose to receive an OTP which will enable to generate  6 digit UPI PIN.  However I was repeatedly getting Error after  following the procedure of enetering last six digits of my DEBIT/ATM card and its expiry date.

It was falling in to a loop of asking for Debit card digits and showing error in OTP generation. suddenly I received 3 OTPs  all having 10 minutes validity. I entered the latest one and when it came to  UPI-PIN confirmation it once again said 'error ' in accessing bank.

I went to user's review in Google play and was pleased to know that I was not alone and many others have had various other problems.  I am sure it is because of the different models and hardware compatibility things are not that easy and it will take time remove the bugs or it will have natural disinclination from both user and vendor point of view with very limited usage.

Compare this complex process with simple Prepaid Swipe Cards where there is no need for mobile phone ( and hence no model dependent technology upgradation). It is far more easier to configure at the Banks or Post offices with equipments of standard features and network. Only GPRS based POS machines with the vendor enables completes cashless transaction.

Moreover suppose one wants to give children in college or school hostels ( where cell phones are not allowed)  some pocket money the prepaid cards are safe. Aged persons or ladies travelling alone carrying substantial cash in the form of Prepaid Card are more secure against fear of theft or loss by absent mindedness. 

Any technology can become successful only when it is user-friendly. By eliminating the bank-account linking of customer for every transaction (by not employing a phone)  the need for data transfer comes down in the internet highway. This alone may save substantial cost for the banks in making the process feasible  for Prepaid Cards.

Visit the Presentation on Prepaid cards