Sounds good, tangible benefits to consumer and engineers. Lets see your updated PPT.
Maybe should address DD actual cost adder and will it use any additional power? Calling it a low cost feature leaves actual numbers open to interpretation. 50 cents 5 dollars? What does it cost? Many appliances have a micro, what is added to make it DD vs something not DD? Be specific.
"wrong end of number-drenched PowerPoint poisoning" Engineers must have numbers to back things up, put them in. If concerned put in appendix, with creditable references. Save the engineers the time looking it up, will make them more likely to follow up on it. (remember saving time is big...)
I am getting to not like energy star willingness to supply 3-4 watts when turned off. If everything draws 3-4 watts were talking 100 watts in my house doing nothing! 24 * 365 * 100 = 876,000 whr/yr or one month electrical bill!
Strongly against investing in Grid infrastructure. With new advances read about in Solar, within next 5 to 10 years, expect the grid only to be of local interest to business/manufacturing. Referring to $1/w solar panels currently in production. New coatings making use of full visible light spectrum converting it to one optional frequency for the solar panel doubling to tripling solar panels output. Power storage in the grid will be the only interest to home owners, they can supply business power during the day, business supplies power at night as payback.
Have fun, Scott Beversdorf.[ Parent ]
The numbers that I have are in my referred-to document (and some are in the notes).
The National Grid estimates that the savings from DD would amount to about £5/customer/year (domestic users).
I estimate that the additional components for DD would cost at most £1 at the factory gate and thus less than £5 at retail per appliance/gadget. Probably much less for something already with a microprocessor, and power consumption could be tiny (microWatts?), and zero when the appliance is off, but that depends on how it has to implement any DD actions.
Anyway, if my guess is right then it implies that as long as on average households don't replace more than one (DD) appliance per year they should be ahead.
I do agree that the numbers (in the Web document) should be tightened up, but I did the best that I could with the information that I had, and even had (for example) National Grid dig out numbers not otherwise readily available! I may have contributed very slightly to the sum total of human knowledge... B^>
This was all just an interested member of the public: no external money, help, status, etc!
Rgds
Damon[ Parent ]
OK, read the web about DD and how it works. Simpler than I expected. Design looks like 60 cents or less for a device without a micro, 20 to 25 cents with micro. (Assumption: has electronic control already etc.)
With that said anything that uses enough power to consider using it, will have a micro for controlling it today. (At least quickly can't think of one)
With the micro were talking a voltage divider and 1 pin of the micro to measure line frequency. Requires a rather stable frequency source, many appliances use the power line for this. Two more pins for the frequency source. 100ppm accurate crystal gives absolute measurement to 50 +-0.1Hz, cost 15-20 cents in millions. 100ppm crystal requires tweaking to get measurement accurate to 0.01Hz. Better crystals can be had for a price. Just what accuracy is needed? (from the webs meter looks like 0.1Hz may be fine.)
On the train right now so can't check,but my sample of UK gtrid frequency every minute for a whole year suggested (IIRC) that DD should definitely be cutting in by about a 0.1Hz drop (with a gradual/stochastic response if possible), so an internal frequency source only has to be a little more stable and accurate than that.
The sort of relatively dumb devices that might not currently be uP-controlled but could be targetted by DD include electric kettles (ie to boil water for tea) and coffee-makers and electric hobs. The former are marginal, but often the cause of demand pickups.
Damon [ Parent ]
My data sample was for a month rather than a year: http://www.earth.org.uk/grid-demand-curves/UK/NationalGridFrequencyData200808-60s.xls
-0.1Hz drop, which is half of the normal operation target and one fifth of the legal limit, does seem to be a reasonably good place to cut in with DD measures and would result in DD activity ~3% of the time at the moment. A -0.05Hz threshold would result in DD activation ~17% of the time.
The device must have a standard to compare line frequency. The ability to accurately measure the line frequency is totally dependent on this frequency standard.
If the actual frequency is 49.9 and the device thinks it 50.000 Hz then your goals may not be achieved.
100ppm crystal Error Math: (100ppm = 100 / 1,000,000 ) * 50Hz = 0.005Hz error is plus or minus or within 0.01Hz range Microprocessor using 100ppm crystal standard can measure 50Hz to within 49.995 to 50.005Hz of actual frequency. 200ppm crystal could be used, couple cents cheaper. About the limit of what you can use. Smallest unit you want to measure is 0.1Hz, then the standard must be 10x better as a general rule (dictated by your needs).
Cheaper frequency standards: resonators and RC are NOT accurate enough. 1000ppm = 0.1Hz range, is better than they can deliver, you need better than that. They are much cheaper.
For off grid appliances may want an override button, their power source frequency may not be accurate enough to let it operate!!
Two factors mitigate however:
Thanks for your analysis!
