The Electrical Harmonizer 4

[djohnst]

A supplier is offering to sell us an Electrical Harmonizer which he claims "Optimizes incoming voltage to appropriate utilization level" for energy cost savings.
This device is actually a step-down transformer that reduces the voltage by about 6% from say 485 volts to 455 volts, the idea being to reduce the voltage to a level that is still within the operating range of the equipment within our building, but since P=E*I reducing E should result in lower P consumed and thereby lower energy costs.
The supplier has impressive documentation that confirm the savings.
My questions: Has anyone had good or bad experiences with this type of product? Does anyone know the long term effect of operating equipment such as fluorescent lights, or chiller, fan and pump motors with variable speed drives at slightly reduced voltages?

 

[ScottyUK]

itsmoked,

Way off thread but just to prove the silly exchange above has some worth:

Which manufacturer makes that breaker design? I have a number of aging Westinghouse HMCP's which originated in the US that are getting tired after 13 years in service on some very high fault level boards. The HMCPs are strikingly similar to the picture - so similar that they are visually identical. I need some replacements.

In Europe Siemens currently market their 3VFxxxx series which is physically a drop-in replacement for the HMCP - the casing is probably from the same mould tool - but this range is going to be end-of-lifed fairly soon according to our Siemens rep. I've also seen one of this design with an A-B badge and pricetag which I won't pay. Who else makes 'em?



----------------------------------

One day my ship will come in.
But with my luck, I'll be at the airport!

 

[itsmoked]

Disgusting! Trying to get something worthwhile out of our Harmonizing discussion!!? Tisk tisk.


Well to be honest I just when willy nilly searching for a picture of a breaker. I went to SquareD my favorites, but it looked tedious due to Schniders lousy site. So I went back to google and hit the next thing I saw.

http://www.circuitbreakersurplus.com/Eaton-Cutler-Hammer-grp-31.html

It got me this list..I picked the first item. I know nuthin about the breaker but I hope it helps.

 

[davidbeach]

The breaker is a Eaton (Cutler-Hammer) breaker. Cutler-Hammer is/was a subsidiary of Eaton, and when Eaton bought the non-T&D portions of Westinghouse in the early 90's, those lines all became park of Cutler-Hammer. Now Eaton seems to be phasing out the Cutler-Hammer name in favor of Eaton Electric.

But anyway, they have the old Westinghouse breaker lines.

 

[ScottyUK]

David / itsmoked,

Thanks. That makes a lot of sense - our board was made by Ottermill who were a Westinghouse company and later became part of Eaton group.



----------------------------------

One day my ship will come in.
But with my luck, I'll be at the airport!

 

[RiverBeaver]

Folks, I am new around here, and this topic caught my eye while browsing. A little clarification is in order based on my experience with it:

I work for an electric utility. Some utilco's lower voltage as a peak demand and/or energy saving measure. We don't, but we have done tests to understand the dependency between load and voltage. On a substation-wide basis, meaning a mix of residential, commercial and industrial facilities, we see a long-term L-V dependency of 0.7. This means for each 1% voltage is reduced, there is a 0.7% energy reduction. We refer to this as conservation voltage reduction (CVR) and it is exactly the same principle that the Harmonizer works on.

The difference is the Harmonizer is targeted at high-potential commercial facilities. In some cases like retail stores and malls with lots of incandescent display lighting the L-V dep. can be as high as 1.4. This creates significant operating cost savings by simply reducing voltage a little. We've monitored installations of the Harmonizer and it does work. There have been about 10 installations that I know of in our service territory and the energy savings have been verified at between 5 and 8%.

All lighting, with the exception of a small number of constant-power ballast models, saves energy when voltage is reduced. Motors that drive ventilation fan loads also consume less because the motor draws less magnetizing current. This causes slip to increase, and we know that fan power is related to the cube of it's speed. Did I mention power factor is improved?

Here's the real kicker: utility engineers are a conservative lot. We like to make sure the voltage is on the high side coming out of the substation so the customers at the end of line don't get low voltage. This means that customers in close proximity to substations get voltage that is higher than necessary for their equipment to operate. Optimizing voltage to match equipment requirements has real and measurable benefits in both energy savings and equipment longevity.

The Harmonizer is expensive and certainly isn't for every customer, but those that operate above nominal voltage and have a high percentage of lighting load can easily achieve a payback in the 3-5 yr range depending on local utility rates.

 

[itsmoked]

RiverBeaver welcome.

An interesting viewpoint that makes some sense.

Being someone who hates dimness, actually leaving some restaurants because I actually prefer to see fire exits, menus, my family, AND THE FOOD, I shudder at the thought of reducing lighting. However if the voltage is high then the lighting is probably high too so it makes sense.

I like your CVR number 1% -> %7 to 1.4%. Nice to know.

 

[jraef]

RiverBeaver,
You make a good point. I think that perhaps our (particularly my) cavalier attitude towards this thread has come off as seeming as though the entire concept is flawed. It is not, and I apologize for my part in that.

Certainly everyone can agree that lowering voltage in lighting applications saves energy, because essentially the brightness of lighting is the "work" that the lighting system performs, and less work consumes uses less energy. Dimmers have proven this without question. You must agree however that the concept is predicated on everyone agreeing that less light is OK, and often it is not. Studies have shown a direct correlation to lighting intensity and even color temperature to sales volume in retail settings. Manufacturing facilities get better production at proper lighting levels. Office environments get better productivity, warehouses get fewer errors and the list goes on and on. Certainly this does not mean that more light is always better, but proper lighting design is essential, and there are specialists in this field who are often brought in by the architect or interior designer to properly engineer this. Coming in and unilaterally dropping voltage to save energy may in fact make that all for naught. Lowering voltage in a facility that then goes out and installs more light fixtures to make the work surface more useful is counter productive.

I also want to offer a bit of a challenge to your assertion on the motor energy savings as well. IF the facility has high voltage to begin with, you'll get no argument from me, but at 485V, I would hardly call that high. For 460V NEMA design motors, that is well within design tolerance of +10%. At rated voltage the savings are only present if the motor is lightly loaded, and it is better to just turn them off. Voltage reduction in motor loads must be tied to a reduction of load or it is inherently counter productive.

From the standpoint of the supplying utility supplying a large area, lower voltage probably does make sense. Here in California CVR is used often when there is a risk of a brownout. For each individual facility in that service area however, it has the potential to do more harm than good but it is a temporary measure only, and effects on customers are part of the risks we must all take when the system is strained. Permanent reduction is another story. The OP never mentioned incandescent lighting as a load concern, only fluorescent, and not all fluorescent fixtures can tolerate much of a voltage drop. As to his chiller, pump and fan motors, if the load on the motor remains the same, lower voltage will mean lower torque, which means more slip, which means more energy to keep that same load spinning. In addition, that 485V measurement may have been made at the switchgear in the basement, but by the time it gets to a chiller on the roof it may be down to 460V. Reducing the line to 455V would reduce the terminal voltage to 432V, which would reduce flow significantly, possibly causing the chiller to run longer (and hotter) etc. etc. Finally as to the motors fed by VFDs, input voltage reduction within the tolerance of the VFD specs is essentially neutral, no harm, but no savings either.

The point we were making is that devices and systems such as this are often sold as being the all encompassing solution to energy problems for everyone, and in fact they seldom are.

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[stevenal]

Okay, if reduction to zero is too extreme, why not ask your utility to reduce the voltage a little? Many of the larger distribution transformers are equipped with adjustable taps. Nothing to buy, and no additional losses from the harmonizer itself. Can also be undone if you find energy use goes up do to the additional losses of the motors, and all the additional lights being plugged in. If talking about utility feeder voltage reduction, check out

http://www.beckwithelectric.com/infoctr/appnotes/App16.pdf.

In general, only demand shows significant reduction. I am doubtful that applying the results of utility feeder voltage reduction to an individual facility is valid. Have you talked to your utility? Often they can suggest ways to reduce your bill.

http://legendpower.com/

is impressive with all the approvals, etc., but it seems like a shotgun approach. One device addresses harmonics, pf, overvoltage, voltage balance, ect. Why overmedicate if you don't need to?

 

[djohnst]

Thanks RiverBeaver
I assume that most Utilities supply power to customers through a step-down transfomer that has taps to adjust the output voltage. Couldn't customers achieve the same energy cost savings by having the Utility adjust the voltage taps lower at presumably much less cost?

 

[jraef]

I think that's what stevenal just posted.

 

[TheBlacksmith]

I had a facility that was very close to the generating plant and we were burning out one or two power supplies a week. We just lowered the voltage by using the taps on the incoming transformer. Didn't check to see if we saved energy, but we saved a lot on power supplies.

Blacksmith

 

[RiverBeaver]

Sorry, I was out of town for a few days. A few loose ends to tie up here:

1. Lighting design is pretty scientific, but that all goes out the window once the system is in operation for a while. Major variables come into play that affect light levels such as dust/dirt on lens, oxidation of reflector, lumen depreciation of the lamp, and degredation of the ballast. These result in MAJOR reductions of light levels, and hence lighting systems are designed with this in mind. With proper lighting system maintenance, the resulting light levels will surely be well above minimum requirements even after CVR. Even with poor system maintenance, the light level reduction due to CVR is small in comparison so is not noticable by workers in the space. I believe the Legend Power guys take light readings before and after installing their device to ensure light levels are within the acceptable range. (Interesting side note: we commissioned wattage tests of lighting systems in operation for a few years and were simply stunned by the results. None of the lamp/ballast combos were drawing rated watts, and some were as low as 50% of rated power draw. The average draw was 70W for a 2 x 4' fixture that should draw 81W. This huge difference was found by our lab to be mainly caused by the failure of the little pf correction cap inside the ballast. We speculate that the noisier the electrical environment, the quicker the cap degrades as caps are known to fail quickly when subjected to repeated voltage transients. The point I am making is that maintenance personal did not replace these partially failed ballasts because they were "perceived" to be operating normally. If you do some reading on light flicker perception of the human eye this point will become very clear.)

2. Unfortunately I don't have any hard evidence of motor power reduction under CVR, but that is on the to do list for our lab. Most induction motors are considered constant power devices, and certainly any thermostatically or pneumatically controlled compressor motor would not be expected to save energy. I do believe that fan and pump loads will save energy as explained in my previous post. These systems are over-designed similar to lighting, so a little reduction in air volume would be undetectable by the occupants of the space.

3. Many transfomers, particularly dry-type transformers used in large commercial facilities have voltage adjustment taps. The transformers that my utility company supplies to customers on a rental basis do not have taps. Typically these are 300 to 750kVA liquid filled individual cans or padmounts, and hence are the main target market for the Harmonizer. Even if a main transformer has taps, Legend will often specify a Harmonizer sized for the lighting load only so motor voltages are maintained on the big mechanical equipment.

RB.

 

[stevenal]

Excluding the pump and fan examples, most induction motors are roughly constant power devices when measured at the shaft. At reduced voltage, the increased I and (I^2)R losses mean more electrical power is measured at the terminals. The losses also mean the motors run hotter. Does the load in question include air conditioning? If so, more energy is then used to remove the extra heat. For a reference, see Table 3-8 of the Red Book. VCR in this case is an oxymoron. Lower voltage means using more resources to run the motors, and also more resources because of more frequent replacement.

As for lighting; if levels can be reduced, apply my method of voltage reduction to zero to some of the fixtures.

Is facility at the end of the feeder, so it sees wider voltage swings? Maybe the utility is satisfied that the range is within ANSI limits, but customer would like it tighter to keep light levels and losses more constant. Then facility based voltage regulation might make some sense.

 

[jraef]

djohnst (and RiverBeaver),
I must admit, that when I posted my first responses I had not found any specific details in the Harmonizer, I was reacting to the OP’s description of the unit. Now after seeing stevenal's posted link for Legend and reading their available literature, I must say that this unit is different that what I thought it was. They tend to point out the benefits of power conditioning, which I wholeheartedly agree with.

That said, I still have problems with how it is marketed. Their emphasis on "energy savings" is too strong for me. There are very similar systems sold, one by Mirus Int’l comes to mind, that emphasize power conditioning and it’s benefits, but stop short of claiming energy savings other than to mention their Energy Star compliance (which doesn't really mean anything). I grant that under certain conditions in some applications it will save some energy. Unfortunately, marketing people have a tough time selling that, especially to potential investors, and believe me, their website appears to me to be geared more towards luring investors than users, which always makes me suspicious.

I have a lot more to say on ths subject, but I don't want to clog up the thread with a long rant response unless someone is interested.



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[djohnst]

jraef( and RiverBeaver)
I agree,the Harmonizer looks like snake oil at first glance, but on taking a closer look, it seems to have some merit. The references and the case studies at the Legend Power website seem to be good and the tests we've done are good, too.
Energy savings for incandescent lighting at lower voltages is well established-but less voltage = less light output as well.
Energy savings for fluorescent lighting or other ballasted lamps operating at reduced voltage is not quite so obvious to me, but we have operated a facility with 20,000 honeywell fluorescent ballasts on reduced voltage for 25 years with few problems. Yes, less initial light output, but greatly extended lamp life and improved lumen maintenance with reduced energy consumption, so the trade off might be worth considering.
But all of the various motors in the faclities must be operating more efficiently at reduced voltage with the Harmonizer, and I have some difficulty uderstanding why, or if there would be a negative consequence.

 

[jraef]

djohnst,
I agree with your take on it. Here is the rant that I originally decided against posting earlier, I state my case for the motor issue, anomg others.

Herein lies my problem with how they go to market. They are making blanket statements of energy savings, and we all know that there is no "magic pill" that works everywhere with everything. Here are some examples of what I have problems with as an engineer:
[ol]
[li]They appear to tout their listing as "Energy Star" and "BC Hydro Power Smart" partners as being proof of their ability to save energy. This is not what it appears. Literally hundreds of transformers are listed as Energy Star certified. It just means that they don't waste energy in what they are doing, not that they actively save it. My computer monitor is Energy Star compliant, does that mean it is saving energy? It does only in relation to one that doesn't have that rating, but it still uses energy. As to BC Hydro Power Smart, I once got approval from them as a "Power Smart" device for using a solid state overload relay, because I proved that bimetal overloads consumed an average of 9 watts of power per phase, and mine did not. I actually got them to rebate some money to a customer for switching to SSOLs! Shows you how difficult it is to convince them of something being energy saving![/li]
[li] They repeatedly emphasize that they have UL listing, as if UL has approved them and tested their claims. UL only tests it to make sure it does not catch on fire, or actually that if it does, it doesn't catch anything near it on fire. Hardly a testament to it's effectiveness in what it claims to do.[/li]
[li] They make this claim, as if it is another testament to efficacy; "After more than a decade, involving over three hundred thousand installations, there has not been a single claim against the insurers of the Harmonizer." What does that mean? It hasn't caused a liability lawsuit? Big deal. I could make that claim on a light bulb or a wad of gum under the table.[/li]
[li]They make the blanket claim "Reduced energy costs (typically in the range of 7 – 12%)". No qualifications, no details, no explanations, no mention of what types of loads or under what existing conditions that would be true, etc. etc. I love the word "typically" in marketing. The auto industry has thrived on that term, along with it's close cousin "your results may vary". We all know what that really means. You may or may not get what we claim, but don't hold us accountable because we warned you up front. Uh huh.[/li]
[li]Their claims about reducing motor maintenance costs and motor heating are apparently based on restoring balanced voltage to the motors. While this would be valid, the problem I have, again as a blanket statement, is that it
a) Assumes the voltage was unbalanced in the first place, and
b) Assumes you are referring to 3 phase motors. Phase imbalance has no effect on single phase motors!
Avoiding simple conditional statements like that is a sign of someone trying to lead you astray IMHO. [/li]
[li]Thier brochure states "Reduced electricity (kilowatt) demand and kWh consumption: Improved power factor, reduced kVAR demand charges." Again, more statements that are entirely conditional, but not explained at all in their literature. The demand charge statement is a real stretch if you ask me, relating back to my previous post. [/li]
[li]Their testimonials are mostly for lighting loads, yet they are making claims relating to energy savings for motor loads. Sorry for beating a dead horse, but the concept of lower voltage to motors has been shown to reduce energy consumption ONLY with a corresponding reduction in load. If the load stays the same, energy remains the same AT BEST, and in fact efficiency may be lowered. As mentioned earlier, IF the voltage was high to begin with I have no problem with that statement. If, however, the voltage is normal or varies between low to high daily as it does in many areas, applying a permanent voltage drop may actually cause more problems than it solves. Refer to this NEMA chart on voltage effects on induction motors. click here for EASA link Notice that at 10% voltage drop, efficiency drops another 2-1/2% from normal. How is that “saving” energy? In addition, torque, both starting and running, drops 18%! I guess you will save a lot of energy if your load fails to start!

One of their big testimonials is from some British Columbia postal centers, which I can assume are bulk mail handling facilities. If so, they would have a lot of small 3 phase loads on mail amchines, but they run unloaded or lightly loaded a lot of the time. I know because I once sold the US Postal Service on Nola Energy Savers, and they did indeed save them energy because of the specific nature of the application. Obviously the BC Mail centers must not already have had those installed, so the Economizer would work. That does NOT mean it will do the same everywhere.[/li]
[/ol]

The only other positive thing I see that they have going for them is their "No Risk Energy Savings" program, which appears to be a system wherein you share the energy savings with them in lieu of paying for the equipment. THAT would be a good thing, because it puts the onus on them if they want to get paid. Unfortunately they provide NO details on that, nor do they even direct you to another web page to explain it, so it is still a big mystery to me.

Rant complete.

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[itsmoked]

That's a nice summation j!

Thanks for the effort.

 

[djohnst]

I won't comment much on the rant except to say that I agree that Legend is not particularly forthcoming in describing how the Harmonizer works. That may be because all of the benefits they claim could be achieved by other methods without using their product, for instance by changing transformer taps or by applying autotransformers at the loads. ( In fact the Harmonizer looks a lot like an autotransformer to me.)

Reducing the voltage on an under-loaded or under-utililzed motor will save energy. In fact, that's the basis for the Nola energy savers that jraef used. The difference with Legend's product is that they're applying it to an entire facility, and I must admit, it is just not something that would have occurred to me.

For what it's worth this is my reasoning why a slightly lower voltage applied to motors in a large facility with many motors would save energy costs in most cases:

The designer of any system that requires a motor (for example a fan or pump)will choose an optimal motor size based on worst-case conditions, and then pick the next-larger standard motor size. For example, if 3-1/4 hp or 401 hp was the optimal motor size for a system to operate effectively under worst case conditions, the designer would choose a 5 hp or 450 hp motor. In practice this means that most motors in a large facility will be operating sightly under-loaded all of the time.

Secondly, motor manufacturers design their motors to tolerate a voltage variation of plus or minus 10 percent. For a 460 volt motor that is a voltage range of 414 volts to 506 volts over which the motor will operate, but the motor will operate most efficiently at the nameplate voltage. In many facilities, however the would be operating at a higher voltage, say 480 volts, which is 4 percent higher than the nameplate, but still within the tolerable operating range.

As a consequence of the these two conditions, many of the motors in many (not all) facilities would be operating in an over-excited condition ( high voltge) at less than full load, even under worst case conditions, and reducing the voltage would reduce the input power ,and improve the power factor.

Notice that on the EASA curve, a motor operating at plus 4 percent voltage operates less efficiently than a motor operating at rated voltage. So reducing the operating voltage from 480 volts to 460 volts should result in an increase in efficiency.

There would be little or no increase in efficiency for motors that were already operating at their rated voltage or for those motors that were contolled by VFD's.

A negative consequence of this reduced voltage strategy would result if the further reduced the voltage to the facility. Then some of the motors could be operating at less than their lowest tolerated voltage and would not operate properly.

 

[stevenal]

Here's a copy of the Red Book table previously referred to:

http://www.eere.energy.gov/industry/bestpractices/printable_versions/spr2005_motor_table2.html

 

[stevenal]

Here's a little more info on the Harmonizer:

http://www.smud.org/education/cat/cat_pdf/Harmonizer Final Report 9-30-04.pdf

Interesting hypothetical situation on page 6. If CVR has any merit, the following approach might make more sense:

http://www.smud.org/education/cat/cat_pdf/MicroPlanet.pdf