Challenge Questions

Well without any figures being given...

say the 19" CRTs consumed 100 Watts more than the 17" LCDs

That is 60 x 100 = 6kW of savings...

BUT - if the ambient temperature goes below 70*F then the savings are reduced as the heating would need to replace the 'lost' 6kW.

So there is no simple answer to this.

John.

I'm with you John, insufficient data. You would need an average year-round temperature, and short of knowing exactly how well the buildings insulated, at least a rough figure (preferably daily to compare) on how much cooling and heating was required and cross-reference that to the outside temperature again preferably a day by day comparison.
About 26 years ago I was involved with the building here in Southern California that had all their fluorescence lighting fixtures replace with new energy-efficient electronic ballast units, the boilers hadn't been used in years, in fact they were in disrepair and inoperative, and you guessed it they were screaming for heat the first cold day.

PS. There is a wildcard here I had a building that I remotely monitored, and I found even on are rarer thirtysomething degree mornings the building required cooling, heat load from personal computers was virtually nonexistent 26 years ago.

So there is no simple answer to this.

Indeed. The ambiguities just pile on on top of one another.

In most parts of the northeast US, the time-weighted average annual temperature is less than 70 degrees. In that case, the waste heat from the monitors is, on average, reducing the heating requirement.

But perhaps the building is heated by gas, in which case the dollar cost of heating-by-monitor would be higher than the dollar cost of heating with gas.

On the other hand, perhaps the people sitting near the monitors would get enough radiant heat from the monitors that the overall temperature of the building could be reduced, possibly making heat-by-monitor a good deal: better to heat just the people, rather than the whole building.

Are we nerds, or what??

Are we nerds, or what??

I'm mostly a 'What'

Surely the answer is...
If it's a fait accompli* then WTF does it matter.
If they haven't done it yet, then leave it as a scheduled replacement when monitors fail..why discard working stuff..the 'throw away ' society is a plague.
Unless of course they are donating them to a Worthy cause like the 'Make Bill Gates even more wealthy Foundation'

Del

*Isn't that a new Italian Car?

".why discard working stuff."

Fear of WEEE regulations?(Waste Electrical and Electronic Equipment)

All Eurozone is covered - Is there something similar in the States?

The lead (Pb) content of CRTs is of concern to the powers that be, and costs of disposal are set to rise to ridiculous levels. Most companies are replacing CRTs now, as end-of -life disposal for NEW items is now the problem of the SUPPLIER, so it sort of makes (financial) sense to switch to new products covered by the new legislation and turf the "old" ones while they can still cheaply go to landfill..... much more environmentally friendly????

But whose energy are we saving anyway?

Fear of WEEE regulations?

That makes NO sense...
We are frightened of waste regualtions ...so we'll waste some stuff...you are obviously in Management

I guess we are all nerds.

One other thing to consider is that productivity may be lower with a smaller screen. It doesn't take a lot of lowered productivity at perhaps $20/hr to $100/hr to negate any energy savings at perhaps $0.01/hr.

Most of the responses appear to be from engineer-types. This question should be asked of an accountant -- and the answer likely would be, "How much do you want the savings to be?" Because there are a number of factors that can be considered, and what an accountant chooses to include or exclude would affect the resulting 'savings' quite a bit. (As has already been alluded to by other posts.)

In addition to some of the factors that have already been suggested is the 'factor' of whether the company's MIS department requires that all monitors go into power-saving 'sleep' mode when no activity has occurred after, say, 10 minutes. A CRT in 'sleep' mode consumes less power than once displaying an MSWord document.

The accountant might also suggest waiting a year or so until LCD monitors using LED lighting are available, since LEDs are now available with better efficacy than fluorescent lamps. LEDs are being used in some home TV-LCDs and in special industrial monitors, and the PC monitor market will see them soon.

And if the company is really concerned about saving a few $$$, why not set the thermostat to 72F in the summer and 68F in the winter? And switch to a 4-day work week. Those two changes in company operation would likely save a lot more money than changing-out the monitors.

I wanted to give this a thumbs up, but apparently responses to 'off topic' are precluded.

Answer: Never

Reason: LCD monitors contain mercury. Any savings gained by reduced electrical usage will be overcome by legal fees required to defend against Al Gore's onslaught of legal suits.

It will be Company X vs. Man-Bear-Pig and it won't be pretty.

So do most of my fillings in my teeth but I am not to worried because it as a compond just like in the monitor!!

The mercury in the lamps is not in a safe compound

I don't know how long it would take to pay for the completely as there is listed no cost of the new LCD monitors or the local rate per kilowatt charged by the utility company. The biggest factor in length of time may be the use habits of the workers. With 60 monitors going switching to sleep mode when unattended. For unknown lengths of time.

But I do know that the energy savings will start paying for the new LCD monitors immediately.

But I do know that the energy savings will start paying for the new LCD monitors immediately.

How do you know that??

The building could be in a very cold area with high heating costs... So the loss of 6kW of waste heat from the old CRT monitors would need to be replaced by the heating working extra hard - and costing more?

There is just not enough information.... a bit like the school boy homework questions we get on here.

John.

hmmm,

Northeast US... Near Gulfstream huh? Is it possible our company is paying only for cooling ??

CRTs should be hot enough to feel like an oven. I'll take the 80% of energy converted to heat with CRT, and say heat of 5W LCD dissipates(i'm working for the director of company!).

A desktop CRT of 19" consumes 100-150W, averaged to 125W.

An LCD of 17" consumes 30-50W, averaged to 40W.

Our company consumes 85W-h less than that of CRTs, per hour. And the coolers operates less duration than that of CRTs exists. I'll take the energy counterpart of this offtime of coolers as 125*80% = 100W. (excellent! we found nonrounded round number, i'll not get also into account the efficiency of coolers etc...)

The total gain of power is 100+85-5=180W per monitor = 0,18 kW.

Say cost of electricity is 10 cent per kW-h, this yields 60*10*0,18 ≥ 1$ per hour for 60 monitors.

How much is a LCD of 17" nowadays? I'll throw it as 200$. Money that company spent is 12.000 $. Period to reclaim this money will be 12000 hours = 500 days.

Assuming this company is working so as 7/24, the 12.000 usd has been taken back after 16 months!

This is the director's decision, it does not seem worthwhile though.

Northeast is about New York or Boston at a guess feridun,

Gulf stream is much further south - near the gulf

Also your maths is assuming a great deal and flawed.

John.

Looking from Istanbul the distances are very little, trust me!

flaws.. Ah! How to find floors with basement falled down?

Best regards

f.h.

Yes they will save electricity but I just had a rude surprise on my LCD. Yesterday I came home from work and there is a blue vertical line down across the center of my screen. Seems that one of the blue column driver transistors fried on. The monitor is no more than 18 months old and of course works fine otherwise. My last monitor, a CRT lasted for 7 or so years and is still working fine where I donated it. I just wanted more real estate for CAD (1200x1600 LCD) but I guess I will have to look at life expectancy with my next purchase. Factor that into your calculations!

This must be that called bad chance!

What about the warranty my dear?

<What about the warranty my dear?>

Yes, it's under warranty, but the manufacturer is trying to get me to take a smaller screen in exchange. This looks interesting! I'm not out of the woods yet.

commercial logic!

They are the same wherever they are.

Unlucky Guest.

I've had my 17" LCD for over 5 ½ years working 6 hours a day and so far its never had a problem.

My last 17" CRT blew its line output transistor after only 2 years!

I guess its the luck of the draw...

John.

"...and there is a blue vertical line down across the center of my screen."

Otherwise referred to as a 'calibration mark'.

If your LCD is an older style TN LCD, in which the LCD is white in the off state and is driven black in the on state, then the blue line may simply be due to an unstuck flex connection at the edge of the LCD for that column of blue sub-pixels. You might be able to apply a slight squeeze and get it to re-connect.

Newer in-plane-switching or vertical-alignment LCDs are normally black, and are driven white in the on state. If the LCD is this type then you're probably right about it being a stuck-on transistor. Too bad.

This is unlikly the case as each pixel uses its own transistor they moved away from coloumn/row driving years ago ... more likely a dry joint as i have seen on many monitors... Also maybe just your video card try a different colour setting ie 32 bit colour to 16 bit colour you mind it is that !!!

I think what they save over the summer they'll lose in the winter, so they'll break even.

Mark

There will be savings, but probably not enough to pay for the LCD screens within their lifetimes. So it's clearly not a winner financially, unless there are other reasons for making the change.

In winter they will have to replace the saved heat using some other source; but, unless they use the crudest electrical heaters there will still be overall savings, as electricity is by far the most expensive source for daytime thermal power (electrically-driven heat pumps might be economical, but that is not what happens in a CRT or LCD display). So at least half of any direct electricity costs should be saved in the winter. The savings in summer will exceed the cost of the electricity saved directly by the change-over, because the air conditioning also takes power..

What is the companies job?

sometimes, LCD monitor cannt replace CRT monitor on functions.

if can replace and dont effect on work, sometines even can reduce number of the monitors and computers to save expence and energy.

is the 70F an average or constant in a year?

What lamp do they use? do they use ERPii for their managment? all need to considerade.

too vague to give answer.

this thread may be making a kidding

I have to agree with most of the other posts, there is insufficient data. In the north east the temperatures can very greatly over the area and from year to year. Last year Pennsylvania only had a couple of 0 to 10 degree F temperatures and most of the winter the temps were above 20 degrees F. If you go farther north you will get colder temps.

As mentioned a lot of the modern buildings are always in a cooling cycle as the bulk of the heat load is the lighting in the building. Also you have copy machines which have on average a 1000 watt heater in them. Another thing to consider is that most airconditioning designers take into account the quantity of human beings in the building, as most of the airconditioning load is used to reduce the humidity expelled by humans. Another issue here can be that many of the more modern AC systems control the humidity and to reduce it the AC systems sometimes have to add heat, even in summer to acheive that.

All things considered, this is a question which is unanswerable. I think the main intent is to encourage dialog, not to get a pat answer.

Cowards! (Although there is clearly insufficient data to do a thorough job, we can still give some indication.)

The office is maintained at constant temperature, so we know there is air conditioning. Heating energy costs for air conditioning used as a heat pump are comparable to other sources, so we can use that as an indicator.

In order to allow calculations, I propose the following additional assumptions:
a) that the air-conditioning is the only source of heating/cooling, and is used as a heat-pump in winter, and that the average pumped energy (summer and winter) is 300% of the input power
b) that the monitors cost them $150, and they pay 12.5 cent/kWHr.
c) that the difference in consumption is 100W for an average eight hours each working day.
d) that the office needs to be cooled for half the year and heated for the other half (this will change according to the heat-load, but is better than nothing for a first estimate)

So the CRT would have directly consumed about 10 cents worth of additional energy each working day.

During the summer, the air-conditioning would consume an additional 5 cents
During the winter, 2.5-cents would be saved from the heat-pump drive.
N.B. that this indicates that moderate variation in temperatures would not change the result by a great deal.

So, over the year, the average additional energy cost due to the CRTs is 12.5 cents per working day; assuming 220 working days per year, we have an annual saving of $27.50.

That makes the payback time (from energy alone) about 5.5 years, based on historical energy costs**. It doesn't seem to be very sensitive to small changes in annual temperatures.

**Given the life of LCD displays, that is probably too long to be viable unless it allows the company to expand without upgrading the air-conditioning; on the other hand, prospective rises in energy pricing might halve this time over the coming five years; and of course there will be additional savings in the maintenance cost and down-time of the air-conditioning system.

First! I was in the business of retrofitting lighting for 14 years with new energy efficient technology as well as motors CRT shut-off hardware and what have you.

The determination has to be made on the value of the new 17" monitors vs. the 19' monitors against the anticipated savings. 100 watts @10hrs/day times 260 work days. is 260kWh (kilo watt hours.) At 20 cents/kWh the savings would about $52/year. The 100 watt differential seems high!

There would be a reduction in air conditioning and an increase in heating which at todays cost of fossil fuel might be a wash. If the "new" monitor cost is about $200.00 your pay back period is about 4 years. By that time LED and/or organic led monitors will be available and, in my opinion, would be the time to replace them for a greater savings as well as end-of-useful-life of the 19" monitors.

In my opinion it doesn't make good financial sense.

Look for other ways to save energy! Check your present lighting system to determine if new lighting technology will give you a greater savings and pay back period. Make sure the HVAC systems are well maintained and replace failed equipment with the latest energy saving equipment.

Good luck