Free cooling Systems

[kwired]

I mentioned in the OP free cooling systems were installed in telephone exchanges.




I already suggested it is an idea of brainstorming.



Do you believe electrical aspects of the problem are already thoroughly discussed or not?

I know you said where they were installed. You wanted to know why you have unexpected readings as compared to a previous period. The only way you will get an accurate comparison is if all conditions are the same during both periods. When I asked what exactly was measured that is what I meant. Were you comparing the energy used by cooling equipment only, cooling equipment and free cooling , the entire facility? If the entire facility, are you certain loads other than cooling were the same? Then comes the temperature and other conditions that may effect how much cooling is needed. If conditions I just mentioned were not the same for both periods being compared you can not determine changes of efficiency as you are not comparing the same conditions.

Most of this discussion (other than your questioning of the accuracy of the meter) is about energy concepts, and not necessarily electrical energy. Just general heating and cooling type concepts.

 

[T.M.Haja Sahib]

I

Most of this discussion (other than your questioning of the accuracy of the meter) is about energy concepts, and not necessarily electrical energy.

What is your stand on disk type KWH meter errors (preferably after your doing a little reasearch on the subject!)?

 

[broadgage]

I would agree with the many others who state that rotating disc type KWH meters have a good record of accuracy.
And if the meter IS reading high or low, I would expect that the error would be broadly similar no matter what cooling system was used.

As regards the energy saving by using outside air instead of mechanical cooling, this is very variable and experiment is indeed the way to proceed in order to determine the usefullness or otherwise of the idea.

I would be inclined to use free cooling and mechanical cooling in alternate weeks, reading the KWH meter each week.
Dont take too much notice of the readings initialy, since the weather can vary a lot from one week to the next. After perhaps 20 weeks, an average KWH consumption for "free cooling" weeks, and "mechanical cooling" weeks should give a good idea as to the viability of the idea.

 

[T.M.Haja Sahib]

I

I would be inclined to use free cooling and mechanical cooling in alternate weeks, reading the KWH meter each week.
Dont take too much notice of the readings initialy, since the weather can vary a lot from one week to the next. After perhaps 20 weeks, an average KWH consumption for "free cooling" weeks, and "mechanical cooling" weeks should give a good idea as to the viability of the idea.

The difficulty is the Telephone Exchange equipment need temperature and humidity to be maintained within definite limits.The free cooling system can not do that at all times.

 

[kwired]

What is your stand on disk type KWH meter errors (preferably after your doing a little reasearch on the subject!)?

I can not speak for where you live, but here there is weights and measures laws when it comes to commerce. If you are selling 1 gallon of something it better be one gallon. Slightly more is accptable, slightly less is not. Measuring devices are periodically checked for compliance. To the seller they do not want to sell more than 1 gallon because that is lost revenue, but they also don't want to be penalized for selling less than one gallon so they try to be as exact as possible. Same applies to sale of electrical energy. If these meters were very unreliable they would have disappeared a long time ago. I don't feel I need to do much reasearch because of what I just said, the power companies alread know this and it is why they still use these meters in many places.

The difficulty is the Telephone Exchange equipment need temperature and humidity to be maintained within definite limits.The free cooling system can not do that at all times.

That is what I have been trying to point out. The actual amount of cooling needed by the primary system verses the alternate system will have an impact on how much energy passes through the meter. If the alternate system can not keep up with cooling demand then the primary has to take over. You have failed to indicate if the cooling demand requirements are the same for both periods being compared. That is also why I said it is more of an HVAC question than an electrical question. The only thing electrical about this is the fact that both systems use electrical energy to operate. The amount they use has to do with HVAC design issues.

 

[T.M.Haja Sahib]

I don't feel I need to do much research because of what I just said, the power companies already know this and it is why they still use these meters in many places.

You are wrong.Power supply companies have started to replace such meters by electronic meters in many parts of the world (India is one of them).Accuracy issue is one of the factors.

 

[kwired]

You are wrong.Power supply companies have started to replace such meters by electronic meters in many parts of the world (India is one of them).Accuracy issue is one of the factors.

Accuracy may be a factor, but it is not because of sudden inaccuracy, outside some unusual physical damage. Lenght of time between calibrations is likely more of a factor. As I said weights and measures are pretty strictly monitored when it comes to commerce in the US. I never see a public service empolyee checking electric meters, but can assure you they are checked somehow, the power companies can not afford to have them be inaccurate. If they are found negligent it will be big fines. I do see weights and measures guys at gas stations all the time measuring the accuracy of the fuel dispensers, I also see them from time to time inspecting weigh scales from the grocery store scale at the cashier to large truck weighing scales. You do not want to be outside of their tolerances which is not very much.

 

[T.M.Haja Sahib]

Accuracy may be a factor, but it is not because of sudden inaccuracy, outside some unusual physical damage. Lenght of time between calibrations is likely more of a factor. As I said weights and measures are pretty strictly monitored when it comes to commerce in the US. I never see a public service empolyee checking electric meters, but can assure you they are checked somehow, the power companies can not afford to have them be inaccurate. If they are found negligent it will be big fines. I do see weights and measures guys at gas stations all the time measuring the accuracy of the fuel dispensers, I also see them from time to time inspecting weigh scales from the grocery store scale at the cashier to large truck weighing scales. You do not want to be outside of their tolerances which is not very much.

May be a factor in developing and developed country?

 

[kwired]

May be a factor in developing and developed country?

Maybe but the meter in your OP if it is inaccurate, is likely still consistant. So you should still get an idea from one period to the other for the comparison you are looking for. I merely brought up the point that other factors need consideration before assuming one period was more or less efficient than the other. Run time is not a sure way to determine how much power is used either. The more heat a refrigerant compressor is moving the more energy it will consume as it is working harder. So you do need to know what the actual cooling demand was to know what kind of effeciency you have.

 

[GeorgeB]

May I assume that you would be less critical, if you assume yourself in a brainstorming session and ...

Please ... I'm not being critical. Even when brainstorming, it is, TO ME, useless to say ... I used 450 therms in 2008 to heat, and only 405 in 2009 without AT LEAST saying that the number of degree days was the same, and that my set-back thermostat had not been changed to different settings, and oh, by the way, my electricity consumption went up be 4% and the new roof is black the old was white, and oh by the way, we added 200mm of insulation, and there were 5 people in the house then and 2 now ...

There must be a reference, IN MY OPINION, on which to base even brainstorming. Now my son has a degree in Operations Research which, to my piddling brain is described as estimating solutions when there are more unknowns than equations ... but even then, they know what they don't know.

Shamelessly stolen elsewhere,

---------------
There are four sorts of people in this world.

There are those who know not, and know not that they know not.
They are fools, shun them.

There are those who know not, and know that they know not.
They are simple, teach them.

There are those who know, and know not that they know.
They are lost, guide them.

Then there are those who know, and know that they know.
They are wise, follow them.
------------

Let us know what we know and not "blow smoke". To me, what you suggest is not gaining knowledge, rather confusing others.

 

[defears]

Switching to electronic meters is NOT because of accuracy. It's because we get way more useful information from them. You can get peak info easily and be able to shut-down air conditioners when needed. The meter reader also gets to sit in the truck to read it, and I've heard of some connecting to the web so you don't need a reader and get more up to date info than before.

 

[T.M.Haja Sahib]

Please ... I'm not being critical. Even when brainstorming, it is, TO ME, useless to say ... I used 450 therms in 2008 to heat, and only 405 in 2009 without AT LEAST saying that the number of degree days was the same.......

That is against the principles of brainstorming:whatever that comes to the mind regarding the subject under discussion should be expressed without minding about its constraints.

There must be a reference, IN MY OPINION, on which to base even brainstorming.

Yes.That reference is the subject under brainstorming.

There are four sorts of people in this world.

There are those who know not, and know not that they know not.
They are fools, shun them.

There are those who know not, and know that they know not.
They are simple, teach them.

There are those who know, and know not that they know.
They are lost, guide them.

Then there are those who know, and know that they know.
They are wise, follow them.

Shall we agree that we both are in the last category?

 

[GeorgeB]

Shall we agree that we both are in the last category?

You may be; I vary between the 2nd and 3rd.

 

[iwire]

Shall we agree that we both are in the last category?

In my opinion there are very few fourth category people and people who think they are in the last category more often than not are actually in the first category.

I would put myself in the second and depending on the subject matter occasional trips into the third category.

 

[kwired]

In my opinion there are very few fourth category people and people who think they are in the last category more often than not are actually in the first category.

I would put myself in the second and depending on the subject matter occasional trips into the third category.

I find myself in all four categories. I can be in the fourth one minute and in the first the next minute. After that I kind of progress to second and then third and eventually it starts all over again

 

[T.M.Haja Sahib]

I find myself in all four categories. I can be in the fourth one minute and in the first the next minute. After that I kind of progress to second and then third and eventually it starts all over again

It is hard to find by yourself in which category you are at present .I think the category''There are those who know, and know not that they know.
They are lost, guide them.''should be''There are those who know, and know not that what they know not.They are lost, guide them.''
and then that would be hardest if you are actually in the third category.I am one such person to find my position by myself.

 

[T.M.Haja Sahib]

I would put myself in the second and depending on the subject matter occasional trips into the third category.

Listen iwire,
You did not know about yourself.
You,as a child, would have been in the first category at times.

 

[George Stolz]

Enough.