Home automation to avoid energy wastage

Please let me know if your co. can provide auto controls for the following problem. I own a vacation home in Lake Placid N.Y. where winter temperatures usually drop to negative numbers every night. I have a tenent occuping a small apartment above an attached garage that has its own zone in a oil fired forced hydronic system. My problem is that the tenent opens the two windows in the apt. and turns the stat to 76 and leaves all day so her cat can get fresh air. I am basically heating the Adirondacks 24/7 when I am not there to shut the windows and turn down heat.

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Retrofit Energy Saving Devices (RESD's) in Kenya

A scheme or scam is being marketed in Kenya, called Electro-Flow Technology, making wild claims about energy saving. I met one of their directors, Mike Merdad, some years ago, when he came to commission a plant next door. When i asked him to give us a straightforward explanation about the system, he insisted on talking about symmetrical components. I wrote my thesis on the subject but to the several electriciens around, it meant nothing.

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I would appreciate information on the use of Switch Mode Power Supplies and their effectiveness to ride through voltage sags

Answer to this reader question

This depends on the energy content in the smoothing capacitor(s). As a rough estimate one might say that energy from the capacitors can be used until their voltage has dropped down to half the peak of the rated input voltage. This would mean that 3/4 of the energy content can be used. The energy contained in a capacitance is calculated as C/2*u^2. Now take this enery and divide it by the DC output power you use, and you obtain an approximation of the ride-through time.

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1 kWh of electricity

Reader Question:

My middle school daughter has been asked to report on the cost of 1 kWh of electrical energy generated by three different sources. She must also determine the environmental impact of them as well as if they are renewable or not. She must create a table showing the sources, costs and impacts. She needs to write a summary describing which of the three sources is the best at producing 1kWh of electrical energy while consider the cost of the energy and the environmental impact.

Answer:

1) For impact, I refer you to our eco-sheet on 1 kWh electricity, listing the environmental impacts from 8 sources:

www.leonardo-energy.org/drupal/node/3665

2) Above eco-sheet follows a life-cycle assessment approach and does not include risks. For risks, you can use our article on 'accidents in the energy sector':

www.sealnet.org/seal/node/17

3) On cost, see our minute lecture on the price of electricity:

www.leonardo-energy.org/drupal/node/783

Above 3 resources should give a reasonably complete view on a complex subject. They have however not been developed for middle school students, so you may need to assist your daughter in their interpretation.

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Sudden Temperature Rise on a Power Transformer

We specialize in power factor and harmonic filters, and our main target
industry is Steel one.

But we face this year with a problem we haven't seen before.

It is a 161-22 KV system, feeding Melt Shop.

The Melt Shop has an old Electric Arc Furnace fed by an old electric arc
Transformer. (This one was reconstructed by Virginia Transformer two years
ago, and is a Shell one).

Actually the system is compensated by 2 capacitor banks.We replaced the capacitors banks, for 2 harmonic filters (3rd and 4th
tuned).

When we turned on the harmonic filters (With the capacitors OFF), The
harmonic distortion (both current and voltage) decrease in the 22 KV system,
the filters operate according as planned, the furnace works properly and as
expected with more production due to voltage increment; but appeared several
hot spots temperature in the walls of the transformer raise very quickly
from 70 to 85 C.

At our first theory was a over excitement of the core due to voltage
increase. But we made a second test, with the incoming taps with 2.5 % less,
and the results were the same.

Do you have any idea, what is happening and if you can help us to solve this
problem?

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Education Programmes (B.Sc or M.Sc) on sustainable energy

Dear Colleagues:

We received a reader question for existing dedicated education programmes on sustainable energy leading to a Bachelor or Master's degree.

If you know programmes dedicated to sustainable energy, energy efficiency or renewables, thanks for letting us know. We're interested in programmes around the world in any language. 

I'll assemble a list for future reference.

Best regards,

Hans De Keulenaer
Leonardo ENERGY

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Sustainable Energy Gym

On the daily basis I could imagine the energy expended in our gyms by individuals to improve on their health, physique etc. Do we have statistics on the amount of energy expended by an individual? Can this energy be tapped for use in order to create a sustainable energy environment whereby the energy obtained would be used to power facilities available in the Gym? This I believe would be an interesting project to work on. I would like to have any details on such projects. Thanks

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Transformer inquiry

Would you please share with us your opion of what impact the new energy conservation program requirements (10 CFR Part 431) regarding Grain-Oriented Silicon Core Steel will have on the industry? Specifically can you tell us what kind of cost increases and lead times we should see in distribution transformers over the next 5 years? 10 years?

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Production of electricity from solar light

Hello, I am a resident of a village from india where we get sunlight for more than 8 hours on average throughout the year. The temperature at my village stays around 30 degree celsius in summer time and 8 degrees in winter. Kindly tell me how much of electricity can be produced using solar energy. Regards, Sanidh

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Efficiency of installed lighting

I read with much interest the notes posted some time back on lighting. This actually did not touch well on the efficiencies associated with the positioning of the luminaire. The available formula for calculating the number of lights for a specific area is based on the lights mounted from ceiling. Do we have formulae that consider wall mounted lights? I believe in some instances it would be more energy efficient to mount lights at certain levels in rooms depending on the size of the room. Do we have any research done to consider this?

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global warming effects on electrictiy transmission and distribution losses

Inquiry received from Nastaran Rahimi.

I am a researcher in the Free University of Berlin where I do research on global warming effects on electricity transmission and distribution losses.

I want to research the effects of any increase or decrease in ambient or mean temperature (due to climate change) on these electricity losses. This relationship depends on what parameters or characteristics?

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Presentation materials on renewable energy

I have to make a presentation to some government and industry representatives on the the Options of Renewable Energy in an island state. I am from Trinidad and Tobago, and oil rich country and would like the government to put renewables on the agenda.

Do you have public material I can use that can give an overview on renewable energy (theory, trend, market, cost..etc)...maybe a power point presentation? I have an hour to present this.

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A few questions on wave power

Question received from Kaitlyn Main

I am a junior in high school and in my chemistry class we are doing alternative energy projects. Mine is wave energy. And I would really like to have an expert's knowledge. So I have a few questions;

1. How much wave power is being used today?
   
2. How much do you predict will be used in the future?
   
3. How exactly is wave power converted to usable energy?
   

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Relationship between installed generator & transformer capacity

I am interested in know if there is a rough rule of thumb that relates a power grids generating capacity to its transformer capacity. For example South Africa has around 40 GW of generating capacity. Ideally what should its aggregate transformer capacity be? I suspect the figure is published somewhere but I am looking at a theoretical relationship. Should aggregate system transformer capacity be twice the system's generating capacity etc.

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Alternative energy options

I have a client, a stone quarry owner, using stone crushing equipment and asphalt heating equipment. Electricity usage is 1 MW per day. Heat is also required for heating stone and asphalt. My question is.. What options are there for this company to obtain electrical energy from other sources? Wind power has been suggested but it is variable! CHP source is another option maybe using biomass or tyres (with clean technologies). Can you advise please on the options and economics within N. Ireland?

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How much energy per Megawatt for wind?

Hello, My name is Evelyn Knezovich and I am a 9th grade high school student enrolled in a school that specifies in teaching advanced math and science courses. We have an entire month where we are focused on our science projects. There is a wind farm planning on being build in Virginia (where I live) and many people dont think that it will be worth building if no money will be made in the long run.

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User requirements on power quality

With interest I have read your

Power Quality Application Guide covering EN50160.

I was wondering if you could point me where to look for for a specific question relating to this:

You mention that power quality is a combined provider/user responsibility. Where can I find requirements on the USER for the maximum distortion of the power quality? Is there a European Norm on the maximum harmonic distortion a user may cause, measured at the supply terminals? Are there special country specific regulations?

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Reactive power due to CFL lighting

Dear Colleagues,

I’ve heard that introducing massively high efficiency lamps like CFL may produce a quite negative effect on the public grid and power quality due to the reactive power increase, and the dropping of the power factor below 0.8.

I’d like to ask you whether this is correct, and, if so, how to avoid such problems without impacting incentives for the implementation of high efficiency lamps?

Regards,

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Ocean Energy

I've wondered lately what amount of energy could be produced if the resources expended in the three Gorges Dam could have been used to construct a waterfall the coast of China, or any nation? How much energy would be developed? It may exceed the total amount of energy expected from Three Gorges, and most dams on waterways now constructed in China. What a wonderful way to eliminate the horrors now visiting China as a result of the damming of the Yangtze River. Carbon emissions would be reduced significantly, fossil fuels would also be eliminated in large part, and millions of acres of arable land could be saved along with ancient river cultures.

Has anyone even broached such a project before? I've read available info on Wave Dragon, and other small scale efforts. It would be helpful to know if such an effort (Ocean Waterfall) is physically feasible.

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Saving energy by increasing voltage?

An Indonesian friend is the electrical engineer at a large shopping mall & has asked me would there be any advantage / disadvantage from an energy consumption point of view if he set the facility transformer tapping to provide a system phase to phase voltage of 400V versus their current setting at 380V?

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