Posts Tagged ‘house’

Micro-CHP (μCHP)

January 15th, 2009

It’s μCHP’s turn. So the prime reason to use μCHP is not to generate electricity, but to generate heat. That’s right, it’s a boiler. But it’s a boiler that generates electricity, how cool! So what happens when it’s not cold, you turn the boiler off, and off goes the electricity as well. So you need a grid, and when you turn your boiler off, you are as efficient as the grid.

The fact that you are connected to the grid however is quite useful, because it means that if in course of generating enough heat for your house you generated too much electricity, it’s won’t go to waste. You just pump it into the grid and maybe make some money out of it.

So the efficiency here really comes from generating electricity as you generate heat and not the other way round, as in normal large CHPs. So μCHPs are useless in the summer (just like your boiler). Again the massive efficiency goes down the drain. It’s still better than those old central massive power plants though, so don’t get me wrong.

There are two problems I can think of right now about μCHP. First the poor people at the massive power plant. Not only are they being attacked for something that’s not their fault, (the fact that they have to dump 2/3 of the energy into the sea to give us 1/3, in reality the numbers are better, but still) but now they have to be ready to offset any electricity coming out of our μCHPs in case we feel like switching it off. Because they can’t control us, and we don’t have to even tell them when we are switching off our boilers, no one knows how much μCHP electricity there will be at any one time to count on. So they should always have backup capacity installed, and they have to be very responsive to our whims. Sounds very expensive and difficult.

This is not a big deal if there are a few units installed here and there, but it could be an issue if you have them everywhere.

Second problem, how much money do you give the people for their electricity. Give me too much money and I will have my heating on all the time. Hey you’re the one who’s paying me to heat my house. In summer, I’ll just open all the windows. The cash is worth it. Pay me too little and I won’t care. Why would I pay more for a fancy boiler and then donate my electricity to you. No thank you, I think I will stick with the old system.

So frankly, if you have the right policy in place you will find that indeed μCHPs are useful. But of course they are no where near as useful as some (Greenpeace) want us to believe. No they won’t save the world, but they’ll help bring us one step closer.

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Being energy efficient is not always good for the enviornment

January 5th, 2009

I can hear you already asking yourself, we all know that energy efficiency is good for the environment, so what kind of play on words is this? What kind of game is he playing here? The game here is to look at the bigger picture. We tend to always look at the smaller picture. Oh my new car only emits this little amount of carbon per Km (or mile), I liked it so much I had it specially flown from Japan to Europe so I can order my own customised one. And voila, the damage is done.

Let’s take another example. What happens when you want to decrease the carbon footprint of your house and also the heating bill? You install insulation. So you insulate the wall, you insulate the loft, you double glaze your windows and you wrap the whole house in a blanket. And just to make sure that the heat doesn’t really escape you have put half a metre thick insulation on your walls. In order to manufacture this insulation however, some energy was expended and some carbon was emitted. As you add more and more insulation the savings this extra layer of  insulation does is not as much as the first layer of insulation. What you want to do is to only add more insulation if it is going to save more carbon than was used to manufacture it, ship it, install it and get rid of it at the end of its life. So there comes a point where adding more insulation will not save as much carbon as was emitted to put it in place. This means that you are actually harming the environment by installing more insulation. You are better off letting the heat escape from the house.

So it is important, in the midst of our extreme enthusiasm to be as green as possible, to realise that sometimes we can take it too far. And when we do take it too far, we end up hurting ourselves and the trees we love. So take it easy and keep an open mind.

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How much water on your roof powers the kettle?

January 3rd, 2009

So I decided that maybe it is a good idea to use micro pumped water storage. Sure why not, have your renewable source pump water to a tank on top of your house and then generate electricity when you release the water and it falls on a turbine. I quickly took a pen and paper and decided to see how much water you would need to power a kettle, so that I can grasp how realistic this really is. This will get pretty mathematical now.

Assume your average kettle burns 2kW, that’s 2000 J/s. Ok so how much water on the roof do you need to get 2000 joules? Assume a perfect conversion of potential energy to electricity and a g of 10. Potential energy = mgh so 2000J = m x 10 x 5 metres (the height of the house). That means we need 40 litres per second. Assume it takes 5 minutes to boil a full kettle. That means 5 x 60 = 300 seconds. Now 40 litres per second multiplied by 300 seconds, that’s 12,000 litres.

A lot of water to make some tea. That means that you need 12 tons on your roof. I think structural engineers might not like this idea, especially if you want to store enough water to power your home. So I guess my idea for non-battery storage in the home just evaporated. Maybe another time I will change the world.

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Target the housewives – so they can save the world.

January 2nd, 2009

The BBC reported in an online article that UK housewives spend 47% of their leisure time online. I guess we can make an assumption about housewives in the rest of the world, that they also spend a large amount of time online. Married men reported in their collective voices that housewives are very influential in making household descisions. They run the house without going back to anyone, they buy everyday items without even thinking about asking (after all they are the experts) and they are highly influential in large household purchases (like cars and houses). They are very good at asking for gifts (they do take care of the house afterall and deserve some appreciation) and so are a result of even more purchases. So can we convince the housewife to ask for a wind turbine for her next birthday? A challenge worth taking.

The idea here is to use the internet to specifically target housewives and make them aware of all the different energy and environmental issues that the world is facing. Convince them to put the heating thermostat down by one degree (who else is there to change it?!) as a start. Then make them aware of the impacts of their choice of electricity supplier, Then talk about insulation. Then talk about double glazing. Then talk about buying cars. Then talk about getting a wind turbine and solar panels on the roof. Soon enough you will realise that men are out there buying wind turbines and solar panels because their wife said so.

There is a lot of energy savings to be done around the house, and housewives rule the house. Convince them and you are there, and if they are spending their time on the internet, then spend your time to meet them there. Target the housewives, and watch them save the world.

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