Category Archives: Nieuws

Insulation

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Isolatie

I’ve been putting it off for two years now but everytime there was a (good) excuse to postpone it again. In 2009 my employer went bankrupt, and in 2010 we got married and our house’s roof needed a renovation. Now the 2011 heating season started and I’m once again confronted with the fact that we;re still burning fossil natural gas to heat our home.

So today I deliberately started the process to finally have our home insulated. I created a letter or flyer in which I invite the people in our block of (eight) houses to an information evening about home insulation. I hope that I can collect a number of households that collectively have their homes insulated at a nice discount.

Depending on the response to the letter I’ll expand the area in which I distribute the letter, because more households should mean a higher discount.

I think I’ll wait about a week and a half for all responses, and then make the decision to expand the distribution area. Exciting!

I visited a passive house

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A passive house schematic

Last weekend many Dutch occupants of passive houses held an open door day to show the world what a passive house is and what it means to live in one. I had a good idea of the concept of the passive house but I had never actually seen one. The open door day was a great opportunity to find out more about the concept.

A passive house is a house that’s insulate so well that in most cases a heating system is not necessary, and when it is necessary, it can be a very small one. In general a passive house features the following properties:

  • The roof, walls and floors are insulated extremely well (30-50cm).
  • All windows have triple-paned glass.
  • It is 100% air-tight, during the building process all gaps were taped.
  • There are no thermal bridges between the outside shells and the inside.
  • It features a balanced ventilation system with heat recovery.
  • It has sun shades of some description on the sun side, because otherwise the house would heat up too much in the summer.

Often (but not always) passive houses also feature:

  • A large thermal mass within the insulation shell (usually concrete or stone, sometimes water). Because of this the temperature in the house is very stable.
  • A solar hot water system for tap water and/or house heating purposes.
  • If a heating system is present, it’s usually a heat pump.
  • Because a passive house is very energy efficient solar panels (producing electricity) are often installed, making is very easy to create an energy neutral house – if the solar panels fully cover the occupant’s electricity consumption.

Because the passive house concept starts with the premiss that it’s important to first reduce the energy demand for heating to the absolute minimum before active technical means are deployed this seems a very sustainable concept to me.

The passive house I visited last Saturday

The passive house in Utrecht I visited last Saturday was built by the occupants. This (Dutch) article has more information on the house.

Although I’m not a big fan of most modern building styles this is a nice, big house and as soon as I entered I noticed a few things. The inside of the house is not only thermally decoupled from the outside, but also acoustically. This means that it’s very quiet indoors. This isn’t very noticeable at first, but as soon as a window or outside door is opened some traffic noise becomes noticeable. It’s striking how constant the temperature is throughout the house. It’s slightly cooler at the top floors because less people are present there, but the difference was minimal.

The heating system had not been switched on since the beginning of 2011 (!) and the temperature was still 20,5 degrees. The heating system is a open well heat pump which upgrades the soil’s temperature (10-12) degrees to 30-40 degrees which can be used to heat the house through a hydronic floor heating system. This heat pump also provides hot tap water.

After having seen a passive house I’m convinced that this is the way forward. A basic passive house can be of very simple design without many complex installations. The most complex part of a simple passive house will be the balanced ventilation system and that’s quite simple, really. Depending on the wishes of the occupants the system can be extended with a solar hot water system, a heat pump and or solar panels – but it’s not mandatory. Potentially, any shape is possible from modern to classic.

See for more information on passive houses:

http://passiefhuis.nl/

http://en.wikipedia.org/wiki/Passive_house

http://www.passiv.de/

http://passipedia.passiv.de/passipedia_en/start

Plugwise news

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Plugwise

As most readers of this website will know I use the Plugwise system to monitor the performance of our solar panels. This works perfectly, it’s reliable, user friendly and it uses hardly any power.

It was, however, quite expensive; a Home Start set with two measuring plugs cost € 120 and a Home Basic set with nine measuring plugs cost € 360. Plugwise lowered the prices for these two sets to € 99,95 and € 299,95 respectively. That’s quite a mark-down.

On top of that there is now a discount code active which – temporarily – gives a fifteen percent discount. This means that a Home Start can be had for €84,96 and a Home Basic set for € 254,96. The latter is a discount of over a hundred euros! The discount code can be entered during the ordering process, and it is: TELEGRAAF2011.

So if you’d like to monitor you solar panels without complicated hardware and a high energy consumption, now might be the time.

Continue reading →

Wattcher on loan

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The Wattcher display

My employer gave a number of employees a Wattcher on loan so that they can analyse and possibly reduce their electricity consumption. In combination with a website where the employees can compare their consumption statistics they set up a sort of contest who can save the most energy. For the coming few weeks I have one of those devices.

The Wattcher is a nifty device which shows the electricity consumption of a house at a glance. The system consists of two parts:

  1. A sensor on the electricity meter which measures the current electricity consumption. This value is wirelessly transmitted to the display.
  2. The display, which can be placed in any wall outlet within ten or fifteen metres from the sensor and which continuously displays the current total electricity consumption of the house.  If an electrical device is switched on the indicated consumption will rise and if one is switched off it will fall.

The sensor has a light-sensitive cell which, in case of an electromechanical electricity meter, counts how often the black tab passes. In case of a digital meter, the cell counts how often a LED blinks. From these values the display calculates the electricity consumption of the house in Watts.

Immediately after unpacking the device and reading the user manual the first disadvantage announced itself: the Wattcher can’t cope (well) with solar panels (or any other device which produces electricity). The sensor has no way of detecting the direction of rotation of the disc of the electricity meter. On a digital sensor only blinks its LED, which also gives no indication of consumption/production.

I will therefore loan the Wattcher to several households and ask them about their reactions. I will publish those reactions here.

Scientific American: The human cost of energy

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Energiedoden

Energy doesn’t only cost money, it also costs human lives. Scientific American published an article in their September issue about how many human lives are lost when generating a given amount of electricity.

In the image on the right (apologies for the low quality, I took a photo with my mobile phone) clearly shows that the ‘fossil three’, coal, petroleum and natural gas, cause the most deaths by far. The graph shows the number of deaths per 100 GigaWatt, generated for year. Coal takes 12 lives per 100 GWyear, especially during exploration and extraction.

Petroleum and natural gas are less lethal with 9,4 and 7,2 respectively, but still many more people are killed using these forms of energy when compared with more sustainable alternatives. Most death occur in the transport and local distribution phases.

Nuclear power performs much better with only 0,73, but the deaths as a result of the nuclear disasters in Chernobyl and Fukushima have not been counted in that number (the article doesn’t state why). I have not way to estimate how much higher this number would be when the number of direct and indirect deaths caused by the Chernobyl and Fukushima disasters would have been counted.

Hydroelectricity is, when calculated in human lives lost, more than a factor two safer than nuclear power with 0,27 deaths per 100 GWyear, while onshore wind and geothermal are a bit safer still with0,19and 0,17 deaths per 100 GWyear respectively

But the absolute star of this graph is photovoltaics (the technology behind solar panels like we have on our roof) with only 0,02 deaths per 100 GWyear. That’s sixty times less than coal power and thirty-seven times less than nuclear power.

It’s very likely that especially the number of deaths in the exploration and extraction phase are in reality even higher because this article only used data from OECD member states. These are all western, well-developed countries where employees in the energy sector are well-protected and which have relatively strict environmental laws. I also can’t tell if deaths caused by the effects of climate change have been counted in the numbers used in this graph.

This article shows that besides being safe and cheap solar power is also very safe. Yet another reason to install solar panels as soon as possible!