Tuesday, January 31, 2012

Game On!

I'm sorry to say that my blog has been somewhat neglected of late. You see, since April last year I have been embroiled in buying and moving into our first house in Belgium

Home Sweet Tervuren Home
The good news is that we are now installed in what started out as a 1960s 2 bedroomed bungalow with garage underneath but which was extended in the mid 1980s to almost double its floor area.  The house is a real mash up  from the 1963 open cavity wall and uninsulated floors of the original bungalow to the cavity wall and insulated block work of the extension and the circa 1985 gas fired heating system which replaced the original oil fired central heating boiler.  The house was double glazed about 7 years ago and so is reasonably thermally efficient. The loft was also converted into living space and seems to have been well insulated in the process. I estimate that the current heatloss is around 10kW @ 0oC.  The current oversized boiler is probably around 75% efficient.  This makes it an ideal candidate to be a test bed for the first Nextgen low carbon heating system installation.

When we moved in I immediately noticed that the the hot water system almost completely innefectual.  The 220 litre storage tank was heated to around 70oC twice a day by the adjacent gas boiler but lost almost all of its heat in two or three hours due to convection currents around a 20 metre long loop of unlagged pipe. A quick calculation shows the daily heat loss to be of the order 20kWh or ~ €2 per day - ouch!  Ironically the loop was designed to save water water by using a circulation pump to circulate hot water around the loop allowing hot water to be instantly available at a sink at the opposite end of the house.   This and the mass of unlagged pipes around the boiler led to the bizarre situation where the otherwise unheated garage was the warmest room in the house! 

Some loss from a hot water system based on a hot water tank is inevitable.  As a comparison Steven Harris of the Energy Savings Trust recently reported in his blog loosing around 7kWh per day from his solar powered hot water system.  In my case three hours of my time with adhesive tape, scissors, a knife and €25 of pipe insulation reduced the hot water heat loss by at least a factor of two with the happy side effect that we now normally have enough hot water for a shower at almost any time of the day!

Boiler post Insulation
Notwithstanding the “emergency” pipe insulation above my intention is to run the system "as is" for the first year to get a benchmark energy consumption for the dwelling.  This will then serve as a cross check against the Nextgen  energy usage simulation computer model which will be used to predict the payback period of the system.  It will also serve as a reference from which future energy reduction steps are measured.  My ambition is to reduce the carbon footprint of our house by at least 50% and perhaps as much as 70% compared to when we moved in.  This radical reduction cannot be achieved without a plan. Now that we are settled in I will have to get busy with simulations and costings.

Let the game begin! 

No comments: