Radiator re-boot
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Radiator re-boot

Almost fifteen years ago I installed a kitchen in a room in the house which had not had a kitchen in it before. So all the kitchen-type services, water, much increased electrical capacity, and drainage had to be put in from scratch. Wall space was at a premium and it seemed the only place for a radiator was under a large window. I fitted the largest radiator that would fit and hoped for the best.  Although part of the room was fitted with under-floor heating (it was only 500 watts) in the dead of winter the capacity was never enough and a 2 K watt electric heater was often resorted to.

Recently I have been trying to improve matters. Before the kitchen was installed I had laid the wooden floor over 2 inches of polystyrene and last year I put 3 inches of Celotex in the roof. I still need to have double glazing in the windows above the radiator and that would obviously make a big difference.

However, in the meantime, I am looking at boosting the output from the radiator with a row of computer fans positioned under the radiator and thermostatically controlled from a sensor somewhere in the middle of the room.

I have experimented with a couple of fan heaters (running on fan only) blowing through the radiator and it seems to work!

Types of fan for the project.

This tangential or cross flow fan was the type I was originally thinking of. It’s used in heating and ventilation  applications etc and would be the type to be found in fan assisted radiators, storage heaters etc. These are mains operated and surprisingly expensive. They would need a housing of some sort with grills and electrical insulation etc

My thoughts then turned to computer fans. They come in all sorts of sizes and can be uber cheap.

They run on 12 volts DC and their speed can be easily controlled with simple electronics.

80 mm diameter would suit the spacing between the radiator panels but would they shift enough air to make a difference? I tested two types and you could certainly feel a flow of air passing out of the top of the radiator.

I am going to take the plunge and buy 20 fans (at £2.30 each that will not break the bank).

The red fan is deeper (and cheaper!) And, I thought, should flow more air.

However, a test (using my hand to judge the flow - so not very scientific!) seems to show the thin fan flows more air. It takes 220 mA as opposed to 110 mA for the thicker fan so it should flow more unless it’s half as efficient. Anyway, I’ve got the red fans now so the comparison is academic really. I could run the fan at 15 volts if I need a bit more oomph.  

I need to think of the easiest way of fitting them into a unit which will fit (inconspicuously, I hope) under the radiator. I don’t think I shall be able to avoid drilling at least eighty 4mm holes.

I’ve purchased a 3.3 volt Adafruit Trinket and a Sparkfun TMP102 temperature sensor as part of the thermostatic control.

More components

Next, some construction details…

What a lot of fans! Have I lost the plot?