Heat from a 15W lamp?

[ericmark]

I have a local Park Electrical, but the price at £29.90 when it is really only doing same as a bulb just seems OTT.

 

[ericmark]

Well I have tried a single 8W CFL in globe format in a double Ikea bulb holder the intention was to add a second bulb. I did not for one minute expect it to maintain enough heat I thought this was really too small.

However it has maintained the temperature in a 112 litre freezer rather old and condemned as having an insulation problem. Assuming it was A rated it would have needed 31W in the compressor average to maintain -18°C i.e. at 25°C ambient 43°C where I am looking at half that amount and there is a logarithmic scale and heat pumps are more efficient than simple heaters. So I was guessing on around the 15W mark.

So at the moment only 10°C and I am thinking it needs to be able to work with 20°C.

The comment on green house heater is all down to where and how it is controlled. Using some form of PLC be it a Arduino or other one can program in some gradual switching to combat hysteresis. So one can measure brew temperature and keep this spot on. However with the simple STC-1000 the difference between heater switching on and off and fridge switching on and off has to be the same. And the smallest that can be set is 0.3°C. Assuming measuring the fermentor temperature which is of course the thing we wish to control. If the heater is too big on switch off the temperature will continue to rise to a point where the fridge turns on.

So either we need to measure air temperature and try to compensate for difference between air and fermentor temperature and to keep that difference low we need a circulating fan and with a circulating fan we need to ensure every crack is sealed which means no cables out of the door. The other option is to use a heater only just big enough.

Again problem is only just big enough will depend on the ambient temperature. Where the room is heated so only correcting a few degrees it is going to be easier than where not heated and again making lager which needs a lower temperature closer to the fridges own thermostat setting will also make control easier.

There are clearly many factors including where the heater is and if heating fermentor direct or transferring heat by air. However what is plain is using the smallest heater that can do the job is going to be an advantage. So I have bottom two draws in place. The bottom draw is not as deep so can't fit fermentor so fermentor has to sit in the second draw. But the bulb is in the bottom draw. And the sensor is held against the fermentor body with a sponge as insulation to stop it measuring air temperature only want fermentor temperature. At the moment the fermentor is a 5 litre demijohn making a Peach Schnapps being so small temperature will change quicker than with a 40 pint Scottish Heavy brew which is the normal brew.

I know it is holding at 10°C ambient and I am watching the temperature and will check it should the ambient temperature drop. Never seen garage below 6°C so only looking at 14°C difference. Should it dip below the 20°C -0.3°C differential it will not harm the brew it will just make it slower. As winter progresses I may need to fit a second bulb. However it would be good to know the point where it is required. Then as it gets warmer again I will know when I can remove second bulb.

Since there are no hops in Peach Schnapps I am not worried about the light. But with beer it may be better to cover with something to stop the light to prevent skunking. My thanks to those who advised. Even if I did not follow the advise I did consider it. The Peach Schnapps will need looking at in three weeks time I will see how it goes.

 

[winston1]

I have a local Park Electrical, but the price at £29.90 when it is really only doing same as a bulb just seems OTT.

But a bulb can and will fail much more regularly than a proper heater.

 

[ericmark]

I have a local Park Electrical, but the price at £29.90 when it is really only doing same as a bulb just seems OTT.

But a bulb can and will fail much more regularly than a proper heater.

You are correct, the Philips CFL is second hand to start with and we stopped using them because of the failure rate. So using two it would seem is a better idea even if 8W is enough. However I was looking at more like 12W not 8W with my first guess on heater size. So until it has run long enough to know if 8W is enough I am better using bulbs. As to if I can actually buy a 10W panel heater is another question.

 

[ban-all-sheds]

.... Schnapps ... Schnapps ... Schnapps

Schnapps is a distilled drink.

 

[big-all]

i used to have a box with a 40 and a 30 pint barrel i had 2 lamp holders with a 40/60/100w bulbs the cubic volume was about 3 times the barrel size
the room was unheated so any combination off bulbs to get the correct temerature
i would check it twice a day if it was a bit cold i would add 20-40w if it was a bit warm i would remove 20-40w

 

[ericmark]

.... Schnapps ... Schnapps ... Schnapps

Schnapps is a distilled drink.

Yes but without distillation you can get 21% ABV and Schnapps is watered down to 20% AVB so in real terms there is no need to distil to get that taste and alcohol level.

The lamp holder idea was my original system. However I would forget and if it gets too warm you get off tastes. The first question was about if the thermostat would work correctly considering the inferred output from the bulbs. The answers seemed to indicate it would so next move was to try it. The sensor is other side of demijohn to lamp so any inferred heat will have needed to pass through the sugar, water, yeast, yeast nutrient mix so unlikely it will reach the sensor direct.

Also the question was about what happens to the light and the point was raised since the light can't get out it will be turned into heat so using a CFL should not be a problem.

So last point was size. 40 pints takes a lot of warming and cooling, 7½ pints is a lot quicker, hence why first experiment is with a 7½ pint batch, checked this morning garage at 12°C both temperature controllers switched off and showing 19.9°C and 19.8°C so in both cases the heaters are large enough to keep the brews warm enough.

In the winter it would not really matter having a larger heater as a hysteresis of 4°C is still workable as no fridge is required. However in the summer I will need to work with a lot tighter hysteresis so worth tests now so by time summer arrives I know what sizes are required. Or if I will need to use two temperature controllers to make it work.

 

[ban-all-sheds]

Yes but without distillation you can get 21% ABV and Schnapps is watered down to 20% AVB so in real terms there is no need to distil to get that taste and alcohol level.

My apologies - we are talking about different things.

I am talking about the real thing, and you are talking about those commercial, industrially produced drinks made from watered down, over-sweetened and artificially flavoured grain alcohol.

https://en.wikipedia.org/wiki/Schnapps#Types

 

[DetlefSchmitz]

Something like this?

http://uk.farnell.com/arcol-ohmite/...s&selectedCategoryId=&categoryId=700000005446

 

[ericmark]

I think once I have worked out size that is the way to go. Years ago one could buy replacement elements from Woolworth you just wound them around the ceramic former and replaced the wire cover until the next time it failed often putting one end against the pan good reason to use pans with plastic handles. But today health and safety seems to have removed the cheap products that as a boy I used for my projects.

ABV 18% I would think that is what most consider as Peach Schnapps and I would think it is what the kit tries to emulate.

 

[bernardgreen]

Nickel Chrome wire makes a good heating element if you are happy to use a transformer to get ELV

https://www.jprelec.co.uk/store.asp/c=200/Nickel-Chrome-wire

 

[ericmark]

Yes had considered that. Any spring makes good heating elements. Not sure if worth the effort if bulb works then if not broke why fix it.
Today 23rd Nov 2015 3:15 am ambient temperature 0.6°C and the freezer compartment of fridge/freezer still holding at 19.7 ~ 20°C this raises the question are heat pumps really as good as made out? As a fridge/freezer it would rum approx 50% of the time with a 82 watt motor yet reverse using an 18W and a 8W heater neither running full time. OK not quite the same temperature differential but still 8W to keep freezer compartment warm does raise questions to how good are heat pumps?