Fridge fan.

[maingate]

I was at a bit of a loose end this afternoon so decided to do a couple of small jobs on the van. When I had done that I turned my attention to a couple of old Fans laid about in the shed. They were bought for the car and used to keep the dogs cool in the back (no A/C fitted). They ran off 2 x D batteries and were therefore 3 volts. I also had a 240 volt powered voltage regulator you could set to a number of DC voltages between 3 and 9 volts (bought to charge up a camera battery but never really used). I rigged one up to the regulator, set at 3 volts and tried it and it works well.

So, my plan is to fit it behind the Fridge/Freezer for when the weather gets hot. I have a small inverter (about 80 watt) and will just use that with an adjacent 12 volt socket above the Fridge to power it. If the weather is that hot and sunny then solar power will be plentiful. It will be a 10 minute job to fit it and run the cable to it, much better than ordering computer fans and temperature sensors. The bonus being that I have upcycled components that would just have been chucked out eventually.

 

[harrow]

Computer fans are dirt cheap 98p

 

[QFour]

Yeeee talk about overkill. The kit you are aiming to fit will use considerably more power than the fans ever will. All you need is a couple of 12v fans and a switch. Fans need to be mounted in the top grill so that they suck the hot air out.

 

[Topmast]

I know everyone says fit a fan on the fridge and yes I do have one but so far have never bothered to use it ,in the summer here the temperature often gets pretty hot often around 40 deg.but can honestly say my old fridge keeps everything beautifully cold and even keeps stuff frozen in the small freezer box.

 

[martinmartin]

Yeeee talk about overkill. The kit you are aiming to fit will use considerably more power than the fans ever will. All you need is a couple of 12v fans and a switch. Fans need to be mounted in the top grill so that they suck the hot air out.

Yes over kill but he is using something that was unused and he does have a surplus of energy in summer.

 

[Canalsman]

Re

I know everyone says fit a fan on the fridge and yes I do have one but so far have never bothered to use it ,in the summer here the temperature often gets pretty hot often around 40 deg.but can honestly say my old fridge keeps everything beautifully cold and even keeps stuff frozen in the small freezer box.

Remember that if you make the fridge more efficient by using a fan the gas consumption will be reduced.

If you have solar power to mitigate the power usage of the fans, which is minimal, it's a win-win. Colder fridge and lower gas cost.

 

[Wooie1958]

Put a couple of fans in the top vent on our motorhome a couple of years back with a simple on / off switch fitted above unit.

They work brilliantly, the fridge / freezer is much more efficient now when the temperature rises

 

[tidewatcher]

The first thing I did was buy a cheap fridge thermometer, you would be amazed at the different temperatures in the fridge between cool and hot days. OK it is not an accurate temperature gauge but it does act as a good means of comparing temperature. The fridge relies on temperature differential between the intercooler and the ambient air temperature to "shift" the heat. The warmer the air, the less the differential, the less efficient the fridge. To maintain efficiency with a small temperature difference you simply need to pass more air over the intercooler, hence the fan.

However...

Try to imagine the airflow from the bottom vent to the intercooler, on my van there was a large gap between the fridge and the body, any extractor fan at the top vent would simply draw the air directly up thus missing the intercooler, I had to fit a guide baffle to ensure the air was forced to the fridge and then I filled the gap with Celotex insulation to help keep direct heat from the sun away from the fridge. The combination of these measures and a simple computer fan on a switch has allowed me to run at a reduced gas setting in most circumstances. Minimal cost and a satisfactory improvement.

 

[harrow]

Celotex insulation is combustible it burns

 

[tidewatcher]

What would you suggest as a stable insulation? It is foil faced and can be firmly held in place, some of it to the plywood interior furniture structure.

 

[maingate]

That's the benefit of having an electromechanical background, being able to use what is to hand. The small 80 watt inverter is possibly the best accessory I have ever bought for the van, it is in constant use to charge phones, ecig, mifi batteries etc. Don't knock it, it has saved having to fit extra 12 volt and 5 volt USB sockets for all the small portable things we carry nowadays. If my van was stolen and I had to start all over with a new van, one of these inverters would be my first buy. I now also have a device to plug into it to charge up anything with a voltage of between 3 volts and 9 volts. Try searching for a ready made voltage reducer for an accessory. Unless the manufacturer supplies them you are stuffed and then you need a separate one for each accessory depending on its voltage and type of connector.

As for buying a 98p computer fan, what are the postage costs Harrow? What about the delay waiting for it to arrive? What about making some kind of mounting for it? The fans I already had have clips to connect them securely already fitted. Actually postage costs are a sore point with me, they are often outrageous. I bought 2 small nylon bushes online at 70p each, the postage cost was £4.85 for tiny, lightweight objects. It was a total ripoff. I paid it because I needed them to repair a Thule double step on a pals Hymer. His only alternative would have been to buy a new one at circa £350 or get a Dealer to buy Thule parts (at outrageous prices) and pay labour costs on top. Not good when you are in your 80's and have Parkinsons Disease.

Still, everyone is allowed an opinion, some have been useful, some of them not.

ps, I have just remembered why I don't start threads very often.

 

[harrow]

As for buying a 98p computer fan, what are the postage costs Harrow? What about the delay waiting for it to arrive?

ps, I have just remembered why I don't start threads very often.

I understand that the fans are free delivery and will arrive by next summer,

12V 2 Pin 40mm Electric Computer Cooler Small Cooling Fan PC Black Heat Sink NEW | eBay

Find many great new & used options and get the best deals for 12V 2 Pin 40mm Electric Computer Cooler Small Cooling Fan PC Black Heat Sink NEW at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

But to be honest I would spend more on the fans

 

[Millie Master]

Celotex insulation is combustible it burns

As far as I know, not the Celotex or similar products that are used by so many self builders as it is closed cell foam.

 

[tidewatcher]

As far as I know, not the Celotex or similar products that are used by so many self builders as it is closed cell foam.

Just done a bit of googling and it seems they do a fire resistant one now which, cunningly enough is prefixed FR I think. Anyway worth getting the proper stuff as it is available. Will have a look at changing mine. Does make a difference thoug so worth the effort.

 

[Millie Master]

Just done a bit of googling and it seems they do a fire resistant one now which, cunningly enough is prefixed FR I think. Anyway worth getting the proper stuff as it is available. Will have a look at changing mine. Does make a difference thoug so worth the effort.

I had the inside of my van insulated with professionally applied closed cell foam which came with a guarantee stating fire resistance.

 

[Millie Master]

Believe it or not Ionly hit the "POST REPLY" tab once....................... help PHIL

 

[Markd]

FWIW Thetford kit provides it's to push into foam insulation of fridge a d screws to mount fan(s) under heat exchanger with updraft operation.
Obviously the more direct the cooling the greater the effect on performance and reduction in gas consumption.

 

[tidewatcher]

Not sure about the pushing air theory, I do have a background in this sort of thing and you tend to get circular vortexes where the "pushed" air meets any slight obstruction. With "drawn" air it is a clean airflow. All wind tunnels are "drawn air for this reason. Maybe Thetford made it that way so they could dictate how it was mounted however the fridge was installed. Tricky making a kit if you have no control over where it is to be mounted.

 

[Millie Master]

I do have a background in this sort of thing and you tend to get circular vortexes where the "pushed" air meets any slight obstruction. With "drawn" air it is a clean airflow. All wind tunnels are "drawn air for this reason.

Perhaps @tidewatcher, if you would be so kind to give some thought to my self built installation.
I fitted a WAECO CR50 fridge to my van and not wanting any eye-sore vents in the vans side, I cut one 10 cm hole in the floor into which I fitted a length of pipe that takes cooling air to the base of the fridge, then above it in the roof I fitted a mushroom vent with this all being inside a sealed unit that the fridge sits in.

I am wanting to fit a fan to introduce more cold air to the back of the fridge, would this be better at the bottom, on top of the pipe from the floor or at the top working almost like an extractor fan?

For a mere mortal like me, this is quite a perplexing issue for my mind to juggle around!!

Many thanks.

 

[tidewatcher]

Perhaps @tidewatcher, if you would be so kind to give some thought to my self built installation.
I fitted a WAECO CR50 fridge to my van and not wanting any eye-sore vents in the vans side, I cut one 10 cm hole in the floor into which I fitted a length of pipe that takes cooling air to the base of the fridge, then above it in the roof I fitted a mushroom vent with this all being inside a sealed unit that the fridge sits in.

I am wanting to fit a fan to introduce more cold air to the back of the fridge, would this be better at the bottom, on top of the pipe from the floor or at the top working almost like an extractor fan?

For a mere mortal like me, this is quite a perplexing issue for my mind to juggle around!!

Many thanks.

I would extract every time. The air drawn in will be "smooth" air and should pass over the intercooler in an organised manner as it is drawn upwards. I like the idea of the open vent below and the exhaust vent above, the convection will be ideal, no nasty corners to go around. The volume of air whether it is pushed or pulled remains the same but the "smoothness" the air around the intercooler will be far better. If you can baffle the intake air towards the intercooler either packing the void with insulation or by some way of ensuring the airflow from the intake is directed over the intercooler then that would be another bonus.