There was a topic on here a while back on how to connect computer fans to the back of a 3 way fridge to help cooling. I have tried to find it in the archives but had no luck. Can any one who has done this exercise give me any ideas how they did it ie. no. of fans, size, if you connected them via thermostat and best place to buy fans. Any info. would be appreciated.
AL
dave06 said
12:02 PM Jan 13, 2010
G'day al, I remember the post but cant remember where it was
he mounted the solar panel externally then wired it direct to the fan and placed the fan at the back of the fridge (where it normally vents) it runs when the sun is out and stops at night
the computer fans are cheap off ebay so are basically throwaway if the solar panel could drive two then I wqould put two
I read somewhere that some folks have put them inside the fridge under the freezer so as to circulate the air more and make the fridge more efficient
-- Edited by dave06 on Wednesday 13th of January 2010 11:09:38 AM
justcruisin01 said
02:04 PM Jan 13, 2010
Al , ive fitted two fans to the bask of the top vent pannel with small cable ties . ran a wire circuit from the 12volt accs to a toggle switch mounted in a small cupboard under sink ,just turn on when needed , day or night .
Fans from old computors , about 90/100ml dia. New are not very expensive if you need to go that way . Power usage is not worth worrring about .
jimricho said
06:08 PM Jan 13, 2010
I have a computer fan cable tied to the top vent as an exhaust fan and it seems to work ok. It is wired similarly to justcruisin01's set up. I only switch it on when needed.
Re a fan mounted inside the fridge...I haven't tried this but I'm inclined to think that a small one would be best as the aim is to gently move the air around rather than act as a blower.
A question justcruisin01.....do you have your fans set up as exhaust fans or as fans blowing air over the condenser (the thingie at the top of the fridge with the fins)? I've been wondering which is the better arrangement.
dave06 said
07:29 PM Jan 13, 2010
as the air at the back of the fridge is exhaust (hot) then extract would be best, I have yet to do this to mine but is "on the list" I like the idea of two, hadnt thought about it before
the fan in the fridge itself would be great if it was at a very low speed as the idea is to circulate and not blow the cream off the milk!
justcruisin01 said
08:55 PM Jan 13, 2010
jimricho wrote:
I have a computer fan cable tied to the top vent as an exhaust fan and it seems to work ok. It is wired similarly to justcruisin01's set up. I only switch it on when needed.
Re a fan mounted inside the fridge...I haven't tried this but I'm inclined to think that a small one would be best as the aim is to gently move the air around rather than act as a blower.
A question justcruisin01.....do you have your fans set up as exhaust fans or as fans blowing air over the condenser (the thingie at the top of the fridge with the fins)? I've been wondering which is the better arrangement.
Hi Jimricho , as the fridge has two vents , a top & a bottom , heat rises so they are working as exhaust drawing the heat out . Havent been in extreme heat yet at the same time never had fridge problems .
jimricho said
09:27 PM Jan 13, 2010
Thanks Jim, pretty much the same as mine
Jim
oldtrack123 said
09:58 PM Jan 13, 2010
Hi Al AS YOU have 2 separate vents I suggest one @ top other @ bottom What is really required is for ALL the cooling air to be forced over the condenser fins. This may require some baffles IF you can gain access,place one full length fire proof vertical baffle between boiler & fins[slot to fit around tubing]& make sure it is fixed to prevent rubbing on tubes The vert baffle should extend from back of fridge to van wall Also make sure the boiler has some vent area top & bottom
THEN fix a horizontal baffle extending from side wall of fridge compartment to the vertical baffle @ either top or bottom of condenser fins & extending out to wall of van. If the bottom of the top vent extends down to this level angle baffle to fit just below the vent openings
If you have done it right you will see that the forced air is not cooling the boiler section but is being directed through the condenser fins WITH very little area for bypassing the fins
Peter
-- Edited by oldtrack123 on Thursday 14th of January 2010 05:08:34 PM
jimricho said
07:23 AM Jan 14, 2010
No doubt OT123's suggestion would provide the most efficient arrangement regarding the airflow. I wonder whether going to this much trouble in practice is worthwhile if a simple exhaust fan arrangement gives an adequate improvement in performance.
Most times I find I don't need to run the fan as the normal convective airflow is sufficient and only need it when the ambient temperature rises above the mid thirties in order to keep the main cabinet temperature below +5 degrees. For this reason I've taken care to ensure the installation does not significantly interfere with the normal airflow
Using a system of ducts and fans as suggested would commit one to using the fans at all times the fridge is running, including during the night when fan and airflow noise could be an issue.
Significantly changing the airflow pattern could have unintended effects such as uneven cooling of the condenser. As I've not tried this set up I can't establish this would definitely occur but this thought comes from my background in radio broadcast transmitters where it is a known issue.
-- Edited by jimricho on Thursday 14th of January 2010 06:32:10 AM
dave06 said
10:57 AM Jan 14, 2010
I agree with Jim I dont know that altering the airflow to that extent would be good, the idea, I think, is to simply dispose of the hot air as soon as possible and give the fridge a better environment to operate in
this simply goes back to one or two fans at the top somehwere around where the fridge exhausts!
inder cooler climes the fan would not be needed and the normal heat loss would occur, under hotter conditions the fan could be emplyed and more efficiency achieved
Delta18 said
11:55 AM Jan 14, 2010
What Peter is saying is correct. If manufacturers fitted fridges correctly there would not be the problems we all seem to have. The important thing is not to have dead areas around or especially above the fridge. These areas hold the hot air preventing the fridge doing its job.
On ours, it was fitted pretty well at the sides but has about 2 inches clear space above it. I have used a baffle to block this area so now the only way air can travel is ...in the bottom vent, up through the fins and out the top vent taking hot air with it.
This has made the fridge function well but for even better performance in 40+ deg northern climes I fitted a fan from Jaycar (I will get a part number off it if anyone interested) and connected this through a temperature switch which is fitted to the boiler tube which turns on the fan if a preset temp is exceeded.
I think any talk of 3 way fridge operation should include a few words on HOW to operate the fridge.
How many people do it correctly?
Too many people fiddle with the thermostat continuously trying to keep the temp down during the day. Wrong! Find the right setting and then leave it alone!
I use a wireless thermometer with the sensor in the cabinet on a middle shelf. This way I can check the temp without opening the door.
On a setting of 3.5 to 4 (on gas) I have found that in the morning the temp will be close to zero. Then during the day with opening & closing the door the temp will rise to 4.5 to 5deg. This is fine. I am happy with that. Even on 240v I may only increase the setting to 5. On 12v of course it makes no difference as it runs flat out.
A couple tips. To prevent, or anyway greatly reduce the frost build up on the fins, I have a tuppaware type box in which I put tomatos & lettuce etc in. It keeps them fresher longer and stops the moisture they give off freezing on the fins. For the same reason if I have a jug of cold water in the fridge I put a plastic bag over it and secure it with a rubber band.
These things work for me and hopefully help someone else.
Cheers Neil
oldtrack123 said
01:31 PM Jan 14, 2010
Hi Dave & Jim
Dead air space is a real problem The problem with many installations is the large gap between fins & wall of van &dead air space above fins, detracting from the natural draft effect. The heat from the boiler adds to the problem with hot air mixing with the cooler air & being drawn thru the fins The boiler does not need /should not be cooled, The fins can not be over-cooled Correct baffling will increase the natural draft effect I have had standard fridges operating very well into upper 30s ambient [a lot hotter in the fridge compartment] To prevent fans running unless required I have fitted Jaycar part #St3831 thermostat on top of fins about 3/4 along from boiler. Actually if there is sufficient room I rather fit the fans directly under the cooling fins again with a shroud & baffles to direct air directly thru the fins This minimizes blockage of the top & bottom vents.
The fans do not normally run in cool weather AS the air vents are NOT obstructed & the air flow is directed to WHERE IT IS NEEDED Fans normally cut in when ambient gets around 30 If YOU want Max possible performance this is the only way to do it
Peter
-- Edited by oldtrack123 on Thursday 14th of January 2010 12:42:20 PM
-- Edited by oldtrack123 on Thursday 14th of January 2010 12:46:48 PM
dave06 said
01:48 PM Jan 14, 2010
ah!!!! the "only way to do it" Hmmm!!!........now I'm thinking where have I heard that before!!!
the ONLY thing that needs doing is disposal of the waste hot air!!! a fan or fans placed in a strategic position will do this, the circualtory positioning of the fridge SHOULD have bee done in the initial installation
if your fridge is not installed correctly then this is the first step to take!!!
oldtrack123 said
02:14 PM Jan 14, 2010
Hi Dave You just cannot help yourself can you
Peter
dave06 said
02:18 PM Jan 14, 2010
at it again I see!
oldtrack123 said
02:26 PM Jan 14, 2010
jimricho wrote:
. As I've not tried this set up I can't establish this would definitely occur but this thought comes from my background in radio broadcast transmitters where it is a known issue.
-- Edited by jimricho on Thursday 14th of January 2010 06:32:10 AM
Hi Jim
My only experience with high frequency power has been with induction heaters
They used air cooled transmitter valves to generate the high frequency, up to 20Kws
They were cooled by fans forcing air upwards thru the fins ,had small thermal link set into body of fins to shut down if overheating occurred
JRH said
04:16 PM Jan 14, 2010
oldtrack123 wrote:
Hi Dave & Jim
Dead air space is a real problem The problem with many installations is the large gap between fins & wall of van &dead air space above fins, detracting from the natural draft effect. The heat from the boiler adds to the problem with hot air mixing with the cooler air & being drawn thru the fins The boiler does not need /should not be cooled, The fins can not be over-cooled Correct baffling will increase the natural draft effect I have had standard fridges operating very well into upper 30s ambient [a lot hotter in the fridge compartment] To prevent fans running unless required I have fitted Jaycar part #St3831 thermostat on top of fins about 3/4 along from boiler. Actually if there is sufficient room I rather fit the fans directly under the cooling fins again with a shroud & baffles to direct air directly thru the fins This minimizes blockage of the top & bottom vents.
The fans do not normally run in cool weather AS the air vents are NOT obstructed & the air flow is directed to WHERE IT IS NEEDED Fans normally cut in when ambient gets around 30 If YOU want Max possible performance this is the only way to do it
Peter
-- Edited by oldtrack123 on Thursday 14th of January 2010 12:42:20 PM
-- Edited by oldtrack123 on Thursday 14th of January 2010 12:46:48 PM
Do we really have to have all this type of crap again, no wonder so many left this forum.
reza said
04:27 PM Jan 14, 2010
oldtrack123 wrote:
.
Hi Jim
My only experience with high frequency power has been with induction heaters
They used air cooled transmitter valves to generate the high frequency, up to 20Kws
They were cooled by fans forcing air upwards thru the fins ,had small thermal link set into body of fins to shut down if overheating occurred
WHAT has high frequency power and air cooled transmitter valves got to do with cooling the fridge down??????
oldtrack123 said
06:06 PM Jan 14, 2010
reza wrote:
WHAT has high frequency power and air cooled transmitter valves got to do with cooling the fridge down??????
Hi Reza My reply was to Jim regarding his post "changing the airflow pattern could have unintended effects such as uneven cooling of the condenser. As I've not tried this set up I can't establish this would definitely occur but this thought comes from my background in radio broadcast transmitters where it is a known issue. """""
I think I have given the OP very detailed description on how to obtain the best results using fans
If anyone can offer better they are welcome to.
By The way I did my 1st such modification way back in the mid 50s So have had plenty of experience I got the idea when I saw kero fridges in an old far north Qld mining town with the condenser in a water bath on top of fridges.
-- Edited by oldtrack123 on Thursday 14th of January 2010 05:19:01 PM
-- Edited by oldtrack123 on Thursday 14th of January 2010 05:22:49 PM
Ma said
06:09 PM Jan 14, 2010
oldtrack123 wrote:
reza wrote:
WHAT has high frequency power and air cooled transmitter valves got to do with cooling the fridge down??????
Hi Reza Are you the self appointed forum censor ?
Thought Reza had just asked a question. Can't see any censorship.
JRH said
06:14 PM Jan 14, 2010
Ma wrote:
oldtrack123 wrote:
reza wrote:
WHAT has high frequency power and air cooled transmitter valves got to do with cooling the fridge down??????
Hi Reza Are you the self appointed forum censor ?
Thought Reza had just asked a question. Can't see any censorship.
That's all Reza did Ma but we are dealing with oldtrack123 here, pedantic as ever.
oldtrack123 said
06:27 PM Jan 14, 2010
JRH wrote:
Do we really have to have all this type of crap again, no wonder so many left this forum.
Hi JRH In your opinion where are my posts crap????
JRH said
06:44 PM Jan 14, 2010
oldtrack123 wrote:
JRH wrote:
Do we really have to have all this type of crap again, no wonder so many left this forum.
Hi JRH In your opinion where are my posts crap????
It is the pedantic manner in which you present them, nobody else is right only oldtrack. And what is more you continually put other peoples backs up.
This is my last word on the subject, I have better things to do with my time.
Popeye said
06:52 PM Jan 14, 2010
I have two fan on the top vent. Twice a year I replace the small cable ties as they tend to deteriorate .
dave06 said
06:54 PM Jan 14, 2010
are they computer fans Ray what size are they and how do you power them! automatically or manually, did you find they are of any benefit!
reza said
07:39 PM Jan 14, 2010
Hi Reza Are you the self appointed forum censor ?
NO SORRY I NOT BUT IF I WAS
God mate you on everything but a ham sandwich and never let up people are sick of your s*** is there a FORUM in the world you not preaching you stuff too hey leave us alone
I have tried to find it in the archives but had no luck.
Can any one who has done this exercise give me any ideas how they did it ie. no. of fans, size, if you connected them via thermostat and best place to buy fans.
Any info. would be appreciated.
AL
it was a placement by Basil and what he did was to use an old computer fan that he salvaged from the dump and a little shed solar panel like this http://cgi.ebay.com.au/Solar-Powered-6-LED-Shed-Light-Workshop-GARAGE-CAMPING_W0QQitemZ290353048146QQcmdZViewItemQQptZAU_Home_Outdoor_Lighting?hash=item439a63ea52 one that was left over from a non working shed light
he mounted the solar panel externally then wired it direct to the fan and placed the fan at the back of the fridge (where it normally vents) it runs when the sun is out and stops at night
the computer fans are cheap off ebay so are basically throwaway if the solar panel could drive two then I wqould put two
I read somewhere that some folks have put them inside the fridge under the freezer so as to circulate the air more and make the fridge more efficient
-- Edited by dave06 on Wednesday 13th of January 2010 11:09:38 AM
ran a wire circuit from the 12volt accs to a toggle switch mounted in a small cupboard under sink ,just turn on when needed , day or night .
Fans from old computors , about 90/100ml dia.
New are not very expensive if you need to go that way .
Power usage is not worth worrring about .
A suitable fan can be purchased from Jaycar http://www.jaycar.com.au/productView.asp?ID=YX2518&CATID=45&form=CAT&SUBCATID=725 other fans can be checked out at http://www.jaycar.com.au/productResults.asp?whichpage=1&pagesize=10&keywords=&CATID=45&SUBCATID=725&form=CAT or alternatively the power supply fans salvaged from old computers as suggested could be used.
Dave's suggestions would be worth looking at too.
Re a fan mounted inside the fridge...I haven't tried this but I'm inclined to think that a small one would be best as the aim is to gently move the air around rather than act as a blower.
A question justcruisin01.....do you have your fans set up as exhaust fans or as fans blowing air over the condenser (the thingie at the top of the fridge with the fins)? I've been wondering which is the better arrangement.
Hi Jimricho , as the fridge has two vents , a top & a bottom , heat rises so they are working as exhaust drawing the heat out .
Havent been in extreme heat yet at the same time never had fridge problems .
AS YOU have 2 separate vents I suggest one @ top other @ bottom
What is really required is for ALL the cooling air to be forced over the condenser fins.
This may require some baffles
IF you can gain access,place one full length fire proof vertical baffle between boiler & fins[slot to fit around tubing]& make sure it is fixed to prevent rubbing on tubes The vert baffle should extend from back of fridge to van wall
Also make sure the boiler has some vent area top & bottom
THEN fix a horizontal baffle extending from side wall of fridge compartment to the vertical baffle @ either top or bottom of condenser fins & extending out to wall of van.
If the bottom of the top vent extends down to this level angle baffle to fit just below the vent openings
If you have done it right you will see that the forced air is not cooling the boiler section but is being directed through the condenser fins WITH very little area for bypassing the fins
Peter
-- Edited by oldtrack123 on Thursday 14th of January 2010 05:08:34 PM
Most times I find I don't need to run the fan as the normal convective airflow is sufficient and only need it when the ambient temperature rises above the mid thirties in order to keep the main cabinet temperature below +5 degrees. For this reason I've taken care to ensure the installation does not significantly interfere with the normal airflow
Using a system of ducts and fans as suggested would commit one to using the fans at all times the fridge is running, including during the night when fan and airflow noise could be an issue.
Significantly changing the airflow pattern could have unintended effects such as uneven cooling of the condenser. As I've not tried this set up I can't establish this would definitely occur but this thought comes from my background in radio broadcast transmitters where it is a known issue.
-- Edited by jimricho on Thursday 14th of January 2010 06:32:10 AM
The important thing is not to have dead areas around or especially above the fridge. These areas hold the hot air preventing the fridge doing its job.
On ours, it was fitted pretty well at the sides but has about 2 inches clear space above it. I have used a baffle to block this area so now the only way air can travel is ...in the bottom vent, up through the fins and out the top vent taking hot air with it.
This has made the fridge function well but for even better performance in 40+ deg northern climes I fitted a fan from Jaycar (I will get a part number off it if anyone interested) and connected this through a temperature switch which is fitted to the boiler tube which turns on the fan if a preset temp is exceeded.
I think any talk of 3 way fridge operation should include a few words on HOW to operate the fridge.
How many people do it correctly?
Too many people fiddle with the thermostat continuously trying to keep the temp down during the day. Wrong! Find the right setting and then leave it alone!
I use a wireless thermometer with the sensor in the cabinet on a middle shelf. This way I can check the temp without opening the door.
On a setting of 3.5 to 4 (on gas) I have found that in the morning the temp will be close to zero. Then during the day with opening & closing the door the temp will rise to 4.5 to 5deg. This is fine. I am happy with that. Even on 240v I may only increase the setting to 5. On 12v of course it makes no difference as it runs flat out.
A couple tips. To prevent, or anyway greatly reduce the frost build up on the fins, I have a tuppaware type box in which I put tomatos & lettuce etc in. It keeps them fresher longer and stops the moisture they give off freezing on the fins. For the same reason if I have a jug of cold water in the fridge I put a plastic bag over it and secure it with a rubber band.
These things work for me and hopefully help someone else.
Cheers Neil
Dead air space is a real problem
The problem with many installations is the large gap between fins & wall of van &dead air space above fins, detracting from the natural draft effect.
The heat from the boiler adds to the problem with hot air mixing with the cooler air & being drawn thru the fins
The boiler does not need /should not be cooled,
The fins can not be over-cooled
Correct baffling will increase the natural draft effect
I have had standard fridges operating very well into upper 30s ambient [a lot hotter in the fridge compartment]
To prevent fans running unless required I have fitted Jaycar part #St3831 thermostat on top of fins about 3/4 along from boiler.
Actually if there is sufficient room I rather fit the fans directly under the cooling fins again with a shroud & baffles to direct air directly thru the fins
This minimizes blockage of the top & bottom vents.
The fans do not normally run in cool weather AS the air vents are NOT obstructed
& the air flow is directed to WHERE IT IS NEEDED
Fans normally cut in when ambient gets around 30
If YOU want Max possible performance this is the only way to do it
Peter
-- Edited by oldtrack123 on Thursday 14th of January 2010 12:42:20 PM
-- Edited by oldtrack123 on Thursday 14th of January 2010 12:46:48 PM
You just cannot help yourself can you
Peter
Hi Jim
My only experience with high frequency power has been with induction heaters
They used air cooled transmitter valves to generate the high frequency, up to 20Kws
They were cooled by fans forcing air upwards thru the fins ,had small thermal link set into body of fins to shut down if overheating occurred
If anyone can offer better they are welcome to.
By The way I did my 1st such modification way back in the mid 50s
So have had plenty of experience
I got the idea when I saw kero fridges in an old far north Qld mining town with the condenser in a water bath on top of fridges.
-- Edited by oldtrack123 on Thursday 14th of January 2010 05:19:01 PM
-- Edited by oldtrack123 on Thursday 14th of January 2010 05:22:49 PM
In your opinion where are my posts crap????
This is my last word on the subject, I have better things to do with my time.
Are you the self appointed forum censor ?
NO SORRY I NOT BUT IF I WAS
God mate you on everything but a ham sandwich and never let up people are sick of your s*** is there a FORUM in the world you not preaching you stuff too
hey leave us alone