Reply
Contributor

3412 Ventilation System - Engine Overheating.

What  should  be  the  sizing  of  Inlet  Louvers  and  Outlet  louvers.  I  believe ,  Inlet  should  be 1.5 times  then  outlet  louver.

 

The  Diesel  Genset  is  having  a  Radiator  cooling  system.  I  am  facing  a  problem  of  overheating  of  the  Engine  at  90%  Load ( 520 Kw ).  I  have  checked the  Air  Flow  for  Inlet  and  Outlet  of  the  Radiator.  Here ,  Site  condition  is  42degC - 45degC   Ambient.

 

Super Contributor

Re: 3412 Ventilation System - Engine Overheating.

Is this unit have a package radiator?

A general rule of thumb is for the radiator outlet duct to be 1.5 times the area of the radiator core, the inlet to be 2-3 times.  These are open area, not total area, meaning if they have louvers, the opening needs to be bigger.

Do you have an Application and Installation Guide?  The ventilation section has some very good information on ducting and sizing.

Mike L.

Visitor

Re: 3412 Ventilation System - Engine Overheating.

To start with the temperatures you have given are a bit on the high side for ambient air temperatures 42-45C (107-113F). Delta T from Ambient is 8.5-11C (15-20F) and Maximum engine room air temperature not to exceed 49C (120F) at the air cleaner (or derate accordingly). Rule of thumb, for every one (1) degree of intake air temperature rise there will be three (3) degrees of exhaust temperature rise. The exhaust ventilation air should be 110-120% of the incoming ventilation air and this will be combined combustion and ventilation air. To add more to the equation this will be multiplied by where the ventilation air enters and exits the room. This could be mutiplied by as much as 3.3 times the required ventilation air at full rated power depending on where the ventilation air enters and exits the room. Duct restriction can be measured fairly easily and should not exceed 2.46kPa (10in.) of water at full rated load. Sizing of combined combustion and ventilation air ducts the rule of thumb is, use 4-6sq cm per KW and 0.5-0.75 sq in. per H/P of duct cross sectional area.

I believe that taking measurements would better evaluate and help with a better correction for the problem and a better more dependable package.

I have argued this very topic many times with boat builders and a few container builder's. The times with the louver issues, the proof was easy, remove the louvers frame and all then retest. Most of my experience in this area is with marine applications I still use this as a basis for any application that I work with.

There is still more to this but I think the basic items are covered.

Hope this helps .

Contributor

Re: 3412 Ventilation System - Engine Overheating.

mikel ,

 

Yes , It  is  a  packaged  Radiator.

 

I  am  also  refering  A &  I  Guide .

Contributor

Re: 3412 Ventilation System - Engine Overheating.

Mikel ,

 

What  should  be  best  place  to  measure  a  required  Ventilation  Air  flow  ,  in  a  package   unit  ?

Any  idea.

Visitor

Re: 3412 Ventilation System - Engine Overheating.

There are two things to check that will tell you whether you have a problem that you can fix or not. 1. Check the Caterpillar bill of material - if you do not have it, give your package serial number to your local cat dealer and ask for the consist. The bill of material will usually reference the ambient capability of the radiator. If the radiator is a standard radiator (as opposed to a high ambient radiator) you will need a different radiator. 2. Measure the static pressure rise across the radiator using an inclined water manometer. Typically most radiators are rated for between 0.5 and 0.75" water column pressure rise. If you have greater than this you will have an air flow problem. Measure the pressure between the fan discharge (high side) and the fan inlet (low side)
New member

Re: 3412 Ventilation System - Engine Overheating.

First Post. Thanks for the invite!

I would keep the simple things simple.  Not knowing the direction of the fan, I would guess that it is a pusher. If it is a pusher, how much exhaust surface area is exposed? What is the ambient temp while the unit is running? Is the fan ratio correct ? Are the drive ratios for the fan correct ? Is the unit recycling the air from the radiator. ( updraft- forward draft, close buildings).

Highlighted
Contributor

Re: 3412 Ventilation System - Engine Overheating.

First of all tell me , your generator is standby or prime power.what is Genset Model.Then i will reply you

 

Contributor

Re: 3412 Ventilation System - Engine Overheating.

Its   Stand by  unit    3412 C.

 

Hope it helps

Contributor

Re: 3412 Ventilation System - Engine Overheating.

Hi ,

Thanks for reply.

 

Basically , Unit  is  running  with  ambient  40-42 deg C.  There  is  many  factors  which  affecting  performance.  I  found , the  outlet / discharge  louver  area  is  almost  equal  to  the  Radiator  core  area.  Which  may  ristrict  the   ehaust / outlet  Air  flow ,

Planning to  remove the  louver  and  will  have  a  load  test  run .

Radiator  Fan  is  directly  coupled  with Engine  shaft.

 

Thanks.