Cooling a marine engine while testing

[ToYo69]

TL;DR Summary

We are trying to test a marine engine in our workshop and were wondering how much extra cooling a radiator might add.

For my internship I have to test and certify a Marine diesel engine. We are trying to run a few tests in our workshop, but this obviously means we can't use the sea or a river as cooling. We bought an IBC tank, which can hold a 1000 liters of water. The water from the tank will be running through the system instead of river/sea water, this water will be taking the heat away from the coolant. After a few calculations we figured out that with this amount of water we can run for about 5 minutes before the water gets to hot to keep cooling the coolant. So I was wondering if we add a radiator to take some heat away from the water how much time this could buy us. I am specifically wondering how much the radiator will cool down the water and what data I would need.

Thanks in advance!

 

[Tom.G]

Depending on the engine size, a few (up to many) car radiators should do the trick rather well.

I say 'a few to many' because the intake water of a marine engine is at or below ambient temperature, whereas the radiator outlet temperature is well above ambient.

You will also need a big fan for each radiator. (noisy)

Lets see if we can get some of the Experts to chime in on this:
@Ranger Mike @anorlunda @jrmichler @Chestermiller

Cheers,
Tom

 

[ToYo69]

Depending on the engine size, a few (up to many) car radiators should do the trick rather well.

I say 'a few to many' because the intake water of a marine engine is at or below ambient temperature, whereas the radiator outlet temperature is well above ambient.

You will also need a big fan for each radiator. (noisy)

Lets see if we can get some of the Experts to chime in on this:
@Ranger Mike @anorlunda @jrmichler @Chestermiller

Cheers,
Tom

Thanks for the quick reply. The engine is quite big, almost sixteen liters. The size of the radiator shouldn't be a problem. Our company also sells generators and those engines also have quite big radiator and fans.

 

[Baluncore]

Marine diesels come in many sizes. Maybe you can identify the model, HP, or capacity.
How will it be loaded during the tests?

An IBC is close to a cube, which has maximum volume, but with minimum cooling surface.

Consider using a 100 m length of black polypipe as a radiator. Run hot water from the diesel through the pipe to cool it, before it enters the IBC reservoir.

 

[ToYo69]

Marine diesels come in many sizes. Maybe you can identify the model, HP, or capacity.
How will it be loaded during the tests?

An IBC is close to a cube, which has maximum volume, but with minimum cooling surface.

Consider using a 100 m length of black polypipe as a radiator. Run hot water from the diesel through the pipe to cool it, before it enters the IBC reservoir.

The marine diesel in question is a Baudouin 6M26.3, between 400-600 KW. During the tests it will be loaded bij attaching a dyno instead of a waterbreak. The plan right now is to add a radiator between the engine and the ibc tank cooling the water whilst it is returning to the tank

 

[anorlunda]

Our company also sells generators and those engines also have quite big radiator and fans.

There you go. Use one or more of those quite big radiator and fans. Just be careful about @Tom.G 's caution.

I say 'a few to many' because the intake water of a marine engine is at or below ambient temperature, whereas the radiator outlet temperature is well above ambient.

I hate to be environmentally insensitive, but there is also the choice of using fresh water once-through to cool the engine, then discard the warm water down the drain instead of recycling it. That water will have no rust-inhibitors but marine engines are designed for use with salt water.

 

[Baluncore]

Radiators need fans. It will rapidly become too difficult to arrange.

How often do you test your fire hydrants?
Have you considered connecting the cooling water input port to a fire hydrant, and the outlet to the storm water. Adjust the flow rate to maintain a stable output temperature, and minimise water used.