radiateur tafelkoeler brandstofdagtank

Heat technology in a nutshell

Nobody can be an expert at everything. That is why we have listed a number of important points below to help you avoid known pitfalls and help you compare quotes.

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  1. Correct capacity and number of revolutions
  2. Ambient temperature
  3. Inflow temperature
  4. Height above sea level
  5. Required cooling airflow
  6. Radiator outlet temperature
  7. Extra head on the airside (duct allowance)
  8. Fan speed
  9. Fan material
  10. Fan capacity
  11. Pushing vs. suction fan
  12. Position cores
  13. Fin distance
  14. Water-glycol percentage
  15. Safe design
  16. Pressure loss on the waterside
  17. Pressure loss on the airside
  18. Duct allowance

1. Correct capacity and number of revolutions

Check whether the quote is calculated for the correct capacity and number of revolutions. Max power / standby power / prime power.

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2. Ambient temperature

To be provided by the customer; cannot be higher than the outside temperature. The minimum ambient temperature is important in order to determine the minimum glycol percentage. The maximum ambient temperature is used as the baseline for calculating the maximum temperature of the cooling air inflow in a radiator with a suction fan.

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3. Inlet temperature

The temperature of the cooling air inflow into the radiator; this is the actual inlet temperature of the air into the radiator, which includes the ambient temperature plus any radiation heat.

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4. Installation height above sea level

The air density decreases with increasing height above sealevel.

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5. Required cooling air flow

The required cooling air flow in order to achieve the required cooling results. The less air required, the lower the installed fan capacity. The required cooling air capacity with a suction fan must be calculated at the outlet temperature of the radiator.

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6. Radiator outlet temperature

The fan selection with a suction fan must take place at this temperature. Fan selection programmes or graphs are usually based on a temperature of 20°C.

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7. Duct allowance

You need this extra pressure to overcome obstacles such as attenuators, etc.

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8. Fan speed

Does this match the available transfer ratios? Has the rotation speed of the fan been checked for mechanical load?

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9. Fan material

Is the fan material anti-static (for ATEX applications)? What is the temperature range for which the fan material is suited?

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10. Fan capacity

What is the fan capacity? And at what temperature? What height above sealevel?

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11. Pushing vs. suction fan

With a pushing fan, the radiator supplier assumes that the fan will press the air through the radiator and therefore suck air over the diesel engine. This means that with a pushing fan the air always heats up as a result of radiant heat (unless not installed in front of the diesel engine). A pushing fan is often used for emergency power generators.

A suction fan sucks the air through the radiator from outside. The advantage of a suction fan is that the cooling air is as low as possible and use can be made of available airflow. That is why suction fan cooling is most often applied on driving equipment.

Whether you need a pushing or a suction fan is important for the design of the radiator: with a pushing fan the ambient temperature must be increased with radiant heat, but with a suction fan this is not necessary.

This means that it is very important that you provide us with information about all radiant heat in the room or area. This could be the radiant heat of the diesel and generator or that of a compressor if installed in the same space. If you do not provide this information, the radiator supplier will assume the radiant heat stated on the engine datasheet and will estimate the electrical losses based on the usual generator efficiency (in case of a gen set).

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12. Position cores

Are the cores next to each other or in front of each other? The advantage of placing them next to each other is that they are easier to clean.

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13. Fin spacing

Fin spacing is usually indicated in FPI (fins per inch). The more fins per inch, the higher the pollution. For dusty environments we recommend a FPI that is as low as possible, together with smooth fins. If the cooling air is filtered, then these requirements do not apply.

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14. Water-glycol percentage

Some engine suppliers require a ratio of 50% water and 50% glycol, while for others this ratio depends on the ambient temperatures (minimum and maximum).

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15. Safe design

A fouling margin of 5-10% is the norm

The inside and outside of the radiator will become polluted after a while, while sufficient cooling must be maintained. The fouling margin is usually calculated based on the heat to be extracted or as a function of the surface. With a 10% margin on the surface, the pollution margin is smaller than with a 10% margin on the heat to be extracted!

Design limits

Cooling water inflow and outflow temperatures. Always compare these with the critical values on the engine datasheet. Are the values below the critical values and above the values at which the thermostat remains fully open?

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16. Pressure loss on the waterside

The pressure loss on the waterside from the radiator together with the pressure loss of the piping/ ducts must not exceed the maximum level on the engine datasheet.

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17. Pressure loss on the airside of the radiator

Pressure loss on the airside is only important if the customer selects the fan himself.

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18. Duct allowance

In order to calculate the proper duct allowance please indicate installation; with or without silencers.

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