Hi All,

Good day to all.

Currently, i'm looking for the calculation of surface temperature of cooling pond with medium of palm oil mill effluent (POME).

This cooling pond is operated in plug flow system with retention time of 2 days for cooling.

On the upper layer of the POME, a layer of oil was found due to poor filtration after the palm oil extraction from the factory #

Generally the process is as below:

Factory

POME

Cooling Pond

Since there is a layer of oil on the top of the medium, evaporation is excluded from the heat transfer calculation. Conduction, convection and radiation are the main heat transfer involved.

Heat inputs:

1. qs = short-wave solar radiation,

2. qa = long-wave solar radiation,

Outputs:

1. qsr = reflected portion of qs,

2. qar = reflected portion of qa,

3. qbr = long-wave black radiation from water surface,

4. qc = conductive heat loss.

therefore,

qt = (qs + qa)-(qsr + qar + qbr) + qc

where,

qt = net heat flux across the air-water interface (pond surface).

Question:

May i know, is there any simplified equation for the above equation? As i found the following equation, but the equation included the evaporation, which is not fit to my current condition.

[The following equation aim to calculate the exit temperature of the medium]

dqt/dt = -K (Ts - E)

where,

dqt/dt : net rate of surface heat exchange,

K : heat transfer coefficient,

Ts : pond surface temperature,

E : equilibrium temperature.

where it simplified from the equation below:

qt = (qs + qa)-(qsr + qar + qbr + qe) + qc

where,

qe : evaporation heat loss.

Appreciate if anyone can share some idea or information at here.

Advance Thanks,

Limon.

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