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,

Charles CL