
Correcting factors
Foul factors
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Foul factor m2 | Capacity factor | Absorbed power | |
°C/kW | factor comp. | ||
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0.044 | 1.000 | 1.000 | |
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0.088 | 0.987 | 0.995 | |
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0.176 | 0.964 | 0.985 | |
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0.352 | 0.926 | 0.962 | |
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Altitude factors
Altitude (m) | Capacity factor | Absorbed power | |
factor comp. | |||
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0 | 1.000 | 1.000 | |
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600 | 0.987 | 1.010 | |
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1 200 | 0.973 | 1.020 | |
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1 800 | 0.958 | 1.029 | |
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2 400 | 0.943 | 1.038 | |
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Correcting factors for real temperature of coil air intake at flows other than nominal
% Flow | 70 | 80 | 90 | 100 | 110 | 120 | 130 |
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Correction in °C on real | 5 | 3 | 1.5 | 0 | |||
temperature of coil | |||||||
intake temperature |
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Factors with water and glycol
Glycol can be used for antifreeze protection, or as brine for operation at low temperatures. We recommend the use of water and glycol when the discharge water temperature is below +6° C. The “Solution with glycol/freezing point” table gives the freezing point of water with glycol, and the “Recom- mended glycol concentration” table shows the glycol concen- tration needed, depending upon application.
Glycol contains anticorrosive and antifoam components that favour circuit protection.
Solution with glycol/freezing point
% Glycol weight per weight | Freezing point °C |
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0 | 0 |
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10 | |
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20 | |
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30 | |
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35 | |
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40 | |
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50 | |
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A mixture of glycol and water has a freezing point below that of pure water. Depending upon the concentration of glycol in the solution, an even lower freezing point can be achieved and this protects the circuit when the unit is off and ambient temperature is low (below 0° C). This table indicates freezing point in accordance with glycol concentration. This concen- tration appears in % per weight.
Recommended glycol concentration
LWT °C | Glycol % per weight |
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6°C > LWT > 0°C | 20 |
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0°C > LWT > | 30 |
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The glycol concentration in the water should be checked regu- larly to ensure adequate protection of the chiller.
Correcting factors
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| Nominal capacity |
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Ethylene |
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glycol |
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LWT |
| Air temperature at |
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percentage |
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by weight |
| condenser intake (°C DB) | |||
(%) |
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| 25 | 35 | 45 | ||
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| 5 | 1.045 | 0.902 | 0.754 | |
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| 4 | 1.004 | 0.866 | 0.726 | |
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| 3 | 0.962 | 0.83 | 0.697 | |
20 |
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2 | 0.921 | 0.794 | 0.669 | ||
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| 1 | 0.879 | 0.758 | 0.64 | |
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| 0 | 0.838 | 0.722 | 0.612 | |
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| 0.795 | 0.681 | 0.574 | ||
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| 0.764 | 0.652 | 0.545 | ||
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30 | 0.734 | 0.623 | 0.515 | ||
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| 0.703 | 0.594 | 0.486 | ||
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| 0.673 | 0.565 | 0.457 | ||
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Water flow correcting factors for ethylene glycol solu- tions
Ethylene glycol | Correcting | factors | |
percentage by weight |
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Water flow | Pressure drop | ||
(%) | |||
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20 | 1.035 | 1.16 | |
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30 | 1.075 | 1.27 | |
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20