This results in a required fresh air volume of approximately 60 m³/min for each 40' container. Some shipping companies, for example, P&O Nedlloyd, specify values of 100 m³/min in their construction regulations, since the maximum incoming air temperature in regions such as the Suez canal can be greater than 35°C. Germanischer Lloyd recommends 75 m³/min in their latest set of ventilation regulations and thus also assumes external temperatures above 35°C.
Design of an air cooling system for refrigerated
containers with mechanical air supply
| Sources of heat | ||||||
| Number of refrigerated containers | 100 | |||||
| Quantity of heat per container: | 10 | kW | ||||
| Container heat to be dissipated: | 1,000.0 | kW | ||||
| Fresh air flow per container | 60.0 | m³/min | ||||
| Air flow: | 360,000.00 | m³/h | ||||
| Approx supply air fan capacity (same for return air): | 163.64 | kW | 2,200 | (m³/h)/kW | ||
| Total quantity of heat to be dissipated: | 1163.64 | kW | ||||
| Heat dissipation | ||||||
| Incoming air temperature: | 35 | °C | PDs | 5,621.6 Pa | ||
| Moisture content | 80.0 | % | PD | 4,497.3 Pa | ||
| Enthalpy on entry | 110.27 | kJ/(1+x)kg | x | 0.029287621 kg/kg | ||
| Specific heat (per kg of air): |
10.30 | kJ/kg | ||||
| Exit temperature: | 44.73 | °C | ||||
| Exit moisture: | 47.6 | % | PDs | 9,448.4 Pa | ||
| Exit enthalpy: | 120.56 | kJ/(1+x)kg | PD | 4,497.3 Pa | ||
| Exit dew point: | 31.0 | °C | ||||
| Air density: | 1.13 | kg/m³ | ||||
| Quantity of dissipated heat: | 1,163.64 | kW | ||||
| Overall energy requirements | ||||||
| For powering the fans: | 163.6 | kW | ||||
| Total | 163.6 | kW | ||||
Table 12: Energy equation for cooling with air