Cooling of fermentation tanks

Indirect cooling method: the refrigerant is a mixture of ethanol or glycol and water, it is cooled in the evaporator box of the ammonia refrigerator, the temperature is generally controlled at around -5°C, the refrigerant flows in from below and out from above.

Direct cooling method: The refrigerant in the cooling jacket is liquid ammonia and flows in a vertical flow type or horizontal flow type in a semi-circular tube. The liquid ammonia enters from above through the distribution tube and flows downwards.

Comparison of the two cooling methods

Compared to indirect cooling, direct evaporative cooling of liquid ammonia has the following advantages.

1. Energy savings of around 20%. The compressor operating temperature for direct evaporation is only about -5C.

In contrast, with indirect cooling, the compressor needs to be at a much lower temperature, thus

This results in a lower refrigeration capacity of the chiller. In addition, the refrigerant liquid ammonia can be delivered in much smaller quantities.

2. Less equipment is required. Direct cooling saves the alcohol or glycol water required for evaporation of liquid ammonia compared to indirect cooling. And also eliminates the need for an evaporator.

3. Fewer insulation materials are required and installation costs are lower. As the flow of liquid ammonia is reduced, the use of pipe diameter becomes smaller, plus the container is reduced, reducing the consumption of insulation materials, but also save installation costs.

The safety of using liquid ammonia

Due to these significant advantages, more and more breweries are using liquid ammonia direct evaporative cooling.

The use of direct cooling requires attention to several aspects:

1. Firstly, liquid ammonia is an irritating odour and can be flammable and explosive under certain conditions.It is toxic and its safety must be considered when designing.

2. Secondly, the working pressure of liquid ammonia is high, and the permeability is very strong, so the welding quality of the jacket of the fermenter is also required.The welding quality of the jacket is also high.

3. The key technology for direct cooling of the fermenter is the structure type of the jacket and the welding quality.