# Climate calculation and determination of cooling capacity for tunnelling and mining

## We determine the required cooling capacity for your project!

Usually the initial question of our customers is: How much cooling capacity is required? Our WAT experts calculate the required cooling capacity for your project – even before the excavation of tunnels, underground sections or entire mining fields.

## Our workflow for the planning of your cooling system

### In case of complex projects:

#### Climate-pre-calculation (computer simulation)

For the determination of the required cooling capacity in cases of very complex and comprehensive projects, the climate-pre-calculation is essential. The climate-pre-calculation is a numerical calculation of the thermo- and fluid dynamics of air in the process of ventilation in tunnelling and mining.

By the help of computer simulation the heat exchange between air and rock as well as mining and conveying technology is calculated. This is done for continuous or auxiliary ventilation by use of air ducts including interactions with the exhaust air flow.

The result is a temperature forecast without air-cooling, that is the basis for the determination of the cooling capacity. Afterwards, in consideration of our  customers climate target a temperature forecast with air-cooling is made and the required cooling capacity is calculated.

#### Design of an air-side plan

Based on the results of the climate-pre-calculation the air-side plan is designed, in which all input parameters as well as the temperature forecasts without resp. with cooling and the required cooling capacity are represented.

#### Design of a water-side plan

The air-side plan is the basis for the water-side plan, in which the cooling system scheme is represented.

### Simplified approach:

#### MOLLIER- h/x-diagram

The determination of the required cooling capacity can also be done by a simplified approach, if not all basic conditions are known or the air temperatures have already been determined by our customers.

The so-called MOLLIER-h/x-diagram represents the change of state of humid air such as cooling, heating or mixing. For processes in which heat is emitted or absorbed, the required capacity for cooling or heating can be determined with the help of the diagram.

The simplified approach with the h/x-diagram always represents only one certain point in the whole ventilation system. In contrast to the climate-pre-calculation, influences through heat exchange between air and rock, air ducts or installed mining and conveying technology are not considered.

#### Design of a water-side plan

With the results of the analysis of the h/x-diagram, the required cooling capacity can be determined – even without a previous climate-pre-calculation. On this basis, the water-side plan can be generated subsequently. The plan shows the system scheme  including all required components in the cold-water circuit for air-cooling and in the cooling-water circuit for re-cooling.

### For all projects:

(see above)

#### Dimensioning of the cooling systems

water-cooled / air-cooled cold-water machines | air-cooling machines

#### Dimensioning of the heat exchangers

air-cooler | re-cooler | direct evaporator | HP/LP – heat exchanger

#### Dimensioning of pumps and further equipment

pump stations | filter stations | re-cooling plants | hydraulic separation

#### Design of the appropriate electrical scheme

(by request programming of a high-level control)