Absorption cycle principle

(1) Generator - (2) Refrigerant steam - (3) Condenser - (4) Evaporator - (5) Absorption unit - (6) Heating recovery unit

(7) Power supply as how water, steam, fumes, gases - (8) Cooling tower - (9) Chilled water

When a liquid evaporates, it absorbs the heat from its surroundings. For example, by pouring a drop of alcohol on your hand, you will feel a cold sensation because the alcohol, during the evaporation, absorbs the heat of the hand. The water can evaporate at a very low temperature in vacuum conditions; at 6 mm Hg of pressure in a watertight container, the water evaporates at 4°C.

Systema S.p.A. uses, as primary fluid, a mixture of water and lithium bromide.

The water acts as a coolant while the lithium bromide as an absorbent. The lithium bromide solution is highly absorbent and it can absorb the surrounding steam by keeping low pressure conditions.

The lithium bromide and the water solution are heated in the heat generator (1), causing the separation of the water and the consequent conversion in steam of high temperature (2).

The water vapor is condensed (3) by the water coming from the cooling tower (8).

In vacuum conditions, the refrigerant water condensed (at 4°C) is sprayed on the evaporator (4) and then it evaporates at low temperature, subtracting the heat from the water coming from the conditioning system (9) that is circulating within the evaporator (4). In this way, the water enters at 14°C and exits at 7°C.

The low temperature water vapor is absorbed by the lithium bromide present in the absorption unit (5), by transferring the heat directly to the cooling tower circuit (8) where it’s cooled down again.

For this reason, the initial solution of water and lithium bromide is reconstituted and it will be transferred again into the heating generator (1) in order to resume the absorption cycle by passing through the heating recovery unit (6) that improves the performances of the absorption chiller.

- Choose your favourite source to see how Systema coverts the energy thanks to the absorption chillers -