Design of helical coil condenser of small-capacity Water/Lithium Bromide absorption cooling machine

Absorption machines are considered as a good alternative to vapor compression systems in terms of energy efficiency and environmental impacts. However, they use undeveloped resources (industrial waste heat …) and renewable energy (solar energy …) as primary energy sources. These considerations focus on the intent of the market on small-capacity absorption machines for domestic applications. The major problem of absorption machines is the high investment cost, which is mainly due to the prices of different components of the machine. In fact, the current machines implement shell and tube heat exchangers, which are largely incompatible with small-capacity compact machines. In this context, we are interested in the study and the development of a falling film compact condenser which allows meeting these expectations and developing domestic absorption machines. This work aimed to size a new type of a falling film helical coil condenser used in an absorption machine operating with the couple water/Lithium Bromide (H2O/LiBr) and delivering a thermal power of 10 kW. It also presents a literature review on the transfer phenomena which react during the falling film condensation and various types and modes of condensation. A dimensioning model of helical coil condenser, based on the equations and the empirical correlations of heat transfer, was developed. The proposed configuration of the helical coil condenser has a great potential because of its compact size and the minimal weight for the design of our H2O/LiBr machine for domestic applications.