Plate heat exchangers in absorption lithium bromide thermal transformers
Energy efficiency of absorption lithium bromide thermal transformer depends on the depth of heat recovery in solution heat exchanger. In the article shell-and-tube and plate heat exchangers used in the absorption lithium bromide thermal transformers are compared. The appropriate design of plate heat-exchanger prototype with flat plate is presented, which is the basis for the development of heat-exchangers with the plates with convex-concave turbulizing surfaces. The evaluation of thermal-hydraulic characteristics of plate heat-exchangers has been made; the efficiency of their using in thermal transformers is shown. The optimum characteristics of the purpose-built plate heat transformers for Russian absorption lithium bromide thermal transformer are determined. For absorption lithium bromide thermal transformer with one-stage desorption system the recommended channel height of weak solution path in plate heat-exchanger is proved to be not less than 3.0 mm, and for absorption lithium bromide thermal transformer with two-stage desorption system - not less than 2.0 mm. For ABHM-1000Vn industrial refrigerating machine with one-stage desorption the characteristics of the recuperative heat-exchangers current in use and the upcoming ones are compared. It is shown that when using plate heat-exchangers with flate plates refrigerant saving is 15% in relation to the total refrigerant amount loaded into absorption lithium bromide thermal transformer; metal and labour savings for manufacturing absorption lithium bromide thermal transformer in relation to total weight is 5%.