Research On The Optimal Design And Operation Of One And Half Stage Absorption Exchanger

A significant reduction in heating network return water temperature, can greatly improve the utilization efficiency of energy. Single-stage absorption heat exchanger, which makes absorption heat pump unit principle applied to the heat exchange system, can achieve that the backwater temperature of primary pipe network is lower than that of the secondary network. But the amplification limits the further reduction of the backwater temperature of primary pipe network. This paper proposes one and half stage absorption heat exchanger, in order to output a lower backwater temperature of primary pipe network by adding a set of evaporation- absorbing parts, which expands the scope of the application of heat transfer technology and increases thermodynamic perfection degree of the units.Paper outlines the working principle of one and half stage absorption heat exchanger, and studies from four aspects: the establishment of the mathematical model, the evaluation, optimum design and operational characteristics simulation. Specific work is as follows:(1)The thermodynamic and heat transfer process are analyzied. The mathematical model of the unit.is built. Giving full consideration to the preheating and boiling, the actual processes of evaporation, a new mathematical model of generator is set up. Fully consider the impact of the phenomenon of flash the absorber solution on the heat transfer process, improves the heat transfer model of the absorber.(2)Based on the technical feasibility terminal temperature difference of heat exchanger, a method used to solve its scope of application is put forward,.According to this method, quantitative analysis is carried out to study the expansion of the unit’s application scope and the influencing factors Besides, five indicators: degree of temperature, effective exchange heat and so on is used to analyze the rationality of the unit, and four to measure the safety of operation, which are unit heat ratio, crystallinity degree of safety, and the safety margin of dilute and concentrated solution.(3)In-depth study of a period of half an absorption heat exchanger unit optimized design, a suitable methods is be built to complete the design of the unit. The accurately reflect fixed asset investment of the unit, which is a accurate reflection of the unit’s cost according to market prices of the raw material and level of manufacturing techniques. A minimum of production cost by using genetic algorithm.(4)On the basis of the established mathematical model, an iterative solution method for the unit’s simulation Calculation model is proposed with good convergence and accuracy. Furthermore, the curves of the unit in a net source parameters and secondary parameters of network users secondary water distribution is be anaslyzed, and the influence of the cyclic flow regulation of dilute solution on the operating characteristics of the unit is be built And the adverse effects of the non-condensable gas accumulation on the heat transfer efficiency and safe operation of the unit are also analyzed quantitatively.(5)One and half stage heat exchanger design and simulation program is edited that can achieve internal parameter calculation unit, optimization, and evaluation unit operating characteristics analysis functions in four areas. For the unit design, production and commissioning theoretical basis.