Conceptual thermodynamic design of a dual mode absorption cycle with an auxiliary heat exchanger
Abstract This paper presents a conceptual thermodynamic design and feasibility study of a dual mode absorption cycle with auxiliary heat exchanger. The system consists of two single stage absorption cycles connected through the condenser of the first stage with the generator of the second stage. The purpose of the auxiliary heat exchanger is to maintain the condenser (1) temperature sufficiently high to operate the generator (2). A case study, using a single fluid pair H2OLiBr in both the stages and two fluid pairs (H2OLiBr at first stage and NH3LINO3 at second stage) has been considered. It is found that the COP for the two pair system in comparison to the single pair system. However, the former has the advantage of providing simultaneous refrigeration and air-conditioning.
Since there exist extrinsic and intrinsic incubation periods of pathogens in the feedback interactions between the vectors and hosts, it is necessary to consider the incubation delays in vector-host disease transmission dynamics. In this paper, we propose vector-host disease models with two time delays, one describing the incubation period in the vector population and another representing the incubation period in the host population. Both distributed and discrete delays are used. By constructing suitable Liapunov functions, we obtain sufficient conditions for the global stability of the endemic equilibria of these models. The analytic results reveal that the global dynamics of such vector-host disease models with time delays are completely determined by the basic reproduction number. Some specific cases with discrete delay are studied and the corresponding results are improved.