Dynamic Cooling Loads Of Ship Air-condition Analysis And Calculation

Calculation of the cooling loads plays an important part in the study of the air conditioning. The common method of the calculation of ship air conditioning cooling loads is rough, in which the conditions of cabins and outside are unchanged, the result is bigger ,then the system of the air conditioning works at part load, efficiency is reduced ,energy is wasted, equipment is damaged. In this paper, cybernetic method is introduced, the body's received heat and cooling loads are distinguished. Regarding the body's received heat as interferer function, cooling loads are output under the action of interferer, the relationship among interferer, heat storage and heat current is clear, the result is close to the real state .In this paper, on the basis of the Fourier heat transfer equation, mathematical model of the ship cabins' heat transfer is founded, on the assumption that the temperature of the ship cabin is invariant, the disturbance outdoors is analyzed. Temperature function and heat current function are obtained using Laplace transform, then the expressions of the response factors are deduced. Furthermore, the cabin's thermodynamics model is built, by means of which the body's received heat, cooling loads and the influencing factors are analyzed. In the end, the each hour's cooling loads of certain sailor cabin are calculated on March 19 along certain navigation area. Using the response factors, the influence of the air layers in the bulkhead on the cabin's thermal environment is discussed. By analyzing four kinds of wall structure, the conclusion is drawn that a structure contains air layer can withstand disturbance from outside and preserve heat better. Because it is inconvenient in course of seeking equation root of B(p) = 0, simplified means is presented .Compared the different thermal insulating materials' simplified result with the exact value , the applicability of the simplified means is discussed.The dynamic calculation of ship cooling loads can be provided in order to design appropriate ship air conditioner and determine the fresh air volume, it can save energy and optimum design.