Abstract: For the purpose of fast design of fan-coil, a calculation model is established. According to different designers’ habits and requirements, three fan-coil design patterns are included in the model. The dichotomy iteration, based on the common laws of thermodynamics, is employed. Each design pattern has different known conditions, and accordingly, needs different variables and criteria chosen for iteration. To ensure the stability and validation of the algorithm in the maximal calculation range, non-reasonable input parameters are excluded precisely, and iterative methods of computing the apparatus dew-point temperature (outside wall temperature) , important for distinguishing between dry and wet conditions are developed. The calculation methods of the outside wall temperature in the second and third design patterns and some design example in the first pattern are particularized to illustrate the comprehensiveness, stability, accuracy and convergence of the model.

Key words: Algorithm, Apparatus dew-point temperature, Dry condition, Fan-coil, Wet condition