Abstract
In the previous paper (Part 1), an approximate transfer functions model was proposed for the heat conduction system of a multi-layer wall. Based on this model, the system is rewritten by the state equation and the output equation as expressed in eqns. (3.9) and (3.10). The system equation is converted into the time discrete domain by using the trapezoid hold function Gh_j(s) and Z-transform. The multi-layer heat transfer problems can be calculated successively by the state transition equation (4.2.6) and either types of the output equation (4.3.4) or (4.4.4). And then, we have following advantages on the calculation process : (a) time interval T can be varied at any time, (b) memory size occupied by the state variables can be reduced to half comparing with single input-output systems, and (c) the radiant heat exchange between interior surfaces can be considered in case of need. It is necessary, however, to examine some precise errors caused by discreting continuous variables. They are shown in Figs. (5.3.1), (5.3.2) and (5.3.3). Futhermore, the heat conduction through an actual slab is measured together with the heat balance at its outside surface under natural changes of outdoor air temperature, solar radiation, atmospheric radiation and wind velocity. Using data obtained this field experiment, the variation of heat flow at the outside surface is calculated. In this calculation, the outside surface film conductance is regarded as a time variable parameter and time interval T is taken as 0.5(h). Close agreement between observed and calculated values is shown in Fig. (6.1).
