Predicting the Time Response of a Building under Heat Input Conditions for Active Solar Heating Systems

摘要

A dynamic model has been developed to determine the response of a residential building to changes in heat input, and to predict room and air temperature changes. The model has been developed to simulate the response of a typical building for possible use with the LBL test facility that evaluates control strategies for active solar systems. The model must properly predict the rapid rise in room temperature resulting from addition of heat with a fan coil, must give the correct average building load, and must require only limited computational capabilities. The building is modeled as a three node capacitance-resistance network which can be solved to determine the room air temperature, interior wall temperature, and building-shell wall temperature as a function of time in response to heat input. Capacitance terms represent the thermal masses of the air within the structure, the interior walls, and the interior surface of the outer building shell. Resistance terms represent the resistance to the heat transfer from the interior and exterior walls to the room air, from the exterior wall to the outside, and from the room air to the outside by transmittance through windows and by infiltration. The heat input is provided directly to the air (as, for example, when a heating fan coil is turned on). The time dependent equations are solved using Laplace transforms to determine the building response to a step increase in heat input power. The dynamic response of the building's temperatures can be characterized in terms of the building heat loss coefficient, UA, and three exponential decay terms with appropriate time constants and weights. (ERA citation 05:015384)