3580 -- Commercial Building Temperature Recovery - Part 1: Design Procedure Based on a Step Response Model (RP-491) PDF

A mathematical model for estimating recovery response is developed based on the dimensionless step response of room temperature to zone heat input. Separate transfer functions are used to represent the walls, floor, and ceiling of a prototypical zone. Additional transfer functions are defined for each of several layered constructions made to represent the contents of a typical office building. A grid of three construction weights (light, medium, and heavy) and five one-node model time constants (5, 10, 20, 40, and 80 hours) is defined to represent a range of zone thermal characteristics. Dimensionless step responses of the resulting 15 prototype zones are generated by simulation. A design method, based on the generalised response curves, is presented as a graphical hand calculation procedure. A microcomputer implementation is developed based on a reduced order, single-input, single-output z-transfer function model and corresponding analytical expression for each of the 15 dimensionless simulated step responses. The recovery response model is experimentally verified in part II (the companion paper). The results of research project 491-RP pertain to heating and cooling load calculation (chapters 25 and 26 of the ASHRAE Handbook of Fundamentals [ASHRAE 1989]).