Analysis of the temperature control characteristics of heated glasshouses using an analogue computer

Abstract Equations describing the temperature/time relationships for a heated glasshouse are used as the basis of an analogue computer simulation of a glasshouse heating system. Response characteristics obtained from the simulation show good agreement with comparable responses recorded in a glasshouse. The simulation has been used to compare the response rates of LPHW, MPHW and steam piped heating systems to changes in demand and to examine the effect of different values of controller sensitivity with proportional controllers. Glasshouse temperature recordings illustrate the performance characteristics of on/off and proportional controllers in commercial installations.