MICROCOMPUTER CONTROL OF GREENHOUSES. I. DEVELOPING CONTROL STRATEGIES FOR A LARGE THERMAL MASS.

Work is underway to maximize the use of a warm floor heating system as the primary greenhouse heating source. To date, simple thermostats control the floor temperature which can lead to an undesirable climate for plant growth. Because of the large thermal inertia of the system, temperature changes of the floor for a given heat input are relatively slow. Initial research has yielded equations which describe the temperature response of the floor to constant heat inputs. These equations incorporated into existing computer software offer improved overall greenhouse temperature control. Results from simulation studies and measured data indicate that classical control strategies will be effective in maintaining optimum climates for plant growth.