SIMULATION FOR DETERMINING GREENHOUSE TEMPERATURE SETPOINTS

Abstract

ABSTRACT Two separately developed simulation models were linked and used to evaluate different environmental control strategies in Florida tomato production greenhouses. POLY-2 is a model of a double poly, quonset-style greenhouse typical of Florida. It is a dynamic model that realistically simulates environmental control equipment actions. TOMGRO is a dynamic crop model that simulates 1) growth, 2) development, and 3) quantity and timing of yield of tomatoes. Both models are based on independent empirical data sets used for calibration and validation, respectively. The two models were linked by incorporating POLY-2 into TOMGRO as a sub-routine. Historical weather data for Tallahassee, Rorida and Raleigh, North Carolina are used by the POLY-2 subroutine to simulate greenhouse environmental conditions which are used in turn by TOMGRO to simulate development and growth of the tomato crop. During simulation runs POLY-2 keeps track of heating fuel requirements and TOMGRO keeps track of tomato yield. Simulations over a range of setpoints showed that the optimal setpoint depends directly on the price of fuel, the value of the tomatoes, and location.