Steady-state simulation of the seawater greenhouse condenser

Abstract

This paper presents an integrated steady-state model simulating the condenser of the seawater greenhouse in Oman. The developed model is capable of predicting the outlet air temperature and humidity, the outlet seawater temperature and the condensation rate. Validation experiments showed a good conformity between the predicted and measured values within the calibration ranges at high and low air flowrates. The mean predictive error (PE) for the predicted condensation rate was 15.25 and 22.67 ml/min at high and low flowrates, respectively and the index of agreement (IA) was 0.96 and 0.98, respectively. The model also accurately predicted the outlet humidity ratio with PE values of -0.00006 and -0.00018 kg/kg for high and low air flowrates, respectively and IA values of 1.00 and 0.99, respectively. The model showed a small discrepancy between the measured and predicted outlet air temperature but yet with an PE value of 0.35 and 2.44^oC at high and low air flowrates, respectively and IA values of 0.92 and 0.86, respectively. This discrepancy was not due to an inaccuracy related to the simulation but rather due to an inaccuracy related to measurements caused by the non-horizontal airflow pattern. The accuracy of the model to predict the outlet seawater temperature was excellent with an PE of -0.33 and -0.10^oC for high and low air flowrates, respectively and IA values of 0.98 and 0.99, respectively. Model’s accuracy was also evaluated using three additional statistical prediction indicators; coefficient of determination, mean absolute predictive error and root mean square error. It was found that all prediction indicators for high and low air flowrates were very good.