Air-water green house heating with tube gas heaters

Abstract

A new heating system for green houses has been proposed in the article. The air-water heating system consists of tube gas heaters (“air-air” and “air-water”) with multi-counter structure. Utilization of “air-water” heaters and “air-air” heaters with multi-counter structure leads to the reduction of heater surface temperature with sufficient total efficiency that is necessary for green house heating. Mathematical model of the heating system is proposed as a model of multi-counter hydraulic circuit with distributive parameters. The stationary and one- dimensional regime has been assumed. Main unknown parameters are pressure, temperature, density and velocity of gas-air mixture. The model includes the set of hydraulic and heat transfer differential equations for every linear tube heaters and equations of the first and the second circuit laws. Heat transfer equations are given for convection, heat conductivity and radiation processes from gas-air mixture into tube exchanger to air or water environment of the heater. Hydraulic equations are given for mass and momentum conservation of gas-air mixture. The task of heat and hydraulic regime calculation has been presented in this work. Algorithm for numerical solving of hydraulic and heat regime has been formulated. It is based on the evolutionary random search of more preferable (Rs –optimal) solutions. For the evolutionary search the convergence with probability 1. has been proved. Unknown quantity is the set of chord flows in the multi-counter heating system. The results of a numerical solution of the task of heat and hydraulic regime calculation have been considered.