Influence of heat gains on heat recovery in a two-zone-industrial building with several available hot refuse flows

Several refuse hot air flows with different flow rates and temperature potential are often generated by an industrial building. A recovery heat exchanger in an industrial building is used to heat incoming air for space heating by using the enthalpies of some mixture of these refuse hot-air flows. A proper scenario for use of their enthalpies is essential for efficient management of the energy system. Moreover, there are also in these buildings different heat gains so as from lightance and machines used in production process. Using a steady-state, bottom-up approach, a set of equations has been obtained. These equations have been linearized and linear programming used to develop LINEHG software. This software has been used for an industrial building with three refuse air flows, hotter and colder building zones and heat gains in these zones to obtain a use scenario corresponding to the highest energy-saving efficiency and minimum life-cycle costs of the recovery-heat exchanger. Depending on the heat gains in the colder and hotter zone of the industrial building, the enthalpies of different refuse-air flows can be recovered in different ways.