EXERGY-BASED CONTROL STRATEGY IN A DWELLING VENTILATION SYSTEM WITH HEAT RECOVERY
The paper presents energy and exergy analysis of a typical dwelling ventilation system with heat recovery for Ukrainian climatic conditions using a quasi-steady state approach over 24-hour time-steps. Evaluation of such systems on the base of the first law of thermodynamics demonstrates that heat recovery is beneficial for the whole variety of operational modes. Such methodology identifies as a thermodynamic inefficiency only energy losses to the surroundings with the exhaust air. The exergy-based analysis can detect additional inefficiencies due to irreversibilities within the components of the system. As a result the exergetic investigations show that for the ventilation systems there are operating conditions for which heat recovery increases exergy of fuel expended to provide the ventilation air compared to cases without bringing any recovery of heat and additional power consumption to drive the air flow by the fans. For the specified system, in case of switching ventilation unit to the operation mode of lower values of spent fuel exergy it is possible to provide annual saving of the primary energy sources from 5 to 15%.
ventilation system; exergy analysis; control; heat recovery; exergy saving
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