Energy efficient residential ventilation control

A concept is investigated for the energy efficient control of residential mechanical ventilation in response to outdoor air temperature and the corresponding stack-driven infiltration. The control concept takes advantage of the natural air leakage characteristics of a house and the ability of temperature-driven stack infiltration to provide ventilation air to the house. As the outdoor to indoor temperature difference increases and natural infiltration increases, the fan operation is reduced, thereby minimizing over-ventilation. By reducing over-ventilation, the energy use associated with providing ventilation air (fan, heating, and cooling) is reduced when compared to a continuous or duty-cycle ventilation control scheme. Analysis results are presented for a test house in several climate zones to demonstrate reduction in ventilation energy use with the proposed control concept. For an unbalanced system in a moderately tight house, energy use is reduced by 26 to 30% for the climates investigated. For a two-story house, the use of temperature-based control allows a simple unbalanced ventilation system to operate with a total energy use comparable to a balanced system with heat recovery, in the three climates investigated, for all but the tightest houses. The proposed ventilation control method is shown to be an effective method for providing energy efficient residential ventilation control.