Abstract: An energy recovery ventilation system is described which allows for continuous fan speed control through pulse width modulation of direct current fans. The energy recovery ventilation described is capable of fine motor speed control without the disadvantages of high noise, low efficiency and a fixed number of speeds present in commonly-used speed-varying techniques used with alternating current (AC) fans. This may be accomplished through the use of direct current (DC) fans and pulse width modulation. A controller is used to optimize the ventilation and energy efficiency of the system through the use of several temperature sensors. The energy recovery ventilation also provides a control process for self-optimization of the energy recovery ventilation, in case the supply and exhaust airflows are unequal. An unbalance may be detected by calculating the thermal efficiencies of the exhaust and supply airflows.

Abstract: An energy recovery ventilation system is described which allows for continuous fan speed control through pulse width modulation of direct current fans. The energy recovery ventilation described is capable of fine motor speed control without the disadvantages of high noise, low efficiency and a fixed number of speeds present in commonly-used speed-varying techniques used with alternating current (AC) fans. This may be accomplished through the use of direct current (DC) fans and pulse width modulation. A controller is used to optimize the ventilation and energy efficiency of the system through the use of several temperature sensors. The energy recovery ventilation also provides a control process for self-optimization of the energy recovery ventilation, in case the supply and exhaust airflows are unequal. An unbalance may be detected by calculating the thermal efficiencies of the exhaust and supply airflows.