Numerical Evaluation Of Residential Ventilation Accompanied With Particle Filtration In Different Climatic Zones Of China

In event of fog and haze in developing countries,ventilation can bring the outdoor particulate matters into rooms and impose exposure to occupants.The indoor air cleaning in terms of particle filtration has to be operated.However,proper coordination of ventilation and indoor particulate filtration as cost-effectively as possible to get indoor CO₂,PM2.5 and VOCs concentrations within the acceptable levels remains unclear.Available studies on ventilation and air purification assume that the outdoor air is clean enough.Few studies address comprehensive evaluation of indoor air quality together with energy consumption.The most affordable means for residential ventilation and air cleaning remains unknown.This investigation adopted EnergyPlus to model ventilation with indoor particulate filtration in a residential apartment located in five cities in different climatic zones of China.The EnergyPlus software was validated with the measurement data obtained in a test room.Then the validated software was adopted to model ventilation with particulate filtration in a residential apartment located in different climatic zones of China.The ventilation and air cleaning modes included the natural ventilation without air cleaning,natural ventilation with indoor particle filtration,mechanical ventilation with particle filtration,and the hybrid mode of natural and mechanical ventilation.The evaluated parameters include CO₂,PM2.5,formaldehyde and TVOC concentrations,CADR and noise of air purifier,energy consumption,and utility bill.The mechanical ventilation in both the central and the decentralized types was modelled.The heat recovery for sensible and enthalpy modes under different heat recovery efficiency were evaluated as well.The feasibility of intermittent ventilation was evaluated,and a suitable replacement plan for the filter element of the purifier was proposed.The results reveal that the EnergyPlus software provided the transient ventilation rates,Indoor PM2.5 concentration when the purifier is turned on and CO₂ concentration when people are in the room in good agreement with the measurement.Indoor particulate filtration must be utilized in northeastern,northern and some southwestern regions with severe outdoor air pollution,The air purifier needs to replace the filter element after one year’s operation.While the indoor particulate filtration can be optional in southern China and the neighboring regions.The natural ventilation is the cheapest,however,the ventilation rate may be insufficient in more than 40%of the occupied time.None of the ventilation means is optimal for all of the time.It may require at least four years for the VOCs concentration decayed into the acceptable level if the lowest grade of building materials and furniture are used during infiltration ventilation.The decentralized mechanical ventilation can cut 20%of the utility expense as compared with the central ventilation.The mechanical ventilation in demand-controlled operation and its hybrid with natural ventilation can further reduce the energy consumption.However the cost reduction is not obvious.The heat recovery does not show favorable advantage in residential of five climate zones to minimize the operating utility if the recovery unit cannot be bypassed in transitional seasons.