Energy saving in buildings by control of ventilation as a function of indoor carbon dioxide concentration.

Many mechanically ventilated buildings are over-ventilated since ventilation rates are based on a fixed number of people (often in excess of the average occupancy) and no allowance is made for infiltration. States that the CO2 concentration in the ventilated space can be related to the ventilation rate per person, and by modulating the fresh air flow to maintain a constant CO2 concentration, a constant ventilation rate per person can be obtained. Discusses the potential savings in energy due to this and analyses two case studies relating to CO2 concentration measurements carried out in a theatre and clothing store. In the case of the clothing store,the estimated cost saving results in an equipment cost pay-back period of about 2 years.