Airtight modern buildings that reduce heat losses have an unfortunate side effect – a decrease in the volume of fresh air that may cause serious problems. An airtight room turns into a sealed chamber with high concentrations of carbon dioxide (CO2). High levels of carbon dioxide can decrease employees’ productivity, cause health problems for the building occupants and become the cause of the Sick Building Syndrome (SBC). The old German proverb ‘Throw the baby out with the bathwater’ has come true in Ukraine: energy saving measures have caused bigger problems like the sick building syndrome. According to the World Health Organization (WHO), indoor air quality is more important for human health and well-being than outdoor air quality. The sick building syndrome is a medical condition where people in a building suffer from acute discomfort or feel unwell for no apparent reason. The symptoms tend to increase in severity with the time people spent in the building and can develop into various chronic diseases. The sick building syndrome and building-related illnesses include the following health risks:
• Transmission of infectious diseases from one person to another;
• Allergic reactions caused by indoor allergens, such as dust mites, pollen, fungal spores and metabolites;
• Exposure to chemical toxic agents generated within the indoor environment;
• Carbon monoxide poisoning..
Health effects of carbon dioxide concentrations are shown in Fig.1.
Heat recovery ventilation, which provides a healthy, comfortable indoor environment, is the best way to solve this problem. Figure 2 shows a recuperator with cross plate heat exchangers. This recuperator takes heat from the extracted indoor air to heat the incoming fresh air.
Fig.3. shows a recuperator connected in series with an air quality sensor