Eddie discusses the importance how misunderstanding surrounds studio air conditioning and how ventilation that has taken on new dimensions since Covid.
The concept of air conditioning originates in a need for space comfort and began with air cooling systems to reject heat within a building. Today this has a wide range of meanings from basic cooling to full environmental control.
Best judgement of air conditioning is that, when in a building, it is transparent and people feel comfortable. Comfort is very personal and emotive because our sensations and perceptions of temperature and humidity vary, most differences being between males and females and these can depend upon body temperature, skin condition and exposure, as well as clothing type and amount. It is, therefore, virtually impossible to please many at the same time.
The design of any system needs to, so far as possible, account for and include human appreciation; for example we are mostly accustomed, from general movement, to air moving towards our face, for temperatures to be a little lower than body temperature such that we may experience out side on a pleasant day and reflect seasonal variations, conditions familiar to us that our senses are comfortable with. If our senses are disturbed they attract our attention and detract from what we are doing or, more importantly, annoy us.
Ventilation is key to comfortable conditions; without adequate fresh air CO2 and other contaminants will build up giving rise to fatigue, tiredness and worse. Systems recirculate air and introduce some fresh air; of concern is the quality of the air, in areas of dense road traffic the air can be heavily polluted and this will make conditions worse. Systems have air filters but many are simple dust filters and do little for air quality.
Green policies and safety; Covid, WELL and other examples have done much to build awareness and raise air quality. Where possible heat recovery is used to add additional filtering, improve air quality and conserve energy. Normal filters have negligible effect on Covid, a virus can be destroyed by UV (ultra violet light) and Ultraviolet C is germicidal and a class of light that is very harmful to humans; there are now filters that use UV-C and plasma that are effective and can lower infections. WELL International provides a flexible framework for improving health and human experience through design and offers assurance of achievement.
Controls can be very sophisticated and control temperature, air flow and humidity according to demand. Entry level systems have temperature and fan speed and these, in basic form, are referred to as split systems. Similar plant can be linked together, share an outdoor unit and provide simultaneous heating and cooling in differing areas, and this can provide huge efficacies and energy savings, however cost can be difficult to justify on smaller projects.
Humidity needs careful consideration because different parts of a building will have differing needs. For example a meeting room with sixty delegates will likely need additional humidity for comfort while a fitness area will likely need less humidity to help perspiration and the natural skin cooling process. For studios and small rooms natural humidity can, with careful design and planning, be used to create acceptable conditions; humans expel water in their breath and this can be used to sustain and possibly raise humidity values. Air conditioning units naturally remove humidity as part of their function to cool air passing through them; the cooling coil (over which the air passes) is cooled to a lower temperature than the air entering and this results in condensation on the coil and the removal of moisture – careful selection can reduce this effect.