What is the temperature of room 3


Because of the individual perception and the adaptability of the human body, comfort cannot be measured uniformly. However, it is possible to create room conditions in which most people feel particularly comfortable. Since most of us spend more than twenty hours in closed rooms every day, this is anything but of secondary importance. In technical building planning, aspects of thermal comfort, i.e. the indoor climate and indoor air quality, must be taken into account. The main factors are the room air temperature, the temperature of the wall surfaces, the relative humidity and the air movement in the room. Another important parameter is the incidence of sufficient daylight (which, however, is not part of this article. For more information on the importance of daylight, see surfing tips.). If one or more of these parameters deviate from the values ​​perceived as comfortable, it can be Sick Building Syndrome that describes symptoms of illness that occur as a result of staying too long in buildings with insufficient comfort.

Room air temperature
The air temperature has the greatest influence on people's feeling of comfort. The temperature that is perceived as comfortable depends heavily on subjective criteria such as clothing, activity, age and gender. The comfortable temperature range in residential buildings in winter is between twenty and 23 degrees Celsius. In summer temperatures of up to 26 degrees Celsius are comfortable due to the lighter clothing.

Wall surface temperature
The comfort felt by a person also depends on the temperatures of the surfaces surrounding the room (walls, windows). Humans are in a radiation exchange with these surfaces. The mean radiation temperature can be influenced in a targeted manner, e.g. using heating surfaces or cooling ceilings. In order to achieve thermal comfort, components such as triple-glazed windows, partition walls, ceilings and floors should have a surface temperature of 18 to 19 degrees Celsius - so there are no unpleasant drafts.

Relative humidity
The relative humidity (φ in%) denotes the ratio of the actual steam content of the air to the maximum amount of steam that can be absorbed at the current air temperature. In rooms it should be at least forty percent, 55 percent relative humidity is perceived as more pleasant.

Air movement in space
Humans are sensitive to drafts because they increase their heat dissipation through convection and evaporation. A permanent air speed of more than 0.3 m / s is uncomfortable for people (except in summer). The colder it is and the more constant it comes from one direction, the more people perceive drafts. This makes air movement particularly critical in air conditioning systems in summer.

Indoor air quality
The room air should be rich in oxygen, odorless and low in pollutants. An important factor is the exhaled air enriched with carbon dioxide (CO₂). Humans perceive CO₂ concentrations as low as 0.1 to 0.15 percent by volume as bad air. Concentrations of around two percent can be tolerated for a short time; from three to four percent, breathing difficulties increase. The limit value for assessing the indoor air quality is the Pettenkofer value, which corresponds to a CO₂ concentration of 0.1 percent in the indoor air.

In addition to thermal comfort, people's wellbeing depends on their sense of smell. Air conditioning distinguishes between the source of the odor and the perceived air quality. The source of the odor is in Olf (from olfactory), where one olf corresponds to the odor exposure of a standard person (adult, showered, sitting). The perceived air quality is in Decipole (expressed by pollution). A decipole describes the perceived air quality caused by a standard person (1 olf) in a room that is ventilated with 10 l / s of pure air. This can be used to estimate how many people would rate the quality of the air in a room as “bad”. Odors can only be removed with adequate ventilation.

Air exchange rate
The air change rate n or the number of air changes is defined as the quotient of the outside air volume flow and the room air volume. The number with the unit 1 / h or h⁻¹ (per hour) indicates how often the room air volume has to be exchanged for outside air in one hour. The ventilation can be roughly dimensioned with the air exchange rate. Reference values ​​for this are:

  • Apartments 0.3 to 0.5 h⁻¹
  • Offices 1.0 to 2.0 h⁻¹
  • Meeting rooms according to occupancy
Outside air requirement
Based on the limit value, the Pettenkofer value for the CO₂ concentration, a guideline value for the outside air requirement of 30 m³ / h per person can be set. In rooms that are polluted with pollutants, that are smoked or that are used by sensitive people (allergy sufferers, sick people, babies), the air exchange rate must be higher.

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