Thermal comfort

The thermal comfort is the central concept of standard EN ISO 7730th He describes human well-being as a function of the heat.

The term is also defined as a quality criterion for heating or air conditioning systems. Apply here to the comfort several parameters, all of which can be changed independently of each other and be conditionally:

• Temperature level and temperature differences
• Radiation intensity and radiation differences
• Thermal currents and thermal stresses
• Melts and flows, vapor formation, sublimation

Physiology

Thermal comfort is achieved for the human physiology by a steady temperature setting and a uniform energy input.

HVAC

According to VDI guideline 6030 radiator shall be designed and arranged that " comfort deficits " such as cold case air, or cold walls are compensated. So radiators are as completely as possible to install windows below to mix cold air case and rising warm air and to cover the heat sink of the cold window surface by direct radiant heat from this heat source.

A space is perceived as pleasant, when the temperature difference between

• Wall surface and the air space less than 4 ° C.
• Foot to head height less than 3 ° C
• Various wall surfaces ( asymmetry radiation ) is less than 5 ° C.

, and if the air velocity and its turbulence is small ( no drafts ).

This requires the different land use individual temperature requirements of the users.

Modeling

The conditions for thermal comfort by heating were systematically treated in a paper by Ole Fanger.

As a result of heat engineering space simulation of indoor thermal condition is characterized by the air temperature and the radiant temperature of the environment. These temperatures are combined with different weighting (eg as a function of work intensity and air velocity ) for the operative room temperature ( perceived temperature ). Basic definitions of these variables and a free downloadable simulation model can be found in.

Ray model and the wave model

Heat radiation is a form of electromagnetic radiation and may cause damage to other radiation. So come under heat radiation skin damage similar to as in a direct contact with a hot surface. Also well known is the radiation damage by the sun.

In medical equipment, not only the superficial effect but also the effect in deeper layers of tissue will be considered.

An analogy to the electromagnetic pollution has not been found in the literature and in the German or English journalism ( Google, Stand: December 9, 2010).