HVAC and VOCs: interaction between building systems and indoor VOC concentrations

HVAC systems in newly built or extensively renovated dwellings were all developed with the aim for energy saving with equal or better comfort. However, these systems (floor heating and DCV systems) have certain characteristics which increase the emissions of Volatile Organic Compounds (VOCs) and give VOCs the chance to accumulate to higher concentrations. This interaction is investigated based on dynamic simulations using a temperature and humidity dependent VOC emission model. 

A field-comparison of thermal comfort with floor heating systems and air conditioning systems in Japanese homes

Floor heating is characterized by small horizontal and vertical temperature differences, and might be especially suitable for Japanese homes where it is customary to sit on the floor. This paper compares thermal comfort in homes while floor heating systems and air conditioning systems were in use during winter. Each dwelling had both a floor heating system and an air conditioning system, each used on alternate weeks during the survey period.  Throughout the survey periods residents were asked about their current thermal sensation, thermal preference, overall comfort and foot-comfort.

An innovative floor heating application -Transfer of excess heat between two building zones

The performance of an innovative floor heating application is explored. A two zone building is studied; one zone is frequently overheated due to intensive solar gains while the second zone is essentially unaffected from incident solar radiation. The aim is to explore the possibility to simply extract excess heat from the overheated zone. The idea is to transfer extracted heat through the hydronic floor heating pipe to the second zone; hence, the heat demand for the second zone is decreased. Simulation results yielded a reduced indoor air temperature in the warm zone.


With radiant heating, it is possible to set room air temperature lower than when heating withair-conditioning because the human body is heated by a radiation. As room air temperature decreases,heat loss from walls and windows decreases, and so does the ventilation load. It is often said that theradiant heating, such as floor heating saves energy. This study calculates heat flow at the windows andthe walls of a living-room using computational fluid dynamics (CFD).


Experiments using human subjects have been conducted to investigate the physiological andpsychological responses to two different heating methods, i.e. floor heating and air conditioner, in ahighly insulated house. This paper describes a study on the effects of the heating methods on skintemperature changes by investigating changes in skin temperature caused by thermal conditions,sexual differences in skin temperature change, the correlation between declared scores and drops inperipheral skin temperature using the experimental results.

Floor heating and displacement ventilation

A question raised about displacement ventilation, is whether floor heating can be utilised without disturbing the thermal stratification in the room. See Figure 1.Q?Figure 1 Too much floor heating may destroy displacement ventilationThis paper deals with the possibilities and limitations to floor heating with displacement ventilation. This paper shows that floor heating can be utilised with displacement ventilation for both industrial and non-industrial premises for normal airflow rates and normal floor heating rates.

Transient modelling of convective movements in a dwelling cell

Numerical modelling of convective air movements inside a heated room was built, using a coupling of a zonal model and integral analysis. The model describes the heat transfer between air and walls, between different air layers inside the room, between air in the room and cold air jet from ventilation air supply, and between air and heat emitter. Experiments were conducted in a testing chamber with floor heating or heating by a hot water radiator, with steps in hot water and ventilation flow rates. Validation results are satisfying.

Study of indoor air quality air flow pattern in a room with floor heating

Airflow patterns, temperature and indoor air quality (ventialtion efficiency) are modelized in a room with floor heating. Results show that ventilation efficiency depends directly of diffusers layout.