ELVHIS research project:
Gas fired radiant plaque heaters in modern industrial buildings
During renovation and building projects, infrared radiant plaque heaters play an important role in heating industrial buildings and shop floors. In 2011, with the aim of bringing existing studies of radiant luminous panels up to date, the German department of ELVHIS awarded the Dresden Institute for technical equipment of buildings and the University Zittau/Görlitz the following research project: what results are obtained for gas fired radiant plaque heaters with an indirect evacuation system for the combustion products in a modern industrial building, in terms of energy efficiency, thermal comfort and air quality?
Throughout the heating season, measurements were made in 10 representative industrial buildings built between 2004 and 2009. These values were further more checked on the basis of simulation calculations over a period of use of one year. This report gives an overview of the results of the study*.
* ELVHIS measurement campaign. Thermal comfort in modern industrial buildings heated by gas fired radiant plaque heaters. (Mr. Bolsius and Oschatz)
ELVHIS measurement campaign. Quality of ambient air in modern industrial buildings heated by gas fired radiant plaque heaters (Mr. Bolsius)
Thermal comfort is rapidly attained
For the thermal comfort felt in the occupied area and/or the work area of 10 industrial buildings, the mark “good” was awarded.
In most of the buildings examined, no significant air movement was observed in the occupied area. The infrared radiation from the radiant plaque heater causes an immediate increase in radiation temperature and therefore in the perceived temperature, and does so even when the air temperature is relatively low. In the light of the results obtained, radiant plaque heaters produce a homogeneous temperature distribution in industrial buildings. In a similar way, local heating for each area can be set up using this system. This type of point heating is often needed on production floors and in stores.
Air quality is excellent
Mark: From good to very good!
The air quality in all the industrial buildings examined (including those where a lot of welding work is carried out) is between “good” and “very good”. In all cases, actual air renewal is sufficient to ensure an air quality between “good” and “very good” in the occupied and/or work areas, with heating running. Measured carbon dioxide and carbon monoxide levels are much lower than the maximum admissible values. They are therefore considered to be non-critical. The measured concentration of nitrogen oxide was negligible in all cases. In as much as the air evacuation system was designed and installed in compliance with standard EN 13410, the results for the measurement and simulation of air quality show that the combustion products from radiant plaque heaters are extracted safely by the building’s evacuation system. Given the very good quality of the air in the buildings examined, it appears relevant from an energy point of view to modulate the extraction volume rate for appliances having several power levels.
Energy efficiency guaranteed!
Mark: Very good!
During the second stage of the research, simulation calculations enables the ITG to examine among other things the annual energy consumption of the radiant plaque heaters installed in 3 of the 10 buildings. In general, decentralised radiant plaque heaters have an advantage in energy consumption.
The heating power offered by these products can easily be adapted to the usual requirements of industrial buildings, with a supply of heat limited in time and space. With the effects of direct radiation from appliances placed at the ceiling, the air temperature measured in the buildings during the heating period is 2 K above the perceived temperature setting and between 1 and 3 K below the floor temperature.
In addition, stable air stratification with a low temperature gradient was observed in the buildings, outside the vicinity of doors.
The lower ambient air temperature in the occupied area, coupled with the low temperature gradient over the height of the room, are proof that radiant plaque heating systems give greater energy efficiency in large volumes.