Simulation and measurement of air temperatures and mean radiant temperatures in a radiantly heated indoor space

Abstract Environmental parameters relating to thermal comfort can be differently challenging to simulate and measure. Air temperature across an environment can easily be measured with multiple air temperature sensors, but its simulation is challenging because simulating changes in air temperature as a result of radiation, advection and convection from the presence of hot or cold surfaces in the environment is computationally intensive for the lengthy timescale required for building simulation. Conversely, measuring MRT is challenging as globe sensors tend to self-obstruct when arranged across space. Simulation of MRT is simpler because it requires only the temperatures of surfaces in an environment, and by comparison to air temperature is computationally ”cheap.” Bearing these challenges in mind, we measured and simulated the air temperatures and MRTs inside a radiantly heated workshop. The spatial variation of the MRTs were computed from measured surface temperatures and found to increase by 5 °Cat the elevation of 1.3 m, which is much larger than the variations observed in air temperatures. The variations in measured air temperature were up to 2 °C. This calls for improvement to current tools and methodologies for measuring and simulating the radiant environment, particularly at locations closer to the exterior envelope where hot and cold surfaces affect both air temperature and MRT. It is important to improve the evaluation techniques for MRT, as its spatial variation is much greater than that of air temperature.