Steady state and transient simulation of a radiant heating system

Radiant heating generally addresses all heat emission systems that have a share of radiant heat emission greater than 50 %, compared to a convector or fan coil where the heat is transferred mainly by means of convection. Recently, so-called infrared-heating systems are increasingly discussed as a cost-effective heating system. Relative small areas with high surface temperatures of typically up to 120 °C are used. In order to investigate in detail radiant heating systems, building models able to reproduce accurately the occurring physics phenomena are required. Physics-detailed steady state and transient room models have been developed in Matlab®. The required view factors for the radiative exchange between all surfaces and between each surface and a sphere representing a person are calculated using COMSOL®. Moreover, the thermal comfort in different positions of the room has been evaluated. 1. Introduction The implementation of the concept of NZEB (Kurnitski et al. (2013) will lead to a further reduction of the heating demand of new buildings. Also the heating demand of the building stock will decrease by applying deep renovation. The technology to achieve very low energy demands is available since about 25 years, when the first Passive House was built in Darmstadt, Germany Feist (2016). Technology and products have been further improved since then and cost-effectiveness has been significantly improved. However, in order to improve the economic feasibility of these very efficient buildings, cost-effective heating systems are required. In parallel the share of renewable energies (such as PV or wind) in the electric grid will further increase. Both these developments make electric heating interesting again in spite of the fact that, because of thermodynamic principles, electricity should not be used for heating.