Study of thermal performance of capillary micro tubes integrated into the building sandwich element made of high performance concrete

The thermal performance of radiant heating and cooling systems (RHCS) composed of capillary micro tubes (CMT) integrated into the inner plate of sandwich elements made of high performance concrete (HPC) was investigated in the article. Temperature distribution in HPC elements around integrated CMT was studied. Thermal heat flux on the inner surface of HPC element, and the increase of heat losses to the outside environment were carefully investigated. Calculations were carried out for different temperatures of the circulating fluid, different spacing between CMT and different thicknesses of the inner HPC layer covering the CMT. This paper shows that CMT integrated into the thin plate of sandwich element made of HPC can supply the energy needed for heating (cooling) and at the same time create the comfortable and healthy environment for the occupants. This solution is very suitable for heating and cooling purposes of future low energy buildings. The investigations were conceived as a low temperature concept, where the difference between the temperature of circulating fluid and air in the room was kept in range of 1–4 °C.