Use of a radiator for user-centric cooling – Measurement and Simulation

Fraunhofer Institute for Building Physics IBP, 83626 Valley, Germany

^* Corresponding author: matthias.winkler@ibp.fraunhofer.de

Abstract

With further increasing temperatures during warm summers, cooling of buildings is becoming more popular even in moderate middle or northern European climate zones. Techniques that allow fast conditioning of rooms with intermittent usage, like conference rooms or certain types of residential rooms, promise high potentials for energy savings. Combining heat pumps, that can be used both in cooling and heating modes, with floor and wall heating systems can be a suitable technology. In many cases houses have a conventional heating system with radiators and the question arise if the oil or gas based heating system can be replaced by a heat pump. Mixed systems combining e.g.gas and a heatpump are also possible. For summertime cooling, the same system that is already installed for heating can be used and the radiators allow comparatively fast reaction times in theory. However, the system comes with potential shortcomings: Cooled surfaces increase the risk of condensation and mold growth significantly while higher surface temperatures decrease cooling power of the system. Also, the system’s reaction times have to be tested in realistic conditions. For a first prove of the system’s applicability a study with combined measurements and hygrothermal building simulations was performed. In a test chamber measurements of a system were conducted under controlled conditions. A simulation model in the hygrothermal whole building software WUFI^® Plus was developed and validated with the measurements. The research shows that the simulation model is able to represent the effects on indoor climate as well as condensation reliably.