PCM cooling ceilings in the Energy Efficiency Center—passive cooling potential of two different system designs

• Two different kinds of cooling ceilings with PCM were measured in an office building.
• The cooling ceilings differed in the position of the PCM—below and on top of the water pipes.
• A passive cooling power of 10–15 W/m2 was measured for operative room temperatures of 26 °C depending on specific heat load.
• The passive cooling power of both cooling ceilings was quite similar.
• A PCM with a phase change temperature lower than 23 °C could improve the passive cooling power.

In the Energy Efficiency Center—the new R&D building of the ZAE Bayern—two different PCM cooling ceiling types are installed and monitored in two office rooms. The ceilings are connected to a water circuit and can be used for heating and cooling. The PCM ceilings are prototypes which differ in the positioning of the PCM layer: ceiling type 1 with the PCM on top of and ceiling type 2 with the PCM below the water pipes. It was found, that cooling ceiling type 2 had a better thermal connection between PCM and room. Nevertheless, the passive cooling power of the two different system designs was quite similar when measured as a function of the globe temperature. Passive cooling powers of 10–15 W per m2 PCM cooling ceiling area were measured for a globe temperature of 26 °C.