P-54

Thermo-acoustic cooling, a solar-thermal technology is an interesting alternative renewable cooling solution to support efforts for reducing CO2 emissions in the build environment. A thermo-acoustic cooler is build-up from four main components: heat-engine, heat-pump and feed-back tubes. However, the technology is not yet considered mature and there are no cases documented which demonstrate their potential during building operation. Still, it can be noted that thermo-acoustic chillers have specific advantages such as: COP’s comparable to absorption chillers, a global warming potential of zero and they require little to no maintenance (Struck et al., 2016). Whilst laboratory tests of a thermo-acoustic chiller with 25 kW cooling capacity (THEAC 25) show that the system-design works, the design is iteratively improved to achieve the anticipated coefficient of performance (COP) of 0.5. Whilst the iterative THEAC 25 design in ongoing, a model of the thermo-acoustic cooler has been developed to assess the potential contribution of the system to provide comfortable indoor environmental conditions.

In this paper the authors document the model-based sensitivity of the THEAC 25’s cooling capacity to parameters such as exegetic efficiency, temperature gradient across heat engine and temperature of the temperature of the secondary cooling circuit. Furthermore, the model of the THEAC 25 is integrated with a model of a conventional office building located in Almelo. The aim is to quantify the energy savings by making use of a thermo-acoustic cooling technology and to identify means for optimizing building operation by for example introducing thermal storage. The paper concludes that, the THEAC 25 is: technologically, an interesting alternative solar thermal cooling solution to reduce emissions; has the potential to be implemented in office buildings to provide space cooling and thereby reduces electrical energy demand; and it shows an increasing cooling capacity in climates such as, but not limited to, Miami, Dubai and Seville.

References

Struck, C., Wit de, J., Weersink, A., Blok de, K., Owczarek, P., & Berkhout, H. (2016). Towards the application of thermoacoustic cooling in office buildings: performance governing parameters and models for performance predictions. Paper presented at the 12th REHVA World Congress, CLIMA 2016, Aalborg, Denmark.