Open Access

Aaron Gerlinger, Jan Cremers, Uli Jakob, Michael Strobel

• The increasing demand for space cooling poses a major challenge to energy systems and buildings, both residential and commercial applications. Cost-effective and easily deployable solutions are widely needed to tackle this challenge. Heat emitted to the indoor from equipment is critical, particularly cooling units such as refrigerators and freezers. The impact of heat rejected from refrigerators on the indoor climate of small shops and supermarkets have been widely overlooked. This study presents and investigates an innovative and low-tech solution to control the heat dissipation of indoor cooling units, leading to increased comfort and reduced cooling demand. The solution, designed to be installed as a retrofit measure, controls the exhaust air ducting. Thus, it does not provide cooling, but manages the waste heat from refrigerators. This study includes the monitoring of an actual kiosk in Stuttgart, Germany, to meter refrigerators’ power consumption, a lab-scale prototype testing to prove the methodology of the solution and additionally dynamic thermal simulations via TRNSYS18 for different climates to analyze the performance and impact of the novel solution. The prototype showed the effectiveness of the control strategy during the lab-testing. The simulation results for Stuttgart show that controlled heat dissipation can reduce overheating degree hours by up to 97%, resulting in a potential cooling demand reduction of up to 83%. Overall, the findings reveal an underutilized potential in existing appliances to contribute to energy-efficient building operation and lay the groundwork for future research into optimization, control strategies, and broader application of such hybrid concepts.