Ongoing Commissioning of a High Efficiency Supermarket with a Ground Coupled Carbon Dioxide Refrigeration Plant

A significant reduction in the energy consumption and greenhouse gas emissions of supermarkets can be reached by the combination of several innovative components and the continuous optimization of their operation. A German food retail chain developed a new supermarket concept combining several innovative solutions for the refrigeration, lighting and heating/ventilation with the goal to reduce the energy consumption by about 30% compared to a standard subsidiary. A highly insulated building envelope, the use of daylight and covered refrigeration units contribute jointly to reach the goals. The key component of the concept is a carbon dioxide refrigeration plant with waste heat recovery. To reduce the efficiency losses in supercritical operation, carbon dioxide is cooled through a borehole heat exchanger using the ground as a heat sink. In the paper the design concept, the results of simulation studies and of the first monitoring year are presented and discussed.