The rebuilding of three Danish supermarket CO2 booster refrigeration plants with heat recovery heat exchangers is in the planning phase. The systems are situated in buildings heated by local district heating grids. The heating and cooling load characteristics have been analysed for one of the installations and control schemes suggested based on the cost profiles for power and heating, including distribution costs and taxes. The sale of excess heat to the grids is evaluated as well as the value of using auxiliary cooling load for maximising the heat produced in heat pump operation mode. The experience from operation of plants with an earlier design is integrated and the payback time for the investments is estimated. The results are analysed considering the state of the heating systems in the building and the local cost structures. The estimated direct payback period varies between three to ten years.