A refrigeration device equipped with: a cascade cycle; a storage unit having a storage space for an object to be cooled by a second evaporator; an internal temperature sensor that detects the temperature of the storage space; a control unit that determines a second rotational speed of a second compressor on the basis of a target temperature for the storage space and the detection result from the internal temperature sensor, and that determines a first rotational speed for a first compressor having a prescribed correspondence relationship with the second rotational speed; and a first power supply unit and a second power supply unit that supply power respectively to the first compressor and the second compressor on the basis of the first rotational speed and the second rotational speed determined by the control unit.

A refrigeration system for use with refrigerated LT and MT display cases in facilities such as supermarkets, has an absorption chiller that uses waste heat from a nearby source to provide cooling to the refrigeration system to take advantage of the synergy and improve overall efficiency of the refrigeration system. The cooling provided by the absorption chiller may be in the form of a coolant (e.g. water, glycol, water-glycol mixture, etc.) that circulates between the chiller and one or more of a pre-cooler, sub-cooler or condenser in the refrigeration system in a manner that uses waste heat from a nearby source to reduce the need for installed condensing capacity in the refrigeration system and improve thermal efficiency and obtain cost savings.

The invention provides the sectional regenerative third-type absorption heat pump which belongs to low-temperature waste heat utilization and refrigeration technique filed. It mainly comprises four generators, four absorbers, a condenser, an evaporator, a throttle, four solution pumps and four solution heat exchangers. The refrigerant vapor of the first generator is provided for condenser. The refrigerant liquid of condenser is provided for evaporator. The refrigerant vapor of evaporator is provided for the first absorber. The second generator and the second absorber, the third generator and the third absorber respectively form the driving heat sectional regenerative process. The third generator and the third absorber form the waste heat regenerative process. The first absorber, the second absorber and the third absorber supply heat to the condenser. The fourth absorber releases the low temperature heat. The sectional regenerative third-type absorption heat pump is thereby formed.