Mold temperature control system and heat exchanger greatly reduces time of heating and cooling molds

The invention provides a mold temperature control system and a heat exchanger for cooling the mold to perform heat exchange. The system comprises a heating module, a cooling module, and a control valve module. The heating module comprises a heating loop, a hot water cylinder, an instant heat sensing heater, and a heat circulation pump. The cooling module comprises a cooling loop, a cold water cylinder, a heat exchanger, and a cold circulation pump. The control valve module comprises a plurality of heat and cold switching valves and controls heating water flowing to the heating loop or cooling water flowing to the cooling loop. When the mold requires cooling, the cooling water stored in the cold water cylinder flows to the mold through the driving of the cold circulation pump and flows back to the heat exchanger having a low temperature water passage to carry out heat exchange. The cooling water is cooled to a room temperature and stored in the cold water cylinder again to effectively increase heat exchange ef