The Low-Carbon economy enhances the use of renewable energy for indoor environmental control. River water could be a nice renewable energy as it can be used as a lowstand heat/cold source to control the indoor environment through Water Source Heat Pump (WSHP) units. However traditional WSHP units are not applicable because the high cost of water treatment to improve the present water property, and the advantages of the WSHP are badly restricted. To overcome the limits of the present WSHP units, we develop an integrated heat exchanger for which the river water or waste water can be effectively used as a cooling medium while heat exchange is keeping and the exchanger is being cleaning. The newly-developed heat exchanger can keep effective operation and well realize the energy saving.