Abstract: Disclosed is a heat pump heating/cooling system that uses a hybrid heat source that may include air heat, groundwater heat, brine and in-line heaters. The heat pump includes 1) a device for compressing, condensing, gasifying, and circulating cooling/heating media and exchanging heat with water refrigerant; 2) a device for storing heat energy in a storage tank; 3) a device for loading a load through a four-way fan coil unit; and 4) a control panel. To remove frost on the exterior of an evaporator, the evaporator is temporarily stopped, and brine at a temperature of 15° C. to 20° C., which receives groundwater heat from a brine heat exchanger and receives heat from an in-line heater, is supplied to a brine supply pipe installed around the evaporator to melt and remove the frost on the exterior of the evaporator and then is discharged at a temperature of ?3° C. to 5° C.

Abstract: An apparatus for defrosting an evaporator in a refrigeration system using an infrared emitting diode includes i) a frost detection sensor configured to receive a frost sensing signal from an output part of a control processor and to transmit a frost detection signal into an input part of a control processor, wherein the frost detection signal is generated by projecting infrared to the frost and receiving reflection-infrared from the frost; ii) a control processor configured to convert the frost detection signal into a digital signal in the signal converting part, to evaluate if the frost detection signal is higher than a threshold value which is set from a signal setting part, and to transmit the operation signal to the defroster, as well as the display signal to the signal display part; and iii) a defroster.