Patent ID: 7290600
Filing Date: 2007-11-06
Classification: F25B

Abstract:
1. A heat pump being reversible between a heating cycle and a cooling cycle, comprising: a compressor; an indoor coil; an outdoor coil; an expansion means between the indoor coil and the outdoor coil, the expansion means being in fluid communication with the indoor coil and the outdoor coil to allow flow of the refrigerant fluid between the indoor coil and the outdoor coil; a sensor for detecting a condition of the outdoor coil and providing a signal indicative of the condition of the outdoor coil; a controller including a predetermined set point and means for receiving the signal indicative of the condition of the outdoor coil, the controller being configured to provide at least one signal when the predetermined set point has been achieved; and a refrigerant bypass circuit between the indoor coil and the outdoor coil, the refrigerant bypass circuit being in fluid communication with the indoor coil and outdoor coil to provide refrigerant from the indoor coil to the outdoor coil at an elevated temperature, the refrigerant bypassing the expansion means, the bypass circuit comprising a valve operable between a first closed position and a second open position in response to the at least one signal from the controller, a refrigerant fluid supply means, the supply means providing refrigerant fluid to the valve from between the compressor and the expansion device, a refrigerant fluid discharge means providing refrigerant discharge fluid passing through the valve to the outdoor coil, the refrigerant from the refrigerant bypass circuit at an elevated temperature defrosting the outdoor coil when the bypass circuit valve is open.