초록 ▼

An improvement in defrosting an air-to-air heat pump system when in the heating mode. A bypass loop transfers refrigerant at a higher temperature and pressure than is normally cycled through the outdoor unit to an outdoor coil to defrost ice on the outdoor coil, The bypass loop includes a valve mova

An improvement in defrosting an air-to-air heat pump system when in the heating mode. A bypass loop transfers refrigerant at a higher temperature and pressure than is normally cycled through the outdoor unit to an outdoor coil to defrost ice on the outdoor coil, The bypass loop includes a valve movable between closed and open positions. A sensor monitors a preselected condition indicative of outdoor coil performance. A controller communicates with the valve and the sensor. Once the controller determines that a preselected set point of a preselected condition indicative of deteriorating performance has been reached, based on received sensor signals, the controller sends a signal to open the valve, allowing warm refrigerant to bypass expansion valves and flow to the outdoor unit to defrost the outdoor unit. Once defrosting is accomplished, the valve can be moved to a closed position to resume normal operation of the heat pump unit.

대표청구항 ▼

What is claimed is: 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

What is claimed is: 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 for allowing 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, the predetermined set point of the controller corresponding to a first temperature, and the controller being configured to provide at least one signal in response to a determination that the first temperature has been achieved in the outdoor coil; and a refrigerant bypass circuit to provide refrigerant 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, the at least one signal from the controller causing the valve in the bypass circuit to open, thereby permitting flow of hot refrigerant gas through the bypass circuit to the outdoor coil to defrost the coil, a timing means for determining closing of the valve in the bypass circuit after expiration of a preselected period of time after activation, the timing means further including an additional means of sending a signal at the expiration of the preselected period to cause the valve in the bypass circuit to close, 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. 2. The heat pump of claim 1 wherein the controller further includes a second predetermined set point and is configured to provide a second signal indicative of when the second predetermined set point has been achieved, the second signal causing the valve in the bypass circuit to close, thereby stopping flow of hot refrigerant gas through the bypass loop. 3. The heat pump of claim 1 wherein the controller is programmable and the timing means is a programmable function of the controller. 4. The heat pump of claim 1 wherein the controller is programmable to permit designation of the predetermined set point. 5. 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 for allowing 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 at 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 to provide refrigerant 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 bypass line having a first end and a second end, the first end of the bypass line positioned between a discharge line from the indoor coil and the expansion means, the second end of the bypass line positioned between an inlet line to the outdoor coil and the expansion means, the valve positioned in the bypass line between the first end and the second end, 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.