A control system for a cooling system configured to selectively operate one or both of a condenser fan an evaporator fan in a reverse direction RD, measure power draw at the motor against configuration data and fan motor profiles, and determine if a blockage has occurred before the static pressure has reached a critical point static pressure where the efficiency, performance, and cooling capability of the cooling system is hindered and maintenance is required to clear the blockage. By determining if blockage has occurred before the static pressure has reached the critical point static pressure, an alert or corrective action can be taken.

A defrosting determination device includes: a condition specifying unit that specifies the air conditioning load condition corresponding to a pair of temperature inside the room and temperature outside the building based on condition information; a slope specifying unit that specifies the slope corresponding to the specified air conditioning load condition based on slope information; a frequency acquiring unit that acquires frequency information specifying the operation frequency of the motor; a calculation unit that calculates a threshold value by multiplying the operation frequency by the slope; a power information acquiring unit that acquires power information specifying power output to the motor; a decision unit that decides whether the power is equal to or less than the threshold value; and a determination unit that determines to start defrosting operation in response to the decision unit deciding that the power is equal to or less than the threshold value.

The resent invention provides a refrigerator comprising: a cabinet having a storage chamber; a door for opening and closing the storage chamber; a case having a discharge port through which air is discharged to the storage chamber; an evaporator provided inside the case and for supplying cold air by means of heat exchange with air; a fan installed on the discharge port and for generating the airflow discharging to the storage chamber the air which has been heat exchanged in the evaporator; and a differential pressure sensor having a first pipe, of which one end is positioned on a part where the air is withdrawn to the fan, and a second pipe of which one end is positioned on a part where the air is discharged from the fan.

Methods and system for providing de-icing a heat pump heat exchanger and heating a vehicle passenger cabin are presented. In one example, a heat pump that experiences icing of exterior heat exchanger fins may be operated in a cooling mode where a passenger cabin heat exchanger operates as an evaporator to improve de-icing of the exterior heat exchanger fins.

A system and method for controlling a refrigeration system is disclosed. The system includes a cooled compartment, at least one heat source selectively activated to provide heat, at least one sensor, and a controller. The sensor detects a temperature and a relative humidity of ambient air that surrounds the cooled compartment. The controller is in communication with the at least one heat source and the at least one sensor. The controller includes logic for calculating a dew point temperature based on the temperature and the relative humidity. The controller also includes logic for selecting a region of operation based on at least one of the dew point temperature and the relative humidity, where the region of operation is representative of ambient conditions that surround the cooled compartment. The controller further includes logic for determining if the at least one heat source is activated based on the region of operation.

Embodiments of the present disclosure are directed to a controller for a heating, ventilation, and/or air conditioning (HVAC) system. The controller is configured to operate in a first defrost mode or a second defrost mode, determine that feedback from a first sensor of the HVAC system is unavailable, receive feedback from a second sensor of the HVAC system, and operate the HVAC system in the second defrost mode instead of the first defrost mode in response to unavailability of the feedback from the first sensor and based on the feedback from the second sensor.

According to certain embodiments, a system comprises a controller and an HVAC system with components comprising an evaporator unit comprising an evaporator coil, an indoor fan, and a discharge air duct and a condenser unit comprising a compressor, a condenser coil, and an outdoor fan. The system is configured to determine that a first or a second level of evaporator coil freeze risk is present and to communicate an instruction to the HVAC system with a first or a second action to counteract the freeze risk. For example, in certain embodiments, the actions comprise changing the indoor fan speed, changing the compressor speed, and changing the outdoor fan speed.

In various implementations, frost in a vapor compression system may be controlled. A property of a fan may be determined. A determination may be made whether a frost event and/or a nonfrost event has occurred based at least partially on the determined fan property.

A refrigerating and air-conditioning system includes a plurality of independent refrigerating and air-conditioning apparatuses each including a refrigerant circuit and a defrosting unit, and further includes a system controller managing the apparatuses in an integrative manner. The system controller includes a defrosting operation control unit. When a time interval between an estimated defrosting start time calculated for a given refrigerating and air-conditioning apparatus and a subsequent estimated defrosting start time calculated for another refrigerating and air-conditioning apparatus is less than or equal to a predetermined target start time interval, the defrosting operation control unit transmits a defrosting start instruction signal to the defrosting unit of the given refrigerating and air-conditioning apparatus.

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.