A refrigerating and air-conditioning apparatus performs, even during a heating operation under air conditions leading to formation of frost, a defrosting operation while simultaneously continuing the heating operation and improves comfort through heating by securing an appropriate amount of ventilation. A plurality of refrigeration cycles independently performs a heating operation and a defrosting operation. By controlling a ventilation damper of an indoor unit that is to perform a defrosting operation to increase the amount of ventilation, a prior ventilation operation for securing the time-averaged required amount of ventilation including the period in which the defrosting operation is being performed is performed before the defrosting operation, and after the prior ventilation is terminated, the defrosting operation is started.

A device for heating by absorbing latent heat of solidification of water, including a compressor (1), a condenser (2) and multiple evaporators (E1, E2) connected in parallel, each evaporator (E1, E2) has an electronic expansion valve (D1, D2) at its inlet, a solenoid valve (V1, V2) at its outlet; after the evaporators (E1, E2) are connected in parallel, outlets of the evaporators (E1, E2) are connected to an inlet of the compressor (1) and inlets of the evaporators (E1, E2) are connected to an outlet of the condenser (2); an outlet of the compressor (1) is connected to an inlet of the condenser (2); the compressor (1), the condenser (2) and the multiple parallel evaporators (E1, E2) form a closed loop system through pipelines; there are circulating refrigerants in the closed loop system, and heating and deicing processes are realized through a circulation of refrigerants; the solenoid valves (V1, V2) at the outlets of the evaporators (E1, E2) are switched between opening or closing to realize switching between evaporating and deicing functions of the evaporators (E1, E2).

A hybrid heating system is disclosed. The hybrid heating system includes a compressor that is configured to compress refrigerant. The hybrid heating system further includes a first heat exchanger that is configured to adjust a temperature of water by exchanging heat between the water and refrigerant compressed by the compressor. The hybrid heating system further includes a second heat exchanger that is configured to evaporate refrigerant by exchanging heat exchange with exterior air. The hybrid heating system further includes a first boiler heat exchanger that is configured to increase a temperature of water using heat generated by combustion. The hybrid heating system further includes a second boiler heat exchanger that is configured to exchange heat between exhaust gas discharged from the first boiler heat exchanger and refrigerant flowing into the second heat exchanger.

A dehumidifier for operation within the 5° C. to 20° C. temperature range and 50 to 100 percent relative humidity range of air includes an evaporator, a condenser, a fan that draws humid air through the evaporator and condenser, and a compressor for pumping refrigerant fluid through both the evaporator and condenser. The evaporation temperature is maintained in the evaporator at least at −4° C., resulting in a temperature within the evaporator and at the outlet thereof being greater than 0° C., thereby preventing the formation of ice in the evaporator and allowing the operation of the evaporator to its full power all the time.

A heat pump system includes a heat exchanger coil and a heater configured to transfer heat to the heat exchanger coil. The heat pump system also includes a controller communicatively coupled to the heater. The controller is configured to activate the heater in response to determining that a detected temperature of the heat exchanger coil is below a threshold temperature for a threshold time period.

A device for heating by absorbing latent heat of solidification of water, including a compressor (1), a condenser (2) and multiple evaporators (E1, E2) connected in parallel, each evaporator (E1, E2) has an electronic expansion valve (D1, D2) at its inlet, a solenoid valve (V1, V2) at its outlet; after the evaporators (E1, E2) are connected in parallel, outlets of the evaporators (E1, E2) are connected to an inlet of the compressor (1) and inlets of the evaporators (E1, E2) are connected to an outlet of the condenser (2); an outlet of the compressor (1) is connected to an inlet of the condenser (2); the compressor (1), the condenser (2) and the multiple parallel evaporators (E1, E2) form a closed loop system through pipelines; there are circulating refrigerants in the closed loop system, and heating and deicing processes are realized through a circulation of refrigerants; the solenoid valves (V1, V2) at the outlets of the evaporators (E1, E2) are switched between opening or closing to realize switching between evaporating and deicing functions of the evaporators (E1, E2).

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.

A hybrid heating system is disclosed. The hybrid heating system includes a compressor that is configured to compress refrigerant. The hybrid heating system further includes a first heat exchanger that is configured to adjust a temperature of water by exchanging heat between the water and refrigerant compressed by the compressor. The hybrid heating system further includes a second heat exchanger that is configured to evaporate refrigerant by exchanging heat exchange with exterior air. The hybrid heating system further includes a first boiler heat exchanger that is configured to increase a temperature of water using heat generated by combustion. The hybrid heating system further includes a second boiler heat exchanger that is configured to exchange heat between exhaust gas discharged from the first boiler heat exchanger and refrigerant flowing into the second heat exchanger.

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.

Methods, devices, and systems for frost management of an evaporator are described herein. One device includes a memory, and a processor configured to execute executable instructions stored in the memory to receive operating information of a heat pump, determine a first set point of at least one of a number of components of the heat pump and a first operating temperature, receive a second operating temperature of the evaporator that is positively offset from the first operating temperature of the evaporator, determine a second set point of at least one of the number of components of the heat pump based on the second operating temperature, and modify a set point of at least one of the number of components of the heat pump to the second set point such that a heating mode of the heat pump is enabled for a heating interval length of the heat pump.