Abstract: An improved heating and cooling system is provided which also includes dehumidification and energy recovery capability. The system includes two or more heat pump circuits operating singly or in concert to provide heating, singly or in concert in reverse to provide cooling, or concurrently but oppositely to provide dehumidification only, dehumidification concurrently with heating, or dehumidification concurrently with cooling. The system is adapted to include desuperheaters while being simultaneously providing heating, cooling, or dehumidification.

Abstract: A control apparatus for a gas injection type air conditioning system that prevents lowering of compressor speed and cycle stoppage under conditions where high pressure is liable to occur. During a system heating mode, a pressure change rate ASP of the high pressure of the refrigerating cycle is calculated. When a pressure change rate .increment.SP rises above a predetermined value, a system electric expansion valve aperture is reduced. Accordingly, by calculation of the pressure change rate .increment.SP, it is possible to control the electric expansion valve in the above manner earlier than in prior art control schemes when there is a sudden rise in the high pressure.

Abstract: A device for selectively controlling the direction of blood flow to and from the patient during hemodialysis comprises two interlocking disks that rotate in relation to each other without separating. The two disks have fluid fittings that allow the blood lines attached to the patient to connect to one of the disks and the blood inlet and outlet for the hemodialysis machine to connect to the other. The center of each fluid fitting is a channel that aligns to a corresponding channel in the other disk. The disks rotate between two fixed relative positions, referred to herein as preferred alignments. The preferred alignments are such that the line drawing blood from the patient in the first preferred alignment becomes the line returning blood to the patient in the second preferred alignment, and the line returning blood to the patient in the first preferred alignment becomes the line drawing blood from the patient in the second preferred alignment.

Abstract: An air-conditioning apparatus forms a refrigerating cycle with a refrigerant heater and a compressor having two cylinders. The apparatus simultaneously carries out a refrigerant heating operation and a heat pump operation when a required heating capacity is high, and when the required heating capacity is low, only the heat pump operation. This operation technique helps reduce the size of the apparatus and expand a variable width of heating capacity. The apparatus also has a defrosting unit for defrosting an outdoor heat exchanger during the heat pump operation.

Abstract: A heating control apparatus of an air conditioner and method thereof are provided to control an indoor fan according to temperature of an indoor heat-exchanger at an initial heating stage of the heating operation, thereby preventing cool air from being discharged indoors, the air conditioner having an indoor heat-exchanger to heat-exchange the room air circulated by an indoor fan and a compressor to circulate a coolant for being heat-exchanged at the heat-exchanger, the apparatus comprising: a temperature detecting unit to detect the changing temperature of the indoor heat-exchanger with the compressor being maintained at the operation state during the heating operation; a controlling unit to control the operation of the indoor fan by counting the time according to the temperature of the indoor heat-exchanger detected by the temperature detecting unit; and an indoor fan motor driving unit to turn the indoor fan off according to the control of the controlling means in order to prevent cool air from being disch

Abstract: An inexpensive control system for a multiple-type air conditioner makes it possible to automatically and independently detect frosting and conduct defrosting control in an outdoor unit during a reverse cycle heating operation in a two-compressor, multiple-type air conditioner which has an outdoor unit equipped only with a simple ON/OFF control function and which is not provided with a signal conductor for transmitting the information on the state of an outdoor unit to an indoor unit. In this case, the operation of the outdoor unit can be determined, monitored, and controlled from the indoor unit side so as to enable proper action to be taken. The control system is provided with means for independently controlling the operation of the outdoor unit and means for determining the operation of the outdoor unit from the indoor unit side according to the state of an indoor side heat exchanger and for controlling the operation of the air conditioner.

Abstract: A heat pump system has a separate outdoor coil which is mounted below the primary outdoor coil and connected in parallel with it by valves. On system start up in the heating mode, the inlet of the auxiliary coil is closed, and the outlet is opened so that compressor vacuum will boil off the more volatile, high pressure components thus filling the system. The outlet valve is then closed trapping the low pressure component in the auxiliary coil. In a second embodiment, the accumulator is utilized to assist the auxiliary coil in vacuum separation of the refrigerant blend. Variants include blocking flow through the expansion valve on start up.

Abstract: A first heat exchanger implements heat exchange between refrigerant and atmosphere. A second heat exchanger implements heat exchange between the refrigerant and air directed to an interior of the vehicle. A third heat exchanger downstream of the second heat exchanger implements heat exchange between the refrigerant and the air directed to the interior of the vehicle. A four-way valve connected among a refrigerant flow restricting device, the first heat exchanger, the second heat exchanger, and the third heat exchanger for changing a flow path of the refrigerant. A bypass device allows the refrigerant to selectively flow through the second heat exchanger and bypass the second heat exchanger. During a first mode of operation, the refrigerant is circulated sequentially through a compressor, the third heat exchanger, the four-way valve, the first heat exchanger, the refrigerant flow restricting device, the four-way valve, the second heat exchanger, and the compressor.

Abstract: In a heat pump system operating in the heat cycle mode, a sensor is provided for sensing either the pressure or temperature of a refrigerant. A speed controller receives an output of the sensor so that the speed (including cycle rate) of an evaporator fan is controlled, resulting in control of the pressure or temperature of the refrigerant. The temperature or pressure of the refrigerant is controlled for a heat pump system comprising one refrigeration circuit and more than one refrigeration circuit. A separate speed control is provided for a fixed speed motor, a sleeve bearing fan motor, and a variable speed ball bearing fan motor.

Abstract: A method for continuously operating a multi-temp refrigeration system at a high compressor speed is provided. Such refrigeration systems include a compressor for compressing a refrigerant at a high speed and a low speed, a condenser coil for receiving and liquefying gaseous refrigerant, first and second evaporator coils for heating or cooling two different conditioned spaces, a hot gas valve for admitting hot gaseous refrigerant to one of the evaporator coils in order to heat its associated conditioned space, and a condenser inlet valve for rerouting a flow of hot gaseous refrigerant from the condenser coil to the evaporator coils. In the method of the invention, the evaporator hot gas valve is first opened to heat one of the conditioned spaces, and the condenser inlet valve is then closed to direct a flow of hot gaseous refrigerant to the opened hot gas valve.

Abstract: According to the present invention, in a gas injection type heat pump apparatus, the high-pressure side pressure of refrigeration cycle is detected in a heating operation, and an upper limit value of an amount of air passing through an inside heat exchanger is determined based on the detection value. The upper limit value and a set air amount set by an air amount switching lever are compared. When the set air amount is larger than the upper limit value, the amount of the air passing through the inside heat exchanger is restricted within the upper limit value. In this way, the high-pressure side pressure increases, and an intermediate pressure in a gas-liquid separator also increases. Therefore, the gas injection amount can be increased, and a heating capacity can be effectively improved.

Abstract: A defrosting control method wherein an indoor unit determines whether a drop in the temperature gradient of an indoor side heat exchanger has been caused by a heavy load protecting operation or frosting of the outdoor heat exchanger during a reverse cycle heating operation of a two-unit-type air conditioner. The defrosting control is not triggered when the heavy load protecting operation is being carried out, and the defrosting control is started when predetermined conditions are satisfied, including the temperature of the indoor heat exchanger being below a raised predetermined temperature during a heavy load protecting operating.

Abstract: An air conditioning system usually referred to as an electric heat pump, which employs reverse cycle refrigeration apparatus to condition air inside a building for heating in the winter months, and for cooling in the summer months, utilizing one heat exchanger coil disposed in heat exchange relation to the flow of conditioned air circulating within a building, and two heat exchanger coils disposed in heat exchange relation to the flow of ambient air circulating outside a building, wherein each said heat exchanger coil comprises a separate and singular component part of a single air conditioning circuit connected to, and served by one single compressor; and wherein, each of the said outside heat exchanger coils are designed to change functions independent of the other, from that of an evaporator, to that of a condenser, for the purpose of inhibiting the accumulation of frost on, and/or removing frost from said outside heat exchanger coil when the heat pump is operating in the heating mode without reversing the

Abstract: An air conditioner for a vehicle has a heat pump type refrigerant circuit capable of operating at least in a heating mode. The air conditioner comprises a motor fan for supplying air heated by a heat exchanger to the interior of the vehicle during operation of the heating mode, a sensor for detecting the temperature of the air at a position downstream of the heat exchanger and a control unit for controlling the volume of the air supplied by the motor fan to a predetermined minimum volume by controlling the drive of the motor fan when the detected air temperature is lower than a predetermined temperature. Even in a condition where a sufficiently large heat radiation from the heat exchanger cannot be expected, a large volume of cold air that has been insufficiently heated can be prevented from being discharged into the interior of the vehicle.

Abstract: An air conditioner for a vehicle includes a heat pump system for heating and cooling. The air conditioner includes a ventilation passage for ventilating air from a passenger compartment of the vehicle outside of the vehicle. An accelerating system is provided with the heat pump system for accelerating the evaporation of a refrigerant during air cooling or the condensation of a refrigerant during air heating by using involved energy recovered from air exhausted outside of said vehicle through the ventilation passage. Thereby, the air conditioner increases the heating and cooling ability and reduces the energy necessary for maintaining a constant temperature in the passenger compartment.

Abstract: In a heating mode, the fluid in the air conditioning circuit flows in a bypass branch avoiding the condenser. The evaporator then receives the fluid in the gaseous state and acts as a heat exchanger for dissipating the heat produced in the compressor. The heat dissipated by the evaporator may be employed to heat the cabin when that produced by the drive motor of the vehicle is insufficient. In addition, special configurations of the circuit enable the mass of fluid flowing in the heating loop to be increased or reduced with a view to regulating the calorific power produced.

Abstract: In a radiation type air conditioning system for cooling or heating fluid such as air or refrigerant through heat exchange and supplying the cooled or heated fluid into a radiant panel to radiatively cool or heat a room, the air is cooled by a heat exchanger (evaporator), and the cooled air is supplied onto the radiation face of the radiant panel by a fan to prevent dew condensation on the radiation face of the radiant panel. If the air which is cooled and dried by the evaporator is heated by a heater when it is supplied onto the radiation face of the radiant panel, the dew condensation preventing effect can be enhanced. Further, plural through holes are formed in the radiation panel and the cooled air is blown out onto the radiation face through the through holes, so that the dew condensation preventing effect can be enhanced.

Abstract: The temperatures of a plurality of rooms are controlled by a refrigerant cycle which enables a user to select desired room temperatures and one of the following operating modes: (i) supplying hot refrigerant to the indoor heat exchangers of all rooms, (ii) supplying cold refrigerant to the indoor heat exchangers of all rooms, and (iii) supplying hot refrigerant to an indoor heat exchanger of one room and cold refrigerant to an indoor heat exchanger of another room.

Abstract: A heat pump apparatus includes a compressor, an expander, at least three heat exchangers and a cooling-medium route switchover device for switching over cooling-medium (refrigerant) route to the heat exchangers so as to selectively provide a two-evaporator operation mode in which two of the heat exchangers are used as evaporators and the other heat exchanger is used as a condenser and a two-condenser operation mode in which two of the heat exchangers are used as condensers and the other heat exchanger is used as an evaporator. The heat exchangers used as evaporators in the two-evaporator operation mode or as condensers in the two-condenser operation mode are serially connected with each other.

Abstract: A thermal zone demand controlled dual cascade arranged heat pump system and system controller for building spaces, having first and second heat pumps and having an air circulation system for circulating air to and from said thermal zones and including a conditioned air chamber having first and second heat exchange refrigerant coils being connected in refrigerant circulating relation respectively with the heat pumps. A plurality of thermal zone blowers conduct conditioned air, heated or cooled, from the conditioned air chamber to respective thermal zones of the building space. Electronic controller circuitry of the system is coupled for thermal demand control of the heat pumps and the thermal zone blowers for operation of the first heat pump to accommodate a predetermined range of thermal load and for operation of the second heat pump along with the first heat pump to accommodate a greater thermal load.

Abstract: In a transport temperature control system having a cooling and heating mode of operation an apparatus and method are provided for enhancing the heating capacity during the heating mode of operation. A second expansion valve is provided to connect the higher pressure liquid line to the refrigerant circuit downstream of the evaporator. When additional refrigerant is needed in the heating circuit to increase heating capacity, especially during low ambient temperature operating conditions, the second expansion valve is caused to open to admit more refrigerant to the system. After passing through the second expansion valve low pressure gas is passed to the compressor, optimizing compressor efficiency such that an increased amount of hot refrigerant gas is delivered to the evaporator for enhanced heating capacity.

Abstract: A direct expansion ground source heat pump operable in heating mode and cooling mode. The heat pump comprises an outdoor coil, an indoor coil and a compressor. The outdoor coil and the indoor coil are coupled to the compressor through a reversing valve and the compressor provides a refrigerant flow through the coils. The indoor coil and outdoor coil are coupled together through a controllable valve. The outdoor coil comprises two coil circuits. In heating mode both ground coil circuits are active, while in cooling mode, the heat pump utilizes one of the coil circuits and alternates between coil circuits each compressor cycle.

Abstract: A heat pump type air conditioner having a heat gas engine having a radiator and a cooler, an outdoor heat exchanger provided in an outdoor unit and an indoor heat exchanger provided in an indoor unit, is further provided with a heat exchanger in the outdoor unit and/or the indoor unit, and control means for controlling water flow in first and second passages so as to perform cooling/heating operation. When slightly-heating or slightly-cooling dry operation or defrosting operation is required, a part of the hot water from the radiator is allowed to selectively flow through the second fluid passage into the heat exchanger by adjusting opening degree of open/close valves disposed between the first and second fluid passages.

Abstract: The invention prevents the temperature of supplied air from being decreased by a defrosting operation when a vehicle is in operation. During the heating operation, it is judged whether the vehicle is in operation. When the vehicle is in operation, it is judged whether an external heat exchanger is frosted or not relying upon the external air temperature, temperature of the external heat exchanger (coolant) and the time of heating operation. When it is judged that frost is formed, the rotational speed of the compressor is increased to increase the ability to supplying the coolant, to maintain heating ability and to prevent the drop of temperature of the supplied air. When the frost is formed after the operation of the vehicle has been finished, it is judged whether the secondary batteries are being charged or not, i.e., whether the charging circuit of the secondary batteries is connected to the external power source for charging or not.

Abstract: A method for controlling a transport refrigeration system is provided that advantageously avoids the top-freezing of items stored in a conditioned space without the need for modulating the flow of refrigerant through the heater-evaporator coil that heats and cools the space. The method includes the steps of operating the refrigeration system in a cooling mode at high speed for no more than 300.degree. minutes below the temperature set point of the conditioned space to rapidly cool the space. Next, the system is operated in a low speed heating mode in order to raise the temperature of the conditioned space to no more than about 5.degree. F. above set point in order to avoid top-freezing items in the conditioned space. Thirdly, the refrigeration system is operated in a low speed cooling mode to reattain a temperature set point assigned to the conditioned space. If necessary, these three basic steps of the method may be reiterated in order to stabilize the temperature of the space at set point.

Abstract: An air conditioner for vehicles includes a refrigerant circuit having a compressor capable of varying its output, a heat sink and a radiator disposed in an air duct for cooling operation, heating operation and dehumidifying operation modes; sensors for detecting air temperatures at the output-side positions of the heat sink and the radiator, respectively; and a control unit for controlling the output of the compressor in response to at least one of the detected air temperatures. The heat absorbing action due to the heat sink and the heat radiating action due to the radiator are appropriately controlled in the refrigerant circuit side in the respective operation modes without unnecessary heat absorbing and heat radiating actions. Further, the temperature of the air discharged from the air duct into the interior of the vehicle can be properly controlled by adjustment of the heat absorbing ability of the heat sink and the heat radiating ability of the radiator by the control of the compressor output.

Abstract: An automotive air conditioning system is provided to be able to minutely control the air blow temperature independently of the ambient temperature to maintain the compartment always pleasant. The difference between the revolution speed of a compressor with a temperature setting lever for setting the revolution speed of the compressor set in the left end position and the revolution speed of the compressor with the temperature setting lever set in the left end position is increased in the mid summer or mid winter and reduced in the spring or autumn, whereby the air blow temperature can be minutely controlled to make the inside of the compartment always pleasant.

Abstract: A controller for a heat pump system wherein the controller has a variable capacity control capability that responds to thermostat output signals. The variable capacity controller computes real-time performance parameters at variable capacity heating/cooling load conditions of the heat pump system. A defrost controller calculates an optimum heat pump operating time period between successive defrost cycles during a heating mode of the heat pump. Such values are calculated as a function of sensed time, temperature and variable capacity operating conditions which are calculated by the variable capacity controller. The controller preferably has a manual mode for verifying correct operation of each actuator of the heat pump system, as a function of a sequenced input signal, while the heat pump system is in a shutdown mode.

Abstract: An automotive air conditioner which conditions air making use of radiation of heat of a condenser and absorption of heat of an evaporator effectively. The evaporator 207 and the condenser 203 are disposed in a duct 100. An condenser disposed in a duct has a heat exchanging section in which heat exchange is performed between refrigerant and draft air. The heat exchanging section is divided into an upper stream area portion, a middle stream area portion and a lower stream area portion, and a temperature sensitive tube of a subcooling control valve is held in contact with a refrigerant passageway which interconnects the middle and lower stream area portions. The subcooling control valve adjusts the opening of a throttle portion thereof so that the subcooling degree on the upstream of the lower stream area portion where the temperature sensitive tube contacts may be a predetermined value (2.degree. to 10.degree. C.).

Abstract: A heat pump type air conditioner having a refrigeration circuit including a variable speed compressor, a four-way valve, an indoor heat exchanger, an expansion device and an outdoor heat exchanger, and capable of operating in a cooling mode to cool a room and a heating mode to heat the room. The compressor speed is set in accordance with air conditioning load, such as the temperature difference between a setting room temperature and the actual room air temperature and the operation mode. An outdoor fan blows air through the outdoor heat exchanger which selectably rotates at a high speed or a low speed. The rotational speed of the outdoor fan is selected based on the operation mode, a cooling mode reference compressor rotational speed value, a heating mode reference compressor rotational speed value and the set compressor rotational speed. The cooling mode reference compressor rotational speed value is smaller than the heating mode reference compressor rotational speed value.

Abstract: A refrigeration unit of the type having an economizer cycle driven by a prime mover cooled by a liquid coolant. Electrical control configures refrigerant flow paths of the unit to provide heating and cooling cycles, as required to control the temperature of a conditioned space to a predetermined set point temperature. Heat from the liquid coolant is used to enhance the heating cycle. A heating cycle is initiated immediately, when required, when the temperature of the liquid coolant is above a predetermined temperature. A heating cycle is delayed by a special refrigeration cycle which increases the load on the prime mover, when the temperature of the liquid coolant is not above the predetermined temperature.

Abstract: A "DX" heat pump is provided herein which is based on the principle of providing optimal heat exchange in the heating mode through at least two, but up to five or more parallel ground loops, all but one of which respectively can be cut off from the system and evacuated of refrigerant in the cooling mode, and selectively reintroduced as required in the cooling mode. The loops are designed in terms of volume so that the refrigerant charge is correct in the heating mode when split in the selected number of loops and also correct in the cooling mode when one or more loops are used, whereby it/they contain the full system refrigerant charge. The headers are provided with solenoid valves which can be individually operated to provide a staged cooling system.

Abstract: A controller for an air conditioner is provided wherein an operation mode is not unnecessarily changed in accordance with variations in temperature. When room temperature t is in a range of T+3.0>t.gtoreq.T+1.5, and when a timer expires (steps 212, 214), it is determined whether the room temperature has a tendency to fall (step 218). When the room temperature has a tendency to fall, it is predicted that the room temperature will be in an observing region although the operation mode is not changed. For this reason, the current operation mode is kept. On the other hand, when the room temperature does not have a tendency to fall, a cooling mode is set (step 210). Further, when the room temperature t is in a range of T-3.0<t.ltoreq.T-1.5, and when the timer expires (steps 222, 224), it is determined whether the room temperature has a tendency to rise (step 228).

Abstract: A refrigeration unit, and method of operating same, having a compressor driven by a prime mover. The prime mover is selectively operable in either a continuous mode which includes heating and cooling cycles, or in start-stop cycling mode which includes cooling and null cycles, to control the temperature of a conditioned space relative to a predetermined set point temperature. In one embodiment, the cycle mode is operable only when the set point temperature is in a predetermined temperature range, the limits of which are selectable. The prime mover is operated in the continuous mode, notwithstanding the selection of the cycle mode, when the set point temperature is not within the temperature range authorized for cycle operation.

Abstract: The air conditioning apparatus for electric automobiles includes a refrigerant cycle having a refrigerant compressor driven by an electric motor, a refrigerant pressure sensor for detecting the high-pressure-side pressure of the refrigerant cycle, and an air conditioner control apparatus. The rotational speed of the electric motor is determined on the basis of a variably controlled frequency. The refrigerant pressure sensor detects the pressure of the refrigerant compressed by the refrigerant compressor and flowing toward the heat exchanger for heating and outputs it to an air conditioner control apparatus. The air conditioner control apparatus controls an inverter on the basis of the value detected by the refrigerant pressure sensor.

Abstract: A method of controlling a current defrost cycle for an outdoor coil of a heat pump system, the heat pump system having a plurality of supplemental heating elements for heating an air stream passing from an indoor coil to an air supply duct during defrost operation, wherein an initial quantity of supplemental heating elements energized is a function of a most recent previous defrost cycle.

Abstract: A method of controlling a current defrost cycle for an outdoor coil of a heat pump system, the heat pump system having a plurality of supplemental heating elements for heating an air stream passing from an indoor coil to an air supply duct during defrost operation, wherein an initial quantity of supplemental heating elements energized is a function of a most recent previous defrost cycle. The initial quantity of supplemental heating elements is energized upon initiation of a defrost cycle. Whether the initial quantity of supplemental heating elements provided is insufficient or excessive is determined. At least one of the supplemental heating elements is deactivated if the initial quantity of supplemental heating elements being provided is excessive.

Abstract: The air conditioning apparatus operable in heating and cooling operation modes for air conditioning a room has an external unit, an inner unit, and a control device. The external unit includes an external heat exchanger. The inner unit disposed in the room includes an inner heat exchanger which functions as an evaporator in the cooling operation mode whereas the external heat exchanger functions as a condenser. The control device has a thermistor disposed on the inner heat exchangers for detecting temperature of the inner heat exchanger, bias means for energizing the thermistor with a predetermined bias potential and term setting means responsive to the operation mode for setting first and second terms for allowing The energization of the thermistor. The the first term is longer than the second term when the inner heat exchanger functions as an evaporator. The control device also has a room temperature sensor disposed in the room for detecting room temperature.

Abstract: Two outdoor units (2A, 2B) are connected to liquid lines (5A, 5B), respectively, and connected to gas lines (6A, 6B), respectively. Each of the gas lines (6A, 6B) is branched to a high-pressure passage (65, 66) and a low-pressure passage (67, 68). The liquid lines (5A, 5B), the high-pressure passages (65, 66) and the low-pressure passage (67, 68) are connected to a main liquid line (4L), a main high-pressure gas line (4H) and a main low-pressure gas line (4W), respectively, in such a manner that the outdoor units (2A, 2B) are arranged in parallel with each other. Three user units (3, 3, 3) are each connected at an end thereof to the main liquid line (4L) and each connected to the main high-pressure gas line (4H) and the main low-pressure gas line (4W) so as to be switchable between the gas lines (4H, 4W).

Abstract: The control system employs multiple, distributed architechure, processors in the indoor unit, the outdoor unit and optionally the thermostat unit. The overall system control functions are distributed across the processors, which communicate with one another over a communications link, employing a messaging system which allows sensor values to be obtained locally and transmitted to the other processors. The processors communicate to automatically refresh or update information during times when it will not degrade performance of critical functions.

Abstract: An air conditioner for a vehicle having a compressor, an outer heat exchanger, a heat-radiating inner heat exchanger an expansion valve, a heat-absorbing inner heat exchanger which are connected therebetween. A connecting condition of these elements is changed into one of a cooling, a first heating and a second heating, by controlling a refrigerant passage switching device. During the cooling, refrigerant in the air conditioner is circulated in the order of at least the outer heat exchanger, the expansion valve, the heat-absorbing inner heat exchanger and the compressor. During the first heating the refrigerant is circulated in the order of the heat-radiating inner heat exchanger, the expansion valve, the heat-absorbing inner heat exchanger and the compressor while bypassing the outer heat exchanger. During the second heating, the refrigerant is circulated in the order of the heat-radiating inner heat exchanger, the expansion valve, at least the outer heat exchanger and the compressor.

Abstract: An air conditioning apparatus comprising an indoor unit. The unit has a first indoor heat exchanger for cooling or heating indoor air and a second indoor heat exchanger for cooling or heating indoor air. A first indoor fan is located near the first indoor heat exchanger, for drawing the indoor air and supplying it through the first indoor heat exchanger to the zone of a room. A second indoor fan is located near the second indoor heat exchanger, for drawing the indoor air and supplying it through the second indoor heat exchanger to the zone of a room. The apparatus further comprises two temperature sensors for detecting the temperatures of the indoor heat exchangers, respectively. The higher or lower of the temperatures detected by the sensors is selected, in accordance with the cooling or heating mode in which the apparatus is operating. In accordance with the temperature selected, the air-supplying rates of the indoor fans are controlled.

Abstract: The present invention is directed to a heat pump system and more particularly to a self-contained heat pump system incorporating a microprocessor based control system, a desuperheater, a dedicated refrigerant-potable water heat exchanger, a refrigerant-air heat exchanger, and an external source-refrigerant heat exchanger wherein said heat pump system is simultaneously or alternatively capable of: heating potable water; air conditioning; heating; and dehumidification.

Abstract: An improved combined ambient-air and earth exchange heat pump system includes a subterranean heat exchanger and an ambient-air heat exchanger, both refrigerant-based, which are adapted to be selectively operated individually, serially or in parallel for heating and cooling purposes. The system also includes a compressor, a dynamic load heat exchanger, a reversing valve for converting the system from heating to cooling and vice versa, storage for excess refrigerant including an accumulator, an optional preheat exchanger, a regulating assembly with bleed port arrangement, a bypass mechanism for repetitive start-up attempts, and a lost charge device.

Abstract: A controller for a gas heat pump system wherein the controller has a variable capacity control capability that responds to thermostat output signals. The variable capacity controller computes real-time performance parameters at variable capacity heating/cooling load conditions of the gas heat pump system. A defrost controller calculates a maximum heat pump operating time period between successive defrost cycles and a minimum heat pump operating time period of each defrost cycle, during a heating mode of the gas heat pump. Such values are calculated as a function of sensed time, temperature and variable capacity operating conditions which are calculated by the variable capacity controller. The controller preferably has a manual mode for verifying correct operation of each actuator of the gas heat pump system, as a function of a sequenced input signal, while the gas heat pump system is in a shutdown mode.

Abstract: A control circuit for a cool/heat pump in which two separate motors are utilized, each with a main winding and an auxiliary winding. A single dual rated capacitor is provided in series with both auxiliary windings. A selectively operative switch, which may be in the form of a thermostat, is provided in series between one of the alternating current lines and the windings of one of the motors to selectively terminate power to that motor while maintaining power to both windings of the other motor. The switch is also used to alternately energize an electric heater unit when the motor power is terminated. Such a control circuit avoids a de-icing operation normally required with cool/heat pumps working in a heating mode, when the outdoor temperature is below freezing.

Abstract: A heat pump type air conditioner for a vehicle has a compressor to which a condenser and a inner heat exchanger are connected through a first switching valve. The condenser is connected at its refrigerant outlet to the inner heat exchanger through a second switching valve. An refrigerant outlet of the inner heat exchanger is connected to an evaporator through an expansion valve. A refrigerant outlet of the evaporator is connected to the compressor. The first switching valve functions to change the operation or the air conditioner between heating and cooling. The first and second switching valves function to allow to flow the refrigerant into the outer heat exchanger even if in heating, according to the thermal condition of the outer heat exchanger. Therefore, it becomes possible to stably implement heating without causing a stagnation of the refrigerant in the outer condenser even under a cold thermal condition.

Abstract: A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein.

Abstract: A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein.

Abstract: A "DX" heat pump is provided herein which is based on the principle of providing optimal heat exchange in the heating mode through three parallel ground loops, two of which can be cut off from the system and evacuated of refrigerant in the cooling mode. The loops are designed in terms of volume so that the refrigerant charge is correct in the heating mode when split in three loops and also correct in the cooling mode when only one loop is used, but it contains the full system refrigerant charge. The loops are provided with "TX" metering valves which can be individually operated to provide a staged cooling system.