Air conditioner monitor and alarm system

A monitor system for an air conditioning unit having a suction refrigerant line and a liquid refrigerant line. The monitor system has two low pressure sensors mounted on the suction refrigerant line; a high pressure sensor mounted on the liquid refrigerant line; a back-up battery; an AC transformer; an AC to DC converter board having three connection points; two double DPDT relays; a terminal board having terminals for connection to the converter board, the relays, a warning device and the pressure sensors. For commercial size air conditioning systems, the monitor system has two 12-volt back-up batteries; two AC transformers; two 16 AC to DC converter boards, and three double DPDT relays.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to air conditioners, and in particular, relates to a monitor and alarm system for air conditioners.

2. Description of the Related Art

Air conditioners are increasingly an essential part of office buildings and residences, particularly in southern climates. Central air conditioners typically include an outdoor condensing unit including a refrigerant compressor, an indoor evaporator unit, and a manually adjustable indoor thermostat responsive to the indoor temperature for selecting and controlling the operation of the air conditioner.

Air conditioning systems use a thermally conductive coolant such as freon in a conduit. Heat exchange systems transfer heat from inside the conduit to the outside of the conduit. In an expansion valve, the high pressure, low temperature coolant is reduced in pressure, which lowers the temperature of the coolant. The coolant then is transferred into a series of coiled tubes that act as a heat exchanger with warm air from the building, thus cooling the warm air which when cooled is circulated through the structure.

The efficient functioning of air conditioners require that there be sufficient coolant in the conduit, that the coolant be cooled, that power to the system is sufficient to operate the air conditioner, that the components of the air conditioner be present and operating. Diagnosing problems when air conditioners do not function properly, or at all, generally requires a service technician, since a typical building owner or tenant is not usually trained or knowledgeable in such matters.

Thus, there is a need for an air conditioner monitor that monitors the unit to determine if refrigerant pressure is too high or too low, to determine if the fan motor has gone out, to determine if there is a leak or if someone is attempting to steal components of the air conditioner such as the copper coils, and the like. The latter problem has become increasingly common as copper has become more valuable as a commodity. There is also a need to have a monitor that functions even if the power to the monitor has been cut, such as might occur in a theft.

There are previous systems that accomplish some of these goals. For example, some air conditioners already have a thermostat with monitors, and a computer to monitor sensors, but there is no alarm.

The patent of Anderson et al. (U.S. Pat. No. 4,038,061) has a control system for protecting an air conditioner and a malfunction indicator. The control system keeps the air conditioner from being turned on in the event of low power, and has a current sensing control.

U.S. Pat. No. 7,234,313 of Bell et al. provides a monitor and superheat calculator system for air conditioners, which has a handheld monitoring device and a remote sensing unit for temperature and pressure which is placed within the return air flow of the A/C system. Additional sensors may be provided with communication between the sensors. Data from these sensors allow a technician to diagnose A/C problems.

The furnace and air conditioner failure alarm of Kennison (U.S. Pat. No. 5,444,436) provides a battery power supply to power circuits in case of A/C power failure. An environmental temperature sensor monitors the area being air conditioned and is connected to alarm circuitry which is activated when the temperature is at an unacceptable level.

It is therefore an object of this invention to monitor the low and high pressure on air conditioning units to warn the owner of problems that need repair by an air conditioning technician, thus preventing extensive damage, and to avert theft of the air conditioning unit or the coils. Thus the invention is designed to allow easier determination of whether there is a problem with an A/C unit and of what the possible problem and its cause might be, particularly if the problem is important to the function of the air conditioning system.

It is a further object of the invention to provide a monitor and alarm that includes one or more visual or audible alarms when the monitor registers problems.

Other objects and advantages will be more fully apparent from the following disclosure and appended claims.

SUMMARY OF THE INVENTION

The invention herein is a monitor and alarm system for an air conditioning unit having a suction (low pressure) refrigerant line and a liquid (high pressure) refrigerant line.

The monitor system in a first embodiment primarily for residential customers monitors low and high pressure and indicates problems that occur, such as low refrigerant, dirty coils, dirty filter, or either of the fan motors has gone out. It has two low pressure sensors mounted on the suction refrigerant line; a high pressure sensor mounted on the liquid refrigerant line; a back-up battery; an AC transformer; an AC to DC converter board having three connection points; two double DPDT relays (one side of relay may be connected with house security system); a terminal board having terminals for connection to the converter board, the relays, a warning device and the pressure sensors. The term “converter board” herein includes power supplies as known in the art.

The second embodiment has another back-up battery; a larger terminal board; two 110 V AC to 16 V AC transformers; and two converter boards. One converter board controls monitoring of the air conditioning system, and the other controls warning devices (may be connected with security system) and will automatically activate alarms if the first is disconnected or loses DC power. Preferably this embodiment provides a warning sound and/or light signal if someone tries to steal the unit or its coils or the A/C unit loses extensive pressure for another reason. There is a battery back-up for loss of A/C power.

Other objects and features of the inventions will be more fully apparent from the following disclosure and appended claims.

The present invention is a monitor and alarm for an air conditioner that has an outdoor condensing unit including a refrigerant compressor, an indoor evaporator unit, and a manually adjustable indoor thermostat responsive to the indoor temperature for selecting and controlling the operation of the air conditioner. The air conditioner monitor of the invention works with any air conditioner, with adjustments of sensors as known in the art depending on the particular coolant used.

There are two embodiments of the invention, both of which monitor the high and low pressure of the air conditioning units to warn the owner of problems that need repair by an air conditioning technician so that extensive damage is prevented and to give advanced warning of problems with the cooling side of an air conditioning system. The second embodiment also enables the owner to avert theft of the unit or coils, by including isolation type relays to prevent a would-be thief from shorting one system in order to avoid setting off alarms.

As used herein the general terms “warning device” and “alarm” are used interchangeably unless otherwise specified. Such alarms include sound producing devices such as sirens and chirping sounds, and others known in the art, and light-producing devices such as flood lights and flashing lights and others known in the art, or combination light- and sound-producing devices.

The first embodiment10air conditioner monitor system of the invention is particularly appropriate for central air conditioners for residences or other small building spaces, while the second embodiment20is particularly appropriate for central air conditioning systems in office buildings, hospitals, schools and other large building spaces that have multiple, large air conditioning units.

Referring in greater detail to the figure, as shown inFIG. 1, the components, discussed below, of both embodiments of the invention are preferably enclosed in a lockable sturdy box, such as a metal enclosure22. While it is preferred that this metal enclosure relatively closely surround the main components of the invention as discussed below, and that the enclosure be sufficiently ventilated to avoid overheating problems, it some instances the enclosure may comprise a small room or other preferably lockable, ventilated space. The location of the components within the enclosure22may be as shown in the figures or as may be varied by the manufacturer as known in the art, so long as the various components function for their intended purpose.

In the first embodiment10of the invention herein (FIGS. 1-2), the complete air conditioner monitor system includes the following components in addition to the enclosure22: one low pressure sensor24to be mounted on the suction refrigerant line27to monitor the refrigerant pressure; one mid/low pressure sensor28to be mounted on the suction refrigerant line27; one high pressure sensor30on the liquid refrigerant line29of the air conditioner, one 12-volt A/C back-up battery32(maximum 40 Ah); one 10-connector terminal board34; one 110 V AC to 16 V AC transformer36; one 16 V AC to 12 V DC power supply (called converter board38herein (5 amp)) with three connection points (12 V DC positive and negative; 16 V AC-2 terminals; and battery terminal positive and negative); two double DPDT relays40,42with 12 V DC control coil (not shown; this is part of the A/C system); 50 feet of 18 gauge electrical wire; 20¼-inch female spade terminal ends which are placed at the ends of the wires as known in the art, and are not shown; and eight ½-inch nylon standoff pieces, which are placed between components and the enclosure22and the like as known in the art. The number of feet of electrical wire may be varied depending on the number and location of air conditioning units being monitored. While two DPDT relays are most preferred, it is possible that a single relay would be acceptable for some uses, even though the functionality of the system would be decreased by decreasing the on/off capability.

The pressure sensors will change with the air conditioner system requirements (e.g. R-22, R-410A, etc.) and should be mounted on the refrigerant lines by a certified technician as known in the art.

The second embodiment20of the invention contains the same components as the first embodiment, with the following preferred modifications thereof for monitoring of the typically larger and more expensive air conditioning units used in commercial buildings. In the second embodiment, the preferred lockable sturdy enclosure22is a steel vented enclosure cabinet. In the second embodiment there is a second 12-volt A/C back-up battery44(maximum 40 Ah); a 12-connector terminal board46; two 110 V AC to 16 V AC transformers48,50; two 16 V AC to 12 V DC power supplies (converter board52being 5 amp for alarm connection and converter board54being 2 amp for monitoring) with three connection points; three double DPDT relays56,58,60with 12 V DC control coil; 80 feet of 18 gauge electrical wire; 25¼-inch female spade terminal ends; and 16½-inch nylon standoff pieces. Because the 5 amp converter board52is vulnerable with the wires going outside box22, if something happens to it, the alarms connected to the 2 amp board54, which is not vulnerable because the relays are opened due to loss of the 5 amp board, causing the 2 amp board to set off alarms. This arrangement allows grouping of five air conditioners in a monitoring and alarm system.

The number and specifications for each of the components used in the invention may be varied by one of skill in the art depending on the particular air conditioner(s) being monitored without departing from the invention herein. The number of feet of electrical wire may be varied depending on the number and location of air conditioning units being monitored.

There are two transformers and back-up batteries so if someone shorts out the operating electrical components, there is a back-up that will set off the alarm(s) in the system of the invention

It is to be noted that the sizes of converter boards, transformers, and relays can and will be changed with respect to a particular system's needs. Similarly, pressure sensors can and will be changed in accordance with the refrigerant used in the air conditioning system, as is known in the art.

FIG. 1shows the components of the first embodiment10of the invention as mounted in the enclosure or as attached to components mounted in the enclosure22. In the preferred method of assembly of the first embodiment10, the components are placed in the enclosure as follows: mount transformer36in the enclosure22; mount the converter board38in the enclosure22using ½-inch nylon standoffs to prevent the converter board38from coming in contact with the metal enclosure22; mount two DPDT relays40,42in the enclosure using ½-inch nylon standoffs to prevent the relays from coming in contact with the metal enclosure22; and mount the terminal board34in the enclosure22; and place the back-up battery32in the enclosure22.

Thus in the arrangement of the terminal board34of the first embodiment10as shown herein (FIG. 2), T1and T2are connected to a warning light177to signal the need for an air conditioning technician. As shown inFIG. 4for the second embodiment, in the first embodiment T3and T4can optionally be attached to a keypad device105through a chirper/light device180or the like to be mounted in a conspicuous place. The keypad device105, which the owner or technician can use to enter a code to turn off the alarms is essentially a switch, which may have a keypad to restrict the ability to turn the invention on and off. Optionally the terminal board may be attached to other components, for example, a door lock mechanism.

T3and T4are optionally connected to a siren/strobe alarm type device180(or other warning device) back into T4(optionally with a keypad105(or switch or lockswitch) as shown). T5and T6are available to attach to a house security system23to be installed by the security system company with the wire attached from T5through the security system and back into T6. T7is connected to the mid/low refrigerant pressure sensor28on the suction side of the air conditioning unit. On the opposite side of the mid/low pressure sensor a wire is attached to a high pressure sensor30mounted on the liquid line of the air conditioning unit. T8is attached to the high pressure sensor30. T9and T10are attached to the low pressure sensor24mounted on the suction line of the air conditioning unit for theft protection. When the pressure is very low or zero, one or more warning devices of the system of the invention are caused to be activated by means known in the art.

Other arrangements of the terminal board are of course possible as known in the art.

FIG. 3shows the components of the second embodiment20of the invention as mounted in the enclosure22or attached to components mounted in the enclosure22. As in the first embodiment, in the preferred method of assembly of the second embodiment, the components are placed in the enclosure as discussed above with respect to the transformers48,50, converter boards52,54, relays56,58,60and terminal board46.

T11and T12are made accessible for optional monitoring by the building security system23as shown inFIG. 4.

Thus in the arrangement of the terminal board46of the second embodiment20as shown herein (FIG. 4), T1and T2are connected to a warning light177to signal the need for an air conditioning technician, and to house breaker box25. T3and T4are optionally attached to a keypad device105through a chirper/light device180or the like to be mounted in a conspicuous place. T5and T6are available to attach to a warning light188. T7and T8are connected to the low pressure sensor24on the suction side of the air conditioning unit. T9and T10are attached to the mid/low pressure sensor28and a high pressure sensor30mounted on the liquid line of the air conditioning unit. Optionally, but not shown herein, a high temperature sensor and a low temperature sensor may be added to the system as known in the art. T11and T12are attached to house security system23.

Other arrangements of the terminal board of the second embodiment are of course possible as known in the art and as may be fashioned for particular types of warning and monitoring devices as well as for particular A/C systems.

It is clear that one of ordinary skill in the art can vary the wiring in the invention embodiments herein, for example, which terminal is used for a particular component, and other standard variations and combinations as known in the art.

While the invention herein is designed for use with air conditioners, the invention may be modified as known by one of ordinary skill in the art for use with other pressure systems, for example air compressors, or for systems that are intended to remain at low pressure.

While the invention has been described with reference to specific embodiments, it will be appreciated that numerous variations, modifications, and embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of the invention.