Safety System For Air Handling Unit

Abstract

The present disclosure provides an interface control relay module including a refrigerant sensor input connected to a refrigerant sensor of an air handling unit (AHU) that generates an input proportional to a concentration of a refrigerant leak in the AHU. The relay module further includes a control unit coupled to the refrigerant sensor input to receive the input from the refrigerant sensor; a first relay output and a second relay output, each connecting the control unit to a cooling unit of the AHU; a third relay output connecting the control unit to a fan of the AHU; and a fourth relay output connecting the control unit to a damper of the AHU. The control unit activates or deactivates at least one of the first relay output, the second relay output, the third relay output and the fourth relay output based on the input received from the refrigerant sensor.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and the benefit of U.S. Provisional Application No. 63/402,223, filed on Aug. 30, 2022, the disclosure of which is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a safety system for controlling operation of an air handling unit.

BACKGROUND

Typically, in a climate control system, such as a heating, ventilation, and air conditioning (HVAC) system including an air handler or furnace coil, a refrigerant is circulated so as to transfer heat out of and/or into an indoor or interior space. The refrigerant is separated from an air flowing within and through the indoor space by one or more conduits (for example tubing, coils, etc.). In some cases, the refrigerant may be toxic and/or flammable such that a leak of the refrigerant may pose a safety issue. Additionally, a loss of the refrigerant due to the leak may prevent the climate control system from effectively transferring heat from and/or into the indoor space during operation.

SUMMARY

According to one aspect of the present disclosure, an interface control relay module is disclosed. The interface control relay module includes a refrigerant sensor input connected to a refrigerant sensor of an air handling unit (AHU), where the refrigerant sensor is configured to generate an input proportional to a concentration of a refrigerant leak sensed in the AHU. The interface control relay module further includes a control unit coupled to the refrigerant sensor input and configured to receive the input from the refrigerant sensor. The interface control relay module further includes a first relay output and a second relay output, each connecting the control unit to a cooling unit of the AHU; a third relay output connecting the control unit to a fan of the AHU; and a fourth relay output connecting the control unit to a damper of the AHU. The control unit is configured to activate or deactivate at least one of the first relay output, the second relay output, the third relay output, and the fourth relay output based on the input received from the refrigerant sensor.

In an embodiment, the control unit is configured to determine a degree of refrigerant leak based on comparing the concentration of the refrigerant leak to a predefined threshold value.

In an embodiment, the control unit is configured to deactivate at least one of the third relay output and the fourth relay output when the concentration of the refrigerant leak is below the predefined threshold value.

In an embodiment, the interface control relay module further includes a fifth relay output and a sixth relay output, each connected to a heating unit of the AHU, where the control unit is configured to activate or deactivate the fifth relay output and the sixth relay output to turn on or turn off the heating unit.

In an embodiment, the interface control relay module further includes an airflow sensor of the AHU, the airflow sensor configured to generate an input indicative of an amount of airflow produced by the fan.

According to another aspect of the present disclosure, a safety system for an air handling unit (AHU) having a heating unit and a cooling unit is disclosed. The safety system includes a refrigerant sensor coupled to the AHU, where the refrigerant sensor is configured to generate an input proportional to a concentration of a refrigerant leak sensed in the AHU. The safety system further includes an interface control relay module including a refrigerant sensor input connected to the refrigerant sensor, and a control unit coupled to the refrigerant sensor input and configured to receive the input from the refrigerant sensor. The interface control relay module further includes a first relay output and a second relay output, each connecting the control unit to a cooling unit of the AHU; a third relay output connecting the control unit to a fan of the AHU; and a fourth relay output connecting the control unit to a damper of the AHU. The control unit is configured to activate or deactivate at least one of the first relay output, the second relay output, the third relay output, and the fourth relay output based on the input received from the refrigerant sensor.

In an embodiment, the control unit is configured to determine a degree of refrigerant leak based on comparing the concentration of the refrigerant leak to a predefined threshold value.

In an embodiment, the control unit is configured to deactivate at least one of the third relay output and the fourth relay output when the concentration of the refrigerant leak is below the predefined threshold value.

In an embodiment, the interface control relay module further includes a fifth relay output and a sixth relay output, each connected to the heating unit, wherein the control unit is configured to activate or deactivate the fifth relay output and the sixth relay output to turn on or turn off the heating unit.

In an embodiment, the safety system further includes a smoke detector alarm, where the control unit is configured to trigger the smoke detector alarm when the refrigerant leak is detected.

In an embodiment, the safety system further includes a processing unit configured to monitor the interface control relay module and trigger an alert when the refrigerant leak is detected.

In an embodiment, the safety system further includes an airflow sensor of the AHU, the airflow sensor configured to generate an input indicative of an amount of airflow produced by the fan.

According to yet another aspect of the present disclosure, method of operating an air handling unit (AHU) is disclosed. The method includes monitoring an input from a refrigerant sensor, the input indicating concentration of a refrigerant leak sensed in the AHU. The method further includes comparing, by a control unit, the concentration of the refrigerant leak with a predefined threshold value; determining, by the control unit, a degree of refrigerant leak in the AHU based on the comparison; and activating or deactivating, by the control unit, at least one of a first relay output, a second relay output, a third relay output and a fourth relay output based on the degree of refrigerant leak. The first relay output and the second relay output connects the control unit to a cooling unit of the AHU, the third relay output connects the control unit to a fan of the AHU, and a fourth relay output connects the control unit to a damper of the AHU.

In an aspect, the method further includes deactivating the first relay output and the second relay output and stopping operation of the cooling unit when the concentration of the refrigerant leak exceeds the predefined threshold value.

In an aspect, the method further includes activating at least one of the third relay output and the fourth relay output to initiate the fan or the damper and dispersing the leaked refrigerant.

In an aspect, the method further includes deactivating, by the control unit, at least one of the third relay output and the fourth relay output when the concentration of refrigerant leak is below the predefined threshold value.

In an aspect, the method further includes activating, or deactivating a fifth relay output and a sixth relay output to turn on or turn off the heating unit, wherein each of the fifth relay output and a sixth relay output is connected to a heating unit of the AHU.

In an aspect, the method further includes triggering, via a processing unit, a smoke detector alarm in response to the refrigerant leak.

These and other aspects and features of non-limiting embodiments of the present disclosure will become apparent to those skilled in the art upon review of the following description of specific non-limiting embodiments of the disclosure in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of embodiments of the present disclosure (including alternatives and/or variations thereof) may be obtained with reference to the detailed description of the embodiments along with the following drawings, in which:

FIG. 1 is a block diagram of a safety system for an air handling unit (AHU), according to an embodiment of the present disclosure;

FIG. 2 is an illustration of distributed components which may share processing with a computing hardware of a control unit of the safety system of FIG. 1, according to certain embodiments;

FIG. 3 is a flowchart of a method for monitoring the refrigerant leak in the AHU, according to an aspect of the present disclosure;

FIG. 4A is a diagram of a circuit of the monitor system, such as the EcoNet®, according to an embodiment of the present disclosure;

FIG. 4B is a diagram of a circuit of a commercial device, such as a smoke detector, coupled to a refrigerant sensor of the AHU, according to an embodiment of the present disclosure;

FIG. 4C is a diagram of a circuit of a thermostat coupled to the refrigerant sensor, according to an embodiment of the present disclosure; and

FIG. 5 is flowchart of a method of operating the AHU, according to an aspect of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding, or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts. Moreover, references to various elements described herein, are made collectively or individually when there may be more than one element of the same type. However, such references are merely exemplary in nature. It may be noted that any reference to elements in the singular may also be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly in the appended claims.

As used herein, the terms “a”, “an” and the like generally carry a meaning of “one or more,” unless stated otherwise. Further, the terms “approximately”, “approximate”, “about”, and similar terms generally refer to ranges that include the identified value within a margin of 20%, 10%, or preferably 5%, and any values therebetween.

As described previously, a leak of refrigerant from a climate control system, such as an air handling unit of a HVAC system, may lead to multiple issues. As a result, it may be desirable to detect such leaks within the system during operations, so as to quickly alert personnel, residents, system controllers, etc. Accordingly, embodiments of the present disclosure are directed to systems and methods for detecting a refrigerant leak from the air handling unit. As described in more detail below, the systems and methods disclosed herein determine the presence of the refrigerant leak and control operation of the air handling unit with aid of an interface control relay module configured to retrofit with the air handling unit. However, it should be understood that while the systems and methods described herein are described with reference to air handling units, they may likewise be used within other systems utilizing refrigerants.

Referring to FIG. 1, a safety system 100 for an air handling unit (AHU) 102 is illustrated. In some embodiments, the safety system 100 is a system interface board. The AHU 102 includes a refrigerant sensor 104 configured to generate an input proportional to a concentration of a refrigerant leak in the AHU 102, a cooling unit 106, a fan 108, an airflow sensor 109 configured to generate an input indicative of an amount of airflow produced by the fan 108, a damper 110, and a heating unit 112. In some embodiments, the refrigerant sensor 104 (for example, A2L refrigerant gas sensor) may be disposed within a cabinet of the AHU 102 to sense the refrigerant leak. The refrigerant sensor 104 may be calibrated to sense a particular refrigerant(s). In some embodiments, the refrigerant sensor 104 may be calibrated to sense R-454B, R-454C, or R-32 type refrigerants. The refrigerant sensor 104 may be configured to operate with a suitable power supply, such as 24 VAC or 24 VDC. The airflow sensor 109 may also be disposed within the cabinet of the AHU 102 to sense an amount of airflow being produced by the fan 108. For example, the airflow sensor 109 may be used to determine if the fan 108 is not functioning properly and is not producing airflow (or is producing airflow that is below a threshold flow rate). In embodiments, the airflow sensor 109 may also be implemented as a switch.

The safety system 100 includes an interface control relay module 114 (hereinafter referred to as “the relay module 114”) having a refrigerant sensor input 116, an airflow sensor input 117, a first relay output 118, a second relay output 120, a third relay output 122, a fourth relay output 124, a fifth relay output 126, and a sixth relay output 128. Each of the refrigerant sensor input 116, airflow sensor input 117, and the relay outputs are embodied as pins configured to engage with a corresponding relay slot in the AHU 102. As such, the safety system 100 may be detachably coupled to the AHU 102 to regulate operations thereof. In some embodiments, the relay module 114 may be a form-C relay or may use RS485 communication. In some embodiments, the relay module 114 may be electrically coupled to the AHU wirelessly.

The safety system 100 also includes a control unit 130 coupled to the refrigerant sensor input 116 and the airflow sensor input 117 and configured to receive the input(s) from the refrigerant sensor 104 and the airflow sensor 109. In an example, the control unit 130 may be a relay. In some examples, the control unit 130 may be implemented as a switch or such electrical devices.

When the relay module 114 is engaged with the AHU 102, each of the first relay output 118 and the second relay output 120 connects the control unit 130 with the cooling unit 106 of the AHU 102, the third relay output 122 connects the control unit 130 to the fan 108 of the AHU 102, the fourth relay output 124 connecting the control unit 130 to the damper 110 of the AHU 102, and each of the fifth relay output 126 and the sixth relay output 128 connects the control unit 130 to the heating unit 112 of the AHU 102.

The control unit 130 is configured to activate or deactivate at least one of the first relay output 118, the second relay output 120, the third relay output 122, and the fourth relay output 124 based on the inputs received from the refrigerant sensor 104 and/or the airflow sensor 109. In some embodiments, the control unit 130 is configured to determine a degree of refrigerant leak in the AHU 102 based on comparing the concentration of the refrigerant leak to a predefined threshold value. In one embodiment, the predefined threshold value may be implemented by defining a voltage or current level coming from the refrigerant sensor 104. In some embodiments, the predefined threshold value may be stored in a memory 204 (see FIG. 2) of the control unit 130.

When no input from the refrigerant sensor 104 is received by the control unit 130, no action is executed by the control unit 130 relating to the activation or deactivation of the relay outputs. In an aspect, when the input from the refrigerant sensor 104 is received, the control unit 130 is configured to determine the degree of the refrigerant leak based on comparing the concentration of the refrigerant leak to the predefined threshold value. In some embodiments, the control unit 130 is configured to deactivate each of the first relay output 118 and the second relay output 120 when the concentration of the refrigerant leak exceeds the predefined threshold value. Such deactivation of the first relay output 118 and the second relay output 120 may turn off the cooling unit 106 of the AHU 102. The cooling unit 106 may be, for example, understood as an evaporator coil through which the refrigerant circulates and absorbs heat from air flowing across the evaporator coil. In case of reduced amount of refrigerant being circulated through the evaporator coil due to the leakage of refrigerant, efficiency of the evaporator coil may be affected and may hence affect overall performance of the AHU 102. In such cases, the control unit 130 is configured to turn off the cooling unit 106 and may subsequently stop the operation of the AHU 102. In some embodiments, the control unit 130 may be configured to activate the third relay output 122 and the fourth relay output 124 subsequent to the deactivation of the cooling unit 106. Activation of the third relay output 122 and the fourth relay output 124 may activate the fan 108 and the damper 110 to flush the leaked refrigerant from the AHU 102.

In another aspect, when it is determined that the concentration of the refrigerant leak is below the predefined threshold value, the control unit 130 may be configured to deactivate at least one of the third relay output 122 and the fourth relay output 124, which turns off the fan 108 and the damper 110 of the AHU 102, respectively. Similarly, activation or deactivation of the fifth relay output 126 and the sixth relay output 128 may turn on or turn off the heating unit 112, respectively. Subsequently, when no further refrigerant leak is detected, the control unit 130 may be configured to selectively activate the cooling unit 106 and the heating unit 112 of the AHU 102.

In some embodiments, when it is determined that the fan 108 is not functioning properly and is not producing airflow (or is producing airflow that is below a threshold flow rate), the control unit 130 may be configured to enter the AHU 102 into a “fault mode” and maintain the deactivation of the first relay output 118 and the second relay output 120. Given that the fan 108 is used to flush the leaked refrigerant from the AHU 102, if the fan 108 is not functioning properly, the fan 108 may not be able to properly flush the leaked refrigerant from the AHU 102. Therefore, the AHU enters into the “fault mode” and ceases operation to prevent operation during further buildup of leaked refrigerant.

In some embodiments, the safety system 100 may further include a processing unit 132 configured to monitor the relay module 114 and trigger an alert when the refrigerant leak is detected and/or when the airflow sensor 109 determines that the fan 108 is not functioning properly and is not producing airflow (or is producing airflow that is below a threshold flow rate). In an example, the alert may be one of an audio alert, a visual alert, or a combination thereof. In some embodiments, the alert may be communicated to a user device and the alert may include details about, but not limited to, the detected refrigerant leak and the actions performed by the control unit 130 in response to such detection.

In some embodiments, each of the control unit 130 and the processing unit 132 may be implemented as a computing device, such as microcontroller, as described with reference to FIG. 2. The computing device may include a CPU 202 which performs processes described above/below. The processes and instructions may be stored in a memory 204 thereof. These processes and instructions may also be stored on a storage medium disk 206, such as a hard drive (HDD) or portable storage medium or may be stored remotely. The hardware elements in order to achieve the computing device may be realized by various circuitry elements, known to those skilled in the art. For example, the CPU 202 may be a Xenon or Core processor from Intel of America or an Opteron processor from AMD of America, or may be other processor types that would be recognized by one of ordinary skill in the art. Alternatively, the CPU 202 may be implemented on an FPGA, ASIC, PLD or using discrete logic circuits, as one of ordinary skill in the art would recognize. Further, the CPU 202 may be implemented as multiple processors cooperatively working in parallel to perform the processes described above.

The computing device in FIG. 2 also includes a network controller 208, such as an Intel Ethernet PRO network interface card from Intel Corporation of America, for interfacing with a network 210. As can be appreciated, the network 210 can be a public network, such as the Internet, or a private network such as an LAN or WAN network, or any combination thereof and can also include PSTN or ISDN sub-networks. The network 210 can also be wired, such as an Ethernet network, or can be wireless such as a cellular network including EDGE, 3G, 4G and 5G wireless cellular systems. The wireless network can also be WiFi, Bluetooth, or any other wireless form of communication that is known.

The computing device further includes a display controller 212, such as a NVIDIA GeForce GTX or Quadro graphics adaptor for interfacing with a display 214 that is configured to provide the alert when the refrigerant leak is detected. In some embodiment, the display 214 may include a touchscreen module to allow a user to provide instructions to the safety system 100 for controlling operation of the AHU 102. A sound controller 216 may also be provided in the computing device to interface with a speaker 218 and configured to provide the audio alerts.

The exemplary circuit elements described in the context of the present disclosure may be replaced with other elements and structured differently than the examples provided herein. Moreover, circuitry configured to perform features described herein may be implemented in multiple circuit units (e.g., chips), or the features may be combined in circuitry on a single chipset. The above-described hardware description is a non-limiting example of corresponding structure for performing the functionality described herein.

FIG. 3 illustrates an exemplary flowchart of a method 300 for monitoring the refrigerant leak in the AHU 102, according to an aspect of the present disclosure. At block 302, the refrigerant sensor 104 is actuated by supplying power thereto based on turning on the AHU 102. The refrigerant sensor 104 generates the input proportional to the concentration of the refrigerant in the AHU 102 and the generated input is received by the control unit 130 via the refrigerant sensor input 116. As described above, the control unit 130 is configured to determine the refrigerant leak based on the input from the refrigerant sensor 104. At block 304, if no refrigerant leak is detected by the control unit 130, a monitor system, such as EcoNet® (or, EcoNet Mobile App), at block 306 is actuated to provide updates and alerts to the user. In some embodiments, for a refrigerant leak up to a predefined minimum value, the safety system 100 may be configured to only report the refrigerant leak to the user via alerts and components of the AHU 102 may not be deactivated. However, at block 304, if the refrigerant leak is detected, the control unit 130 is configured to energize the third relay output 122 and the fourth relay output 124 to activate the fan 108 and the damper 110, respectively, to flush the leaked refrigerant. Additionally, the control unit 130 may energize the first relay output 118 and the second relay output 120 to turn off the cooling unit 106. The control unit 130, at block 310, is configured to apply a time delay to turn on of the AHU 102 by a predetermined time interval to ensure the leaked refrigerant has been dispersed. Once the AHU 102 resumes functioning, the control unit 130 is configured to detect whether the refrigerant leak still exists. If no further refrigerant leak is detected, the control unit 130 may be configured communicate to the monitor system at the block 306 to provide alerts to the user about the event of refrigerant leakage and mitigation steps carried out. However, if further refrigerant leak is detected, the control unit 130 may be configured to again energize the relay outputs as described hereinabove. In some examples, the control unit 130 communicates the refrigerant leak event and mitigation to the monitor system periodically or as soon as the leak event occurs.

FIG. 4A, FIG. 4B, and FIG. 4C illustrate embodiments of end use applications implementing the refrigerant sensor 104. In some examples, FIG. 4A, FIG. 4B, and FIG. 4C are individual circuits derived obtained from FIG. 1 for simplicity of explanation. Particularly, FIG. 4A illustrates an exemplary circuit of an auxiliary device. In an embodiment, a relay output of the refrigerant sensor 104 may be connected to the auxiliary device having the control unit 130. When the refrigerant leak (fault) is detected, the refrigerant sensor 104 generates the input and the control unit 130 receives the input and energizes respective relay outputs to control operation of the AHU 102.

FIG. 4B illustrates one embodiment of a circuit of a commercial device, such as a smoke detector, coupled to the relay module 114. In an embodiment, a relay output of the refrigerant sensor 104 may be connected to a DDC smoke detector input. Based on receiving the input from the refrigerant sensor 104, the control unit 130 may activate a smoke extinguisher which is configured to spray liquid to settle the smoke in the AHU 102. In some embodiments, the safety system 100 may include a smoke detector alarm, where the control unit 130 is configured to trigger the smoke detector alarm when the refrigerant leak is detected.

FIG. 4C illustrates one embodiment of a circuit of a thermostat coupled to the refrigerant sensor 104. In an embodiment, a relay output of the refrigerant sensor 104 may be connected to the thermostat. When a fault, such as increase in temperature of the heating unit 112, is detected, the control unit 130 may be configured to turn on the fan 108 and turn off the cooling unit 106 of the AHU 102. However, heating operation via combustion of gas may be carried out without any interruption.

It should be noted that while FIGS. 4A-4C may illustrate relays in a normally open or normally closed configuration, this is not intended to be limiting and the relays may be provided in either configuration.

FIG. 5 illustrates a flowchart of a method 500 of operating the AHU 102. The method 500 is described in conjunction with FIG. 1. In an aspect, the method 500, at step 502, includes monitoring the input from the refrigerant sensor 104, where the input is indicative of the concentration of the refrigerant in the AHU 102.

At step 504, the method 500 includes comparing, by the control unit 130, the concentration of the refrigerant with the predefined threshold value. At step 506, the method 500 includes detecting, by the control unit 130, the refrigerant leak in the AHU 102 based on the comparison.

At step 508, the method 500 includes activating or deactivating, by the control unit 130, at least one of the first relay output 118, the second relay output 120, the third relay output 122 and the fourth relay output 124 based on the detection of the refrigerant leak. The first relay output 118 and the second relay output 120 connects the control unit 130 to the cooling unit 106 of the AHU 102, the third relay output 122 connects the control unit 130 to the fan 108 of the AHU 102, and the fourth relay output 124 connects the control unit 130 to the damper 110 of the AHU 102.

Although not explicitly illustrated through blocks, in an aspect, the method 500 further includes deactivating the first relay output 118 and the second relay output 120 and stopping operation of the cooling unit 106 when the concentration of the refrigerant due to the leak exceeds the predefined threshold value.

In an aspect, the method 500 further includes activating at least one of the third relay output 122 and the fourth relay output 124 to initiate the fan 108 or the damper 110 and dispersing the leaked refrigerant.

In an aspect, the method 500 further includes deactivating, by the control unit 130, at least one of the third relay output 122 and the fourth relay output 124 when the refrigerant concentration is below the predefined threshold value.

In an aspect, the method 500 further includes activating, or deactivating the fifth relay output 126 and the sixth relay output 128, each connected to the heating unit 112 of the AHU 102. The method 500 further includes activating or deactivating, by the control unit 130, the fifth relay output 126 and the sixth relay output 128 to turn on or turn off the heating unit 112.

In an aspect, the method 500 further includes triggering, via the processing unit 132, a smoke detector alarm in response to the refrigerant leak.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

1. An interface control relay module comprising:

a refrigerant sensor input connected to a refrigerant sensor of an air handling unit (AHU), the refrigerant sensor configured to generate an input proportional to a concentration of a refrigerant leak sensed in the AHU;

a control unit coupled to the refrigerant sensor input and configured to receive the input from the refrigerant sensor;

a first relay output and a second relay output, each connecting the control unit to a cooling unit of the AHU;

a third relay output connecting the control unit to a fan of the AHU; and

a fourth relay output connecting the control unit to a damper of the AHU,

wherein the control unit is configured to activate or deactivate at least one of the first relay output, the second relay output, the third relay output and the fourth relay output based on the input received from the refrigerant sensor.

2. The interface control relay module of claim 1, wherein the control unit is configured to determine a degree of refrigerant leak based on comparing the concentration of the refrigerant leak to a predefined threshold value.

3. The interface control relay module of claim 2, wherein the control unit is configured to deactivate at least one of the third relay output and the fourth relay output when the concentration of the refrigerant leak is below the predefined threshold value.

4. The interface control relay module of claim 1, further comprising a fifth relay output and a sixth relay output, each connected to a heating unit of the AHU, wherein the control unit is configured to activate or deactivate the fifth relay output and the sixth relay output to turn on or turn off the heating unit.

5. The interface control relay module of claim 1, further comprising an airflow sensor of the AHU, the airflow sensor configured to generate an input indicative of an amount of airflow produced by the fan.

6. A safety system for an air handling unit (AHU) comprising a heating unit and a cooling unit, the safety system comprising:

a refrigerant sensor coupled to the AHU, wherein the refrigerant sensor is configured to generate an input proportional to a concentration of a refrigerant leak sensed in the AHU;

an interface control relay module comprising: a refrigerant sensor input connected to the refrigerant sensor; a control unit coupled to the refrigerant sensor input and configured to receive the input from the refrigerant sensor; a first relay output and a second relay output, each connecting the control unit to a cooling unit of the AHU; a third relay output connecting the control unit to a fan of the AHU; and a fourth relay output connecting the control unit to a damper of the AHU, wherein the control unit is configured to activate or deactivate at least one of

the first relay output, the second relay output, the third relay output and the fourth relay output based on the input received from the refrigerant sensor.

7. The safety system of claim 6, wherein the control unit is configured to determine a degree of refrigerant leak based on comparing the concentration of the refrigerant leak to a predefined threshold value.

8. The safety system of claim 7, wherein the control unit is configured to deactivate at least one of the third relay output and the fourth relay output when the concentration of the refrigerant leak is below the predefined threshold value.

9. The safety system of claim 6, wherein the interface control relay module further comprises a fifth relay output and a sixth relay output, each connected to the heating unit, wherein the control unit is configured to activate or deactivate the fifth relay output and the sixth relay output to turn on or turn off the heating unit.

10. The safety system of claim 7, further comprising a smoke detector alarm, wherein the control unit is configured to trigger the smoke detector alarm when the refrigerant leak is detected.

11. The safety system of claim 7, further comprising a processing unit configured to monitor the interface control relay module and trigger an alert when the refrigerant leak is detected.

12. The safety system of claim 7, further comprising an airflow sensor of the AHU, the airflow sensor configured to generate an input indicative of an amount of airflow produced by the fan.

13. A method of operating an air handling unit (AHU), the method comprising:

monitoring an input from a refrigerant sensor, the input indicating concentration of a refrigerant leak sensed in the AHU;

comparing, by a control unit, the concentration of the refrigerant leak with a predefined threshold value;

determining, by the control unit, a degree of refrigerant leak in the AHU based on the comparison; and

activating or deactivating, by the control unit, at least one of a first relay output, a second relay output, a third relay output and a fourth relay output based on the degree of refrigerant leak, wherein the first relay output and the second relay output connects the control unit to a cooling unit of the AHU, the third relay output connects the control unit to a fan of the AHU, and a fourth relay output connects the control unit to a damper of the AHU.

14. The method of claim 13, further comprising, deactivating the first relay output and the second relay output, and stopping operation of the cooling unit when the concentration of the refrigerant leak exceeds the predefined threshold value.

15. The method of claim 13, further comprising, activating at least one of the third relay output and the fourth relay output to initiate the fan or the damper, and dispersing the leaked refrigerant.

16. The method of claim 13, further comprising deactivating, by the control unit, at least one of the third relay output and the fourth relay output when the concentration of refrigerant leak is below the predefined threshold value.

17. The method of claim 13, further comprising, activating, or deactivating a fifth relay output and a sixth relay output to turn on or turn off the heating unit, wherein each of the fifth relay output and a sixth relay output is connected to a heating unit of the AHU.

18. The method of claim 13, further comprising triggering, via a processing unit, a smoke detector alarm in response to the refrigerant leak.