Apparatus and methods for self-cleaning and maintaining HVAC heat transfer coils

A self-cleaning HVAC system, comprising:

• a heat transfer coil configured to disperse heat, the heat transfer coil having a first side where warm air enters and a second side where cooled air exits during normal operation of the HVAC system;
• a fan configured to cause warm air to flow into the first side of the heat transfer coil and cooled air to flow out of the second side of the heat transfer coil during normal operation of the HVAC system;
• a foam or spray generator configured to generate foam or spray comprising water, enzymes, and optionally one or more of surfactant, detergent, chlorine, chlorine dioxide, hydrogen peroxide, antimicrobial, or fragrance;
• one or more manifolds configured to receive the foam or spray generated by the foam or spray generator, each of the one or more manifolds including one or more emitters configured to emit the foam or spray;
• one or more couplers configured to couple the one or more manifolds onto the heat transfer coil, such that the one or more emitters are configured to emit the foam or spray onto the first side of the heat transfer coil;
• and
• a controller configured to cause the foam or spray generator to generate the foam or spray and cause the one or more emitters to emit the foam or spray onto the first side of the heat transfer coil when the fan of the HVAC system is running and causing air to flow in the same direction as it flows during normal operation of the HVAC system, such that the fan causes the foam or spray to flow through the heat transfer coil to dislodge and remove microbes, dirt, or debris from small spaces and surfaces inside the heat transfer coil, and flow out the second side of the heat transfer coil together with microbes, dirt, or debris removed from the small spaces and surfaces inside the heat transfer coil.

A self-cleaning HVAC system of comprising:

• a heat transfer coil configured to disperse heat;
• a fan configured to cause air to flow in from a first side of the heat transfer coil and flow out of a second side of the heat transfer coil;
• a foam or spray generator configured to generate foam or spray;
• one or more manifolds configured to receive the foam or spray generated by the foam generator, each of the one or more manifolds including one or more emitters configured to emit the foam or spray;
• one or more couplers configured to couple the one or more manifolds onto the heat transfer coil, such that the one or more emitters are configured to emit the foam or spray onto the first side of the heat transfer coil;
• and
• a controller configured to cause the foam generator to generate the foam or spray and cause the one or more emitters to emit the foam or spray when the fan is running, such that the fan causes the foam or spray to flow through the heat transfer coil to clean debris off the heat transfer coil,
• wherein the foam or spray generator comprises:
• an air compressor and a pressure chamber, the pressure chamber comprising:
• a chemical input port configured to receive one or more chemicals;
• optionally an air input port configured to receive pressurized air from the air compressor;
• a water input port configured to receive water;
• a pressure controller configured to control a pressure in the pressure chamber, causing a pressurized mixture of the one or more chemicals, optional air, and water to form the foam or spray;
• one or more output ports configured to output the foam or spray;
• and
• a communication interface configured to communicate with the controller.