Method and system for cleaning heating, ventilation and air conditioning systems

1. A method for cleaning a heating, ventilation and air conditioning (HVAC) system of a building, comprising:

applying a cleaning foam at low pressure into a plurality of spaces between or within one or more heat-transfer coils of a heat exchange system of the HVAC system, the heat exchange system having a front side for air intake during operation of the HVAC system and a back side through which air exits during the operation of the HVAC system, wherein the cleaning foam is applied to the front side of the heat exchange system, wherein the cleaning foam comprises water, air, surfactant, enzymes, and least one of chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent;

causing or allowing the cleaning foam to pass through the plurality of spaces;

the cleaning foam breaking down and removing dirt or debris from surfaces adjacent to the plurality of spaces, including killing and/or removing at least one of bacteria, viruses, fungi, or biofilm from the surfaces, the enzymes assisting in breaking down biofilm if present; and

the cleaning foam carrying away the removed dirt or debris from the plurality of spaces and exiting the back side of the heat exchange system with the removed debris.

2. A method for cleaning and disinfecting a heating, ventilation and air conditioning (HVAC) system of a building, comprising:

applying a cleaning foam comprising water, air, surfactant, and enzymes into a plurality of spaces between or within one or more heat-transfer coils of a heat exchange system of the HVAC system, the heat exchange system having a front side for air intake during operation of the HVAC system and a back side through which air exits during the operation of the HVAC system, the heat exchange system containing biofilm and dirt or debris, wherein the cleaning foam is applied to the front side of the heat exchange system;

operating an air handler of the HVAC system, the air handler causing forced air to enter the front side of the heat exchange system and pass through the plurality of spaces and assist movement of the cleaning foam through the plurality of spaces;

the cleaning foam breaking down and removing the biofilm and the dirt or debris from surfaces adjacent to the plurality of spaces; and

the cleaning foam carrying away the removed biofilm and the dirt or debris from the plurality of spaces and exiting the back side of the heat exchange system with the removed debris.

3. The method of claim 2 , wherein the cleaning foam further comprises at least one of hydrogen peroxide, chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent.

4. A method for cleaning a heating, ventilation and air conditioning (HVAC) system of a building, comprising:

applying a cleaning foam containing enzymes that break down biofilm into a plurality of spaces between or within one or more heat-transfer coils of a heat exchange system of the HVAC system, the heat exchange system having a front side for air intake during operation of the HVAC system and a back side through which air exits during the operation of the HVAC system, wherein the cleaning foam is applied to the front side of the heat exchange system; during operation of the HVAC system,

causing or allowing the cleaning foam to pass through the plurality of spaces;

the cleaning foam breaking down and removing dirt or debris from surfaces adjacent to the plurality of spaces, the enzymes assisting in breaking down biofilm if present; and

the cleaning foam carrying away the removed dirt or debris, and biofilm if present, from the plurality of spaces and exiting the back side of the heat exchange system with the removed debris.

5. The method of claim 4 , wherein the cleaning foam breaks down and removes biofilm from the surfaces and dirt associated with the biofilm.

6. The method of claim 4 , wherein the cleaning foam kills and/or removes at least one of bacteria, viruses or fungi from the surfaces.

7. The method of claim 4 , wherein the cleaning foam is injected under sufficiently low pressure so that the heat-transfer coils are not damaged and bendable heat-transfer fins of the coils are not damaged.

8. The method of claim 4 , wherein the cleaning foam is produced on-sight by a foam generating system, the foam generating system including one or more inlets for receiving water, air and a surfactant, a foam-generating mechanism, an outlet for generated cleaning foam, and a hose or conduit for conducting the generated cleaning foam to the one or more heat-transfer coils.

9. The method of claim 4 , further comprising introducing air from at least one of an external air supply, external fan, pressurized air line, or portable blower into the plurality of spaces to assist movement of the cleaning foam and removed debris through at least some of the plurality of spaces.

10. The method of claim 4 , the method comprising:

initially applying a thicker cleaning foam to the plurality of spaces to increase residence time and contact of the cleaning foam to the surfaces; and

thereafter applying a thinner cleaning foam to the plurality of spaces to accelerate movement of the cleaning foam and removed debris through the plurality of spaces.

11. The method of claim 4 , wherein following cleaning of the HVAC system, the HVAC system operates with reduced energy consumption and improved air flow.

12. The method of claim 4 , further comprising:

identifying one or more blockage areas within the one or more coils of the HVAC system; and

applying additional cleaning foam to the one or more blockage areas.

13. The method of claim 4 , wherein the cleaning foam comprises water, air, and surfactant.

14. The method of claim 13 , wherein the cleaning foam is free of volatile organic compounds (VOCs) and/or is pH neutral.

15. The method of claim 13 , wherein the cleaning foam further comprises at least one of hydrogen peroxide, chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent.

16. The method of claim 4 , further comprising operating an air handler of the HVAC system, the air handler causing forced air to pass through the plurality of spaces between or within one or more heat-transfer coils, the forced air assisting movement of the cleaning foam and removed debris through the plurality of spaces.

17. The method of claim 16 , the air handler comprising a blower that applies air pressure to a side of the coils and pushes air through the plurality of spaces.

18. The method of claim 16 , the air handler comprising a blower that reduces air pressure to a side of the coils and pulls air through the plurality of spaces.