Why We're Publishing This
EcoSnap generated intellectual property during development of an earlier HVAC product line. Rather than allowing these provisional applications to lapse quietly or pursue costly patent protection on technology we believe should be freely available, we are publishing the full text here as a public disclosure.
This publication establishes prior art and places these inventions in the public domain. Anyone is free to build on them. That's the point.
for Mini-Split A/C Systems
Background
[0001]Air conditioning (or A/C) is the process of removing heat from an enclosed space to achieve a more comfortable interior temperature, and in some cases, also controlling the humidity of internal air. Air conditioners (or A/C units) typically use vapor-compression refrigeration to condition the air and range in size from small units used in vehicles or single rooms to large units that can cool entire buildings. Heat pumps are similar in many ways to air conditioners but use a reversing valve, allowing the heat pump to both heat and cool an enclosed space. Mini-split (or ductless) systems supply conditioned and/or heated air to a single room or area of a building, without ducts, and in a decentralized manner. In various applications, the mini-split system may include an air conditioner / resistance heater combination or a heat pump to generate on demand the conditioned or heated air.
Brief Description of the Drawings
[0002]FIG. 1 illustrates an example system diagram of a mini-split system using an adaptive vibration calibration process to minimize unwanted vibration.
[0003]FIG. 2 illustrates an example human within a conditioned space experiencing the effects of noise and/or vibration emanated from a mini-split system.
[0004]FIG. 3 illustrates an example system diagram of a computing device suitable for implementing aspects of an adaptive vibration calibration process for a mini-split system.
[0005]FIG. 4 illustrates example operations for running an adaptive vibration calibration process for a mini-split system.
Detailed Description
[0006]The presently disclosed technology relates to vibration management in A/C units or heat pumps, particularly to systems and methods for reducing vibrational noise and improving installation outcomes in ductless mini-split systems through automated calibration routines using embedded sensor data and frequency-modulated inverter controls. Although the present disclosure primarily references mini-split systems, aspects of the invention may be applied to other HVAC systems with variable-speed drives, including Packaged Terminal Air Conditioners (PTACs), window units, and packaged systems.
[0007]Mini-split systems can experience unwanted vibrational noise due to variable compressor speeds, fan harmonics, and non-uniform mounting conditions (e.g., wood studs vs. masonry). Traditional A/C systems rely on passive damping (e.g., rubber feet and spring isolators), fixed-speed profiles, which do not adapt to site-specific resonances or system degradation over time. This can lead to a poor customer experience, service calls, and design compromises. This also limits installations of outdoor units to exterior walls as this can cause harsh vibration. Traditional A/C systems often separate and distance the condenser unit from the space to be conditioned to minimize noise and/or vibration.
[0008]In mini-split systems, the condenser (outdoor unit) and the evaporator (indoor unit) are directly connected via a refrigerant lineset on opposite sides of a wall, and the evaporator is placed within the conditioned space on one side of the wall. This limits possible separation between the conditioned space and the evaporator and condenser. While some installations recommend increasing lineset length to mitigate transmitted vibration, this may incur additional cost and further limit possible installation locations of the condenser. As a result, it is advantageous to limit vibration in mini-split systems where the conditioned space, condenser, and the evaporator are all in close proximity, with the condenser and the evaporator sharing a wall and the evaporator within the conditioned space.
[0009]A variable-frequency drive (also referred to as a VFD, adjustable-frequency drive, adjustable-speed drive, variable-speed drive, AC drive, micro drive, inverter drive, or variable voltage variable frequency drive) is an AC motor drive that controls motor speed and torque by varying the frequency of the input electricity. VFD-driven mini-split systems introduce new opportunities and challenges due to the ability to run the compressor and/or fan at variable speeds using continuous frequency changes. While this allows for efficiency and comfort optimization, it also creates a wider range of potential resonant conditions that are installation-specific and difficult to predict.
[0010]The presently disclosed technology includes an automated vibration calibration routine used during installation, startup, and/or periodically during operation of the mini-split system. Using one or more embedded accelerometers (e.g., 3-axis micro-electromechanical systems (MEMS) accelerometers), a controller (e.g., a dedicated circuit board or circuitry or additional componentry adopted on an existing circuit board or within existing circuitry for control of the mini-split system) executes a sweep of vibration-inducing mechanical components (e.g., a compressor, and one or more fan motors) across their frequency ranges permitted by the VFD. The controller then identifies resonance peaks and adjusts: 1) compressor ramp and modulation profiles; 2) fan speed step sizes and limits; and/or 3) startup sequencing or pulse-width modulation (PWM) patterns using motor drivers from the VFD.
[0011]As the compressor and/or fans are VFD-driven, the controller can make fine-grained adjustments to compressor and/or fan speed, avoiding specific frequency bands or transitions where vibration amplitudes spike due to system resonance. This allows for a dynamic vibration minimization strategy that is not possible with conventional fixed-speed mini-split systems.
[0012]The presently disclosed technology may apply to mini-split systems of varying capacities, up to 18,000 BTU/hr, for example. The presently disclosed technology may also be used in single-family residential construction, multi-family residential, accessory dwelling units, and light commercial applications, as examples. In other implementations, the presently disclosed technology may also be applied to packaged A/C units, such as packaged terminal air conditioners (PTACs), through-the-wall A/C units, and window A/C units.
[0016]As the condenser within the outdoor unit and the blower fan(s) within the indoor air-handling unit include rotating masses, the condenser and the blower fan(s) individually and/or collectively may create undesirable vibration within the mini-split system and specifically projected into the conditioned space. To detect and counteract this undesirable vibration, each of the indoor unit and the outdoor unit are equipped with accelerometers, respectively. In other implementations, a greater number of sensors (including but not limited to accelerometers) is used or one sensor is used. These sensors may be placed in varied locations, including but not limited to on or near the compressor, on or within either of the enclosures for the indoor unit or the outdoor unit, on a bracket for mounting the indoor unit or the outdoor unit, or on its own bracket or mounting structure in varied locations within the conditioned space.
[0017]A calibration controller is connected to the accelerometers and can run a vibration test by ramping the speed of the condenser and the blower fan(s) up and down, individually or together to identify speeds of the condenser and/or the blower fan(s) that yield more undesirable vibration than other speeds of the condenser and/or the blower fan(s). The calibration controller can then perform an adjusting operation to adjust the operating parameters of the condenser and/or the blower fan(s) to quickly move past the identified speeds when ramping speed up or down or avoid those speeds altogether if they are at the operating limits of the condenser and/or the blower fan(s). In sum, the calibration controller is capable of dynamic avoidance of resonance bands using inverter controls that allow for fine-tuning frequency profiles at mini-split system runtime, not just pre-set speed points for the mini-split system. The calibration controller adjusts operating curves for the indoor unit and/or the outdoor unit to avoid detected peaks using inverter frequency modulation on the input power.
[0018]This frequency avoidance logic is applied to HVAC, specifically mini-split systems, such as the mini-split system where it has not traditionally been used. In some implementations, the frequency avoidance logic may be implemented as a feedback loop with real-time vibration sensing that actively shapes mini-split system ramp-up and ramp-down behavior over time.
[0022]As a potential added benefit of the adaptive vibration calibration process, avoiding undesirable vibration caused by resonance within the mini-split system and its surrounding installation may also reduce possible harmonic damage to components of the mini-split system over time, reducing the likelihood for repair or replacement of the mini-split system. The accelerometers may also be used for equipment monitoring and to identify impending failures before they occur.
Through-the-Wall HVAC Installation
Background
[0001]Air conditioning (or A/C) is the process of removing heat from an enclosed space to achieve a more comfortable interior temperature, and in some cases, also controlling the humidity of internal air. Air conditioners (or A/C units) typically use vapor-compression refrigeration to condition the air and range in size from small units used in vehicles or single rooms to large units that can cool entire buildings. Heat pumps are similar in many ways to air conditioners, but use a reversing valve, allowing the heat pump to heat and cool an enclosed space. Mini-split (or ductless) systems supply conditioned and/or heated air to a single room or area of a building, without ducts, and in a decentralized manner. In various applications, the mini-split system may include an air conditioner / resistance heater combination or a heat pump to generate conditioned or heated air on demand.
Brief Description of the Drawings
[0002]FIG. 1A illustrates an isometric view of a mini-split system using an example adjustable helical conduit before a through-the-wall installation.
[0003]FIG. 1B illustrates a side view of the mini-split system of FIG. 1A.
[0004]FIG. 2 illustrates a side view of a mini-split system partially installed through a wall using an example adjustable helical conduit.
[0005]FIG. 3 illustrates a side view of a mini-split system completely installed through a wall with a sheath extended over a connection to a condenser unit.
[0006]FIG. 4 illustrates a partial sectional isometric view of an example adjustable helical conduit according to the presently disclosed technology.
[0007]FIG. 5A illustrates an isometric view of a mini-split system partially installed through a wall using the example adjustable helical conduit.
[0008]FIG. 5B illustrates an isometric view of the mini-split system of FIG. 5A completely installed through the wall using the example adjustable helical conduit.
[0009–0025]FIGs. 6A through 14 illustrate additional cross-sectional, isometric, and detail views of the adjustable helical conduit, combined connector assemblies, wall sleeve components, and example installation operations.
Detailed Description
[0026]The presently disclosed technology relates to adjustable refrigerant line assemblies for HVAC systems, particularly ductless mini-split heat pumps. It provides an adjustable helical conduit between indoor and outdoor units through a building wall using helically wound copper tubes, electrical wiring, and an axially extendable drain line. The helically wound copper tubes are of a fixed length, even though the helical conduit is adjustable in length, by stretching and compressing the wound helix of copper tubes within the adjustable helical conduit.
[0027]Installing HVAC systems often requires routing refrigerant lines, electrical wiring, and a condensate drain through an exterior wall. In mini-split systems, the condenser (outdoor unit) and the evaporator (indoor unit) are connected on opposite sides of the exterior wall. This creates a variable separation between the evaporator and condenser based on walls having variable thicknesses. Standard line sets are measured and cut to precise lengths, increasing installation time, limiting installation flexibility, and complicating sealing penetrations through walls of varying thickness. Installers often compensate by oversizing, coiling excess length, or using expensive pre-charged flexible line kits, which adds cost and complexity. Currently, no integrated, length-adjustable assembly simplifies this process across diverse wall geometries.
[0028]The presently disclosed technology minimizes the length of the helically wound copper tubes to achieve a desired degree of adjustability of the adjustable helical conduit, which in turn minimizes the refrigerant charge within the helically wound copper tubes. Minimized length of the helically wound copper tubes and refrigerant charge therein allows for a cost-efficient installation of the presently disclosed technology compared to prior art solutions that may manually coil large amounts of excess length of the copper tubes behind the outdoor unit. These manually coiled excess lengths of copper tubes found in some conventional installations can reduce system efficiency by thermal transfer with the surrounding environment, resulting in increased risk of kinking the copper tubes. They may also risk trapping oil therein due to their large radii. These conventional exposed excess coils of copper tubes may also be unsightly and vulnerable to theft, particularly when the prices of copper are high.
[0029]The presently disclosed technology introduces an adjustable refrigerant conduit assembly that accommodates varying wall thicknesses using a helically coiled bundle of copper tubing and electrical conductors surrounding an axially extendable drain line. The assembly is preformed into a compact helical coil that can be inserted through a wall sleeve. Once inserted through the wall and affixed indoors, the end can be manually pulled to adjust the length. This action deforms the helically wound copper tube, extending its length without cutting or brazing, and simultaneously extending the drain line, which may be configured as either a telescoping assembly or a corrugated, axially stretchable tube. The adjustable refrigerant conduit assembly maintains structural integrity and sealing across the wall penetration.
[0030]The adjustable refrigerant conduit assembly provides a bundled solution for refrigerant (liquid and vapor), power, signal, and drainage lines. Once extended, the wall penetration can be mechanically secured and sealed around the adjustable refrigerant conduit assembly, ensuring proper refrigerant flow, electrical continuity, and condensate drainage without custom field modifications.
[0031]In some implementations, the presently disclosed technology includes self-sealing connectors on one or both ends of the adjustable helical conduit that ensure the helically wound copper tubes are closed when disconnected from corresponding indoor and/or outdoor units and open once properly connected to the indoor and/or outdoor units. This allows for the helically wound copper tubes to be pre-charged with refrigerant before installation, simplifying installation as the installer does not directly handle the refrigerant, as no line splicing is required in the field. This simplified installation also allows for faster setup and temporary or permanent installations of corresponding HVAC systems.
[0032]Although the present disclosure primarily references mini-split systems, aspects of the presently disclosed technology may be applied to other HVAC systems with separate units (e.g., evaporator and condenser units) connected through a wall. The presently disclosed technology may apply to HVAC systems of varying capacities, up to 18,000 BTU/hr., for example. As examples, the presently disclosed technology may also be used in single-family residential construction, multi-family residential, accessory dwelling units, and light commercial applications. The presently disclosed technology may also be used in vehicles, such as automobiles and recreational vehicles. The presently disclosed technology may be applied to a wide range of wall thicknesses, including those as little as 3.5" thick in commercial applications in mild climates, to 12" (or more) thick in residential applications in cold climates, and various thicknesses therebetween.