Patent Description:
One type of air conditioning system is a heating ventilation air conditioning (HVAC) system with an integrated microemulsion-based air dehumidification system is a technology that may provide latent air cooling while enhancing system performance. A microemulsion-based air dehumidification system may present an efficient and cost-effective alternative to dehumidification technologies involving corrosive liquid desiccant solutions (LiCl, LiBr) and desiccant wheels. A microemulsion-based air dehumidification system may be enabled by organic liquid-based microemulsion sorbents which may provide the following relative benefits: <NUM>) heat required for microemulsion organic liquid regeneration e.g. via a microemulsion-based desorber may be a fraction of that required when using other desiccants; <NUM>) desiccant regeneration temperature may be comparably low; <NUM>) when heat is supplied, absorbed fluids may be released as liquid rather than vapor thereby reducing the need for certain condensers while desorbed fluids may be used to cool other condensers; and <NUM>) the utilized organic solutions are not corrosive thereby reducing operational complexity and cost.

In view of the benefits of an HVAC system using a microemulsion-based air dehumidification system, there is a desire to address oil carryover downstream of a microemulsion-based desorber. Two categories of oil carryover include: (<NUM>) carryover in a form of an aerosol (liquid droplets); and (<NUM>) carryover in a form of a vapor. Oil droplets may occur from airflow velocity profiles created by geometrical features of oil wetted surfaces. Oil vapor may occur from temperature of the process vis-à-vis the oil vapor pressure. Typical processes for capturing oil aerosols may involve impacting and coalescing oil droplets onto a high surface area organic or metal fiber mesh. Processes for capturing oil vapors may involve refrigeration or/and adsorption of the oil vapor using a high-capacity solid sorbent.

Industrial devices may experience oil carryover issues including for example oil-lubricated rotary screw air compressors. Devices that address oil carryover may be designed for systems which produce large quantities of oil carryover compared with an HVAC system and may be designed for continuous removal of captured oil droplets, which can result in energy waste. <FIG> illustrate known industrial desorbers 10a, 10b having automated drains. Such systems may be very complex and costly. In addition, such systems may be designed for operations that involve relatively high pressures providing oversized components that allow for an undesirably high pressure drop.

<CIT> describes a spiral mist eliminator comprising a layered assembly for removing fine oil aerosols from an airflow.

Viewed from a first aspect, the present invention provides a desorber for minimizing aerosol concentration of oil for an air conditioning system with an integrated microemulsion-based air dehumidification system, the desorber comprising: a spiral-wound sheet that is wound to form an exterior end, an interior end, a top end and a bottom end, wherein a collection tube is disposed at the interior end, wherein the spiral-wound sheet comprises: a plurality of de-entrainment mesh layers extending between the exterior end and the interior end of the spiral-wound sheet, and a plurality of substantially air impermeable connector layers extending between the exterior end and the interior end of the spiral-wound sheet, and wherein: the connector layers are interlaid with the mesh layers between the top end and the bottom end of the spiral-wound sheet; the connector layers are interlaid with the mesh layers in a stripe pattern; and the collection tube is at a radial center of the spiral-wound sheet, characterized in that: the collection tube is surrounded by an inner vapor filter, the inner vapor filter being an activated carbon cartridge having a diameter and length that is sufficient to provide desired filtering of oil vapor in air traveling therethrough; and the desorber includes another activated carbon cartridge, wrapped around the spiral-wound sheet, forming an outer vapor filter.

The top and bottom layers of the spiral-wound sheet may be connector layers.

The mesh layers and/or connector layers may be substantially dimensionally alike.

An air conditioning system with an integrated microemulsion-based air dehumidification system, may include the desorber for minimizing aerosol concentration of oil having one or more of the above features.

Viewed from a second aspect, the present invention provides a method of desorbing oil from oil impregnated air in an air conditioning system with integrated microemulsion-based air dehumidification system, the method comprising: channeling the air into a desorber for minimizing aerosol concentration of oil having a spiral-wound sheet, the spiral-wound sheet having been wound to form an exterior end and an interior end, a top end and a bottom end, wherein a collection tube is connected to the interior end, wherein the spiral-wound sheet comprises: a plurality of de-entrainment mesh layers extending between the exterior end and the interior end of the spiral-wound sheet, and a plurality of substantially air impermeable connector layers extending between the exterior end and the interior end of the spiral-wound sheet, and wherein: the connector layers are interlaid with the mesh layers between the top end and the bottom end of the spiral-wound sheet, the connector layers are interlaid with the mesh layers in a stripe pattern; and the collection tube is at a radial center of the spiral-wound sheet, characterized in that: the collection tube is surrounded by an inner vapor filter, the inner vapor filter being an activated carbon cartridge having a diameter and length that is sufficient to provide desired filtering of oil vapor in air traveling therethrough; and the desorber includes another activated carbon cartridge, wrapped around the spiral-wound sheet, forming an outer filter.

<FIG> illustrate a desorber <NUM>, according to an embodiment for a microemulsion-based dehumidification system that is part of an air conditioning system, e.g., a heating venting air conditioning (HVAC) system and/or a refrigeration system. The desorber <NUM> may provide advantages typically found in a more complex system. The desorber <NUM> may be in the form of a replaceable module or cartridge, have a relatively small footprint and provide a relatively low pressure drop.

Referring now to <FIG>, <FIG>, the desorber <NUM> may minimize aerosol concentration of oil in part by functioning as a centrifugal separator <NUM>. The centrifugal separator <NUM> may include a housing <NUM> with a plurality of openings, including first opening 34a, second opening 34b and third opening 34c. The first opening 34a functions as an inlet for oil impregnated air, and the second opening 34b functions as an outlet for partially desorbed air. The third opening 34c functions as a drain for oil collected in the separator <NUM>. A centrifugal separator <NUM> forces incoming air into a spiral flow, which drives the larger and heavier droplets toward the walls of the housing <NUM> to be separated out by gravity.

Similarly, as illustrated in <FIG>, the disclosed desorber <NUM> has a spiral wound configuration, e.g., in a top view thereof, to form a centrifugal separator. The spiral curve of the desorber <NUM> is illustrated as planar and more specifically as an Archimedean spiral or involute of a circle. Other two dimensional spirals and three dimensional spirals may be applicable. Oil impregnated airflow enters in the outer radial segment <NUM> of the desorber <NUM> and speeds up while traveling to the center <NUM> of the desorber <NUM> into an oil collection tube <NUM>. Larger, heavier droplets are centrifugally driven outward.

Referring now to <FIG>, <FIG>, smaller aerosol particles in oil impregnated air may not be removed with centrifugal motion because smaller particles follow air streamlines. A known centrifugal separator <NUM> may therefore be fluidly followed by a known demister <NUM>. The demister <NUM> includes a demister housing <NUM>, a demister inlet carrying oil impregnated air, a demister vapor outlet <NUM> carrying oil vapor demisted from the oil impregnated air, a demisted air outlet <NUM> carrying demisted air. The demister <NUM> may also include a pressure release loop <NUM> fluidly connected to the demisted vapor outlet <NUM>. Internally, the demister <NUM> may contain a diffuser <NUM> and one or more mesh pads <NUM>, illustrated in greater detail in <FIG>. The mesh pads <NUM> capture smaller oil droplets by impaction.

Similarly, the disclosed embodiment in <FIG> provides a plurality of layers of de-entrainment mesh material, including layers 24a-24d. The mesh layers 24a-24b may be spaced along a top-down direction for the desorber <NUM>, i.e., from the top end <NUM> of the desorber <NUM> to the bottom end <NUM> of the desorber <NUM>. The mesh layers 24a-24d may extend along the direction of airflow, so that each layer extends between the radial outside of the desorber <NUM> and the radial inside of the desorber <NUM>. The top-down span or height of the layers of mesh material 24a-24d are illustrated as each being substantially the same, though this is not a requirement. The area of each of the mesh layers 24a-24d, and the area summation of the layers, may be sufficient to demist air traveling through the desorber <NUM>. The mesh layers 24a-24d may be plastic.

Turning now to <FIG>, the impregnated air in a known desorber may pass over coalescing membranes <NUM>, <NUM>. The membranes <NUM>, <NUM> may coalesce remaining oil droplets into larger drops, which drain by gravity. In the disclosed embodiment, illustrated in <FIG>, as impregnated air travels through the desorber <NUM>, the shape of the mesh layers 24a-24d provides a large area for impaction and oil droplets coalesce as oil collides with the mesh surfaces and eventually drains downwards. For less demanding applications, such as with microemulsion-based dehumidification systems, the flow path could include a helically shaped desorber providing a continuous change of directional flow. Such shape can be obtained with a 3D curve (not illustrated) rather than a spiral 2D curve.

A plurality of connector layers 27a-27e are interlaid with the mesh layers 24a-24d between the top end and the bottom end of the desorbing sheet. The connector layers 27a-27e are substantially air impermeable and extend between the external end <NUM> and the internal end <NUM> of the desorber <NUM>. The plurality of connector layers 27a-27e are, e.g., plastic. Other spacer material may be utilized for the connector layers.

Turning now to <FIG> and <FIG>, an outer filter <NUM> is used as a fourth desorbing element for processes where oil vapors in addition to oil aerosols are not tolerated. In a known desorbing system a refrigerant dryer (not illustrated) may be utilized or an activated carbon cartridge such as found within certain drinking bottles <NUM> may be wrapped around the desorber <NUM> to form the outer filter <NUM>. Similarly, the disclosed embodiment provides an inner vapor filter which is an active carbon filter cartridge <NUM> at the inner radius <NUM> of the desorber <NUM>. The specific diameter and length of the active carbon cartridge <NUM> is sufficient to provide desired filtering of oil vapor in air traveling therethrough.

For microemulsion-based dehumidification systems, the use of four separate devices described above results in excessive cost and pressure drop. The above disclosed desorber <NUM> may provide a relatively compact system designed to accomplish the same goal of more complex systems by combining the actions of centrifugal motion, impaction and coalescing.

In sum as illustrated in <FIG> the packaging of the desorber <NUM> is a spiral-wound sheet. The desorber <NUM> comprises one or more membrane envelopes, wrapped around the central oil collection tube <NUM>, and the tube <NUM> is surrounded by the active carbon cartridge <NUM>. The permeating air travels toward the oil collection tube <NUM> along the spiral path with minimum pressure drop.

Claim 1:
A desorber for minimizing aerosol concentration of oil for an air conditioning system with an integrated microemulsion-based air dehumidification system, the desorber comprising:
a spiral-wound sheet that is wound to form an exterior end (<NUM>), an interior end (<NUM>), a top end (<NUM>) and a bottom end (<NUM>), wherein a collection tube (<NUM>) is disposed at the interior end,
wherein the spiral-wound sheet comprises:
a plurality of de-entrainment mesh layers (24A-24D) extending between the exterior end (<NUM>) and the interior end (<NUM>) of the spiral-wound sheet, and
a plurality of substantially air impermeable connector layers (27A-27E) extending between the exterior end (<NUM>) and the interior end (<NUM>) of the spiral-wound sheet, and
wherein:
the connector layers (27A-27E) are interlaid with the mesh layers between the top end (<NUM>) and the bottom end (<NUM>) of the spiral-wound sheet;
the connector layers (27A-27E) are interlaid with the mesh layers (24A-24D) in a stripe pattern; and
the collection tube (<NUM>) is at a radial center of the spiral-wound sheet (<NUM>),
characterized in that:
the collection tube (<NUM>) is surrounded by an inner vapor filter, the inner vapor filter being an activated carbon cartridge (<NUM>) having a diameter and length that is sufficient to provide desired filtering of oil vapor in air traveling therethrough; and the desorber includes another activated carbon cartridge, wrapped around the spiral-wound sheet, forming an outer vapor filter (<NUM>).