Compact marine air conditioning unit with optional electric heat

Abstract

A package marine air conditioning unit places an evaporator coil on the inlet side of an enclosing cabinet, an axial supply fan on an opposing outlet side of the cabinet, and a compressor disposed between the evaporator coil and the supply fan. Locating the compressor within the air stream on the leaving air side of the evaporator coil allows cold air to flow around the compressor thereby providing beneficial compressor cooling. An axial flow supply fan located downstream of the compressor functions to draw return air in a generally lineal flow path across the evaporator coil and around the compressor, for discharge in an axial direction thereby resulting in a generally linear air flow path through the unit. A cabinet is provided to enclose the components thereby allowing for the installation of electric heating elements. Enclosing the components within a cabinet avoids the need to paint or otherwise coat the enclosed components thereby reducing manufacturing costs.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of provisional U.S. Patent Application Ser. No. 61 / 166,308 filed on Apr. 3, 2009.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]N / ACOPYRIGHT NOTICE[0003]A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise retains all copyright and all other rights reserved.BACKGROUND OF THE INVENTION[0004]1. Field of the Invention[0005]The present invention relates generally to marine air conditioning systems, and more particularly to a compact, self-contained water cooled package air conditioning system for the marine industry.[0006]2. Description of Related Art[0007]Air conditioning (“A / C”) systems have been installed on marine vessel...

AI Technical Summary

Benefits of technology

"The present invention provides an improved compact package marine A / C system that overcomes the limitations and disadvantages of prior art systems. The system is more practical, reliable, quieter, and smaller. The compressor is placed between the evaporator coil and the supply fan inlet, which prevents evaporator coil icing and ensures even air flow across the coil. The system uses an axial flow fan and a spiral wound tubular refrigerant-to-water condenser to achieve a linear air flow path. The compressor is located downstream from the evaporator coil to improve its performance and reliability. The system is enclosed by a cabinet, which reduces manufacturing costs and noise. The invention provides a multi configuration marine A / C unit that is quieter, more esthetically pleasing, and easier to manufacture."

Problems solved by technology

These systems are typically specially designed for installation on marine vessels wherein space is extremely limited and quiet operation is required.

The installation of air conditioning systems in marine vessels is wrought with difficulties and limitations that are unique to such applications.

The use of split systems results in significantly increased installation costs, and requires running refrigerant lines throughout the vessel to connect the compressor to a remotely located evaporator coil.

One significant limitation presented when attempting to install package A / C units on a marine vessel involves is a lack of space.

More particularly, space on marine vessels is very limited, and interior rooms and cabins often present little or no unused or free space to accommodate the installation of an air conditioning unit.

Another problem experienced with marine air conditioning units involves excessive sound / noise levels.

Space limitations often dictate that marine air conditioning systems be installed in proximity to frequently occupied spaces such as cabins and sleeping quarters.

A further problem experienced with conventional marine air conditioning units relate to performance.

Such configurations have been found to perform unsatisfactorily.

A common problem experienced with such configurations is the formation of ice on the evaporator coil.

The icing problem is a result from uneven air flow across the coil due to the close spacing of the evaporator coil and the supply fan inlet, which causes low face velocities along the coil periphery.

In an attempt to rectify such problems, some models incorporate complex control schemes that temporarily terminate cooling mode operation in an attempt to de-frost the evaporator coil thereby interrupting the flow of cold air to the conditioned space.

Another problem associated with package marine air conditioning units in the art involves the migration of moisture from the coil into the discharge airstream resulting from localized excessive air velocity across the coil.

A further problem found in package marine air conditioners in the art involves the location of the compressor.

More particularly, prior art designs (both packaged and split systems) typically locate the compressor in an area that is not exposed to air flow thereby failing to cool the compressor leading to compressor overheating.

Both of said locations fail to provide the compressor with adequate ambient cooling resulting in performance degradation.

Yet another limitation present with commercially available package marine A / C units involves air flow paths.

The present inventor has found that an L-shaped air-flow path renders installation exceedingly difficult in a large number of cases wherein the available space is long and narrow leaving little if any room to re-direct the air 90-degrees from the evaporator coil inlet to the supply fan outlet.

The design disclosed by Dodge, however, failed to significantly reduce noise as a result of positioning the blower in close proximity to the evaporator coil thereby allowing blower sound to propagate from the unit.

The design disclosed by Dodge, is further burdened by evaporator coil freeze-up (e.g. icing) resulting from the close spacing between the evaporator coil and blower inlet in the draw-thru configuration (e.g. wherein air is drawn across the evaporator coil), which configuration results in uneven airflow across the coil.

It has been found, however, that in warm operating conditions this system is prone to compressor overheating, and in cold operating conditions liquid refrigerant has been found to migrate back to the compressor, both undesirable situations can lead to compressor failure.

A further limitation present with the configuration disclosed by Dodge, as well as all other configurations that do not incorporate a cabinet or enclosure to house the components is the inability to incorporate electric heat.

One disadvantage of exposing the components involves the inability to incorporate electric heating elements due as exposed heating coils would be a fire hazard.

As should now be apparent, self-contained marine air conditioning units, such as the one disclosed by Dodge, are burdened with significant limitations and disadvantages.

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