Marine vessel dehumidification system
10538302 ยท 2020-01-21
Assignee
Inventors
Cpc classification
International classification
Abstract
A dehumidification system for a marine vessel includes a dehumidifier having a supply and return. The dehumidifier is supported in an interior space of the marine vessel, separated from the outside ambient environment. The supply provides dehumidifier to air through dedicated ducting to one or more locations throughout the vessel. The return includes dedicated ducting that draws air from a return grate located away from any doors on the vessel that are open directly to the outside ambient air. For example, the return grill is positioned in a space below deck. The dehumidification system includes a controller that is positioned near the return grate.
Claims
1. A marine vessel comprising an interior cabin space which is independent of untreated ambient atmospheric air, at least one cabin door that is selectively openable to permit a transfer of the untreated ambient atmospheric air into the interior cabin space and configured to permit an entry and exit of a person into and out of the interior cabin space, an air-conditioning system having an air handler, a supply outlet, a return inlet, and a dedicated air conditioning system ductwork between the supply outlet, the return inlet, and the air handler, and a dehumidification system comprising a first dehumidification system supply outlet positioned in the interior cabin space, a first dehumidification supply duct that is independent of the dedicated air-conditioning system ductwork and having a first end coupled to the first dehumidification system supply outlet, a first dehumidification system return inlet positioned in the interior cabin space, a first dehumidification return duct that is independent of the dedicated air-conditioning system ductwork and having a first end coupled to the first dehumidification system return inlet, and a dehumidifier coupled to a second end of the first dehumidification supply duct and coupled to a second end of the first dehumidification system return duct, wherein the dehumidifier draws air from the interior cabin space through the first dehumidification system return inlet and first dehumidification return duct, removes moisture from the air, and discharges the air having reduced moisture to the first dehumidification supply duct, wherein the dehumidification system further comprises a controller including a humidity sensor positioned inside of the cabin adjacent the first dehumidification system return inlet, wherein the controller activates the dehumidifier while the moisture detected by the humidity sensor exceeds a threshold value independently of the operation of the air-conditioning system.
2. The marine vessel of claim 1, wherein the air-conditioning system operates independently of the dehumidification system and air chilled by the air-conditioning system is passed through the dehumidification system independently of the air-conditioning system, the dehumidification system operable to remove water from the air to reduce the moisture of the chilled air and thereby control moisture within the marine vessel to reduce for mold growth.
3. The marine vessel of claim 2, wherein the controller further includes a temperature sensor, the controller operable to compare the temperature detected by the temperature sensor with the humidity detected by the humidity sensor to determine a relative humidity and operate the dehumidification system based on the relative humidity determined by the controller.
4. The marine vessel of claim 1, wherein the dehumidifier further comprises a drain which transfers water removed from a conditioned environment to the atmospheric ambient atmospheric air.
5. The marine vessel of claim 4, wherein the drain transfers the water directly overboard.
6. The marine vessel of claim 4, wherein the drain transfers the water to a sump.
7. The marine vessel of claim 4, wherein the drain transfers the water to a gray water storage container.
8. The marine vessel of claim 4, wherein the dehumidification system has a plurality of supply ducts and a plurality of supply outlets, the plurality of supply ducts transferring the air having reduced moisture to each of a respective one of the plurality of supply outlets.
9. The marine vessel of claim 8, wherein the dehumidification system has a plurality of return ducts and a plurality of return inlets, the return ducts transferring the air from a respective one of each of the plurality of return inlets to the dehumidifier.
10. The marine vessel of claim 9, wherein each of the plurality of supply ducts and each of the plurality of return ducts for the dehumidification system is dedicated and independent of any other HVAC system on the vessel.
11. The marine vessel of claim 1, wherein the dehumidification system includes a return plenum having a first damper operable under control of the controller to vary a flow of air from the first dehumidification system return inlet.
12. The marine vessel of claim 11, wherein the dehumidification system includes a supply plenum having a first damper operable under the control of the controller to vary a flow of air to the first dehumidification system supply outlet.
13. The marine vessel of claim 1, wherein the air-conditioning system includes a heat source configured to heat the air.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The detailed description of the drawings particularly refers to the accompanying figures in which:
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DETAILED DESCRIPTION OF THE DRAWINGS
(9) A marine vessel or yacht 10 includes a hull 12 and an upper cabin 14 as shown in
(10) As illustrated in
(11) Referring now to
(12) The compressor 422 feeds refrigerant to the coil 426 through a supply line 448 and the refrigerant is returned to the compressor 422 through a return line 450. Similarly, the compressor 424 feeds refrigerant to the coil 436 through a supply line 452 and the refrigerant returns to the compressor 424 through a return line 454.
(13) The compressors 24, 25, 422, and 424 are each in electrical communication with their respective air handler 406, 408, 428, 438 and a respective controller for each (not shown). The controller causes the air handler and respective compressor to turn on when the air temperature rises above a predetermined set point as is well known in the art.
(14) In some embodiments, the compressors are replaced by a single chiller that has a complete refrigerant circuit. In such an embodiment, the chiller utilizes a closed loop water system that feeds a standard radiator coil over which cold air is blown by an air handler. In such a system, the heat gathered by the cooled water is absorbed by sea water that is drawn in over a heat exchanger and discharged outside the vessel 10. In still other embodiments, there may be a dedicated compressor at each air handler so that the heat is dissipated in unconditioned space near the air-conditioned space. In each embodiment, the air conditioning arrangement has dedicated ducting in each conditioned area.
(15) Referring now to
(16) The dehumidification system 40 also includes a return 50 which is connected to a return duct 58 and draws return air through a return register 60 positioned in the rear stateroom 18. The dehumidification system 40 including the associated ducting is independent of the air-conditioning system 22. The dehumidification system 40 includes a drain 96 which transfers water removed by the dehumidifier 42 through the hull 12 and overboard. In some embodiments, the drain 96 is not directed to discharge the water overboard, but may be discharged into a sump or a gray water tank 98 and re-used for other uses that do not require potable water on board the vessel 10. When the water is discharged to a sump 98, a separate sump pump may be used to occasionally discharge the water overboard.
(17) While the illustrative embodiment shows only an air-conditioning system 22, it should be understood that the air-conditioning system 22 may also include a heat source configured to heat air to warm various areas of the interior of the vessel 10. According to the present disclosure, the dehumidification system 40 is independent of any HVAC system, such as the air-conditioning system 22, and utilizes separate ductwork and controls to address humidity within the interior of the vessel 10. The separation of the dehumidification system 40 and the associated ducting from the HVAC systems has been found to improve the performance of both the HVAC system and the dehumidification system 40. Reduction of the moisture in the air before it is treated by the HVAC system prevents unexpected condensation throughout the HVAC system and improves the efficiency of the HVAC system. In addition, air chilled by a chiller of the HVAC system is passed through the dehumidification system independently of the air-conditioning system, the dehumidification system operable to remove water from the air to reduce the moisture of the chilled air and thereby control moisture within the marine vessel to reduce the opportunity for mold growth
(18) Referring now to
(19) In an another embodiment, shown in
(20) Referring now to
(21) In one illustrative embodiment, the dehumidifier 42 is an Ultra-Aire 70H dehumidifier available from Therma-Stor LLC of Madison, Wis. The Ultra-Aire Control Part No. 4028539 also available from Therma-Stor LLC of Madison, Wis. is a suitable controller that may be used as the dehumidification controller 80. It has been found that for installations where the total ducting is less than twenty-five (25) feet, return ducting and grilles must have at least fifty (50) square inches of cross-section. For ducts lengths of greater than twenty-five (25) feet, but less than fifty (50) feet, return ducting and grilles must have at least seventy-five (75) square inches of cross-section.
(22) Through experimentation, it has been determined that the use of a separate, dedicated, dehumidification system reduces the load on the air conditioning system and permits a higher set-point temperature to be used to reach an acceptable level of comfort. It has also been observed that the reduction in moisture, down to 40% relative humidity, even up to temperatures of seventy-seven degrees Fahrenheit, tends to provide sufficient comfort for many users. In addition, it has been found that the reduction in humidity reduces the amount of odors experienced in the internal space of a marine vessel. This reduction in odors is believed to be a result of the reduction of amount of moisture available to carry volatiles that evaporate from fuel storage structure on the vessel. The reduction in moisture also reduces the potential for mold spores to colonize by reducing the amount of moisture that condenses on the cold surfaces of the vessel, including the surface of supply outlet such as grates, for example.
(23) It should also be noted that the enclosed interior of marine vessels tend to have high concentrations of formaldehyde. It has been determined experimentally that the level of formaldehyde in the air is reduced substantially by use of an independent dehumidification system. In one embodiment, testing showed that the level of formaldehyde was reduced from 60 parts per billion when the independent dehumidification system was not active to 52 parts per billion when the independent dehumidification system was activated and the relative humidity with a relative humidity set point of 50%. The removal of humidity is believed to reduce the presence of formaldehyde because of the attraction of the formaldehyde molecules to the water in the air. Both formaldehyde and water are polar molecules and there is a natural attraction of their dipoles. As the water is removed from the air by the dehumidification system, the formaldehyde which is attracted to, and in some cases, dissolved in the water in the air, the formaldehyde molecules are carried out of the interior spaces by the removal of the water. As described above, the occasional in-rush of humid air into the interior spaces through opened hatches will tend to cause a temporary increase in humidity in the interior space which will subsequently be removed by the independent dehumidification system. This increase in humidity will attract and remove additional formaldehyde molecules.
(24) Formaldehyde is known to be continuously produced by various building materials used in the construction of marine vessels such as marine vessel 10. While formaldehyde tends to decompose in open space and under sunlight, the enclosed spaces that are present in marine vessels tend to limit the opportunity for decomposition of formaldehyde, thereby increasing the concentration. In addition, the presence of humidity tends to draw the formaldehyde from the building materials into the humid air. It has been found that the operation of the independent dehumidification systems disclosed herein reduce the concentration of formaldehyde in the air. For example, the results of a first test are presented in Table 1 below. This test was conducted in the enclosed space of a Viking 66 foot long marine vessel. The readings were taken in a main cabin of the vessel. The test was conducted with the dehumidification system in an off condition and then subsequently turned on with measurements being taken after the dehumidification system was turned on as reflected at sample 2. The temperature, relative humidity, and concentration of formaldehyde were each measured at various points in time. It can be seen that the reduction in formaldehyde concentration is correlated to the reduction in humidity. Table 2 presents the results of a second test that was conducted on a Viking 61 foot vessel. The test associated with Table 2 was conducted with the dehumidification system operating at steady state and was subsequently turned off at sample 46. As can be seen from sample 47 and beyond, the concentration of formaldehyde rose in the enclosed space. The data supports a conclusion that maintenance of a reduced relative humidity level tends to reduce the concentration of formaldehyde, but the correlation between relative humidity and concentrations of formaldehyde is not as strong when the humidity level is not being actively controlled.
(25) TABLE-US-00001 TABLE 1 Relative Formaldehyde Temperature Humidity Sample Time ppb F. % RH 1 12:41 PM 70 65.3 58.3 2 7:02 PM 50 67.1 43.1 3 7:32 PM 46 67.1 42.7 4 8:02 PM 45 66.2 42.3 5 8:32 PM 43 66.2 42.8 6 9:02 PM 41 66.2 41.9 7 9:32 PM 41 66.2 42.0 8 10:02 PM 39 66.2 41.9 9 10:32 PM 37 66.2 41.7 10 11:02 PM 39 66.2 41.1 11 11:32 PM 39 66.2 42.3 12 12:02 AM 41 66.2 41.7 13 12:32 AM 38 65.3 42.1 14 1:02 AM 41 65.3 42.2 15 1:32 AM 38 65.3 41.7 16 2:02 AM 39 65.3 41.7 17 2:32 AM 40 64.4 42.2 18 3:02 AM 40 64.4 42.0 19 3:32 AM 39 64.4 41.8 20 4:02 AM 39 64.4 41.5 21 4:32 AM 38 63.5 41.7 22 5:02 AM 38 63.5 41.7 23 5:32 AM 38 63.5 41.5 24 6:02 AM 39 63.5 41.1 25 6:32 AM 38 63.5 41.1 26 7:02 AM 39 62.6 41.1 27 7:32 AM 37 62.6 41.1 28 8:02 AM 39 62.6 41.2 29 8:32 AM 38 62.6 40.8 30 9:02 AM 37 62.6 40.8 31 9:32 AM 35 62.6 40.8 32 10:02 AM 32 62.6 40.6 33 10:32 AM 33 62.6 40.6 34 11:02 AM 33 63.5 40.7 35 11:32 AM 34 63.5 41.7 36 12:02 PM 34 63.5 42.6 37 12:32 PM 32 63.5 41.7 38 1:02 PM 33 63.5 42.5 39 1:32 PM 35 63.5 42.4 40 2:02 PM 36 63.5 42.2
(26) TABLE-US-00002 TABLE 2 Relative Formaldehyde Temperature Humidity Sample Time ppb F. % RH 1 5:09 PM 49 74.3 48.5 2 5:39 PM 48 74.3 48.7 3 6:09 PM 48 74.3 49.1 4 6:39 PM 49 74.3 49.7 5 7:09 PM 50 74.3 48.9 6 7:39 PM 50 73.4 48.5 7 8:09 PM 48 74.3 47.9 8 8:39 PM 51 74.3 49.6 9 9:09 PM 51 73.4 49.1 10 9:39 PM 49 74.3 47.7 11 10:09 PM 51 73.4 49.6 12 10:39 PM 51 73.4 48.4 13 11:09 PM 50 73.4 49.4 14 11:39 PM 52 73.4 48.1 15 12:09 AM 50 73.4 48.9 16 12:39 AM 48 74.3 49.2 17 1:09 AM 51 74.3 48.5 18 1:39 AM 51 74.3 49.5 19 2:09 AM 55 74.3 48.7 20 2:39 AM 51 73.4 48.1 21 3:09 AM 50 74.3 49.8 22 3:39 AM 56 73.4 48.9 23 4:09 AM 51 73.4 49.3 24 4:39 AM 54 73.4 49.5 25 5:09 AM 51 73.4 50.9 26 5:39 AM 53 73.4 50.2 27 6:09 AM 53 73.4 51.0 28 6:39 AM 53 73.4 49.7 29 7:09 AM 53 73.4 50.9 30 7:39 AM 54 73.4 49.9 31 8:09 AM 53 73.4 50.1 32 8:39 AM 51 73.4 50.6 33 9:09 AM 50 73.4 49.9 34 9:39 AM 50 74.3 49.9 35 10:09 AM 51 74.3 49.3 36 10:39 AM 57 74.3 48.0 37 11:09 AM 54 74.3 49.4 38 11:39 AM 56 74.3 48.9 39 12:09 PM 55 74.3 47.5 40 12:39 PM 53 74.3 46.1 41 1:09 PM 54 74.3 48.5 42 1:39 PM 54 74.3 47.9 43 2:09 PM 51 74.3 46.6 44 2:39 PM 54 74.3 46.5 45 3:09 PM 53 74.3 48.1 46 3:39 PM 55 74.3 48.4 47 4:09 PM 52 74.3 55.0 48 4:39 PM 45 74.3 58.1 49 5:09 PM 57 74.3 53.8 50 5:39 PM 57 73.4 58.2 51 6:09 PM 55 74.3 56.1 52 6:39 PM 63 73.4 59.2 53 7:09 PM 55 74.3 58.4 54 7:39 PM 59 74.3 58.2 55 8:09 PM 68 73.4 59.2 56 8:39 PM 58 73.4 59.7 57 9:09 PM 58 73.4 59.5 58 9:39 PM 62 73.4 59.7 59 10:09 PM 60 74.3 59.4 60 10:39 PM 63 73.4 59.7 61 11:09 PM 62 73.4 59.8 62 11:39 PM 62 73.4 60.0 63 12:09 AM 62 73.4 60.2 64 12:39 AM 63 73.4 60.2 65 1:09 AM 61 73.4 60.3 66 1:39 AM 62 73.4 60.5 67 2:09 AM 62 73.4 60.3 68 2:39 AM 62 73.4 60.5 69 3:09 AM 62 72.5 60.8 70 3:39 AM 61 72.5 60.8 71 4:09 AM 61 72.5 61.0 72 4:39 AM 62 72.5 61.0 73 5:09 AM 61 72.5 61.0 74 5:39 AM 61 72.5 61.2 75 6:09 AM 60 72.5 61.3 76 6:39 AM 61 71.6 61.6 77 7:09 AM 60 71.6 61.6 78 7:39 AM 61 71.6 61.6 79 8:09 AM 60 71.6 61.7 80 8:39 AM 58 71.6 62.1 81 9:09 AM 56 71.6 62.7 82 9:39 AM 56 71.6 62.9 83 10:09 AM 54 72.5 63.0 84 10:39 AM 55 72.5 63.4 85 11:09 AM 55 72.5 63.7 86 11:39 AM 56 73.4 63.6 87 12:09 PM 55 73.4 63.4 88 12:39 PM 56 74.3 63.1 89 1:09 PM 71 73.4 61.3 90 1:39 PM 56 73.4 63.9 91 2:09 PM 68 73.4 65.2 92 2:39 PM 63 73.4 60.5 93 3:09 PM 57 74.3 64.8 94 3:39 PM 70 73.4 65.4
(27) The dehumidification systems of the present disclosure are suitable for retrofitting a marine vessel to upgrade the vessel to include the independent reunification system. To implement the dehumidification system, an installer, after having determined the appropriate size of dehumidification system, installs the dehumidifier 42. In many cases, the dehumidifier 42 is within a bulkhead, such as bulkheads 70, 72, or 74. On larger vessels, such as recreational vessels in excess of fifty (50) feet in overall length, there is sufficient space between interior walls and the whole, or between surfaces of the bulkhead, permit the dehumidifier 42 to be positioned out of sight. The installer then determines the appropriate locations for each of the supply grates. The installer may then install appropriate ductwork behind any walls or within any bulkheads to route the ductwork between the dehumidifier 42 and any supply outlets, such as supply outlets 62, 66, or 68. The installer must also identify the appropriate location of the return register 60, install the return register 60, and install any return ductwork, such as return duct 58. Once the location of each of the supply outlets 62, 66, and 68 are determined, along with the return register 60, the installer may determine the appropriate location for the dehumidification controller 80 and install it, routing the appropriate electrical connections between the dehumidification controller 80 and the dehumidifier 42. The dehumidifier 42 is connected to an appropriate power source from the vessel 10 and tested as necessary to confirm appropriate airflow is occurring between the various components of the dehumidification system 40.
(28) While the present disclosure is presented relative to marine vessels, it should be understood that the teachings may be equally applicable to other enclosed spaces that are subject to high humidity climates. For example, it is contemplated that the independent dehumidification system disclosed herein may provide similar benefits in recreational vehicles or manufactured/temporary housing units. Centralized dehumidification independent of HVAC systems has the ability to better control the environment in the enclosed spaces as well as reducing volatiles.
(29) Although the invention has been described with reference to the preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.