WO2012123960A2

WO2012123960A2 - A condenser heat recovery based distilling process and apparatus

Info

Publication number: WO2012123960A2
Application number: PCT/IN2012/000106
Authority: WO
Inventors: Milind Vishwanath RANE; Yogesh Suresh Padiya
Original assignee: Indian Institute Of Technology, Bombay
Priority date: 2011-02-15
Filing date: 2012-02-15
Publication date: 2012-09-20
Also published as: WO2012123960A3

Abstract

A condenser heat recovery based distilling process and apparatus is provided in various embodiments of the present invention. The apparatus 100 includes a housing 102, at least one longitudinal trough 106 connected to a pair of opposite sidewalls 104 of the housing 102 for storing contaminated water, the trough 106 has a channel 110 couplable to a compressor outlet for receiving a high pressure high temperature refrigerant vapor. Heat of the refrigerant vapor is rejected within the contaminated water. A plurality of contacting discs 122 is stacked together on a 124 connected to the pair of opposite sidewalls 104 of the housing 102. The contacting discs 122 are positioned within the trough 106 in a manner that a portion of each of the contacting disc 122 contacts the contaminated water and a remaining portion of each of the contacting disc 122 being exposed to air. The contacting discs 122 allow the heated contaminated water contacting thereof to exchange heat and mass with the air. Further, at least one dehumidifier 126 having a cooling medium flowing therein is disposed proximally to the plurality of contacting discs 122 to dehumidify the humid air.

Description

TITLE OF THE INVENTION

A condenser heat recovery based distilling process and apparatus

FIELD OF THE INVENTION

[0001] The present invention relates to condenser heat recovery process and apparatus that generates distilled water.

DESCRIPTION OF THE BACKGROUND ART

[0002J Availability of potable water is limited and its generation from raw water with minimum energy consumption is the need of today. Seawater contributes almost 97.5% of total available water and its desalination can provide fresh water. Desalination can also work effectively with low temperature heat sources, if techno-economical system is designed.

[0003] Humidification and dehumidification (HDH), membrane distillation (MD), solar distillation and pervaporization are some of the prominent techniques that come under low temperature operation. The humidification and dehumidification based technology has a potential to generate potable water economically for small as well medium capacity systems, with less maintenance issues. However, the available HDH techniques have high air side or water side pressure drop and hence has high energy consumption. Further, low packing density of existing humidifier resulted in lower overall mass transfer coefficient per unit volume. The size of the system further increases at low temperature operation and hence increases energy consumption.

[0004] An attempt in the HDH system was made which includes heating of seawater in separate heat exchanger in the range of 50 to 80 °C using solar or waste heat and evaporating it into air at humidifier. Humidifiers are mostly of spray or pad type. In spray humidifier, heated seawater was atomized through nozzle/s and sprayed in flowing air. The flowing air in humidifier gets heated and humidified depending on vapour pressure difference between seawater saturation pressure corresponding to its surface temperature and water vapour pressure in air. The system has advantages of less air side pressure drop, however presence of demister pad to remove water carryover, if any, causes large air pressure drop. The pumping pressure of seawater through nozzles increases over a period of time which increases pumping power. In pad humidifier, preheated seawater and air comes in contact at pad surface and water evaporates into air. Typically for dehumidification, fin tube heat exchangers were used where seawater used as coolant and humid air flows over fin surfaces condenses it moisture. Further existing HDH system are large and cannot be tailor made for smaller capacity used in household applications. Solar distillation unit has no moving part but it generates maximum of potable water as 3 to 5 1/d.m²' while multistage solar unit could generate potable water as 12 1/d.m. However, later has high power consumption.

[0005] Thus, there is a need to have a HDH apparatus/system that addresses atleast some of the above mentioned drawbacks.

SUMMARY OF THE INVENTION [0006] Disclosed herein is a condenser heat recovery based distilling apparatus disposed in fluid communication between a compressor and an expansion valve of a refrigeration system for generating distilled water, the apparatus including a housing, at least one longitudinal trough connected to a pair of opposite sidewalls of the housing for storing contaminated water, the trough including a channel that extends between an inlet and outlet and formed on a bottom portion of the trough, the inlet couplable to a compressor outlet for receiving a high pressure high temperature refrigerant vapor, heat of the refrigerant vapor being rejected within the contaminated water, a high pressure high temperature liquid refrigerant being transferrable to an inlet of the expansion valve through the outlet of the channel, a plurality of contacting discs stacked together on a rotatable shaft that is connected to the pair of opposite sidewalls of the housing, the contacting discs being positioned within the trough in a manner that a portion of each of the contacting disc contacts the contaminated water and a remaining portion of each of the contacting disc being exposed to air, the contacting discs when rotated allowing the heated contaminated water contacting thereof to exchange heat and mass with the air, and at least one dehumidifier having a cooling medium flowing within and disposed proximally to the plurality of contacting discs to dehumidify the humid air, by exchanging heat between the cooling medium and the humid air, moisture from the humid air being condensed on the heat and mass exchange surfaces.

[0007] In some embodiments, one or more blowers for circulating the humid air between the plurality of contacting discs and the dehumidifier. [0008] In some embodiments, the channel is disposed within a thickness of the trough or thermally bonded and formed to have multiple refrigerant flowing paths, the high pressure high temperature refrigerant exchanging heat with the contaminated water across a sufficient area of the trough when flowing therein.

[0009] In some embodiments, the dehumidifier includes a pure water carrying trough connected to the pair of opposite sidewalls of the housing and disposed parallely at a distance from the contaminated water carrying trough, a channel extending between an inlet and an outlet being inbuilt within a thickness of the pure water carrying trough or thermally bonded, the channel being in thermal contact with the bottom portion of the trough and having multiple flow path for circulating cooling medium that exchanges heat with the pure water across a sufficient area of the trough, the inlet being couplable to a cooling medium reservoir and the outlet being couplable to a sink.

[0010] In some embodiments, the plurality of heat exchanging members include a plurality of another contacting discs stacked together on a rotatable shaft, the plurality of another contacting discs positioned within the pure water carrying trough in a manner that a portion of each of the contacting discs contact the pure water and a remaining portion of each of the contacting discs exposed to the humid air, each of the contacting discs defining the heat exchange surface so that when the contacting discs are rotated, the picked pure water exchanges heat and mass transfer with the humid air..

[0011] In some embodiments, the dehumidifier includes a pure water collection trough located below a heat and mass exchanger preferably of fin tube type, with contaminated water circulating through the fin tubes that exchanges heat with humid air to cool and dehumidify the humid air enabling condensation of moisture from the humid air, and collection of same in the trough located below the fin tube dehumidifier.

[0012] Additional features and advantages of the invention will be set forth in the detailed description which follows, and . in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0013] It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention. A BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above-mentioned and other features and advantages of the various embodiments of the inyention, and the manner of attaining them, will become more apparent and will be better understood by reference to the accompanying drawings, wherein: [0015] FIG. 1 is a schematic view of a basic condenser heat recovery apparatus according to an embodiment of the present invention;

[0016] FIG. 2 is a perspective elevational view of a condenser heat recovery apparatus according to an embodiment of the present invention;

[0017] FIG. 3 is a perspective view of a trough used in the condenser heat recovery apparatus of FIG. 2 according to an embodiment of the present invention;

[0018] FIG. 4 is schematic view illustrating connections of refrigerant and cooling medium with the troughs within the condenser heat recovery apparatus of FIG. 2;

[0019] FIG. 5 is a front cut-sectional view of the condenser heat recovery apparatus according to another embodiment of the present invention; [0020] FIG. 6 is a side cut-sectional view of the condenser heat recovery apparatus having a fin tube dehumidifier according to another embodiment of the present invention;

[0021] FIG. 7(a) is a front elevational view of the dehumidifier that includes a structure formed by a polypropylene sheet;

[0022] FIG. 7(b) is a front elevational view of the dehumidifier that includes a structure formed by a metal sheet; and [0023] FIG. 8 is a front cut-sectional view of the condenser heat recovery apparatus having the dehumidifier of FIG. 7a/FIG. 7b according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] FIG. 1 is a schematic illustration to explain the distillation process within a basic form of condenser heat recovery based distilling apparatus 50. The distilling apparatus 50 includes at least three troughs namely, a first trough 52, a second trough 54, and a third trough 56. Each of the three troughs 52, 54, 56 contains effluent therein and each of the three troughs 52, 54, 56 is semicircular in shape (FIG. 3). Each of the troughs 52, 54, 56 is made up of thermally conducting material with suitable corrosion prevention treatment. Corrosion prevention treatment could be of various types like painting, anodizing, or the like techniques. Examples of the effluent includes sea water, brackish water, industrial waste water, juices, chemical process streams containing salts or other chemicals in suspension or in solution, and their like. For the purposes of explaining various embodiments of the specification reference will be given to sea water 58. However, all of the above noted examples of contaminated water may also be used and considered to be within the scope of the present invention. [0025] Further, each of the troughs 52, 54, 56 includes a channel 60 that extends between an inlet 62 and an outlet 64. The channel 60 is formed on a bottom portion 66 of the trough and may have multiple passages so as to cover a sufficient portion of the bottom portion 66. In one embodiment, the inlet 62 of the channel 60 may be coupled to the compressor C (FIG. 4) and the outlet 64 of the channel 60 may be connected to the expansion valve (not shown) of the refrigeration system. The inlet 62 receives the high pressure refrigerant vapor coming from compressor (See FIG. 4). The high pressure refrigerant vapour rejects its partial heat to seawater 58 in the trough.52. After exchanging heat with the sea water 58, the high pressure refrigerant vapour is cooled and partially condensed. The outlet 64 of the channel 60 of the first trough 52 may be connected to an inlet 62 of the channel 60 of a second trough 54. An outlet 64 of the second trough 54 may be connected to an inlet 62 of a third trough 56. Finally, an outlet 64 of the third trough 56 may be connected to inlet of the expansion valve of the refrigeration system. Such an arrangement allows the high pressure refrigerant vapor, which is received from the compressor C, to be circulated across all of the troughs. As a result of this circulation, the high pressure refrigerant vapor exchanges heat with the seawater within the respective troughs (See FIG. 4). Simultaneously, the high pressure refrigerant vapor is progressively cooled into a high pressure liquid refrigerant. It is also to be noted that any other form of high temperature heat source can be used for heating the effluent/sea water 58 within the troughs and considered to be within the scope of the present invention.

[0026] Further, as shown in FIG. 1, a non-transparent corrugated or plastic sheet 68, which is folded in shape that represents a dome 70, is positioned over each of the troughs 52, 54, 56 so as to fully ' cover the trough. Further, the bottom of each of the domes 70 is formed to have two bulge portions 72 on either side of the troughs 52, 54, and 56. Each of these domes 70 act as an individual dehumidifier. Over the top of each of the domes 70, ambient air flows and makes contact with the outer surface 74 thereof. An external fan 76 may be placed to increase the cooling rate over dome 70. As a result of this, an inner surface 78 of the dome 70 remain continuously at lower temperature. The trough and dome structure acts as a humidifier-dehumidifier unit for generation of distilled water. As shown in FIG. 1, there is three such units stacked one above the other within the apparatus 50. The heat rejection by the high pressure refrigerant vapour within the sea water 58 of the first trough 52, the sea water 58 gets heated and air in its vicinity within the dome gets humidified and moves up due to lesser density. The humid air makes contact with the relatively cold inner surface78 of the dome 70. As the temperature at the inner surface 78 of the dome 70 is lower than the dew point temperature of humid air coming from the trough, the humid air condenses resulting in transformation of drops of pure water. The drops of pure water trickle down due to gravity along the inner surface of dome and get collected within the two bulge portions 70. So, if the high pressure vapor refrigerant is assumed to be entering at the inlet 62 of first trough 52 at 70°C then the temperature of humid air would be approximately 45°C and the temperature of the refrigerant vapor at the outlet 64 of the first trough 52 would be 50°C. Similarly, a skilled person in the art would understand that the temperatures of refrigerant vapor at the inlet 62 and outlet 64 within the second and the third troughs 56, respectively, would be approximately 50°C, 45°C and 45°C, 40°C, respectively.

[0027] An advantage of such distilling apparatus 50 is that it can be made portable and easily installed for household applications and provides sufficient distilled water that may be further processed into potable water. Another advantage of such distilling apparatus 50 is that the apparatus 50 has less maintenance issues due to absence of rotating parts. [0028] In various other embodiments of the present invention, a plurality of rotating contacting discs may be positioned within one or all of the three troughs to increase heat and mass transfer area and enhanced the humidification process.

[0029] FIG. 2 illustrates a perspective elevational view of a condenser heat recovery apparatus

100 according to an embodiment of the present invention. The condenser heat recovery apparatus 100 may be coupled within a refrigeration system (not shown) in place of a condensing unit and coupled to a compressor and an expansion valve, respectively. An evaporator (not shown) may be deployed indoors for air-conditioning purposes and for process cooling for refrigeration systems. The compressor compresses the low pressure low temperature refrigerant vapor to higher pressure refrigerant vapor. In accordance with all the embodiments of the present invention detailed below, this higher pressure refrigerant vapor is supplied into the condenser heat recovery apparatus 100 for generation of distilled water. The distilled water may be further processed to be transformed into potable water.

[0030] The condenser heat recovery apparatus 100 includes a housing 102 that has a pair of opposite side walls 104. Between the opposite side walls 104, a first longitudinal trough 106, which retains contaminated water, is connected. Preferably, as shown in FIG. 3, the first longitudinal trough 106 is semicircular in shape so as to have a better overall heat transfer coefficient during heat exchange (described below). Additionally, the first longitudinal trough 106 is made up of thermally conducting material with suitable corrosion prevention treatment. Corrosion prevention treatment could be of various types like painting, anodizing, or the like techniques. Examples of the contaminated water includes sea water, brackish water, industrial waste water, juices, chemical process streams containing salts or other chemicals in suspension or in solution, and their like. For the purposes of explaining various embodiments of the specification reference will be given to the sea water. However, above noted examples of contaminated water may also be used and considered to be within the scope of the present invention. [0031] As shown in FIG. 3, the first sea water trough 106 includes a channel 1 10 that extends between an inlet 112 and outlet 114. The channel 1 10 is formed on a bottom portion 1 16 of the first sea water trough 106 and may have multiple passages so as to cover a sufficient portion of the bottom portion 1 16. Preferably, the channel 106 is inbuilt within a thickness of the first sea water trough 106 Alternatively, the channel 1 10 may also be thermally bonded to the bottom portion 116 in known manner. The inlet 112 of the channel 110 may be coupled to the compressor C (FIG. 4) and the outlet 1 14 of the channel 1 10 may be connected to the expansion valve (not shown) of the refrigeration system. The inlet 1 12 receives the high pressure refrigerant vapor coming from an outlet of the compressor (See FIG. 4). The high pressure refrigerant vapour rejects heat into the contained sea water 108, which is generally introduced kept at room temperature, across the bottom portion 116 of the first sea water trough 106. After exchanging heat with the sea water 108, the high pressure refrigerant vapour is cooled.

[0032] Reference is given to FIGS. 2 and 4 that illustrate a second sea water trough 1 18 and a third sea water trough 120 connected to the pair of opposite sidewalls 104 of the housing 102. Both the second sea water trough 118 and the third sea water trough 120 are constructed in a similar manner as that of the first sea water trough 106. The first, the second, and the third sea water troughs 106, 1 18, 120 are parallely positioned to each other in the housing 102. Further, each of the second and the third sea water troughs 1 1.8, 120 also have a corresponding channel 1 10 inbuilt or thermally bonded to the bottom portion 116 thereof. Furthermore, as shown in FIG. 4, the outlet 114 of the channel 110 of the first sea water trough 106 may be connected to an inlet 1 12 of the channel 1 10 of the second sea water trough 1 18. An outlet 1 14 of the second sea water trough 1 18 may be connected to an inlet 1 12 of third sea water trough 120. Finally, an outlet 114 of the third sea water trough 120 may be connected to an inlet of the expansion valve of the refrigeration system. Such an arrangement allows the high pressure refrigerant vapor, which is received from the compressor, to be circulated across all of the sea water troughs 106, 118, 120. As a result of this circulation, the high pressure refrigerant vapor exchanges heat with the sea water 108· contained within the respective troughs (See FIG. 4). Simultaneously, the high pressure refrigerant vapor is progressively cooled into a high pressure liquid refrigerant.

[0033] It is to be understood that in several embodiments of the present invention, more or less than three sea water troughs 106, 1 18, 120 may also be connected with the condenser heat recovery apparatus 100. In some embodiments, the condenser heat recovery apparatus 100 may have only one sea water trough. In such cases, a skilled person could assume that the high pressure liquid refrigerant may be introduced within the expansion valve from the outlet 114 of the channel 1 10 of the first trough 106. All of these embodiments should be considered to be within the scope of the present invention by a skilled person in the art. As shown in FIG. 4, in each of the first, the second, and the third sea water troughs 106, 1 18, 120 provisions could be made to add sea water 108 continuously or at regular intervals depending on the rate at which the sea water 108 is consumed during operation. Additionally, within each of the first, the second, and the third sea water troughs 106, 118, 120 provisions may also be made to extract the formed brine. [0034] As seen in FIG. 2, a plurality of rotatable contacting discs 122 is stacked together on a rotatable shaft 124 and positioned adjacent to the first sea water trough 106. The rotatable shaft 124 is connected to the opposite sidewalls 104, in known manner. The rotatable shaft 124 may be connected to an external power source that provides the necessary drive to rotate the shaft 124. Preferably, as shown in FIG. 2, each of the rotatable shaft 124 may be connected to a corresponding disc motor 125 connected from outside to each of the opposite sidewalls 104. Preferably, the contacting discs 122 have a higher packing density of about 400 to 600 m /m with air side pressure drop of less than 10 mm of water column.

[0035] The rotatable shaft 124 is disposed within the first sea water trough 106 in a manner that the plurality of contacting discs 122 are submerged within the sea water 108. A portion of each of the contacting discs 122 is dipped in sea water 108 whereas, a remaining portion of each of the contacting disc is exposed to flowing air present in the vicinity of the first sea water trough 106 within the housing 102. The contacting discs 122 when rotated allow the heated sea water 108 contacting thereof to exchange heat and mass transfer with the flowing air so as to humidify the flowing air. Further, as seen in FIGS. 2 and 4, a plurality of rotatable contacting discs 122 are also submerged within the second and the third sea water troughs 118, 120, and arranged in the same manner as that of the first sea water trough 106. As such, contacting discs 122 present within each of the first, the second, and the third sea water troughs 106, 1 18, 120 collectively humidify the flowing air present within the housing 102 when the apparatus 100 is in operation. [0036] Referring to FIGS. 2 and 4, the housing 102 also includes a first dehumidifier 126 positioned adjacent to the first sea water trough 106. The first dehumidifier 126 includes a first pure water trough 128 connected to the pair of opposite sidewalls 104 and contains pure water 130 therein. The first pure water trough 128 is disposed in parallel orientation at a distance from the first sea water trough 106. During dehumidification process when the condenser heat recovery apparatus 100 is in operation, the pure water 130 remains at a substantially lower temperature than the dew point temperature of humid air from contacting disc 122. Further, the first pure water trough 128 also has the channel 1 10 extending between the inlet 112 and the outlet 1 14 and inbuilt within its thickness. Alternatively, the channel may also be thermally bonded to the first pure water trough 128. Preferably, the channel 110 is formed in same manner as that of the sea water troughs 106, 118, 120 and may have multiple passages so as to cover a sufficient portion of the bottom portion 116 of the first pure water trough 128. The inlet 1 12 of the channel 1 10 is couplable to a cooling medium reservoir (not shown) whereas the outlet 1 14 is couplable to a sink (not shown). For the purposes of the specification the sea water 131 is used as the cooling medium, however other known coolants such as air, air- water mixture, and other fluids may also be used and considered to be within the scope of the present invention. Through the inlet 1 12 the sea water 131, which is slightly above ambient temperature, is received within the channel 110. Further, the sea water 131 picks up heat from the pure water 130 during heat exchange when the apparatus 100 is in operation.

[0037] Again referring to FIGS. 2 and 4, the apparatus 100 also includes a second and a third dehumidifier 134, 136 disposed within the housing 102. Each of the second and the third dehumidifiers 134, 136 includes a second and a third pure water trough 138, 140, respectively, connected to the pair of opposite sidewalls 104. As seen in FIG. 4, the first, the second, and the third pure water troughs 128, 138, 140 are parallely positioned against each other and oriented linearly along a vertical plane of the housing 102. It is to be noted that the sea water troughs 106, 118, 120 and the pure water troughs 128, 138, 140 are oriented in a way that they are offset from each other by a predetermined distance. Further, each of the second and the third pure water 138, 140 troughs also have a corresponding channel 110 formed in a similar manner noted above in various embodiments. Additionally, the first, the second, and the third pure water troughs 128, 138, 140 are also interconnected with each other, via their channels, in a similar manner as the sea water troughs 106, 118, 120. The coolant from reservoir (not shown) connected to 1 12 of the dehumidifier trough 140 and its outlet is connected to inlet 1 12 of second pure water trough 138. The outlet 1 14 of trough 138 is connected to inlet 112 of the first pure water trough 128, and finally outlet 114 of the first pure water trough 128 may be connected to the sink (not shown). This allows the sea water 131 to circulate across the pure water troughs 140, 138 and 128, and to pick up heat from the pure water 130 during heat exchange.

[0038] It is to be understood by a skilled person that that more or less than three pure water carrying troughs 128, 138, 140 may also be used in the foregoing condenser heat recovery apparatus 100. In above noted embodiments, a skilled person would observe that the sea water 131 flows in a series configuration through the pure water troughs 128, 138, 140 between the reservoir and the sink. Alternatively, the sea water 131 may also flow in a parallel configuration through each of the pure water troughs 128, 138 and 140. All of these embodiments should be considered to be within the scope of the present invention by a skilled person in the art. It is to be understood that before the whole operation starts, some amount of pure water 130 is added to each of the pure water carrying troughs 128, 138, 140 in advance.

[0039] As seen in FIGS. 2 and 4, each of the first, the second, and the third pure water troughs

128, 138, 140, also include a corresponding heat exchanger 142 submerged within the pure water 130. A portion of each of the heat exchanger 142 is dipped within the pure water 130. In one embodiment of the present invention, as shown in FIGS. 2 and 4, the heat exchanger is in the form of a stack of contacting discs 122 that are arranged on the rotatable shaft 124. Outer surfaces of each of the contacting discs 122 define a heat exchanging surface and when rotated, allow the picked low temperature pure water 130 to exchange heat and mass transfer with the humid flowing air available therearound. As such, there are at least three humidifiers 146, 148, 150 and at least three dehumidifiers 126, 134, 136 formed within the housing 102 for humidifying and dehumidifying the circulated air. A skilled person will also understand that the direction of rotation of the contacting discs 122 dispose within the sea water carrying troughs 106, 1 18, 10 is opposite or in the same direction of rotation of the contacting discs 122 disposed within the pure water carrying troughs 128, 138, and 140. [0040] The condenser heat recovery apparatus 100 works on the humidification and dehumidification (HDH) technique. Working of the condenser heat recovery apparatus 100, which may be coupled to the compressor and the expansion valve of the refrigeration system, is described with reference to FIGS. 2 and 4. For achieving maximum possible efficiency in generation of distilled water and high pressure liquid refrigerant, the high refrigerant vapor is made to flow from the first sea water trough 106 towards the third sea water trough 120. Further, the sea water 131 traverses from the third pure water trough 140 towards the first pure water trough 128. Furthermore, in HDH technique, humidification of the air takes place when heated sea water 108 comes in contact with the flowing air to humidify it. Later the humidified air condenses in the dehumidifier to obtain pure water 130. The phenomenon of evaporation and condensation of moisture present within the flowing air depends on the pressure difference between the partial pressure of water vapor in the . flowing air and vapour pressure of the condenser water. One or more blowers are generally disposed within the apparatus 100 for providing flow to the air available within the housing 102. Preferably, as seen in FIGS. 2 and 4, a longitudinal blower 152 is rotatably disposed adjacent to each of the first, the second and third pure water troughs 128, 138, 140 for circulating the air between the humidifiers 146, 148, 150 and the dehumidifiers 126, 134, 136. Ends of the longitudinal blower 152 are also connected to the pair of opposite sidewalls 104.

[0041] Further, in order to understand the working of the apparatus 100, it is assumed that the high pressure refrigerant vapor entering within the inlet 112 of the first sea water trough 106 has a temperature of approximately (6570) °C. As the high temperature refrigerant vapour circulates through the second and the third sea water troughs 1 18, 120, progressively condensation of the refrigerant vapour takes place. As a result, the temperature of the condensed high pressure refrigerant vapor within the second and the third sea water troughs 1 18, 120 is around 45°C and 40°C, respectively. After sufficient heat exchanged between the refrigerant and the sea water 108, temperature of the sea water 108 in the first, the second, and the third sea water troughs 106, 118, 120 reaches approximately to 39°C, 38°C, and 37°C, respectively. Furthermore, it is also assumed that the temperature of the sea water 131 entering the inlet 1 12 of the third pure water trough 140 is approximately 27°C. After circulation through the second and the first pure water troughs 138, 128, the temperature of the sea water 131 therein is about 29°C and 30°C, respectively. Due to this heat exchange with the pure water 130 in the third, the second, and the first pure water troughsMO, 138, 128, the temperature of the pure water 130 reaches to about of 32°C, 33°C, and 34°C, respectively.

[0042] As noted above, the contacting discs 122 within each of the first, the second, and the third sea water troughs 106, 118, 120 are submerged within the sea water 108. Accordingly, the sea water 108 picked on the surface of the contacting discs 122 has a temperature of 40 °C, 39 °C, and 38 °C respectively. The sea water 108 exchanges heat and mass with the respective flowing air, which is generally at temperature 36 °C, 35 °C, and 34 °C in the troughs 106, 1 18 and 120 respectively. Accordingly, the flowing air is humidified to a temperature of 38 °C, 37 °C, and 36 °C respectively. Due to the presence of longitudinal blower 152, the humid air flow towards the dehumidifiers 126, 134 and 136 respectively, and contacts the contacting discs 122 positioned within the first, second, and the third pure water troughs 128, 138, and 140 respectively. Each of the contacting discs 122 have pure water 130 picked up thereon. Thus, during operation of the apparatus 100, the heat exchanging surface of each of the contacting discs 122 of the first, the second, and the third pure water troughs 128, 138, 140 also has a temperature of about 34 °C, 33 °C, and 32 °C. As there is a temperature and vapor pressure difference between the water vapor in the humid flowing air and the pure water 130, the water vapor from the humid air condenses on the contacting discs 122. Accordingly, the condensed water vapor, which is a pure form of water, is collected within each of the first, the second, and the third pure water carrying troughs 128, 138,140. Provisions may be made within each of the first, the second, and the third pure water carrying troughs 128, 138, 140 to dispose the pure water 130 out therefrom for being collected (FIG. 4).

[0043] It is to be understood by a skilled person that the above mentioned temperatures are not critical for the performance of the invention rather, these are just chosen for explaining the working thereof. Variations in the above stated temperatures are very likely depending on the operating condition of the apparatus 100. [0044] Further, during the operation of the condenser heat recovery apparatus 100, the high pressure liquid refrigerant is received at- the outlet 114 of the third sea water trough 120. Keeping into consideration the above noted temperatures, the high pressure liquid refrigerant received at the outlet 114 has a temperature of about 40°C. Furthermore, the outlet 1 14 may be connected to the expansion valve that transforms the high pressure liquid refrigerant to low pressure low temperature liquid refrigerant. Thus, a skilled person would also observe that there may be improvement in the cooling capacity and coefficient of performance, COP, may be expected as a bonus due to lowering of the condenser pressure. Additionally, the use of condenser heat recover apparatus 100 of this kind improves the compactness of system with lower air pressure drop because both humidification and dehumidification is carried out in a single device. [0045] FIG. 5 shows another embodiment of the condenser heat recovery apparatus 100' according to the present invention. Contrary to the heat recovery apparatus 100 of the above mentioned embodiments where the at least three dehumidifiers 126, 134, 136 are disposed below the at least three humidifiers 146, 148, 150, in this embodiment, only one humidifier, say humidifier 146', and one dehumidifier, say dehumidifier 126', may be connected to the housing 102' in the above known manner. Further, the humidifier 146' is positioned below the dehumidifier 126' with the longitudinal blower 152' positioned therebetween. Constructional arrangement and working principle of the humidifier 146' and the dehumidifier 126' in this embodiment is similar to that of the previously described embodiments. [0046] Another embodiment of the condenser heat recovery apparatus 100" according to the present invention is shown in FIG. 6. In this embodiment humidifier 146 "and at least two sets of dehumidifiers, say dehumidifiers 126", 134", are used. The constructional feature of the humidifier 146" remain the same whereas, dehumidification of the humid air may be carried out in a fm tube heat exchanger. The dehumidifiers 126" and 134" include fins 156 stacked together on tubes 157. The cooling medium, say seawater 131, from reservoir passes through these tubes 157 and lowers the surface temperature of fins 156. The surface temperature of fins 156 was at a temperature lower than the dew point temperature of humid air coming from humidifier 146". The heat and mass transfer between fm surface and humid air, condenses the moisture of the humid air. The humid air from humidifier 146" flows over the fins 156 of dehumidifiers 126" and partially condenses its moisture. The air further moves to dehumidifier 134" and condenses its moisture in similar way as in dehumidifier 126". The condensed water, which is in the form of pure water 130", from dehumidifiers 126" and 134"is collected within a tray positioned below their respective dehumidifiers 126" and 134". The air from dehumidifier 134" is re-circulated to humidifier 146" by use the use of longitudinal blower 152" and humidifies. The cooling medium outlet from dehumidifier 134" is connected to inlet of dehumidifier 126". The outlet of tuber 157 from dehumidifier 126" is connected to sink (not shown) to collect heated cooling medium. The high pressure liquid refrigerant is received at the outlet 1 14" of the sea water troughs 106", 1 18" as shown in FIG. 6 and is further connected to an expansion valve as discussed in the previous embodiments. [0047] FIG. 7a and FIG. 7b shows another embodiment of the dehumidifier 126"' according to the present invention. This dehumidifier 126"' uses air as the cooling medium instead of the sea water 131 as in case of the previous embodiments. The dehumidifier 126"' includes a structure 160 formed by a multiwall, preferably polypropylene/metal sheet 162, in a manner shown in FIG. 7a/7b. The structure 160 includes a first plurality of passage sections 164 and a second plurality of passage sections 166. Gap between any two sections 164 forms the section 166. As seen in FIG. 7, the first plurality of sections carries air therein and the humid air from the humidifier flows through each of the second plurality of passage sections 166.

[0048] The dehumidifier 126"' as shown in FIG. 7a/FIG. 7b may be coupled to the humidifiers which has similar construction as 126, 134, 136 explained in the above mentioned embodiments to form another embodiment of the condenser heat recovery apparatus 100"'. Such an apparatus 100"' is shown in FIG. 8 and having at least two sets of humidifiers 146"', 148"'and dehumidifiers 126"', 134"'. The first plurality of passage sections 164 of the dehumidifier 126"', 134"' is positioned adjacent to a flow of air at room temperature whereas the second plurality of passage sections 166 is positioned adjacent to the contacting discs 122"' submerged the sea water carrying troughs 106"', 1 18"' of the humidifiers 146"', 148"'. Each of the dehumidifiers 126"', 134"' is positioned in between the longitudinal blower 152"' and the humidifier as shown in FIG. 8. The constructional feature of the humidifiers 146"', 148"'remains the same and the high pressure liquid refrigerant is received at the outlet 114"' of the sea water troughs 106"', 1 18"'. Water condensed in the passages of 166 drains down due to gravity and is collected in the pure water trough 130"' in a suitable receptacle placed below the dehumidifier.

[0049] It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

CLAIMS:

1. A process for distilling effluent using condenser heat within condenser heat recovery based distilling apparatus, the process comprising: heating and vaporizing a portion of the effluent contained within an effluent containing device in the ambient air, the effluent being heated up by a high pressure fluid circulating within the effluent containing device; condensing the humid ambient air within a dehumidifier positioned in proximity to the effluent containing device using a cooling stream; receiving the condensed distilled water within a receptacle; and optionally circulating the humid air within the apparatus for intensifying the humidification and dehumidification process.

2. The process according to claim 1, wherein a plurality of rotating discs stacked together on a rotatable shaft is positioned within the trough in a manner that a portion of each of the contacting disc contacts the effluent and a remaining portion of each of the contacting disc being exposed to air, the contacting discs when rotated allowing the heated effluent contacting thereof to exchange heat and mass with the ambient air.

3. The process according to claim 1 , wherein the high pressure fluid is refrigerant from a refrigeration ) system.

4. The process according to claim 1, wherein the cooling stream includes air, air/water mixture, process fluids, sea water, or the like for condensing the humid air within the apparatus.

5. A condenser heat recovery based distilling apparatus disposed in fluid communication between a compressor and an expansion valve of a refrigeration system for generating distilled water, the apparatus comprising:

a housing;

at least one longitudinal trough connected to a pair of opposite sidewalls of the housing for storing contaminated water, the trough including a channel that extends between an inlet and outlet and formed on a bottom portion of the trough, the inlet couplable to a compressor outlet for receiving a high pressure high temperature refrigerant vapor, heat of the refrigerant vapor being rejected within the contaminated water, a high pressure high temperature liquid refrigerant being transferrable to an inlet of the expansion valve through the outlet of the channel;

a plurality of contacting discs stacked together on a rotatable shaft that is connected to the pair of opposite sidewalls of the housing, the contacting discs being positioned within the trough in a manner that a portion of each of the contacting disc contacts the contaminated water and a remaining portion of each of the contacting disc being exposed to air, the contacting discs when rotated allowing the heated contaminated water contacting thereof to exchange heat and mass with the air; and

at least one dehumidifier having a cooling medium flowing within and disposed proximally to the ) plurality of contacting discs to dehumidify the humid air, by exchanging heat between the cooling medium and the humid air, moisture from the humid air being condensed on the heat and mass exchange surfaces.

6. The condenser heat recovery apparatus according to claim 5, further includes one or more blowers for circulating the humid air between the plurality of contacting discs and the dehumidifier.

7. The condenser heat recovery apparatus according to claim 5, wherein the channel is disposed within a thickness of the trough or thermally bonded and formed to have multiple refrigerant flowing paths, the high pressure high temperature refrigerant exchanging heat with the

contaminated water across a sufficient area of the trough when flowing therein.

8. The condenser heat recovery apparatus according to claim 5, wherein the dehumidifier includes a pure water carrying trough connected to the pair of opposite sidewalls of the housing and disposed parallely at a distance from the contaminated water carrying trough, a channel extending between an inlet and an outlet being inbuilt within a thickness of the pure water carrying trough or thermally bonded, the channel being in thermal contact with the bottom portion of the trough and having multiple flow path for circulating cooling medium that exchanges heat with the pure water across a sufficient area of the trough, the inlet being couplable to a cooling medium reservoir and the outlet being couplable to a sink.

9. The condenser heat recovery apparatus according to claim 8, wherein the plurality of heat exchanging members include a plurality of another contacting discs stacked together on a rotatable shaft, the plurality of another contacting discs positioned within the pure water carrying trough in a manner that a portion of

⁾ each of the contacting discs contact the pure water and a remaining portion of each of the contacting discs exposed to the humid air, each of the contacting discs defining the heat exchange surface so that when the contacting discs are rotated, the picked pure water exchanges heat with the humid air.

10. The condenser heat recovery apparatus according to claim 8, wherein the contaminated water carrying trough and the pure water carrying trough are positioned in such a manner that they are offset by a distance from each other along a vertical plane.

11. The condenser heat recovery apparatus according to claim 5, wherein the dehumidifier includes a pure water collection trough located below a heat and mass exchanger preferably of fin tube type, with contaminated water circulating through the fin tubes that exchanges heat with humid air to cool and dehumidify the humid air enabling condensation of moisture from the humid air, and collection of same in the trough located below the fin tube dehumidifier.

12. The condenser heat recovery apparatus according to claim 5, wherein the dehumidifier includes a structure formed by a multiwall sheet that includes a first plurality of passage sections for carrying the coolant therein and a second plurality of passage sections for receiving the humid air, each of the sections of the second plurality of sections being sandwiched between any two sections of the first plurality of sections to form a plurality common contact surfaces, each of the common contact surface allowing heat exchange between the humid air and the cooling medium.

13. The condenser heat recovery apparatus according to claim 12, wherein the multiwall sheet is formed from propylene sheet.

)

.

14. The condenser heat recovery apparatus according to claim 12, wherein the first plurality of sections is orthogonal to the second plurality of sections, the first plurality of sections being positionable adjacent to a flow of air kept at room temperature and the second plurality of sections being positionable adjacent to the contacting discs positioned within the contaminated water carrying trough for receiving the humid air.