|Title of Invention||
A BUBBLE PUMP ABSORPTION COOLER
|Abstract||A bubble pump absorption cooler which composes of an air cooled absorber and condenser. The evaporator and absorber have multiple connections in between them, but are placed separately. An U tube is connected to the condenser and evaporator and another one to the boiler and a cyclone separator.|
This invention relates to a bubble pump absorption cooler.
There are two types of known absorption refrigerators; (1) the conventional and (2) the natural circulation type.
The conventional type has the solution pump, while the latter makes use of bubble pump technique to circulate the solution in between the absorber and generator.
Both known types above mentioned use water cooled condenser and absorber.
However, the proposed bubble pump absorption cooler employs air cooled absorber and condenser, since this system is especially intended, and suited, for small capacity installations applicable to refrigerators used for domestic purposes; for shops, including pharmacies and solar based cooling equipment.
Cooling of cabinets down to 8 deg. C using electric heat or even low temperature heat sources, such as, solar heat, waste heat and the like for storage of medicines, milk foods and so on, in remote places, is rendered possible by the bubble pump absorption cooler proposed herein.
Water coolers using electric heat or even low temperature heat sources of the nature exempllfled above are also rendered possible by the bubble pump absorption cooler proposed herein.
Unlike the known absorption refrigerator, the absorber and evaporator cannot be placed in a single shell: they have necessarily to be placed apart in the Invention proposed herein, since an air cooled condenser and absorber are used.
In the bubble pump absorption cooler proposed herein, unlike the known absorption cooler, parallel paths are provided between the evaporator and absorber to reduce the pressure drop which is essential for the satisfactory operation of the cooler; a combined U tube and expansion device
positioned between the condenser and evaporator which automatically adjusts for steady operation at varying ambient temperatures; a U tube positioned between the cyclone separator and generator.
The bubble pump absorption cooler, according to this invention, is characterised by an air cooled absorber and condenser; a plurality of parallel connections between the evaporator and absorber; a combined U tube and expansion device connected to the condenser and evaporator; and a U tube connected to the boiler and a cyclone separator.
This invention will now be described with reference to the accompanying drawings, which illustrate, by way of example, one of various possible embodiments of the bubble pump absorption
cooler proposed herein,
Fig.l illustrating the layout diagram of the said embodiment;
Fig.2 illustrating the evaporator and absorber layout indicating the provision of parallel connections between them:
Fig.3 illustrating the U tube and expansion device connections between the condenser and the evaporator;
and Fig.4 illustrating the U tube connections between the cyclone separator and boiler.
The weak solution (weak in absorbent) of lithium bromide salt in water from the solution reservoir SR flows by gravity to the bubble pump BP through the solution heat exchanger HX.
In the bubble pump the solution is heated by an electric cartridge heater H1 and partial boil off takes place. The rising refrigerant vapour bubbles lift the solution to the boiler B by bubble action. In the boiler the solution is
further heated by another electric cartridge heater H2 to derive more refrigerant vapour.
While the strong solution flows back to the absorber A through the solution heat exchanger, the rising vapour goes to the condenser C. The vapour liquefies by releasing the heat of condensation to ambient air. The condensate flows through a U tube and an expansion device (UTl) (capillary tube) to the evaporator E where it vaporises absorbing heat from water in the tank WT.
The water vapour then flows back to the absorber where it gets absorbed by the strong solution, releasing the heat of absorption to the ambient air. The solution reservoir collects the resulting weak solution. Hydrostatic pressures exerted by the solution in the two solution columns SC and the liquid refrigerant in the U tube UTi maintain the requisite pressure difference between the components of the refrigerator.
As already stated, air cooled absorber and condenser are employed in the bubble pump
absorption cooler proposed herein. The heat is dissipated to atmosphere by natural convection, to avoid the use of electrical energy for cooling absorber and condenser by water.
To reduce the pressure drop between the evaporator and absorber, parallel flow paths are provided between them as illustrated in Fig.2.
The U tube (UTl) and expansion device (capillary tube in series) combination is important, since this combination automatically adjusts for the steady operation at varying ambient temperatures.
Another- U tube (UT2) is provided between the cyclone separator and boiler as illustrated in Fig.4. This U tube arrangement avoids direct vapour entry to the cyclone separator from the generator.
To balance the pressure difference between the generator and absorber, there is a minimum height requirement (hydrostatic head) for the weak solution column. During the operation of the cooler, the temperatures of the absorber and condenser vary from 20 deg. C to 58 deg
C. depending on ambient temperature. The minimum head requirement of 1.0 m is required for the weak solution column to balance the pressure difference between the boiler and absorber.
The condenser, evaporator and absorber are to be placed one below the other in order to allow gravity flow.
The terms and expressions in this specification are of description and not of limitation, there being no intention in the use of such terms and expressions of excluding any equivalents of the features illustrated and described, but it is understood that various other embodiments of the bubble pump absorption cooler proposed herein are possible without departing from the scope and ambit of this invention.
l.A bubble pump absorption cooler, characterised
by an air cooled absorber and condenser; a
plurality of parallel connections between the
evaporator and absorber; a combined U tube and
expansion device connected to the condenser and
evaporator; and a U tube connected to the
boiler and a cyclone separator.
2.A bubble pump absorption cooler as claimed in Claim 1 wherein the absorber and evaporator are placed separately.
3.A bubble pump absorption cooler as claimed in Claim 1 or Claim 2 wherein the expansion device comprises a capillary tube.
4.A bubble pump absorption cooler as claimed in any one of the preceding Claims wherein the minimum head requirement for the weak solution column is 1.0 m.
5.A bubble pump absorption cooler as claimed in any one of the preceding Claims wherein the condenser, evaporator and absorber are placed one
below the other.
6.A bubble pump absorption cooler substantially as herein described with reference to, and as illustrated in, the accompanying drawings.
Dated this the 11th day of May 1998..
|Indian Patent Application Number||1009/MAS/1998|
|PG Journal Number||08/2007|
|Date of Filing||12-May-1998|
|Name of Patentee||INDIAN INSTITUTE OF TECHNOLOGY|
|Applicant Address||IIT P.O CHENNAI 600 036|
|PCT International Classification Number||F25B15/12|
|PCT International Application Number||N/A|
|PCT International Filing date|