Thermal Powered Gas Generator

The invention relates to an apparatus for converting thermal energy into mechanical energy and particularly to a method and system for producing a flow of pressurized gas in a closed system.

Each day the Earth is flooded with thermal energy from the sun far beyond what mankind can utilize. Further thermal energy is a by-product of many human activities. The greatest challenge of mankind today is to harvest even a tiny portion of this energy efficiently and economically.

One of the greatest problems in using thermal energy is the difficulty of storing and transporting thermal energy. To be practically used, thermal energy must be converted to mechanical energy which is then used to produce electricity. Another problem is that the thermal energy produced by solar generators is at relatively low temperatures, typically below the boiling point of water.

The present invention relates to a simple, unique and practical system for converting thermal energy in a hot water flow at a relatively low temperature to pressurized gas at a relatively high pressure which can then be use to generate electricity. The unit has only one moving and operates at relatively high efficiency and reliability.

FIG. 1 shows a block diagram of one embodiment of the present invention;

FIG. 2 shows a detailed schematic of the block diagram of FIG. 1;

FIG. 3 shows a side view of an assembled system according to the embodiment of FIGS. 1 and 2;

FIG. 4 shows a schematic view of a system including a plurality of stages;

Reference is now made to FIG. 1 which illustrates a block diagram of one embodiment of the present invention. According to this embodiment, the system operates in a continuous cycle in which pressurized gas is produced from mother liquor in a gas pressurizing unit 20 until the motor liquor is depleted and the pressure drops. At this time, unit 20 is flooded with mother liquor which is then evaporated to produce a pressurized gas flow. More particularly, heat, e.g., generated by solar or other sources as described in greater detail below, is supplied to gas pressurizing unit 20 to evaporate mother liquor therein, preferably, a mixture of water and ammonia. An aqua-ammonia mixture is very heat responsive in the 50.degree.-150.degree. F. range which is a suitable range for hot water from solar panels. The evaporated gas collects in the top of the unit 20 and provides a flow of pressurized gas, e.g., to an electric generator of the type described in the co-pending application Ser. No. 738,759 by the applicant herein filed on Nov. 4, 1976. The gas pressure produced by evaporation of the gas also forces the mother liquor in the bottom of unit 20 through a control valve and through a heat storage unit 22 where the mother liquor serves to preheat mother liquor with absorbed spent gas which is flowing through heat storage unit 22 as will be apparent from the discussion below.

After passage through heat storage unit 22, without intermingling with the gas or mother liquor therein, the mother liquor, from unit 20, cooled by passage through a heat exchanger in heat storage unit 22, is sprayed into a cooling unit 26 by a suitable nozzle. Further cooling takes place in unit 26. The mother liquor then moves into a gas absorbtion unit 24, where it moves through a microporous tube and absorbs spent gas supplied to unit 24, e.g., from the electrical generator as described in the above patent application, Ser. No. 738,759. Gas pressurizing unit 20 is also connected directly to the heat storage unit 22, so that the gas produced by evaporation of the mother liquor also collects within heat storage unit 22. As the mother liquor within unit 20 is depleted by evaporation, the pressure of the gas within that unit and within unit 22 drops until it is less than the pressure produced by the mother liquor in unit 24 by gravity at which time the mother liquor in unit 24 flows through the ball float valve which serves as a check valve, through the heat storage unit 22, where it is heated, and into the gas pressurizing unit 20 to flood that unit with mother liquor. The mother liquor thus added is then heated within unit 20 and evaporates to begin the cycle anew.

Many other objects and purposes of the invention will be clear from the following detailed description of the invention.

Reference is now made to FIG. 2 which illustrates the embodiment of FIG. 1 in greater detail. In the arrangement of FIG. 2, heat is supplied to the system from a hot water source 30 and flows through the tank 32 which comprises unit 20 in a conventional heat exchange coil 34. Source 30, for example, may be a solar panel or waste water from a industrial source. The gas which evaporates as a result of the heat added to the mother liquor within tank 32 by the flowing hot water collects at the top of tank 32 and leaves via outlet 36 which is connected to an electric generator 38 or the like as described in the above-mentioned patent application Ser. No. 738,759. The pressure in tank 32 produced by the evaporation of the mother liquor forces the mother liquor in the bottom of tank 32 through the collecting sump 40 and the orifice valve 42 to the input to heat exchange coil 46 in the tank 48 comprising unit 22 and to an aqua-ammonia liquor source 50. Source 50 supplies a small quantity of mother liquor to generator 38 as may be needed to assist in proper operation. Coil 46 surrounds a finned, open ended, iron sleeve 54 through which the mother liquor flows during replenishment of tank 32 as described in greater detail below. The heated mother liquor flowing through coil 46 in tank 48 operates to preheat the mother liquor which floods the tank 32 as described below.

The outlet of coil 46 is connected to a conventional nozzle 56 which injects the cooled mother liquor into a tank 58 which forms part of unit 26. Water, at a temperature below the temperature of the water flowing through coil 34, flows through heat exchange coil 60 within tank 58 from a suitable cold water source 62 to further cool the mother liquor which then flows from an outlet of tank 58 through line 64 into a microporous tube 66. The spent gas from generator 38 is supplied to the tank 70 via nozzle 72 and as the gas flows over the microporous tube it is absorbed into the cooled mother liquor which then collects as a cooled strong liquid in the bottom of tank 70.

The outlet of tank 70 is connected to tank 48 via line 76 in which a conventional ball float check valve 78 is disposed. The interior of tank 48 is also connected to the top of the tank 32 so that the pressurized gas produced by evaporation of the mother liquor flows into tank 48 and holds the check valve 78 in its closed position. However, when the mother liquor has been substantially forced from tank 32, the pressure within tank 32 begins to drop, and when it has dropped to a point in which replenishment of the mother liquor is desirable, the check valve 78 opens to permit the mother liquor to flow through the finned iron sleeve 54 where it is preheated by the mother liquor flowing through coil 46. After passage through sleeve 54, the mother liquor floods into the tank 32 to replenish the supply therein, and the above cycle is repeated.

The pressure at outlet 36 will, of course, drop during flooding and continue until substantial evaporation has occurred. If this intermittent drop is a problem, a pressure reservoir can be inserted.

Reference is now made to FIG. 3, which illustrates a practical arrangement of tanks 32, 48, 70 and 58, one about the other, to carry out the functions described above. The tanks are preferably insulated to increase efficiency.

FIG. 3 shows a connection of a number of individual generators 80, 82 and 84 arranged in series in order so that the pressurized gas passes through each stage in turn with each stage extracting energy until the gas is spent.

Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, that scope is intended to be limited only by the scope of the appended claims.