Heat pump and power production utilizing hydrated salts

Abstract

A thermodynamic cycle for heat upgrading and power production, combining absorption, adsorption and desorption processes, promises high efficiency for heat pump applications and low temperature renewable energy production. The adsorbent regeneration has been replaced from dissolution and separation of electrolyte crystals from a solution electrolytes, saving the regeneration heat consumption.

1 . Method for heat transfer to higher temperature and power production, in which electrolyte solutions are used and such a saturated solution is cooled from high temperature from a dissolution equipment (Δ 1 ), the solubility lowers, another phase like crystals of the electrolyte are formed, separated and stored in a storage tank (K 1 . 1 ), the resulting solution is vaporized at successively higher pressure through vapor generators (E 1 ), so that vapor of the solvent is produced, the vapor of each vapor generator is absorbed (A 1 ) by a solution of lower solvent activity at the same pressure but higher temperature, which is the temperature of the next vaporization, so that absorption heat is used for vaporization, the vapor generator which works at the higher than the others temperature, is connected with a vapor expansion machine through a flow regulating valve which can direct part of the vapor for expansion and the rest for absorption, this machine is connected with an absorber working at low temperature and connected with the other absorbers, the remaining from the vaporization process solution as well as the separated crystals (K 1 . 1 ) return to the dissolver (Δ 1 ) to form the initial solution whilst the solution, the vapor and the crystal fluxes that are heated recover heat from the solution which is cooled, which method is characterized by:
 the initial solution is saturated in an electrolyte which is hereafter called basic electrolyte and is hydrated at the lower temperature of cooling, while other soluble electrolytes are included, in such a concentration that they do not separate from the solution, 
 the vaporization processes are replaced by vapor desorption and the vapor generators (E 1 ) by desorbers(E 2 ) supplied with crystals from (K 1 . 1 ), they are heated producing vapor, 
 the remaining after the crystal separation solution, is heated, expands and enters the first of the absorbers (A 1 ) and then is successively compressed and driven to other absorbers (A 1 ) where vapor is also driven and absorbed and then the solution enters dissolver (Δ 1 ), where the remaining in desorbers (E 2 ) crystals also enter, forming the initial solution, 
 when the pressure in each desorber (E 2 ) reaches the determined value, the valve opens and supplies vapor to the connected absorber (A 1 ), 
 each absorber (A 1 ) is connected with a few desorbers (E 2 ) operating at the same pressure, so that when the vapor coming from one of them is exhausted, vapor from the next is provided, 
 solution cooling and crystal separation may take place in more than one stages, as the dissolution may also be done, 
 polar substances of low boiling point like water, ammonia, low boiling point amines, alcohols and mixture of those like ammonia in high boiling point substances, can be used as solvents, where in the last case, the desorption pressure is regulated so that the most volatile substance is desorbed, 
 electrolytes consisting of multi charge ions that form high degree hydrates, like calcium(CaCl2) and magnesium(MgCl2) chlorides are preferred, while when vapor is mainly produced by the moisture of the crystal, single ion electrolytes can also be used. 
 
     
     
         2 . Method as in  claim 1 , characterized by the fact that:
 the hydration degree of the basic electrolyte increases as the crystallization temperature decreases, the solution is first cooled at the temperature in which this electrolyte, is formed, separated and stored (K 1 ) with the lowest degree of hydration, preferably as pure electrolyte and from there they are driven to adsorbers (A 2 ),   the solution keeps cooling at lower temperature, crystals of higher hydration degree are separated and stored in (K 1 . 1 ) and from there, they are driven to desorbers (E 2 ) where they are heated for the vapor to be desorbed, remaining in lower hydration,   the remaining solution after the last crystal separation, expands and the solution enters at successively higher pressure into vapor generators (E 1 ) where part of the solvent is vaporized and then the solution is compressed, heated and enters (Δ 1 ),   the vapor from the desorbers (E 2 ) and vapor generators (E 1 ) is absorbed through adsorbers (A 2 ),   each adsorption and consequently each desorption and evaporation process, may take place at different pressure,   the crystals from (K 1 ) are dried by heating in a desorber (E 2 . 2 ) before driven to (A 2 ) and the vaporized moisture is further heated, compressed and returns to the desorber (E 2 . 2 ) as a heating means to dry next crystals from (K 1 ), while the condensed vapor is driven to an evaporator (E 1 ),   no other soluble electrolytes are dissolved in the solution.   the solution in (Δ 1 ) may be saturated in a second electrolyte which vapor adsorption temperature is considerably higher that that of the basic electrolyte, while the solution is saturated with the basic electrolyte at lower than (K 1 ) temperature   
     
     
         3 . Method as in  claim 1 , characterized by the fact that first and second electrolyte solutions are combined,
 the two solutions have an electrolyte and a solvent in common   the first solution consists only from the common electrolyte and solvent,   the first solution is cooled in a few steps so that in the first step the separated crystals are of low hydration, preferably pure electrolyte and stored in (K 1 ) and the separated crystals from the last step are stored in (K 1 . 1 ),   the resulting liquid solution is expanded and driven to vapour generators (E 1 ), compressed successively and evaporated there,   the second solution includes more electrolytes that are soluble, causing negative deviation from ideal and at a concentration such that they do not separate,   the second solution is cooled from a dissolution equipment (Δ 2 ), crystals of the common electrolyte are formed and separated (K 2 ) at the lower applicable temperature so that they are highly hydrated, the pressure of the remaining solution is regulated and the solution is driven to the absorbers (A 1 ) to absorb the vapor coming from (E 1 ), compressed, heated and enters dissolution equipment (Δ 2 ),   the low hydration separated crystals from (K 1 ) are driven and dissolved into (Δ 2 ), whilst crystals from (K 1 . 1 ) as well as those separated from the second solution in (K 2 ) are dissolved into (Δ 1 ),   the crystals from (K 1 . 1 ) may first driven to a desorbent (E 2 ) where vapour is produced and absorbed into an absorber (A 1 ) and then driven to (Δ 1 ),   the amount of the hydrated crystals which are dissolved in the first solution (Δ 1 ), is such that the accompanying solvent is equal to the solvent transferred as vapour through (E 1 ) to (A 1 ) and the amount of this transferred electrolyte equals the amount of electrolyte transferred from the first solution (K 1 ) to the second.   
     
     
         4 . Method as in  claim 1 , characterized by the fact that the solution from the dissolution equipment (Δ 1 ), expands, enters the absorber (A 1 ) and absorbs vapour from (E 1 ), is compressed to the pressure of (Δ 1 ), enters an absorber AE 1  where absorbs the vapour coming from a vapour generator (EA 1 ) stated below, keeps cooling .and the dissolved in (Δ 1 ) electrolyte is separated, from there, the remaining solution enters dissolution equipment (Δ 2 ) where another electrolyte is dissolved, next the solution expands, enters vapour generators (E 1 ), next it is heated, compressed and enters vapour generator (EA 1 ) where is vaporized producing the vapour which is absorbed by (AE 1 ), is cooled so that the dissolved in (Δ 2 ) electrolyte is separated, the solution is heated and enters dissolution equipment (Δ 1 ),
 the solvent is a pure substance and the dissolved in (Δ 2 ) electrolyte is of low solubility and high hydration whilst the dissolved in (Δ 1 ) is the opposite, 
 the method is also applicable when used with a mixed solvent which consists of a gas dissolved in a liquid, in such case, the dissolved in (Δ 2 ) electrolyte is of reducing gas solubility and the dissolved in (Δ 1 ) is of increasing gas solubility, 
 the method can work applying only one electrolyte dissolution and separation process, 
 a second pair of (EA 1 /AE 1 ) can be introduced in a way that the solution that exits the first (EA 1 ) enters the second (EA 1 ) and exiting the first (AE 1 ) enters second (AE 1 ), 
 a second similar apparatus can cooperate with the first, in a way that vapour from E 1  of the first apparatus enter A 1  of the second and vapour from E 1  of the second enters A 1  of the first. 
 the outlet of the expansion machine, when used, is absorbed at the liquid outlet of (K 1 ) 
 
     
     
         5 . Method as in  claim 1 , characterized by the combination of two solutions, where, in the first one, the solution from the dissolution equipment (Δ 1 ) is first driven to an absorber (A) and then cooled to separate the electrolyte, which is driven to (Δ 1 ),
 the absorbers (A 1 ) have been replaced by vapour generators (El) and the produced vapour is absorbed by the second solution, 
 the second solution from its dissolution equipment (Δ 2 ), is first driven to a vapour generator (E) and then cooled to separate the electrolyte, which is driven to (Δ 2 ), 
 the absorbers (A 1 ) absorb the vapour produced by the first solution, 
 the amount of vapour absorbed by (A 1 ), is produced from the vapour generator (E) and absorbed by the first solution through (A), 
 the solvent is preferably a mixed solvent in which a gas is dissolved, and the dissolved in the second solution electrolyte is of reducing gas solubility while in case of pure solvent it is highly hydrated, in contrast to the first solution electrolyte, which may not be used. 
 
     
     
         6 . Apparatus for heat transfer to higher temperature and power production, consisted of:
 a dissolution equipment (Δ 1 ), a crystallizer unit which consists of a crystallizer, a crystal separating equipment and a crystal storage tank provided with a liquid inlet, a liquid outlet and a crystal outlet connection, disorbers (E 2 ) provided with a crystal inlet and outlet and a vapor outlet, absorbers (A 1 ), a heat exchanger, a pressure expansion valve, low pressure liquid pumps and the pipe network connecting the equipments in a way that:   the outlet of the dissolution equipment (Δ 1 ) is connected with the liquid inlet of the crystallizer unit through a heat exchanger, the crystal outlet of which unit is connected with a crystal conveyor means with the desorber (E 2 ) and the liquid outlet is connected through the pressure expansion valve with an absorber (A 1 ),   this absorber is connected with a next absorber (A 1 ) through a liquid pump and the exit of the this absorber is connected with the dissolution equipment (Δ 1 ) through the heat exchanger and a liquid pump,   the vapour outlet of each disorber (E 2 ), is connected with the vapour inlet of one of the absorbers (A 1 ) and the crystal outlet is connected with the dissolution equipment (Δ 1 ),   the one direction of the heat exchanger is connected with the dissolution equipment (Δ 1 ) outlet and the crystallizer unit input and the other direction with the liquid outlet of the crystallizer unit and the dissolution equipment (Δ 1 ) liquid input, while in this direction there are outputs and inputs before and after each absorber (A 1 ),   heat transfer equipments connecting absorbers (A 1 ) with the disorbers (E 2 ).   
     
     
         7 . Apparatus for heat transfer to higher temperature and power production as in  claim 6 , in which a disorber (E 2 . 2 ) for crystal drying, which includes a heat transfer surface separating the crystals from the vapor by which they are heated, a crystal inlet and vapor and crystal outlet in the drying space and a vapor inlet and liquid outlet in the heat supplying space, is included, where:
 there is a first and a second crystallizer unit in which the liquid outlet of the first is connected with the liquid inlet of the second,   the absorbers (A 1 ) are replaced by vapor generators (E 1 ),   the crystals outlet of the first crystallizer (K 1 ) unit is connected with the crystal inlet of the disorber (E 2 . 2 ), the crystal outlet of which is connected with adsorber equipments (A 2 ) with crystal convey means and the crystal outlet of these is connected through crystal convey means with (Δ 1 ),   the vapor outlet of disorbers (E 2 ) and vapor generators (E 1 ), are connected with the vapor inlet of (A 2 ) so that each of the (E 2 ) and (E 1 ) that works at the same pressure level is connected with the same (A 2 ),   the vapor outlet of the drying space of the disorber (E 2 . 2 ) is connected with a heating means and the vapor outlet of this means is connected with a vapor compressor, the outlet of which is connected with the vapor inlet of the heating space of the oven,   heat transfer equipments connecting adsorbers (A 2 ) with disorbents (E 2 ) and evaporators (E 1 ).   
     
     
         8 . Apparatus as in  claim 6 , characterized by the fact that two such apparatus are combined, in the first of which,
 the outlet of the dissolution equipment (Δ 1 ), is connected with the liquid inlet of a first crystallizer unit, the liquid outlet of which is connected with the liquid inlet of a second unit,   absorbers (A 1 ) have been replaced by vapour generator (E 1 ),   in the second apparatus, the disorbers E 2  are not used,   the crystal outlet of the first crystallizer unit of the first apparatus, is connected with the crystal inlet of the dissolution equipment of the second apparatus,   the crystal outlet of the crystallizer unit of the second apparatus, is connected with the crystal inlet of the dissolution equipment of the first apparatus   
     
     
         9 . Apparatus as in  claim 6 , characterized by the fact that,
 the outlet of the dissolution equipment (Δ 1 ), is connected with the liquid input of an absorber (A 1 ) through a heat exchanger and a pressure expansion valve, the outlet of this absorber, is connected with the liquid inlet of another absorber (AE 1 ), through a liquid pump and the outlet of this absorber is connected with the crystallizer unit through a heat exchanger (H 1 . 1 ), the crystal outlet of which is connected with (Δ 1 ),   the liquid outlet of the crystallizer unit is connected with a vapor generator (E 1 ) through an expansion valve, the outlet of which is connected with another dissolution equipment (Δ 2 ), through a liquid pump and the heat exchanger (H 1 . 1 ).the liquid outlet of this is connected with another vapor generator (EA 1 ),   the liquid outlet of (EA 1 ) is connected with another crystallizer unit through another heat exchanger, the liquid outlet of this unit is connected with the first dissolution equipment (Δ 1 ) through the same heat exchanger and the crystal outlet with the second dissolution equipment (Δ 2 ),   the vapour outlet of (E 1 ) is connected with the vapour inlet of (A 1 ),   the vapour outlet of (EA 1 ) is connected with the vapour outlet of (AE 1 ),   this apparatus can cooperate with a second one which is the same, in a way that the vapour outlet of the vapour generator (E 1 ) of the first is connected with the vapour inlet of the absorber (A 1 ) of the second and the same with the absorber (A 1 ) of the first with the vapour generator (E) of the second.   the absorber at the outlet of the expansion machine is connected at the liquid outlet of (K 1 )   
     
     
         10 . Apparatus as in  claim 6 , characterized by the combination of two such apparatus, in the first of which,
 the outlet of the dissolution equipment (Δ 1 ), is connected with the inlet of an absorber (A), the outlet of which is connected with the crystallizer unit,   dissorbers (E 2 ) are not used,   the absorbers (A 1 ) has been replaced by vapor generator (E 1 ) and in the second apparatus,   the outlet of the dissolution equipment (Δ 1 ), is connected with a vapor generator (E), the output of which is connected with the crystallizer unit of this apparatus,   dissorbers (E 2 ) are not used,   the vapor outlet of the vapor generators (E 1 ) of the first apparatus is connected with the vapor inlet of the absorbers (A 1 ) of the second and the vapor outlet of the vapor generator of the second is connected with the vapor inlet of the absorber (A) of the first apparatus.