Heat cascading regenerative sorption heat pump
In general since sorbents take up the working fluid when cooled and desorb the working fluid when heated, heat pump is said to be heat driven. Often in adsorbent and chemisorbent heat pumps two beds of sorbents are used, one to adsorb the working fluid while the other bed is desorbing the working fluid. Alternate heating and cooling of the beds is the conventional procedure. When used in air conditioning, heat from an interior room may be used to evaporate the working fluid in an evaporator with heat rejection to the environment at ambient temperatures.
The following terms are used herein. By the term chemisorbent as used herein is meant chemical absorbent. By the term chemisorption as used herein is meant chemical absorption. By the term physisorbent as used herein is meant physical absorbent or physical adsorbent. By the term physisorption as used herein is meant physical absorption or physical adsorption. The term canister is used for the reactor containing the chemisorbent. The term compressor is used for the reactor containing the physisorbent or physical adsorbent.
Accordingly, there is provided by the principles of this invention a heat cascading regenerative sorption heat pump process with waste or rejected heat from a higher temperature chemisorption circuit powering a lower temperature physical adsorption circuit. The process comprises providing a higher temperature ammonia chemisorption circuit containing ammonia and a chemisorbent having a first chemical composition operable for chemisorbing and desorbing ammonia. The ammonia chemisorption circuit comprises a plurality of canisters each containing the chemisorbent, first condensing means, first evaporating means for cooling a low temperature load, first heating means for heating the chemisorbent to a first upper temperature for desorption of ammonia, and first cooling means for cooling the chemisorbent, operatively connected together. Each canister has a heat transfer element in thermal communication with, but not in fluid communication with, the chemisorbent therein.
The process further comprises providing a lower temperature ammonia physical adsorption circuit containing ammonia and a physical adsorbent having a second chemical composition operable for physically adsorbing and desorbing ammonia, the second chemical composition being different than the first chemical composition. The ammonia physical adsorption circuit comprises adsorption/desorption means containing the physical adsorbent and having a first part for desorbing ammonia and a second part for adsorbing ammonia, second condensing means, second evaporating means for cooling a low temperature load, second heating means for heating the physical adsorbent in the first part of the adsorption/desorption means to a second upper temperature for desorption of ammonia, and second cooling means for rejecting heat therefrom, operatively connected together.
The process also comprises providing at least one first closed heat transfer circuit containing a first heat transfer liquid which is different than the chemisorbent, the physical adsorbent and ammonia. The first closed heat transfer circuit comprising the heat transfer element of at least one canister, and heat exchange means in thermal communication with the first part of the adsorption/desorption means but not in fluid communication with the physical adsorbent.
In the process, cooling the chemisorbent by the first cooling means is by flowing the first heat transfer liquid through the heat transfer element of the at least one canister thereby cooling it and the chemisorbent therein. In this process, heating the first part of the adsorption/desorption means and the physical adsorbent therein by the second heating means to a second upper temperature for desorption of ammonia is by flowing the first heat transfer liquid from the at least one canister through the heat exchange means thereby heating the first part, and thereby cascading heat from the higher temperature ammonia chemisorption circuit to the lower temperature ammonia physical adsorption circuit. The process further includes regenerating heat within the adsorption/desorption means by transferring heat from the first part thereof to the second part thereof.
In one embodiment, the first heating means for heating the chemisorbent to a first upper temperature for desorption of ammonia provides the entire net heat added to the process.
In another embodiment, rejecting heat from the lower temperature ammonia physical adsorption circuit is by transferring heat from the second part of the adsorption/desorption means to a third low temperature heat sink, thereby cooling the second part.
In one embodiment of this invention the heat cascading regenerative sorption heat pump process further comprises providing each canister with a heat transfer element in thermal communication with the chemisorbent therein but not in fluid communication with the chemisorbent, and providing each compressor with a heat transfer element in thermal communication with the physical adsorbent therein but not in fluid communication with the physical adsorbent. In this embodiment the process includes providing a plurality of heat exchangers, the number of which are equal to the number of the compressors.
There is also provided by the principles of this invention a heat cascading regenerative sorption heat pump process with rejected heat from a higher temperature chemisorption circuit powering a lower temperature water absorption circuit. The process comprises providing a higher temperature ammonia chemisorption circuit containing ammonia and a chemisorbent, the chemisorbent having a first chemical composition operable for chemisorbing and desorbing ammonia.
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