Heat pump system selectively operable in a cascade mode and method of operation
First Claim
1. A system for the transfer of heat between a conditioned space and an ambient heat sink of variable temperature, said system being operable to transfer heat from said ambient heat sink to said conditioned space in a first mode then the temperature of said ambient heat sink is at a relatively high level and in a second mode when its temperature is at a relatively low level, said system comprisinga. a first refrigerant circuit includingi. first compressor means operable in said first and second modes to compress a vaporized first refrigerant,ii. first heat exchange means connected to said first compressor means operable in said first and second modes to transfer heat from said compressed first refrigerant to said conditioned space to condense said first refrigerant.iii. first expansion means connected to said first heat exchange means operable in said first and second modes to expand and reduce the pressure of said condensed first refrigerant, andiv. second heat exchange means connected to said first expansion means and said first compressor means selectively operable in said first mode to transfer heat at ambient temperature from said ambient heat sink to said expanded first refrigerant to vaporize same, and in said second mode to transfer heat from a compressed second refrigerant to said expanded first refrigerant to vaporize same, said vaporized first refrigerant being returned to said first compressor means in said first and second modes;
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Accused Products
Abstract
A system is disclosed for the transfer of heat from an ambient heat sink of variable temperature to a conditioned space, said system being operable in a first mode when the temperature of the heat sink is at a relatively high level, and in a second mode when its temperature is at a relatively low level. The system includes a first refrigerant circuit which is operable in said first mode as a heat pump of the vapor compression type to absorb heat from the ambient heat sink and transfer same to the conditioned space. A second refrigerant circuit is provided which is operable in the second mode, when the temperature of the ambient heat sink is at a relatively low level, to absorb heat from the ambient heat sink and transfer same to the first refrigerant circuit, which then transfers the heat to the conditioned space. Thus, in second mode operation, the first and second refrigerant circuits operate in a "cascade" relationship. Suitable control means are disclosed for effecting operation of the system as described above, and, in addition, a suitable method of operation for such a system is disclosed.
81 Citations
25 Claims
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1. A system for the transfer of heat between a conditioned space and an ambient heat sink of variable temperature, said system being operable to transfer heat from said ambient heat sink to said conditioned space in a first mode then the temperature of said ambient heat sink is at a relatively high level and in a second mode when its temperature is at a relatively low level, said system comprising
a. a first refrigerant circuit including i. first compressor means operable in said first and second modes to compress a vaporized first refrigerant, ii. first heat exchange means connected to said first compressor means operable in said first and second modes to transfer heat from said compressed first refrigerant to said conditioned space to condense said first refrigerant. iii. first expansion means connected to said first heat exchange means operable in said first and second modes to expand and reduce the pressure of said condensed first refrigerant, and iv. second heat exchange means connected to said first expansion means and said first compressor means selectively operable in said first mode to transfer heat at ambient temperature from said ambient heat sink to said expanded first refrigerant to vaporize same, and in said second mode to transfer heat from a compressed second refrigerant to said expanded first refrigerant to vaporize same, said vaporized first refrigerant being returned to said first compressor means in said first and second modes; - and
b. a second refrigerant circuit including i. second compressor means operable in said second mode to compress a vaporized second refrigerant, ii. third heat exchange means connected to said second compressor means and associated with said second heat exchange means, operable in said second mode to transfer heat from said compressed second refrigerant to said expanded first refrigerant to vaporize same and to condense said compressed second refrigerant, iii. second expansion means connected to said third heat exchange means means operable in said second mode to expand and reduce the pressure of said condensed second refrigerant, and iv. fourth heat exchange means connected between said second expansion means and said second compressor means operable in said second mode to transfer heat from said ambient heat sink to said expanded second refrigerant to vaporize same and return it to said second compressor means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of transferring heat to a conditioned space from an ambient heat sink of variable temperature comprising the steps of:
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a. compressing a vaporized first refrigerant; b. transferring heat from said compressed first refrigerant to said conditioned space to condense said first refrigerant; c. expanding said condensed first refrigerant to reduce its pressure; d. transferring heat at ambient temperature from said ambient heat sink to said expanded first refrigerant to vaporize same when the temperature of said ambient heat sink is at a relatively high level and, when its temperature is at a relatively low level, executing the following steps (i.) through (v.); i. compressing a vaporized second refrigerant, ii. transferring heat from said compressed second refrigerant to said expanded first refrigerant to condense said second refrigerant and vaporize said first refrigerant. iii. expanding said condensed second refrigerant to reduce its pressure, iv. transferring heat from said ambient heat sink to said expanded second refrigerant to vaporize same, and v. returning said vaporized second refrigerant to said compressing step (i.); and e. returning said vaporized first refrigerant to said compressing step (a.). - View Dependent Claims (23, 24, 25)
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Specification