US 12,449,121 B1
Air source heat pump system and method of use for industrial steam generation
Nickolas Roberts, Fort Collins, CO (US); Todd M. Bandhauer, Fort Collins, CO (US); Ashwin Salvi, Fort Collins, CO (US); and Addison Stark, Fort Collins, CO (US)
Assigned to Colorado State University Research Foundation, Fort Collins, CO (US); and AtmosZero, Inc., Loveland, CO (US)
Filed by COLORADO STATE UNIVERSITY RESEARCH FOUNDATION, Fort Collins, CO (US); and ATMOSZERO, INC., Fort Collins, CO (US)
Filed on Apr. 19, 2024, as Appl. No. 18/640,484.
Application 18/640,484 is a continuation of application No. 18/324,066, filed on May 25, 2023.
Application 18/324,066 is a continuation of application No. PCT/US2022/072937, filed on Jun. 14, 2022.
Claims priority of provisional application 63/290,784, filed on Dec. 17, 2021.
Claims priority of provisional application 63/211,297, filed on Jun. 16, 2021.
Int. Cl. F22B 1/02 (2006.01); F24V 40/00 (2018.01); F25B 7/00 (2006.01)
CPC F22B 1/028 (2013.01) [F25B 7/00 (2013.01); F24V 40/00 (2018.05)] 22 Claims
OG exemplary drawing
 
1. A method for generating steam, said method comprising:
(a) providing two or more heat pump cycles comprising a bottom heat pump cycle and a top heat pump cycle coupled via at least one intermediate heat exchanger;
(b) circulating a first working fluid in said bottom heat pump cycle to absorb heat from an ambient air source;
(c) using a first centrifugal compressor stage in said bottom heat pump cycle and a second centrifugal compressor stage in said bottom heat pump cycle in series to increase a pressure of said first working fluid;
(d) circulating a second working fluid in said at least one intermediate heat exchanger to transfer said heat from said first working fluid to said second working fluid;
(e) circulating said first working fluid in a first economizer, thereby
splitting said first working fluid into a first primary fluid stream and a first secondary fluid stream;
expanding said first secondary fluid stream of said first working fluid to a lower pressure via a first expansion valve in said bottom heat pump cycle, and absorbing heat in said first secondary fluid stream of said first working fluid; and
rejecting heat from said first primary fluid stream of said first working fluid to said first secondary fluid stream of said first working fluid;
(f) cooling said second working fluid in a first location and heating said second working fluid in a second location by rejecting heat from said first location and absorbing heat in said second location in said top heat pump cycle;
(g) using a first centrifugal compressor stage in said top heat pump cycle and a second centrifugal compressor stage in said top heat pump cycle in series to increase a pressure of said second working fluid and to compress said second working fluid;
(h) circulating said second working fluid in said top heat pump cycle to transfer said heat from said second working fluid to a feed stream comprising water, thereby generating said steam at a target steam saturation temperature of at least 120 degrees Celsius, wherein said transfer of said heat from said second working fluid to said feed stream occurs in a steam generator, and wherein a pressure of said feed stream in said steam generator is greater than or equal to a pressure of said steam at said target steam saturation temperature; and
(i) circulating said second working fluid in a second economizer, thereby
splitting said second working fluid into a second primary fluid stream and a second secondary fluid stream;
expanding said second secondary fluid stream of said second working fluid to a lower pressure via a first expansion valve in said top heat pump cycle, and absorbing heat in said second secondary fluid stream of said second working fluid;
rejecting heat from said second primary fluid stream of said second working fluid to said second secondary fluid stream of said second working fluid; and
directing said second secondary fluid stream of said second working fluid to an inlet of said second centrifugal compressor stage in said top heat pump cycle.