Browsing by Author "Chen, Weibo"
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Item A Robust, Gravity-Insensitive, High-Temperature Condenser for Water Recovery(46th International Conference on Environmental Systems, 2016-07-10) Chen, Weibo; Conboy, Thomas; Ewert, MichaelRegenerative life support systems are vital for NASA’s future long-duration human space exploration missions. A Heat Melt Compactor (HMC) system is being developed by NASA to dry and compress trash generated during space missions. The resulting water vapor is recovered and separated from the process gas flow by a gravity-insensitive condenser. Creare is developing a high-temperature condenser for this application. The entire condenser is constructed from metals that have excellent resistance to chemical attack from contaminants and suitable for high-temperature operation. The metal construction and design configuration also offer greatest flexibility for potential coating and regeneration processes to reduce biofilm growth and thus enhancing the reliability of the condenser. The proposed condenser builds on the gravity-insensitive phase separator technology Creare developed for aircraft and spacecraft applications. This paper will first discuss the design requirements for the condenser in a HMC system that will be demonstrated on the International Space Station (ISS). Then, it will present the overall design of the condenser and the preliminary thermal test results of a subscale condenser. Finally, this paper will discuss the predicted performance of the full-size condenser and the development plan to mature the technology and enhance its long-term reliability for a flight system.Item A Cryogenic CO2 Scrubber with an Integrated Switchable Heat Pipe(2023 International Conference on Environmental Systems, 2023-07-16) Chen, Weibo; Fonseca Flores, Luis; Roberts, ScottHuman missions to explore Moon, Mars, and beyond will require reliable, compact air revitalization systems. Using a cryogenic separation system to sublimate CO2 in the processed air steam and thus remove it from the air flow is a very attractive approach for long-duration missions because it eliminates the need for consumable adsorption systems. The required cryocooling power to achieve the target CO2 removal rate for a spacecraft with four crewmembers is quite high, more than tens of Watts below 125 K. A critical need for this technology is a cryogenic CO2 scrubber with an integrated heat transport mechanism to efficiently transfer heat to a remotely located active or passive cooler during the collection phase, and to thermally disconnect from the cooler during the regeneration phase to eliminate the need for two separate cryocoolers. To meet this need, we are developing a CO2 scrubber with a built-in cryogenic liquid trap switchable heat pipe to connect the scrubber with a cooler. The scrubber has enhanced heat transfer surfaces to collect CO2 snow. The enhanced surfaces are directly cooled by evaporation of heat pipe working fluid, instead of relying on thermal conduction cooling to minimize temperature gradients on the enhanced surfaces. The enhanced surfaces also have features to promote a uniform air flow and minimize impact of channel clogging as CO2 accumulates. The design of the scrubber and switchable heat pipe is built on JPL’s experience in additive manufacturing of two-phase thermal devices with porous media. This paper discusses the design of the scrubber and the switchable heat pipe, as well as the test setup and preliminary test data for the proof-of-concept switchable heat pipe.Item Development of a Miniature, Reliable Ammonia Pump for Spaceborne Two-Phase Pumped Loops(49th International Conference on Environmental Systems, 2019-07-07) Chen, Weibo; Conboy, Thomas M.; Daines, GregoryNASA’s future remote sensing science missions require advanced thermal management technologies to maintain multiple instruments at very stable temperatures and utilize waste heat to keep other critical subsystems to stay above minimum operational temperatures. Two-phase pumped loops are an ideal solution for these applications. A critical need for these pumped loops is an ammonia pump that reliably circulates very slightly subcooled liquid ammonia in the loop. To meet this need, Creare is developing a reliable, pump that has innovative features to prevent cavitation in the pumping chamber and in the hydrodynamic fluid bearings, enhancing the overall pumped loop reliability. This paper first discusses design challenges for ammonia circulation pumps for two-phase pumped loop applications. It then discusses the key performance features of Creare’s ammonia-compatible pump and presents the hydrodynamic performance test data of a brassboard pump and its measured Net Positive Suction Head before cavitation occurs. Finally, the paper discusses the preliminary assessment of the pump reliability and exported vibrations.Item High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)(45th International Conference on Environmental Systems, 2015-07-12) Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, GregoryFuture human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Spacesuit Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity and regeneration in only half the time. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the Space Station.Item Multifunctional Cooling Garment for Space Suit Environmental Control(45th International Conference on Environmental Systems, 2015-07-12) Izenson, Michael; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Ferl, Janet; Cencer, DanielFuture manned space exploration missions will require space suits with capabilities beyond the current state of the art. Portable Life Support Systems for these future space suits face daunting challenges, since they must maintain healthy and comfortable conditions inside the suit for long-duration missions while minimizing weight and water venting. We have demonstrated the feasibility of an innovative, multipurpose garment for thermal and humidity control inside a space suit pressure garment that is simple, rugged, compact, and lightweight. The garment is based on a conventional liquid cooling and ventilation garment that has been modified to directly absorb latent heat as well as sensible heat. This hybrid garment will prevent buildup of condensation inside the pressure garment, prevent loss of water by absorption in regenerable carbon dioxide removal beds, and conserve water through use of advanced lithium chloride absorber/radiator technology for nonventing heat rejection. We have shown the feasibility of this approach by sizing the critical components for the hybrid garment, developing fabrication methods, building and testing a proof-of- concept system, and demonstrating by test that its performance is suitable for use in space suit life support systems.Item Performance of a Multifunctional Space Evaporator- Absorber-Radiator (SEAR)(44th International Conference on Environmental Systems, 2014-07-13) Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, GregoryThe Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection sufficient for most EVA activities by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 ft2 prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable rejection of metabolic heat from the LCAR. We used results of these tests to assess future performance potential and suggest approaches for integrating the SEAR system with future space suits.Item Power Optimization of Cryogenic CO2 Deposition Capture in Deep Space(2020 International Conference on Environmental Systems, 2020-07-31) Jagtap, Pranav; Belancik, Grace; Jan, Darrell; Hall, Scott; Chen, WeiboAn extremely reliable cabin air revitalization system is needed for human deep space exploration missions. Deep space offers an environmental temperature close to 4 Kelvin. This low environmental temperature enables heat rejection for systems that are thermally power-intensive, i.e. CO2 cold surface deposition (CDep). The CDep system relies on phase change temperatures of air components to deposit CO2 onto a cold surface. The cold surface can be generated utilizing cryocoolers, including Stirling and Reverse Brayton, or deep space environmental temperature. This paper presents a numerical study on a power optimization of cold surface generation via a cryocooler or thermal radiator. An example system for each type is presented. However, a hybrid system would not only reduce power required to remove CO2, but also increase redundancy and reliability of the CDep system.Item A Robust Two-Phase Pumped Loop with Multiple Evaporators and Multiple Radiators for Spacecraft Applications(47th International Conference on Environmental Systems, 2017-07-16) Chen, Weibo; Conboy, Thomas M.; Daines, Gregory W.; Fogg, David W.NASA’s future remote sensing science missions will require advanced two-phase pumped loop systems to enable precise thermal control of multiple advanced instruments and electronics, and effectively utilize waste heat to keep propellant to stay above its minimal allowable temperature. To meet this need, Creare is developing an innovative two-phase pumped loop with multiple evaporators and multiple radiators. The pumped loop has several performance features, including: (1) reliable refrigerant circulation even when the refrigerant flow exiting the radiators is a two-phase flow during thermal transients; (2) reliable flow distribution in a network of evaporators to minimize flow maldistribution when instrument heat loads vary; (3) actively controlled two-phase refrigerant pressure at the evaporator inlet to precisely control evaporator cooling temperature; and (4) freeze-tolerant radiators. This paper first discusses the baseline layout design of Creare’s two-phase pumped loop system, and then describes a brassboard two-phase pumped loop test setup that is used to assess the effect of the system accumulator designs and its location in the loop. Finally, the paper compares the performance of pumped loops with different accumulator designs and installation locations during heat sink thermal transients.Item Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft(45th International Conference on Environmental Systems, 2015-07-12) Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, GregoryFuture manned exploration spacecraft will need to operate in challenging thermal environments. State-of-the-art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments, and or heavy phase change material heat exchangers for thermal storage. These approaches can lead to large loss of water and significant mass penalties for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber module has the potential to absorb over 500 kJ, compared to phase change heat sink systems that typically achieve ~50 kJ/kg. This paper describes analysis models to predict performance and optimize the size of the SEAR system, estimated size and mass of key components, and an assessment of potential mass savings compared with alternative thermal management approaches. We also describe a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.