Current Search:  active heating (x)

View All Items

  • CSV Spreadsheet
(1 - 2 of 2)
DESIGN OF SEA WATER HEAT EXCHANGERFOR MINIATURE VAPOR COMPRESSION CYCLE
Title
DESIGN OF SEA WATER HEAT EXCHANGERFOR MINIATURE VAPOR COMPRESSION CYCLE.
Creator
Hughes, James, Chow, Louis, University of Central Florida
Abstract / Description
Recent advances in the development of miniature vapor compression cycle components have created unique opportunities for heating and cooling applications, specifically to human physiological requirements that arise in extreme environments. Diving in very cold water between 1.7 and 5°C requires active heating because passive thermal insulation has proven inadequate for long durations. To maintain diver mobility and cognitive performance, it is desirable to provide 250 to 300 W of heat from...
Show moreRecent advances in the development of miniature vapor compression cycle components have created unique opportunities for heating and cooling applications, specifically to human physiological requirements that arise in extreme environments. Diving in very cold water between 1.7 and 5°C requires active heating because passive thermal insulation has proven inadequate for long durations. To maintain diver mobility and cognitive performance, it is desirable to provide 250 to 300 W of heat from an un-tethered power source. The use of a miniature vapor compression cycle reduces the amount of power (batteries or fuel cell) that the diver must carry by 2.5 times over a standard resistive heater. This study develops the compact evaporator used to extract heat from the sea water to provide heat to the diver. The performance is calculated through the application of traditional single-phase and two-phase heat transfer correlations using numerical methods. Fabrication methods were investigated and then a prototype was manufactured. A test stand was developed to fully characterize the evaporator at various conditions. The evaporator is then evaluated for the conditions of interest. Test results suggest the correlations applied over predict performance up to 20%. The evaporator tested meets the performance specifications and design criteria and is ready for system integration.
Show less
Date Issued
2009
Identifier
CFE0002917, ucf:48016
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002917
Shape Recovery Behavior of Carbon Nanopaper Shape Memory Polymer Composite
Title
Shape Recovery Behavior of Carbon Nanopaper Shape Memory Polymer Composite.
Creator
Ozdemir, Veli Bugra, Kwok, Kawai, Gou, Jihua, Ghosh, Ranajay, University of Central Florida
Abstract / Description
This thesis presents analytical, experimental and modeling studies of the shape recovery behavior of electrically activated Carbon Nanopaper (CNP) Shape Memory Polymer (SMP)composite. The composite structure studied consists of a CNP layer sandwiched by two SMP layers where the CNP layer acts as a ?exible electrical heater when a voltage difference is applied. The behavior of CNP/SMP composite presents a coupled electrical - thermal - structural problem. The governing equations for the...
Show moreThis thesis presents analytical, experimental and modeling studies of the shape recovery behavior of electrically activated Carbon Nanopaper (CNP) Shape Memory Polymer (SMP)composite. The composite structure studied consists of a CNP layer sandwiched by two SMP layers where the CNP layer acts as a ?exible electrical heater when a voltage difference is applied. The behavior of CNP/SMP composite presents a coupled electrical - thermal - structural problem. The governing equations for the multiphysics behavior are derived. Derived parameters as a result of multiphysics analysis and effects of these parameters on the shape recovery behavior are investigated. The mechanical properties of the carbon nanopaper and viscoelastic properties of the shape memory polymer are characterized. A nonlinear, fully coupled electrical -thermal-structural ?nite element model is developed, and shape recovery experiments are carried out to validate multiphysics analysis and ?nite element model of the shape recovery of the CNP/SMP composite. Finite element model captures the general behavior of shape recovery, but overpredicts shape ?xity and shape recovery rate.
Show less
Date Issued
2019
Identifier
CFE0007700, ucf:52417
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007700