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Design, modeling and performance of miniature reciprocating expander for a heat actuated heat pumpHerron, Thomas G. 21 September 2004 (has links)
A miniature reciprocating expander is being developed as part of a larger program
to develop a heat actuated heat pump for portable applications. By utilizing the higher
energy density of liquid hydrocarbon fuels relative to batteries, a heat actuated heat pump
would be able to provide cooling for much longer than motor driven units of equal
weight. A prototype expander has been constructed and demonstrated to produce up to
22 W of shaft power at 2500 rpm using 60 psig, room temperature nitrogen as the input.
Assuming adiabatic conditions, the expander appears to operate at up to 80% isentropic
efficiency. However, when heat inflow to the expander is accounted for, the resulting
polytropic efficiency is about 10% lower. In addition to experimental results, models of
expander performance with different loss mechanisms are presented. These mechanisms
include over- and under-expansion, in-cylinder heat transfer, clearance volume, friction,
and valve pressure drop. / Graduation date: 2005
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An analytical study of the performance characteristics of solid/vapor adsorption heat pumpsFuller, Timothy Alan 05 1900 (has links)
No description available.
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Design and modelling of novel absorption refrigeration cycles / by Stephen David White.White, S. D. January 1993 (has links)
Nine pages of Addenda and eight pages of Errata in back pocket. / Includes bibliographical references. / vii, 192, [78] : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemical Engineering, 1994
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Constrained thin film desorption through membrane separationThorud, Johnathan D. 17 February 2005 (has links)
A constrained thin film desorption scheme has been experimentally tested to
determine the desorption rates for water from an aqueous lithium bromide mixture
through a confining membrane. Variable conditions include the inlet
concentration, pressure differential across the membrane, and channel height.
Desorption takes place in a channel created between two parallel plates with one of
the walls being both heated and porous. A hydrophobic porous membrane creates
a liquid-vapor interface and allows for vapor removal from the channel. Inlet
concentrations of 32 wt%, 40 wt%, and 50 wt% lithium bromide were tested at an
inlet sub-atmospheric pressure of 33.5 kPa. Pressure differentials across the
membrane of 6 kPa and 12 kPa were imposed along with two channel heights of
170 μm and 745 μm. All cases were run at an inlet mass flow rate of 3.2 g/min,
corresponding to Reynolds numbers of approximately 2.5 to 4.5. The membrane
surface area for desorption was 16.8 cm². A maximum desorption rate (vapor
mass flow rate) of 0.51 g/min was achieved, for the 32 wt%, 12 kPa pressure
differential, and 170 μm channel. Increasing the pressure differential across the
channel allowed for higher desorption rates at a fixed wall superheat, and delayed
the transition to boiling. As the inlet concentration increased the desorber's
performance decreased as more energy was required to produce a fixed desorption
rate. Results are also presented for the variation in the heat transfer coefficient
with the wall superheat temperature. The increase in the channel height had a
negative influence on the heat transfer coefficient, requiring larger superheat
values to produce a fixed desorption rate. / Graduation date: 2005 / Best scan available for tables and computer code in the appendices. The original is faded.
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