Water-source and ice-maker heat pumps share many
characteristics. However, each presents different
technical difficulties that have prevented them from being
used more widely. In a water-source heat pump a very
important consideration is to reduce water consumption,
while in an ice-maker heat pump a major concern is to
reduce the number of deicing cycles while keeping a high
performance.
Previous research by this author has indicated that
the use of the flow reversal method (reversing periodically
the water flow direction in the evaporator) has the effect
of partly deicing the evaporator, reducing pressure drop
and enhancing heat transfer. This thesis shows the
development and application of analytical and numerical
models to study the effect of different evaporator
parameters on heat pump efficiency, as well as the possible
advantages of using the flow reversal method in a water-source
or ice-maker heat pump.
The conclusion reached from these studies is that
periodic water flow reversals inside an evaporator with
freezing help improve the performance of a heat pump
system in two different ways. First, periodic water flow
direction reversals serve to enhance heat transfer in the
evaporator. Second, reversing the water flow direction
also delays ice blockage in the evaporator, or totally
prevents blockage from happening. Delaying ice blockage
represents a substantial improvement for ice-maker heat
pumps, since these may then operate for a longer time
without deicing. Preventing ice blockage represents a
substantial improvement for water-source heat pumps, since
these may then operate at lower water flow rates.
Suggestions for future work include further testing of
the flow reversal method for different evaporator
geometries, as well as an experimental evaluation of the
flow reversal method. / Graduation date: 1990
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/38141 |
| Date | 14 November 1989 |
| Creators | Aceves, Salvador M. |
| Contributors | Reistad, Gordon M. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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