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<H1 style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px"><FONT
face="Times New Roman">Deep Mesh Solar Air Heating Collector -- Test
1</FONT></H1>
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<P><FONT face="Times New Roman">Nick Pine proposes a solar home heating
concept using solar heating system that is aimed at producing a very high
solar fraction with relatively inexpensive solar air heating collectors.
In order to accomplish the high solar fraction, the system must include
several days worth of heat storage for extended cloudy periods -- a large
storage capacity.</FONT></P>
<P><FONT face="Times New Roman">The physical size of this large heat
storage depends on the maximum temperature that the storage can be raised
to -- higher temperatures store more heat in less space. But, producing
higher temperatures normally means that the solar air heating collectors
would operate less efficiently as the losses out the collector glazing go
up with collector temperature -- thus the desire for high storage
temperatures can result in an undesirable increase in collector
area.</FONT></P>
<P><FONT face="Times New Roman">There is a potential collector design that
may produce the desirable higher collector temperatures at good
efficiency. This design uses several layers of mesh for the absorber. The
advantages are said to be: 1) the pressure drop caused by the mesh spreads
the airflow evenly over the full surface of the absorber, and 2) the first
layer of mesh acts as a radiation shield to reduce the radiation from the
hotter inner layers toward the glazing. The first layer of mesh runs
relatively cool in part because in this heating scheme, the air introduced
into the collector is relatively cool (70F) room air -- this cooler first
layer of mesh thus reduces losses out the glazing.</FONT></P>
<P><FONT face="Times New Roman">So, in an ideal design, 70 F room
temperature air is introduced between the glazing and the first (south
most) layer of mesh. This coolish air spreads evenly over the full mesh
surface because of the mesh pressure drop. Even though the airflow rate is
low (to achieve higher temperatures), the first layer of mesh runs at a
low temperature because of the relatively cool 70F air, and the ability of
the mesh absorbers to provide very even airflow over the full surface. As
the air progresses through the layers of mesh, it heats up, and since flow
rate is low, the residence time is long and the air heats up to high
temperatures (say 140+F). This hot air is then passed through an air to
water heat exchanger and the hot water produced goes to heating the heat
storage. By using the hottest air to heat the storage, the max storage
temperature can be higher and it can store more heat. The still warm air
leaves the heat exchanger and is blown into the house for immediate space
heating. </FONT></P>
<P><FONT face="Times New Roman">A key element in making this scheme work
is the low flow, deep mesh collector that operates efficiently while
producing high temperatures. This test is a starting point in trying to
see if this can be accomplished in a collector that is straight forward
and inexpensive to build. My standard air heating collector which has just
3 layers of aluminum screen mesh is the starting point. The idea is to see
how well it does in achieving the high temperatures AND high efficiency,
and to identify changes that might make it do better, and possibly test
those.</FONT></P>
<P><FONT face="Times New Roman">On this page:</FONT>
<P style="MARGIN-LEFT: 40px" class=auto-style7><FONT
face="Times New Roman">- </FONT><A
href="http://www.builditsolar.com/Experimental/DeepMeshCol/#Collector"><FONT
face="Times New Roman">Collector Description</FONT></A>
<P style="MARGIN-LEFT: 40px" class=auto-style7><FONT
face="Times New Roman">- </FONT><A
href="http://www.builditsolar.com/Experimental/DeepMeshCol/#Setup"><FONT
face="Times New Roman">Test Setup</FONT></A>
<P style="MARGIN-LEFT: 40px" class=auto-style7><FONT
face="Times New Roman">- </FONT><A
href="http://www.builditsolar.com/Experimental/DeepMeshCol/#Results"><FONT
face="Times New Roman">Results</FONT></A><FONT face="Times New Roman">
(temperatures, flow rates, heat out, efficiency, glazing
temperature)</FONT>
<P style="MARGIN-LEFT: 40px" class=auto-style7><FONT
face="Times New Roman">- </FONT><A
href="http://www.builditsolar.com/Experimental/DeepMeshCol/#Where"><FONT
face="Times New Roman">Where to go from here?</FONT></A>
<P style="MARGIN-LEFT: 40px" class=auto-style7><FONT
face="Times New Roman">- </FONT><A
href="http://www.builditsolar.com/Experimental/DeepMeshCol/#Details"><FONT
face="Times New Roman">More detail in some areas</FONT></A>
<P style="MARGIN-LEFT: 40px" class=auto-style7><FONT
face="Times New Roman">- </FONT><A
href="http://www.builditsolar.com/Experimental/DeepMeshCol/#Puzzle"><FONT
face="Times New Roman">A glazing temperature puzzle</FONT></A>
<P><FONT face="Times New Roman">First </FONT><A
href="http://www.builditsolar.com/Experimental/DeepMeshCol/Nick01.htm"><FONT
face="Times New Roman">comments from Nick on this
test...</FONT></A><BR></P></TD></TR></TBODY></TABLE>
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href="http://www.builditsolar.com/Experimental/DeepMeshCol/120116Test.htm">http://www.builditsolar.com/Experimental/DeepMeshCol/120116Test.htm</A></DIV></DIV>
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size=2 face="Courier New">Nick</FONT></DIV></DIV>
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