| Loren Amelang 2006-12-11, 8:25 pm |
| On Sun, 10 Dec 2006 19:17:50 GMT, Bruce in Alaska <bruceg@btpost.net>
wrote:
>In article <j7fnn2p7oo7nksjg642su1jljpcugaicf8@4ax.com>,
> hchickpea@hotmail.com wrote:
>
>
>Well not quite, You CAN get "Over Unity" in the sense that you can
>MOVE more BTU's than you will expend moving them, BUT you can never
>increase the TOTAL BTU's in the system. Those BTU's that your moving
>have to come from somewhere, and that will be an external input of
>energy into your System.
Which reminds me of the other momentary fantasy I had while
researching this - air conditioning. One of the yacht devices
<http://www.polarpowerinc.com/produc..._cogen_lomb.htm>
has as an option an automotive-looking 28 KBTU/Hr Sanden compressor.
They imply that it can be used simultaneously with the DC charger
function, but don't give any output reduction data. This unit is the
~10 KW engine with 5 KW charger output, so getting 8 KW of heat pumped
shouldn't take all of its output.
The two times I need non-solar power are when it is cold and cloudy
with no sun for a week, and when it is very hot, PV output is reduced,
and the refrigerator and garden irrigation are maxed out. A heat pump
could be handy at both times. For winter, I'd want the heat output in
my hydronic loop, and the cold rejected outdoors. But... I couldn't
easily just switch my hydronic loop to cooling in summer because it is
integrated with my solar thermal panels, DHW, and hot tub. I'd need a
separate fan/coil unit or chiller loop, with pumps and fans requiring
power. And I couldn't absorb the rejected heat into my hot water
system which is already too efficient on hot days, it would have to be
moved outdoors. So both sides of the compressor would need to be
converted seasonally.
The first reference I found suggests one might get somewhere between
0.8 and 2.0 times as much pumped heat as one could get just burning
the fuel. Subtract the energy for the pumps and/or fans required on
both sides of the compressor and the reality of intentionally burning
diesel for heat sounds pretty marginal - at least compared to the wood
it would replace.
Air conditioning alone sounds much simpler and more realistic. Hooking
a compressor directly to a small diesel engine has to be more
efficient than making AC power and running a normal home A/C unit. The
28 KBTU/Hr output would seem comparable with whole-house units. Has
anyone really done this in a remote home? Looks like some truck APUs
are built this way...
Loren
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