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Is your lake/well loop sizing option set to "Secondary" or "Primary".
I don't actually remember if this matters for lake/well loops, but if
you input a capacity for the heat pump and set to "Primary", the
program should size the flow based on the heat pump's capacity and the
dT across the condenser. You can also adjust the loop size (flow) with
the LOOP-SIZING-RATIO<br>
<br>
A few other things to consider:<br>
<br>
1) If you have a heat exchanger with the ground loop, it is probably
best to account for the approach of the HX with the lake/well supply
temp. The default temp of the loop is the ground temp included in the
weather file, which varies on a monthly basis rather than constant all
year. You can create your own schedule based on the weather file temps
that includes an approximation of the HX approach...<br>
2) Is your HP really a loop to loop? I have seen projects that attempt
to use this type of chiller when really it is a series of
water-to-water HP manifolded to provide simultaneous hot and chilled
water. These are very different systems...<br>
2) Regardless, I would recommend getting performance data for your heat
pump to generate your own performance curves, as the default curves are
quite dated. <br>
3) Once you have done step 2, check hourly reports to see if can
compare some part load conditions in the simulation result with those
reported by the manufacturer. This can be difficult, but is about the
best way I can think of to know if the simulation of this type of
equipment is reasonable.<br>
<br>
<pre class="moz-signature" cols="72">David Reddy
360 Analytics
Building Energy Analysis Consultants
mail: 12354 16th Ave NE, Seattle, WA 98125
phone: 206.406.9856
email: <a class="moz-txt-link-abbreviated" href="mailto:david@360-Analytics.com">david@360-Analytics.com</a></pre>
<br>
On 6/2/2010 3:01 PM, jacob goodman wrote:
<blockquote cite="mid:4C06D4AF.5020600@lseng.com" type="cite">
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I'm working on a system that uses an open loop ground well tied to a
loop-to-loop heat pump (see screen shot below) with Lake/Well loop type
and GSX type. This heat pump serves hot and cold water loops tied to
fan coils. The "ground temp" is water being pulled out of a deep
aquifer and set to 50 deg year round.<br>
<br>
I have gotten the model to run without errors, but I am getting very
high pump energy use from the ground loop. The head and pump sizing
seem high but reasonable, but the flow seems way too high. I'm getting
540 gpm peak and was expecting closer to 300 gpm. This results in 18%
of electricity use going to pumps, 17% going to heating and cooling
combined.<br>
<br>
Any suggestions?<br>
<br>
<img src="cid:part1.04030608.06070406@gmail.com" alt="" height="386"
width="482"><br>
<div class="moz-signature"><br>
<span
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Jacob Goodman
</span><span
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LEED
AP, Green Building Specialist
</span><br>
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v:509.280.7051 i:<a moz-do-not-send="true" href="http://www.lseng.com"
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color="#666666">www.lseng.com</font></span></a></span><br>
<span
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L&S
</span><span
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Associates,
Inc.
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<span
style="font-size: 8pt; font-family: Arial; color: rgb(102, 102, 102); font-weight: normal;">'High
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Design'</span>
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