GSHP and PV using eQUEST

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Are there any sample input files that show how to use the PV input forms, explain what the input fields mean, and how the results are calculated? Has the eQUEST PV analysis and results been checked with other PV programs?

Attached are results for a building that has PV and GSHP. The .inp and .pd2 files are in the zipped folder. The building model is a simplified layout of the CCGT building that was awarded LEED Platinum. The questions are in italics (PV in red and GSHP in blue). The options to look at are 4 and 4a (PV Surface and Shade Mount) and 5 and 5b (GSHP 200'-8x4 and 100'-2x2).

ECO-3 shows the electric energy for lights, equipment, cooling and fans.

ECO-4 added PV panels tilted at 30 degrees on the south window shades and on the roof. How did the program determine the reduction in electric energy?
ECO-4a attached the PV panels of the same area to fixed shade. Why did the electric energy use go up?

ECO-5 added GSHP ? 200? deep and 8 x 4 configuration. The lights, equipment and cooling load electric use goes down. The electric use for pumps and fans go up and so also does the natural gas use for heating. What is the explanation?
ECO-5a changed the GSHP to 100? deep and 2 x 2 configuration. Why does this smaller system save more energy?

What are the different types of PV systems? For this study I entered MC-SI. What do the terms below mean and what should be their typical or default values (my dumb guesses are shown in parenthesis)?

VOLTS-OPEN-CKT (= 110)
VOLTS/T-OPEN-CKT (= -0.004)
AMPS-SHORT-CKT (= 10)
AMPS/T-SHORT-CKT (= -0.001)
VOLTS-MAX-PWR (= 75)
AMPS-MAX-PWR (= 5)
MIN-TRACK-VOLTS (= 0)
MAX-TRACK-VOLTS (=110)

The original analysis was with DOE2.1E which does not have PV analysis. The study assumed that the light energy corresponds to the solar energy and about 10% of the direct solar energy was assumed to be converted to 110V electricity.

I have sent this message before and received no response. Has anyone used the eQUEST program?s GSHP and PV analysis for energy code compliance and LEED certification?

Varkie Thomas's picture
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Joined: 2011-09-30
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Varkie,

I have used eQUEST for the GSHP and found that it oversizes the CW loop where it is working with a very low delta T (2F) and hence had a high pump energy component. I tried to solve this by undersizing the loop to get a higher deltaT and at that point got almost 1/4th the pump energy. I dont know if others have faced this, it would be great to hear about other solutions to this.

'thanks
Amarpreet

Sethi, Amarpreet's picture
Joined: 2011-09-30
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Varkie,

Relative to the PV panels, you should be able to get this information from the manufacturer.

For example ? this is from a Kyocera cut sheet:

The eQUEST help file gives you some guidance for the input values when you right click and go to item help:

I have used this and compared it to RETscreen outputs and found them to be in the same ballpark.

Vikram Sami, LEED AP

Vikram Sami's picture
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Joined: 2011-09-30
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