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Thread: Could use your thoughts on a solar electric system

  1. #1
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    Could use your thoughts on a solar electric system

    This is a residential application.

    I don't have many details about the equipment involved. My first contact with the customer was to inspect their two furnaces and AC units.

    While speaking with the customer, she said that her monthly electric bills have gone from $350/mo to over $800/month since having the local utility company install a solar array that was tied into the 100 gal. water heater and the forced air heating and cooling system. They have been using a swamp cooler instead of the AC's for the last couple of years.

    I measured amps on all the circuits, and I found nothing more than 1.4 amps on the circuit running the refrigerator.

    Any ideas on what the issue might be, or what additional information might be needed to identify the problem.

    Is there a possibility that the electrical usage could be somewhere after the meter, but before the main panel?

    The customer is not aware of any batteries that might be constantly charging.

  2. #2
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    Frankly, I sense the possibility for a lot of red herrings in what you posted. Here are my thoughts.

    A solar system that is 'tied into' the heating and cooling system does not sound like a solar electric (photovoltaic) system. I would guess that it is either really a solar thermal system of some sort, or that the 'tied into' phrase is not meaningfully accurate and the customer does not know how it really works. A typical grid-tied solar electric system provides electric energy to the entire premises electrical system and once that energy enters through the parallel connection it cannot really be distinguished what it powers vs. what the utility powers. I suppose it's possible that a solar thermal system might have pumps or something that increase electricity consumption. Can't guess what's really going on this way though.

    Is there a possibility that the electrical usage could be somewhere after the meter, but before the main panel?
    Only if there is a circuit tapped into that spot. You're the guy on site, you tell us. And no, it is not possible for the solar system to consume massive amounts of energy.

    Any ideas on what the issue might be, or what additional information might be needed to identify the problem.
    Pretty much you haven't told us anything useful. First thing is to find out the specs of the system. Next question I would ask is whether there is a monitoring system for the solar that records its energy production. Also would need to see the customer's actual kWh energy usage measured at the meter before and after, know the difference in consumption between the swamp coolers and the ACs, find out if anyone moved into the house that might have affected usage, was the meter replaced when they went on net-metering, etc. etc.. Another thing is the electrical rates, since the Nevada legislature pulled the rug out from under solar customers and screwed them out of the savings that they expected when they invested in their solar systems.

  3. #3
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    Quote Originally Posted by jaggedben View Post
    Frankly, I sense the possibility for a lot of red herrings in what you posted. Here are my thoughts.

    A solar system that is 'tied into' the heating and cooling system does not sound like a solar electric (photovoltaic) system. I would guess that it is either really a solar thermal system of some sort, or that the 'tied into' phrase is not meaningfully accurate and the customer does not know how it really works. A typical grid-tied solar electric system provides electric energy to the entire premises electrical system and once that energy enters through the parallel connection it cannot really be distinguished what it powers vs. what the utility powers. I suppose it's possible that a solar thermal system might have pumps or something that increase electricity consumption. Can't guess what's really going on this way though.

    Only if there is a circuit tapped into that spot. You're the guy on site, you tell us. And no, it is not possible for the solar system to consume massive amounts of energy.

    Pretty much you haven't told us anything useful. First thing is to find out the specs of the system. Next question I would ask is whether there is a monitoring system for the solar that records its energy production. Also would need to see the customer's actual kWh energy usage measured at the meter before and after, know the difference in consumption between the swamp coolers and the ACs, find out if anyone moved into the house that might have affected usage, was the meter replaced when they went on net-metering, etc. etc.. Another thing is the electrical rates, since the Nevada legislature pulled the rug out from under solar customers and screwed them out of the savings that they expected when they invested in their solar systems.
    I wasn't trying to be confusing or misleading. I am trying to learn where to look to find answers.

    Is there normally a control of some sort in the attic? I was in the attic inspecting the furnaces, and I didn't see anything unusual other than an electronically controlled damper system for zone controls.

    It was the home owner/customer who believed that the solar system was primarily for the AC and hot water. I didn't find any type of controller near or in the main panel. The water heater had a box mounted to it that didn't have any identifying plate on it. I install water heaters, and I didn't recognize this device. I should have taken a photo. Photovoltaic solar arrays were clearly on the roof. The "tie in" was not by the use of any fluid heat exchanger system.

    I am simply dumbfounded!

    Lennox has condenser units that are marked as "Solar Ready". Their literature states that the energy produced is first used to heat and cool the house. So, somehow this unit receives the power first.

    I'll try to go back to take some pictures. Maybe then you can describe what you see.

  4. #4
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    The most common cause for an increased bill when a grid tied PV system is connected for net metering is failure to properly configure the meter for bi-directional operation.
    The result is that the meter counts up power usage even when the PV system is pushing excess power back into the grid.
    (Simple meters are commonly configured to turn the dials forward even when the disk is spinning backwards, as a precaution against customers who turn the meter upside down in its socket to reduce their apparent total usage for the month.

    Sent from my XT1585 using Tapatalk

  5. #5
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    It has to be the meter being set wrong.
    What else could it be?

    http://www.telegraph.co.uk/finance/p...ake-money.html

  6. #6
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    Quote Originally Posted by David Goodman View Post
    I wasn't trying to be confusing or misleading. I am trying to learn where to look to find answers.

    Is there normally a control of some sort in the attic? I was in the attic inspecting the furnaces, and I didn't see anything unusual other than an electronically controlled damper system for zone controls.

    It was the home owner/customer who believed that the solar system was primarily for the AC and hot water. I didn't find any type of controller near or in the main panel. The water heater had a box mounted to it that didn't have any identifying plate on it. I install water heaters, and I didn't recognize this device. I should have taken a photo. Photovoltaic solar arrays were clearly on the roof. The "tie in" was not by the use of any fluid heat exchanger system.

    I am simply dumbfounded!

    Lennox has condenser units that are marked as "Solar Ready". Their literature states that the energy produced is first used to heat and cool the house. So, somehow this unit receives the power first.

    I'll try to go back to take some pictures. Maybe then you can describe what you see.
    No offense intended but it seems to me that someone with more experience in dealing with PV systems should be assessing the effects of solar electricity on the customer's electric bill. Judging from the questions you have posted I have some doubts that you understand what you are looking at. Solar is not that complicated, but dealing with it does require some specialized knowledge and expertise.

  7. #7
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    Quote Originally Posted by David Goodman View Post
    since having the local utility company install a solar array...
    This might sound nuts, but is the meter even running?

    Check out the 7th complaint down from top-
    https://www.consumeraffairs.com/util...nv_energy.html

    Your state is not the most solar friendly- it may in fact be the least friendly.
    http://www.greenbuildingadvisor.com/...-metering-rule

  8. #8
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    Quote Originally Posted by David Goodman View Post
    Is there normally a control of some sort in the attic?
    No. Not for a PV system.

    It was the home owner/customer who believed that the solar system was primarily for the AC and hot water.
    It may have been installed primarily to cover that energy use, but that does not mean it there is any special tie in to those appliances.

    I am simply dumbfounded!
    ...
    I'll try to go back to take some pictures. Maybe then you can describe what you see.
    If it's a PV system, follow the wiring from the solar array on the roof. You're either going to find it directly tied into one or more breakers somewhere (micro-inverters), or you're going to find an inverter on a wall and then a second conduit going to a breaker somewhere. You can measure voltage on that breaker circuit just like any other to find out if the system has a proper hook up.

    ...

    Goldigger's guess seems like a good one. If the system was intended to bring the customer's bill to zero and instead her bill doubled, then what he suggested makes a lot of sense.

  9. #9
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    Quote Originally Posted by ggunn View Post
    No offense intended but it seems to me that someone with more experience in dealing with PV systems should be assessing the effects of solar electricity on the customer's electric bill. Judging from the questions you have posted I have some doubts that you understand what you are looking at. Solar is not that complicated, but dealing with it does require some specialized knowledge and expertise.
    No doubt. This is not my area of expertise. That is why I was trying to get some help here to guide my customer.

    Part of my confusion was that the customer insisted that the solar system was photovoltaic and connected to the power grid. I didn't see anything that supported that possibility.

    It turns out that the solar panels are in fact just for a glycol heat exchanger for the water heater.

    Still no explanation of the high electric bills. The meter number on the customer's bill matches the "smart" meter outside.

  10. #10
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    Quote Originally Posted by David Goodman View Post
    No doubt. This is not my area of expertise. That is why I was trying to get some help here to guide my customer.

    Part of my confusion was that the customer insisted that the solar system was photovoltaic and connected to the power grid. I didn't see anything that supported that possibility.

    It turns out that the solar panels are in fact just for a glycol heat exchanger for the water heater.


    Still no explanation of the high electric bills. The meter number on the customer's bill matches the "smart" meter outside.
    There you go, pretty much what I said in my first post. Congrats on figuring it out.

    Also I said this: "...it's possible that a solar thermal system might have pumps or something that increase electricity consumption." Or, is the new water heater electric, and the solar is only covering part of the heating need? I would say it's either something like that, or something totally unrelated, like their kid coming back from college.

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