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Reconciling Models with Actual Usage for Existing Homes

  • 22 Jun 2022 11:56 AM
    Message # 12825304
    Anonymous

    Just wondering if any of the EAs on the forum who do work with existing homes might have some input on trueing up Hot2000 models to actual usage. I'm having some difficulty getting the model to accurately reflect what the house is actually doing, particularly in regards to hot water energy consumption. Is this something that can be done/people are doing with Hot2000 through baseloads/setpoints, etc? 

    On a related note, does anyone have some feedback on using RETScreen for this type of stuff on single family residential?

  • 29 Jun 2022 1:02 PM
    Reply # 12832941 on 12825304

    Hi Andreas,

    I've done this before, and am about to take on similar project for a NZ house. First of all you'd have to use General mode. Then you can adjust the # of occupants, temperature setpoints, appliance kwh/y, etc...

    The other main thing to do is look at their gas or electricity bills in the spring/fall/summer only to see if you can distinguish the HW baseload independent of the heating and cooling.

    If you are still not getting close then you may have to normalize the utility data to the HDD and CDD so that it's more representative of the average weather which is what Hot2000 uses. Here is a link to help you through that process. https://www.abraxasenergy.com/articles/intro-weather-normalization-contractors/

    Good luck and maybe we can have a chat in a couple weeks when I've had a time to work on my project too - or sooner if you need to.

    Toby Smith 226 218 2532 toby@buildingknowledge.ca

  • 4 Jul 2022 9:09 AM
    Reply # 12837495 on 12825304
    Anonymous

    Hey Toby,

    Thanks for the reply and the link, I'll have to check that out. I've managed to get half decent at disaggregating energy bills for the space heating and DHW usage, and hoping with a couple of Emporia monitors out in the field now, to dial it in a little more on some of the messier all-electric houses around here. For whatever reason, even with hot water usage reduced beyond realistic levels, I've been having some issues getting the gas usage right when it's natural draft equipment, so I'd be interested to get your input on that.

    I'd love to have a chat and hear about your net zero project, when you do get that wrapped up, and discuss things a little further. I'll send you an email with my contact details.

    Andreas

  • 5 Jul 2022 3:56 PM
    Reply # 12838935 on 12825304

    Does this gas hw home you're talking about have any other gas uses? I would probably allocate more of it to the space heating. Pool heating?

    I've also seen on one project where the homeowner would use their 60-70% efficient gas fireplace to heat up their kitchen/living room every morning instead of their furnace or heat pump. Their gas usage was way more than we were expecting.

    Looking forward to chatting further.

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