Washington Hp Home DIY Geothermal

Discussion in 'Geothermal Heat Pump Testimonials' started by Hp Home, Dec 30, 2015.

  1. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    The issue might be that the inline thermometers are un-precise. You have to use a needle thermometer, and it has to be the same one, keep in mind that if one is 1 degree F off, you might be off by 20%. The same must be said for top mounted buffer tank temperatures, which usually lag behind. The differential is not the delta T!.

    The temp might lag behind and will likely off by a few degrees. So your temp sensor indicates 50F, but your tank is maybe 40F, which means the leaving water t amp might be 35F. In order to get the temp down to 35F, the wall of your heat exchanger might be 28F, and ice starts to form, on the walls of the heat exchanger, indicating a lot pressure and a large pressure drop, which you think indicates a lot of flow, when in reality you have not enough flow.

    I do have enough scar tissue with sensors and thermodynamic inertia, and sensors lagging behind.

    1) Get a needle thermometer.

    Measure temp in and out at the load side. measure flow and temp without the compressor running. Let us know the numbers. What model numbers do you have?

    036 and 060?
  2. geoxne

    geoxne Active Member Forum Leader

    HP Home has a TBW036.

    I don't mean to side track here but I just noticed after careful review of the TBW pressure drop table #8 posted the previous page and published here-

    There is an approximately 2x disparity between source and load pressure drops for the TBW036. Pressure drops for the other sized units show very little difference between load and source pressure drops. It is my experience that source and load HX's on water to water HP's are very similar if not exactly the same. So what is going on here?

    Is it possible the TBW036 has drastically different source and load HX's with different flow characteristics?
    Or are the published pressure drops in errata?

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