A combination of geo and air to air!
Hello,
I have a very newbie question. I was exploring geothermal using shallow pit geo. However, in Southern California, the ground temperatures don’t really make sense for such a system. The efficiencies are not too different than air to air.
我们家里有一个大的爬行空间。它永远不会比75度更温暖 - 我在去年秋天的最热日之一检查它。房子的一半，在山上的上行中没有通风口到外面。这个爬行空间的总平方英尺约为1,000平方英尺。我可以将压缩机放在房子西侧的门廊下。使用短的管道或更相当的压力大小管道，我可以从家庭爬行空间的这一侧引导空气，这些爬行空间会在房子的北侧进入。随着房子西侧到东部的爬行港口被门挡住，热泵将仅在房子北侧汲取空气。土壤将保持压缩机冷却器的进气温度。房子下方的额外绝缘将使地板更加温暖。
这里各种各样的未知。但是，我猜想爬行空间会在夜间重新获得大部分酷景。东部墙上没有暴露在阳光下。它在地下很好。当温度低于80度的温度低于80度时，可能会运行慢的风扇，这夜晚通常在我们的干旱地点做。
现在我想知道这是否只是纽伯愚蠢，或者线圈上的空气真的在运行时的较低温度下进入吗？
Thank you for your patience!!!
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Replies
>"The total square footage for this crawlspace is about 1,000 sq. ft."
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>"The soil would keep the intake temperature of the compressor cooler."
That's a common misconception, usually from people who don't do math (or understand much about thermal physics.)
A 1000 square feet of insulative dirt isn't a very good heat exchanger for tapping the thermal mass of the subsoil for heat pump blowers churning through 1000+ cfm. Even the crawlspace were 4' tall (4000 cubic feet) just about all 3/4 ton mini-splits would be driving 15+ air exchanges per hour, bigger minisplits would drive even higher ACH. The temperature in the crawlspace would quickly rise to something VERY close to the outdoor temperature, and the cooling/heating contribution of that soil heat exchanger would be "in the noise" from a measurement point of view, well under 1% (probably less than 0.01%) of the total whenever there is a real cooling or heating load.
That's what I wanted to know. Now I know that digging a ditch for geo would be a waste of time and money and bringing air through my crawlspace would be ineffective at best. Air to air for me! Thanks!
Well, since I have your attention, here's a trickier one. Our house has a couple of 4x6's that are visible in the crawlspace. They presumably extend from the foundation up to the double top plates of the upper floor. We know that the owner/builder had in mind putting more fenestration in the outside wall upstairs, but decided against it because they chose to put in single glaze windows instead of double - this limited their total window/door area to pass California codes (1984). Could these 4x6's be there as a structural solution to satisfy codes for structural integrity if they decided to put in another sliding glass door? We also discovered a steel member in that wall upstairs, a heavy steel stud. We'd be pleased to put in more windows/doors in the wall but have thought that it takes a very heavy duty steel structure to make that happen.
Thanks again!