答复

1. GBA Editor
   马丁·霍拉迪（Martin Holladay）|5月27日, 2016 10:52am|#1

   院长，
   The most obvious way to reduce your equipment cost would be to buy just one Marathon, not two. Why do you need to install a Marathon heater directly beside the heat-pump water heater?

2. 
   Ven Sonata|2016年5月27日上午11:48|#2

   院长，
   I am in the same situation, 80 feet to two bathrooms with showers and sinks. My thoughts follow similar to yours however.... The heat pump water heater is noisy so it must be isolated in the mechanical room. But waiting for hot water becomes an exercise in patience, doesn't it? So a point source electric only heater is necessary. On demand uses too much peak power and requires rewiring so that is a write off. The question comes down to the size of the tank being fed at a distance by the heat pump tank. I suspect that even a 3-5 gallons storage tank is adequate. The long line empties into the small hot tank and the line attains full heat since there is only 1.5 gallons in the line. The hot water from the heat pump merely passes through the small point source heater then. So it is not necessary to have a large expensive remote heater at all. The little tank does the same job better.

3. 
   里德·鲍德温（Reid Baldwin）|5月27日, 2016 11:52am|#3

   It depends upon how much of your hot water demand is in short draws. Suppose that your HPWH uses 1/3 as much electricity as your Marathon to heat a given amount of water. For simplicity, assume your cold water supply is near the same temperature as your interior air. For a draw of less than 1 1/2 gallon that is not close in time to another draw, your setup uses 1/3 more electricity because both water heaters have to heat the water. For a long draws (but less than 80 gallons), your setup approaches 2/3 less electricity.

4. 
   Charlie Sullivan|2016年5月27日下午12:23|#4

   It depends on the usage cycle. If were dominated by handwashing and short bouts of dishwashing most of the heat that the heat pump puts in would get lost from the 3/4" line, so you'd be better off feeding that remote marathon with cold water directly. On the other hand, if it's mostly longer draws, the 1.5 gallons in the line is a small fraction of the total water drawn each use, and you'd be better off feeding it from the heat pump water heater.

   您可能处于不清楚的边缘 - 一个真正好的洗碗机可能只使用三加仑。如果我正确地进行了数学，则用热泵加1.5（坐在管道中）加热3加仑的马拉松比赛，使用与马拉松一起加热3加仑的能量。但这是假设房屋中的环境温度与进入的水温相同。如果您处于寒冷的气候，那是不正确的，因此这会使您的计划看起来更具吸引力。

   我怀疑远程坦克需要是50加仑。将1.5加仑的室温水倒入一个位于130 F的20加仑水箱中，即使在流动过程中没有主动加热，也只能将其降低至125.5 F。如果这似乎有问题，则输出或淋浴控制上的恒温阀应照顾好它。然后，您需要更少的空间，并且待机损失较低。

   I am guessing that you are using the extra tank next to the heat pump because you have the heat pump set to never use resistance heat, and you want the marathon to recover faster than the heat pump's tank recovers using just the heat pump. Whether that saves energy compared to just using one of the heat pump water heaters combined heat-pump/resistance heater modes depends on usage cycles, and of course on the control strategy the HPWH uses to decide when to use resistance heat. So it's hard to say whether it's a good idea.

   与获取热水使用周期的数据相比，获取天气数据来评估信封和加热系统的选项要容易得多。在一个地区，从家庭到家庭的差异对于热水的使用更多。因此，即使通过详细的建模，也很难以极大的信心预测不同方案的影响。

5. 
   Dean Sandbo|May 28, 2016 12:11am|＃5

   I am definitely getting into the weeds here for sure... Is there any way to determine what kind of standby loss is in the 3/4" insulated pipe filled with 1.5 gallons? because that is really the only downside right? I imagine if an hour later the sink is run again... could that water still might be 90 degrees or so? which will take much less energy to heat in the marathon?

   还是我只是在房屋远端再循环。..

6. Expert Member
   Dana Dorsett|2016年6月3日02:23 pm|＃6

   该图像最初是在网站上，是在不同管道绝缘值的饮用水系统中温度测量的结果：

   http://www.terrylove.com/images/pipe_cooling.jpg

   Clearly with R2 you have maybe 15-20 minutes before the hot water is too tepid to be useful for many applications, and at R4 that might stretch to 30 minutes before it drops below 90F.

   当前代码最小是R3。

   No matter what, after a full HOUR in a ~60F basement the residual temp of the water isn't a very useful for most hot water purposes, and nowhere near 90F.

   该文章可以存档在网络空间中的某个地方，现在已停产的网站已出售，想要吗？:-)

   http://www.leaningpinesoftware.com/hot_water_pipes.shtml