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是的，在明尼苏达州的热泵工作。。。也是阿拉斯加，佛蒙特州和安大略省。今天我会告诉你明尼苏达州明尼阿波利斯的一个特定房子，这是在过去的四个冬天的热泵中加热。这是Gary Nelson，创始人的家The Energy Conservatory，这使得明尼阿波利斯鼓风机门和用于测试房屋和管道系统中的空气泄漏的管道间谍。
First, fix the building enclosure
正如您可能期望从过去几十年所花费的人量化渗透率，那么尼尔森的房子很漂亮。他在同一个房子里住了很长时间，并且在2017年11月的2017年11月搬回了这座房子的大量装修，已经努力了。
这是机箱的当前状态：
- 渗透率：每小时1个空气变化，50帕斯卡（ACH50），500立方英尺，50帕斯卡（CFM50）
- 墙壁：R-30至R-40
- 天花板：R-50
- 地板：旧零件中的R-0，R-20带有泡沫的加法下
- Windows：三重窗格，氩气，三个低E涂层
The result of improving the enclosure so much is that the heating load is very low. He didn’t do a formalload calculation，但他确实知道在装修之前他使用了多少热量。然后，他的加热系统由北极星热水器（化石燃气烧制）和空气处理器组成，以分配热量。他发现，当室外温度为-10°F时，系统几乎连续运行99% design temperature, and the amount of heat he got from the water heater was 17,000 BTU/hr. Then he calculated that the load reduction from his enclosure improvements would be offset for the additional load from an addition that was part of the renovation, so he figured he needed a heat pump with a capacity of 18,000 BTU/hr.
因此，他放入富士通管道的热泵，其容量为18,000 btu / hr。而且因为他了解热转印和明尼阿波利斯天气，他将这种热泵置于没有辅助热量。真的！
Heating performance
Winter 2017-18: This was the first winter after the renovation, and the low in Minneapolis was -15°F. The system performed very well. Even though the outdoor temperature went 5°F below their design temperature, the 18k heat pump held the house at the 72°F setpoint.
2018-19冬天: The outdoor temperature got down to -27°F. The house temperature got down to 62°F but they were away in Australia at the time. Nelson told me that if they had been home, they probably could have gotten the house up close to the setpoint with their body heat and by baking some cookies.
当然，尼尔森措施和记录一切，所以他也知道热泵泵送的热量以及有多高效。在-27°F冷鲷期间，他计算出热泵容量为8597 BTU / HR（2.52千瓦），功耗为1834瓦（W）。性能系数为2.52¼1.834 = 1.37。相比之下，电阻热量具有1的性能系数。
When the temperature rose to -17°F, the heat pump output rose to 13,000 BTU/hr and the power consumed to 1959 W. The resulting coefficient of performance was nearly 2, or double what electric resistance would have provided. (And to think that some HVAC techs tell people toswitch to emergency heatwhen the outdoor temperature drops into the 30s°F!)
2019-20冬季: He had nothing remarkable to report. They didn’t have any weather cold enough to call for any kind of auxiliary heat.
冬天2020-21：这是另一个冬天，测试了他跳过辅助热量的决定。这是他写信给我的：
冷却性能
纳尔逊的热泵是f大小几乎完美or heating. In a place like Minneapolis, that means it’s oversized for cooling. Minneapolis does get humid, too, and the result is a house that can stay at the setpoint temperature easily but doesn’t get dehumidified enough. After two summers of dealing with muggy indoor air, he installed an Ultra-Aire dehumidifier in the summer of 2020. As a result, he “enjoyed much better humidity control” during the cooling season.
Yes, heat pumps can carry the load in Minnesota
Gary Nelson是一个聪明的家伙，知道如何计算传热。他了解他家的供暖需求。他可以阅读和应用热泵性能的规范。他在过去的四个冬天中被证明在他的家中，即热泵在寒冷气候中工作很好。他的热泵靠近加热负荷，甚至安装了系统而无需任何备用热量。是的，他需要一些补充热量，以为一个不寻常的寒冷，多云的天气，但他使用的40千瓦时可能会增加约5美元的电费。
如果您完成作业，没有理由在寒冷的气候下安装热泵。由于纳尔逊已成为尺寸，您不需要作为保守派，因为纳尔逊，您可以获得安装的辅助热量，以覆盖那些使热泵难以供应所需的热量的稀有天气事件。
使用热泵是一个很好的主意，特别是如果你更换气体加热系统。与化石瓦斯不同，电力越来越清洁all the time.
______________________________________________________________________
Allison Bailes佐治亚州亚特兰大，是一位发言者，作家，建筑科学顾问和能源先锋的创始人。beplay体育官方下载他也是作者的能源先锋博客并且是writing a book。You can follow him on Twitter at@energyvanguard.。
43 Comments
Good article, looking forward to the new book so I can place it next to the Sigenthaler books and the Manual J. Curious to know what is used for the DHW. The new air to water heat pumps can cool, heat and produce DHW. Water for heat only needs to be 83 to 103f, so DHW at 120F would require more BTU.
Bill, Gary has a GE GeoSpring heat pump water heater, which you can see behind him in the photo above. GE has since stopped producing it.
感谢您的客气话！
>是的，在明尼苏达州的热泵工作
有些人，许多冷却时关闭。随着备用电阻热的广泛采用，对网格的负面影响将使夏季峰值负荷看起来微不足道。
> he also knows how much heat the heat pump was pumping
How does he know? It's not like measuring the heat output accurately is easy.
> -17°F, ...The resulting coefficient of performance was nearly 2
There are various models, but looks to me like Fujitsu measured a COP of 2.0 at +5F (NEEP). So COP = 2 at -17F sounds wildly optimistic.
Jon，Gary他的热泵连接到大量的电线和管，以监测温度，压力和相对湿度。他有一个永久安装在系统中的能量保守型Trueflow。当您知道空气流速，温度变化和湿度变化时，计算产生的热量是直截了当的。
My particular mini split was 1.3 at those temps. Now, that's a senville unit, so not as good as Fujitsu. However, when the temps dropped below zero, the system went from around 600cfm to around 400. I made the mistake assuming airflow was the same at below zero temps, and after correcting the mistake, cop went from 2 to 1.3.
>“... Cop = 2在-17F听起来很乐观。”
Agreed, but "...nearly 2... " is what it being alleged, not "... COP=3..." .
The "...nearly..." part is subjective- a COP of 1.5 would qualify in some peoples' minds, 1.8 (still a credible number for best in class air source heat pumps) in others'.
Jon＆Dana，我应该从一开始就把实际数字放在一开始，但我确实包括您可以使用的数字来计算-17°F的警察。
Output = 13,000 BTU/hr x (1 kW / 3,412 BTU/hr) = 3.81 kW
输入= 1,959 W = 1.959 kW
COP = 3.81 / 1.959 = 1.94
So, nearly 2 means very close to 2.
Now, whether that's correct or not is another matter. Gary did tell me, "This seems pretty impressive. I believe Manufacturer’s data only go down to -5 and my data agree pretty well with theirs at -5 and above."
Would be nice to see much more of the collected COP data. Including the exact model #, so we can find the manufacturer’s data.
Can the few COP points that manufacturers list be accurately linearly extrapolated for lower temps? The data here suggests a suspiciously different COP degradation slope from 5F down to -17F vs -17F down to -27F.
别忘了，62F室内温度的加热容量远远大于72F的容量，就像我想象的效率一样。太糟糕了，没有人坐在62F的房子里。:)
新时代热泵可能只是我们需要突出非常有效的建筑信封。这真的对自然气体网格的房屋进行了经济意义，其中有许多Mn。在Mn中添加了如此多的风力，并且对于可预见的未来，ND和SD电费可能是稳定的。
My 99% design temperature is a comparatively balmy 0°F. We've never had an issue over six winters with our Fujitsu heat pumps keeping up with cold weather. I'm surprised that the COP is as high as reported at very low temperatures, but it sounds like he's pretty organized about data collection. And even if some supplemental heat is needed once in a while, it's no big deal.
Obviously, the key is a robust, efficient envelope because it allows you to cruise through the occasional cold snap without interior temperatures dropping much.
如果他正在运行烤箱来为房子产生热量，因为他的加热系统在没有击中设定点的情况下跑了4天，所以它真的感觉他应该安装奥克斯热量。
电烤箱备份的唯一缺点是其手册。如果他们不是在家，如果它不能达到设定点，那就关心谁，只要事情不冻结？热泵必须完全失败，以发生这种情况，如果所有者离开时，Mn中的每个其他家庭都会运行相同的风险。
> he should have installed aux heat
或者可能是一个较大的四端热泵，因此可以完全满足冬季负荷，夏季可能不需要除湿器。
Always do a proper Manual J/S.
>>经过两次处理摩根室内空气的夏天，他在2020年的夏天安装了超航站器除湿机
我知道我很疯狂地过度简化，但除湿ifier基本上是一个带有微小风扇的ac。对这种情况的交流提供了不寻常的情况。我觉得在交流中沿着设定值掉下来，然后手动设置风扇速度非常低[带走其到达设定值的能力]应该工作。
I say this many times in the questions, that people kind of expect the minisplits to just 'work' but they are just manufactured items, they do not understand the conditions around them. Using them for AC I tend to leave the setpoint and manage comfort with the fan speed. Sure it would be nice if the auto setting was perfect, but until they get 50:1 turndown ratio and wifi integration with the National Weather Service, we may have to deal with occasionally hitting the button on the remote.
如果我将22k三菱到自己的设备，我有时会醒来到一个穆加密的客厅，终于放弃并在半夜关闭了压缩机。如果我将粉丝设置为低电平，我必须记住在早上或下午中期转动它无法跟上。
同意，流行且错误的看法是过大的AC提供较差的湿度控制（与右侧和尺寸的热泵相比）。但它几乎完全是关于CFM / TON的。得到正确的，甚至2x过尺寸的逆变器热泵工作正常。
Jon R - 只是想补充一点，我经常在与AC设备和除湿相关的线程上看到您的评论，我很感谢您对此事的看法。您与（佛罗里达州的一些装备）相关的实地研究是有用的，但超越了我的肯，你做了很好的简化它。
我现在住在4C的地方，我不必考虑除湿化，但是当我的妻子让我恢复南时，我可能会逼你的建议！
最大限度，
我同意。我已经从Jon涉及湿度和压力差异来学习了很多有用的东西。
That's because that rule applies to fixed capacity systems, not variable capacity.
你能指出关于右上尺寸CFM / TON的更多信息吗？
I'm struggling with this exact question right now trying to size a ducted heat pump for the house we're building in Zone 6. Installer wants to go bigger so the heating is right sized, I'm inclined to go small so the AC is right sized and use the wood stove as needed. But if the larger unit will work just fine for cooling then that would be great.
A dehumidifier is different in that it doesn't cool the space. It's not just about fan speed. If the load is 100% latent, then A/C alone probably can't manage the humidity. My heat pump is matched to both peak heating and cooling loads. I still can't keep the humidity below 60% a lot of the time, no matter what settings I use on the heat pump.
Can't recall if Mitsubishi units can measure humidity. Only one carrier midea unit I know of can.
Realize the more your unit focuses on humidity removal, the more energy it will take and efficiencies nosedive. Also, you'll have more moisture inside and more chances for mold buildup. That's why they try to not do that. To remove humidity, the unit has to generate low refrigerant temps by high compressor speeds and run near 0 superheat.
很高兴看到像明尼苏达州的寒冷地区的性能结果，但是在温尼伯，MB中的1个气候区的类似系统将如何在1个气候区域中进行。有什么洞察力？
温尼伯的设计温度约为-33C。这是任何住宅热泵的运行范围。但是，请记住，平均年仅1％的时间将在该温度下或低于该温度。一个好的，冷的气候热泵仍将处理大部分加热载荷。补充热量将是一个好主意，在无法跟上时覆盖时间。
Hi Trevor
我目前在北部修建两个小房子n BC that are using Arctic heat pumps out of Winnipeg. They say that at -20c they have a COP of 1.7. In addition as a backup system for below -25, I'm using a storage tank with an electric boiler build in, again supplied by Arctic. The hydronic hot water is heating the house, preheating the domestic hot water and heating incoming kitchen exhaust make up air all from the storage tank.
Neilt，
I'm in Northern Minnesota, -30C/-22F design temp. We have a house that's been up an running on a Mitsubishi central ducted system (one of the PVA Multi-position air handler heat pumps, 24,000 BTU) with an integrated electric plenum heater for the past two winters. During this past winter's polar vortex, where temps didn't get above -18C/0F for nearly 10 days, the homeowner said temps never dropped more than 2 degrees below the setpoint in the home. They said there was a slight lag between the ASHP cutout temp and the electric plenum heater, but no major comfort issues.
我们使用ASHP的问题是室外单位下方的大量冷凝。三菱表示这不是正常的，但这是发生的两种冬天，它一直在运作，这是一个不必要的条件，我们将要解决。
Randy,
The house you are referencing is highly insulated and very airtight. Just as is Gary Nelson's house (from retrofit) in Minneapolis. To get good results from cold climate heat pumps in MN the building envelope will have to be high performance.
谢谢，伟大的信息和提醒“电力正在变得更加清洁”。是否有机会知道SQ FT和CU FT以及它是单一级别还是多级房屋（以了解外表面积的想法到SQ FT / CU FT，脚印等）和附加车库？（我懒得从500立方英尺每分钟在50麦克斯人中退出Cu ft，但也许我会把它放在一边，像1 ach有500 cu ft / min = 60 min / hr x 500 cuFt / min = 30,000 Cu ft为1个空气变化一小时，因此30,000 Cu Ft内部体积，假设10英尺的天花板产生3,000平方英尺的房屋？）18,000 Btu / h在明尼苏达州3,000平方英尺3,000平方英尺？
> 50个Pascals 500立方英尺
AFAIK,刮风的一天(20英里/小时)可以背包e 50 pascals across roughly 1/2 of the house. So say 250 CFM and that it's a mild 0F outside. That's 19,440 btu/hr for the infiltration load alone. Then switch on a kitchen exhaust fan and double that...
I'd want to see a lot more data from Nelson's house before forming any conclusions.
Hmm, so have the blower door test on a calm day ;-) Or, have multiple blower door tests under multiple wind conditions to see impact of wind on things like sliders, maybe an argument for the aerodynamic passive house, on a spindle to always point into the wind.
有趣的是，这种情况和评论中讨论的案件所有使用的管道系统。我将预期的导管是这里的首选（和更好的表现）系统。有什么想法吗？我正在考虑哈德森谷（东海岸 - 4/5区），并正在努力假设导管是实现Subxero Temp性能的唯一途径。
Dave,
我对此不太了解。你可以肉体肉吗？为什么没有管道会影响寒冷的天气性能？
Everything I've seen indicates that ducted mini-splits and ductless mini-splits are similar in performance. Just a little more energy to move air around.
你在导管中失去了能量，但如果它在生活空间中可能没关系。否则，您的系统会使线套越长。
I'm definitely not an expert here, which is why I phrased it as a question. But besides the inherent losses you'll find in even the best ducted systems, the HSPF and SEER ratings of mini-splits are much higher than central (ducted) heat pumps. It's pretty hard to find central heat pumps with HSPF of 10, which is required to be a certified Cold Climate Heat Pump. The HVAC contractors I talked with all said this as well (don't always trust what they say though). Anyway, I would love to hear if anyone has researched information on this.
It's an interesting question. Luckily just an academic one for me as our climate here is so temperate.
If you go to the NEEP database:
https://ashp.neep.org/# !/product_list/
您可以找到充足的数千个千分之一 - 具有Hspf> 10的中央管道模型，有些> 12。
[还发布在问答]：如果明尼苏达不需要辅助电热，我甚至需要在新奥尔良安装热带吗？这减少了加热灯丝的75级成本，更重要的是，即使是4.5kW的热带也会耗尽电池备份系统的速度。NB：运行电烤箱似乎是作弊。
与Q＆A相同的答案：对您来说，拥有它们的唯一原因是，如果您的热泵机械故障 - 在压缩机中或制冷剂泄漏 - 热带可以以高电平的成本，保持在等待服务时，房子温暖。但他们也可以错误地踢出自动踢，如果有控制失败，可以使用大量的能量。我要么安装它们并留下断路器，需要在您的部件上进行手动操作以在紧急情况下激活它们，或省略它们。
>"For you, the only reason to have them is that if you have a mechanical failure of your heat pump--in the compressor or perhaps a refrigerant leak--the heat strips could, at high electric cost, keep the house warm while you wait for service."
The other reason for strip heat is for comfort during defrost cycles. It's a common feature in ducted heat pumps to engage strip heat during defrost to avoid blowing tepid/cold air out the registers.
但是4.5千瓦（约15,000 btu / hr）的条带热量足以覆盖大多数代码的实际设计热负荷或比洛杉矶的代码房屋更好。在热泵条带控制和热带本身之间安装开关，以便在热泵失败时能够启用它，而不是巨大的成本加法器。
Have the heating and cooling loads of this house in New Orleans been carefully calculated with a Manual-J? Most AC and heat pumps that get installed are way oversized for the actual loads, and installing a right-sized modulating heat pump could be the best of all worlds, even without strip heat during defrost.
查理：我在楼上（卧室）单位上有发热条，所以如果我在等待压缩机修复的同时，我就不会冻结。
达纳：我没有想过在除霜周期中使用电热条！近在咫尺，近一点，那些只是冷天气A / C循环与压缩机扇子，如果条带截止，它会在内部吹风空气，并且我将当前的空气保持关闭。我想我会在除霜循环期间避免冷空气楔子。如果我们切换到电池备份，我总能锁定它们......如果我醒了。
Manual J will be done once I've settled on a contractor. They ballpark a tonnage for the free estimates, but the two finalists both say they will do the full calculations. They know I know.
那位警察令人印象深刻，我在这里没有比-17f低得多，所以我会得到大约2.0或更多。这包括鼓风机吗？如果是这样，是一个独特的空气处理程序和什么样的规格？
我通过整个文章寻找的一件事是富士通的型号。我错过了吗？我不能成为唯一一个想知道的人。
我带着一粒盐。假设它是1.37。我说，因为可能在那些温度下减少实际空气流量。此外，在那些瞬间，压缩机必须真正努力工作。
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