地源冷却 - 没有热泵？
我一直在阅读很多问题和评论的地面源热泵的不同变体，我一直在踢一个想法，而这可能是非常规的，因为我还没有看到它尚未提到。
My requirements may be unconventional as well, as I am interested in comfort, more that cooling, and a solution I am interested in needs to minimize its affect on the original fabric of our 1928 brick Colonial. Which I will explain.
我们的1928年殖民地是一个木制成身家，在两门砖课程中包装。它保留了99％的原始石膏墙。它保留了原来的木制窗户，它与复古互锁天气剥离相当好，这意味着冬天窗户没有明显的伐木。此时没有有意义的绝缘。
我们凉爽的房子古老的方式，我们在晚上打开窗户并在白天关闭它们并保持着绘制的色调。凉爽的夜晚的夜晚让房屋凉爽，有一个100岁的橡木，遮住了一半的房子。
The house is almost always cooler inside. Normally the house won’t exceed 78 degrees throughout the day during the summer. The house does a fantastic job of absorbing the heat during the day and releasing it during the night.
Until the 95+ day/night heat waves hit. Without the cool nights, after a couple days the home loses its capacity to cool off. We live in NJ in a NYC Suburb.
We are not interested in the cost/intrusion of central air, window units are out because of the negative visual impact to the home, and mini-splits are out as well for the internal visual impact.
我们正在寻找舒适的舒适，因为我们在大多数情况下都是在白天出来的。降低特定温度的家并不重要。我们现在只使用粉丝所以寻求改进，并专注于卧室。
My idea is to use a whole house dehumidifier to lower the humidity in the home when needed, this should improve comfort. And to use water cooled air handlers which I can install in the attic above the bedrooms to exchange and cool the air there. I expect I can run the cool water piping in the 2×4 walls and insulate them in the space. This will minimize the impact to the fabric of the home, and can be accomplished during other renovations.
The unconventional part of this is the method of chilling the water. I want to use a 500+ gallon (whatever is required) underground cistern to store and allow the ground to cool the water over time. The cost of deep drilling a heat exchanger puts that aproach out of reach, I don’t think we have enough space in our back yard to lay out loops. The idea is to have a large volume of water that can absorb the heat and return it to the ground during the day when we are not using the system. I borrowed this idea from the electric companies that installed large water tanks in customer homes, heated them during the evening for heating during the day to time shift the electricity usage.
I think this could work. The ground temperature of 57 is higher than normally used, but I think would still be effective. I think the trick is to size the cistern effectively.
And again, the important part is improving comfort, not necessarily lowering the temperature of the home to a specific number. Dehumidifying and cooling the air in the bedroom may be enough to make sleeping during the heat waves possible without waking up in a pool of sweat.
So what could I be missing ? What may trip me up if I try this out ? What haven’t I thought of and should consider ?
提前谢谢你的想法。
Kurt
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Replies
Kurt,
There are a lot of possible reasons why this isn't a great idea, but I'll focus on one: Your idea would cost thousands of dollars to implement. You can get a window-mounted air conditioner for your bedroom for $200 or $300.
您的坦克周围的土壤将从57F开始，但在开始将热量推入它时，就会快速上升。考虑一种管道的迷你分裂。或者如果你想用水，那么Chilltrix。
嗨马丁，
感谢你的回复。让我们假设我已经给了Window空调一些想法并决定看替代方案，你想到的其他原因会不会让这个好主意？
谢谢，
Kurt
To have any reasonable cooling efficiency you need at least a 20F difference between the water temperature an the air temperature in the room you are trying to cool (30F would be much better.) With 57F water the efficiency will be pretty good for a 90F room, but much diminished for an 80F room. Below 77F the power used by the blower motor becomes a larger fraction of the heat you need to remove.
Note: A smaller sized window-shaker AC unit is about 5000 BTU/hr.
The painfully simple math:
500 gallons of water weighs about 4200 lb.
Putting 1 BTU of heat into 1lbs of water raises it's temperature 1F.
By the time you've been running a hydronic cooling coil at 4200 BTU/hr (about the capacity of a tiny window unit) for a couple of hours, the 57F water in your 500 gallon buffer will have risen in temperature by 2F to 59F. By the time you've run it 4 hours it would be over 60F. It doesn't take many days of heat wave use (even when used sparingly) to raise the water temperature to a uselessly high number. After 20 hours it would not even very efficient at cooling the room to even 90F.
Over a five day heat wave, four or five hours per day... you're toast. In a day, three at most, you'd just be heating up the rooms with the power consumed in the blower motors. Maybe if you started out with a 50,000 gallon tank you would have enough cooling capacity to keep it under 80F through a single heat wave, but seriously, heat pumps are the only viable solution.
In order for hydronic cooling systems to work you need some means of cooling the water in the buffer tank, which is why chillers were invented. With a small air source 2-ton chiller like the Chilltrix & a 50 gallon buffer tank can do a lot, but it has most of the same aesthetic issues of mini-splits.
You could site a mini-split compressor or chiller a few yards away from the house visually shielded by shrubbery, and trench the lines below grade to a basement buffer tank or ducted mini-split cassette, but that increases the installation costs considerably.
Dana's math on the underground tank shows the limitations of that approach.
I grew up in a NJ house that was cooled by a whole house fan at night, and kept cool by the shade of big trees. It now has central air conditioning, because the humidity starting causing mold and mildew inside.
So I understand the focus on dehumidification as the primary task. However, the hardware in a dehumidifier is the same as an air conditioner, with the difference being that the dehumidifier heats the air after cooling it to drop the moisture out, whereas the A/C leaves it cold. So it doesn't make much sense to use a conventional dehumidifier unless the temperature in the room is already cooler than you want.
这样让我的乔恩·R的耳朵lier answer: A ducted mini-split, or perhaps a Chiltrix system. For example, you could mount the ducted mini-split head in the top of a closet, and run ducts a foot or two from it through walls to each of the rooms that adjoins the closet. Unfortunately, I don't know of anyone who makes the equivalent of a ducted mini-split heat for the chiltrix system, even thought that would seem like a versatile component to have in the system.
谢谢达娜和查理。
达娜，
I am guessing from your numbers the ability of the tank to transfer the heat into the ground is going to be overwhelmed by the heat being deposited in it ? If that is the case then you have identified the choke point in my plan, and I would be back to some sort of ground loop system to cool the water that is in the tank. Which may not need to be as large if I use the tank as a buffer and can spread the cooling over time. But still adds cost I was looking to avoid.
Charlie,
Chilltrix系统是一个有趣的选择。我会做更多的研究。
除了浴缸泄漏，我们没有任何可辨别的模具问题。NJ湿度是一个主要的舒适问题。房子很酷，但湿度仍然是一个问题。
Thank you for the advice.
Kurt
Kurt,
You've been given good advice and analysis by Dana Dorsett and Charlie Sullivan.
The basic problem with ideas like yours -- using ground loops or buried tanks to temper indoor air temperatures -- is that the value of the heat gathered (or the "coolth" gathered) is too low to justify the high cost of the equipment installation. In many cases, the cost to operate pumps and blowers is also higher than the value of the gathered energy.
您可能有兴趣阅读我对用于锻炼流过HRV的空气的地面环的分析：使用乙二醇地环通风空气. The best data I was able to gather showed that this type of system has a payback period of 4,400 years.
"...the ability of the tank to transfer the heat into the ground is going to be overwhelmed by the heat being deposited in it ? "
Yes. It's all about the RATE of heat transfer between the tank and soil, which isn't nearly high enough.
用于热传递到地面的罐的表面积的量是相对于它的体积微小的，污垢有些绝缘。土壤的导热系数因土壤型和水分含量而变化，但甚至湿粘土几乎不足以使热量以足够高的速率移动。这就是地面源热泵接地热交换器是长瘦身管的原因，具有高表面积到体积比，但它们仍然必须在地下温度以下10度的流体温度以获得足够的热交换速率。500加仑的500伏水500伏水500伏水55级土壤将花费（几个月）冷却至56F，甚至55°F的60倍水的长瘦身管甚至在55岁的土壤中占有平好，将水带到56°以下。
Unless you're planning to heat with it as well, even a small chiller like the Chilltrix + buffer tank would be an outlandishly expensive way to go, but it would allow you to micro-zone the place for both heating & cooling. A ducted mini-split would likely be half the installed cost (assuming you have somewhere to run an interior duct chase from a basement-mounted mini-duct cassette to the upper floor), and that too could see dual-use for heating, but you won't be able to micro-zone it.
即使您以某种方式管理被动地创建水源或空气冷却，即将到来，70年代中期，您可以脱离除湿。舒适性的足够的水分除尘取决于将供应空气温度降低约20×F以下所需室温。我们通常设计为提供55 ^ F空气至75 * f空间。
使用冷却水来实现该结果意味着冷冻供水需要为45 * F或其。
既然你愿意要牺牲一个中央除湿机的费用和加重，但是你厌恶经典管道中央空气系统的想法，为什么不分裂差异并使用低静态管道迷你迷你？我们部署了Mitsubishi Suz / Sez Combo，用于紧凑的地板计划，需要在1.5吨加热和冷却下。
设备很小，高效，耳语安静......什么不喜欢？