发帖数: 1 | 1 德克萨斯大学达拉斯分校机械系戴贤明教授课题组 (8月入职，参考simondai.weebly.
com) 全奖招收博士生。专业不限，机械、能源动力、电子、材料、化学、生物相关专
业都可考虑。具体方向为: (1) 热能利用, 传热传质或电池的热管理; (2) 超疏水/超
亲水表面微纳米加工或电化学合成; (3) 生物检测，生物传热或其它与生物工程相关的
方向。目前德州政府投资80亿美金致力于打造一批更高水平大学。德州大学达拉斯分校
是德州政府重点打造的公立大学，其目标是进入美国大学前50名，近几年区域经济十分
活跃，学校各项排名稳步上升。具体信息如下:
Multiple PhD positions in Mechanical Engineering with full financial support
are available starting from Fall 2016 or Spring 2017 in Prof. Xianming Dai'
s group (simondai.weebly.com) at The University of Texas, Dallas. Th... 阅读全帖 |
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l*********y
发帖数: 155 | 2 I have similar crack on my basement. It is also from the corner of a window
all the way to the ground.
My inspector told me
"This is a typical crack in the concrete. Concrete has water ,sand, Portland
cement and stone. When the water evaporates during the curing process the
concrete shrinks and cracks. All foundations crack. It may be a problem when
wall cracks are greater then a ¼ inch, have deflection, travel
horizontal, are in a v pattern on an outside corner or water is leaking
through. |
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s**********d
发帖数: 36899 | 3
因为不够冷。普通空调evaporator很冷，水都凝出去了，
所以可以除湿，但地下温度并不很冷，所以除湿能力很差。 |
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R**R
发帖数: 3318 | 4 对于 2500 sf 的房子,you need:
1, 2.5 ton 的 compressor, about $1.2k;
2, Installation Kit with 30' Lineset, about $250;
3, Evaporator Coil , about $300.
If you can buy pre-charged units. DIY is not very hard. |
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g*****9
发帖数: 4125 | 5 Buy a good quality Impregnator online, do not use the cheap sealer HD sells.
There is an easy way to find out if a given stone needs to be sealed.
Just spill a few drops of water on its surface, let it dwell for 5 minutes
or so and then wipe it dry. If under where the water had been sitting you
will notice a darkening of the stone (it will disappears once the water will
evaporates) it means that some of it was absorbed; therefore, if the stone
will be installed in an environment prone to stainin |
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R**R
发帖数: 3318 | 6 帮你找到了。看贴：Price for installing AC unit?
如果是force air 的heater,以有通风管道，大约3-5k.
如果是水暖，没有通风管道。那就多了去了。
对于 2500 sf 的房子,you need:
1, 2.5 ton 的 compressor, about $1.2k;
2, Installation Kit with 30' Lineset, about $250;
3, Evaporator Coil , about $300.
DIY is not hard. |
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s**********d
发帖数: 36899 | 7 什么问题查一下好了，96年的就换奢侈了一些。
如果是小漏一年一百多charge一次就行了。
换evaporator也就几百块。 |
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G*****r
发帖数: 369 | 8 谢谢！看来1K可以把dehumidifier & evaporator一块搞定了。
空调的寿命一般是多少年呢？去年验房的时候太冷，没法开空调测试，但房检师提过
builder给的空调太小，寿命也快到了，需要尽快换。看了看邻居家的外机，好像大部
分也都换过了。
8月好像是换空调最便宜的时候，5月跟8月会有多大差价呢？
加氟以后效果会好很多？ |
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R***U
发帖数: 1860 | 9 My bill posted.
EQUIPMENT: BRYANT 95% VARIABLE SPEED FURNACE AND AIR CONDITIONING
1st Floor
1 – Bryant, model #355CAV060100, 3 stage natural gas furnace with variable
speed motor with 95+% A.F.U.E.
1 – Bryant cased indoor evaporator coil, 4 ton, model #CNPVP4821ATA
1 – Bryant, model #167ANA048000, 16 SEER, 3 ton, 2 stage central air
conditioner with scroll compressor and R-410a, environmentally friendly
refrigerant
1 – Bryant Digital heat and cooling thermostat, evolution thermostat, with
3 |
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T*U
发帖数: 22634 | 10 ft, 得在coil那么多散热片中找漏，补漏就好象你要修cpu里的晶体管。 |
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B*****g
发帖数: 193 | 13 还是换了吧，如果换high efficiency 的话，还有1500 的 fed tax rebat. 12年的空
调可能也差不多了。 |
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B*****g
发帖数: 193 | 14 是的，新的空调必须是high efficiency， max rebate $1500.和暖气一起换比较合算。 |
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j********r
发帖数: 129 | 15 Servicing airconditioner without proper EPA certificate could result a fine
up to $XX,XXX, and potentially need to go to a federal court. |
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j********r
发帖数: 129 | 17 The rule is mainly to prevent releasing refrigerant in to atmosphere. You
might be OK if you only charge your vehicle AC.
But strictly you need EPA 609 certified to service a vehicle AC. |
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j********r
发帖数: 129 | 18 Assuming u have certificate, then you won't be in trouble with EPA.
Many counties also require special HVAC license to service AC. But this
would be a much less serious offense.
Also you'll need lots of special HVAC tool to service AC.
(1) Recover the refrigerant from your AC. Need special equipment and
container.
(2) Use compressed nitrogen to test leaking location.
(3) HVAC piping tool to fix leak.
(4) Pump to evacuate AC to required vacuum.
(5) Recharge refrigerant (Only sold to licensed tech |
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g*****9
发帖数: 4125 | 20 Water as early as 你老公 can in the day so that evaporation is minimized.
Try to avoid watering in the evening to prevent black spot, powdery mildew,
and other fungal diseases, but it's better to water in the evening than not
at all. |
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l*****t
发帖数: 107 | 21 Thank you for your help!
Do you mean I just need to keep using it until all water or spilled oil
outside
engine is all evaporated? |
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g*****9
发帖数: 4125 | 22 What size AC? condenser coil or evaporator coil? |
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m*********e
发帖数: 248 | 24 and 4 tons R22 evaporator coil |
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m*********e
发帖数: 248 | 25 The leak is at the connection out side of the evaporation coil case and
copper tube. it seems to be TRANE, I am not sure. here is the picture. |
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g*****9
发帖数: 4125 | 26 What? don't even take me 3 hours to clean the evaporator coil. That is
vacuum/recover all the Freon first, remove the coil, take it outside, hose
it wet, spray coil cleaner, wait, rinse for a long time, put it back,
connect/solder the pipes back, put the freon back.
Unless the new coil does not fit and he need to do some duct work to fit. |
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p**q
发帖数: 535 | 27 freon won't evaporate. lt supposed to be in the system forever if there is
no leak.
a/c check steps
temperature of inlet/outlet, airflow/filter, coil cleaning. replacing
freon is the last step from a professional. |
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g*****9
发帖数: 4125 | 28 Please feel free to post questions and comments regarding the AC 科普
article in this thread (do not post follow up there, thank you)
Your evaporator coil is frozen, usually caused by a lack of refrigerant, due
to a refrigerant leak or leaking.
Turn off AC, leave the fan running to melt the ice.
Call someone to find the leak, fix and charge refrigerant to spec.
Some leak can not be fixed, you need to get a new unit.
http://toad.net/~jsmeenen/ice.html |
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g*****9
发帖数: 4125 | 29 It is hard to believe a 4 year old compressor could leak (possible, but not
very likely).
I would guess your outdoor condenser coil could have a small leak if someone
bump into it by accident (kids on a bike, maybe). Your indoor evaporator coil could leak due to formicary corrosion. Of couse, it could leak any where along the lines, most likely a bad soldering job.
Leak in coil itself is very difficult to repair, so you might get new coil,
leak in line can be easily fixed.
The guy that is coming |
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s********n
发帖数: 4535 | 30 新装的可能是split system,也就是compressor/condensor在外面，evaporator coil在
阁楼。
制冷原理跟冰箱一样，“氟利昂在气体状态时，被压缩器加压，加压后，经喉管流到电
冰箱背部的冷凝器，借散热片散热(物质被压缩后，温度就会升高)后，冷凝而成液体。” |
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s**********d
发帖数: 36899 | 31
一般没必要。不等外面的锈里面evaporator就锈烂了。 |
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m****u
发帖数: 6 | 32 the compressor was dead because power outage last month. We need to
replace ac unit(not include oil furnace), I got a quote of 3800 for a
carrier 13 seer plus evaporator coil (2 year labor, 5 year system, 10
parts warranty), how is this quote ? fair or expensive? |
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z*********n
发帖数: 94654 | 33 thanks. so if it's just an overkill, I'm fine. because I wanted to pave over
there for long time. For decoration purpose.
my question is, if my setup would actually solve the problem :D
80-85% of that area is actually covered by my roof. so I don't need totally
water proof. As long as most water can run off or evaporate before it seeps
in, I'm fine. Also only when it rains hard in maybe 7 days, do I see wet "
basement". only happened once a year to twice maybe in LA, where we do get
heavey rains... 阅读全帖 |
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m********n
发帖数: 782 | 34 Carrier Performance Series
95% multi variable speed gas furnace
4 Ton/Puron AC unit
5 Ton Evaporate Coil
Is $7500 (including labor) a good deal?
How much do you spend on replacing your system? |
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j***b
发帖数: 5901 | 35 中央空调难道就不是分体的？难道是压缩机，condenser，evaporator 一体的？
你说mini split不舒服怎么个不舒服法？我看到到处评价都是说mini split安静舒服。
mini split跟central比优势有几点，一个是没有duct，没有duct上的损失。再一个是zoning的灵活性。再有就是基于inverter的mini split可以实现很小的温度浮动而不用担心造成compressor short cycle，这个也能提高efficiency和comfort。其实个人家用中央空调就是很落后的设计。很显然一点就是整个房子救一个t-stat。它对温度控制只能保证安装它的地方是那个温度。 |
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S*******s
发帖数: 10098 | 36 设计原理不如窗机效率高， 要买的话最好买双筒排气的。http://174.129.132.250/home/2008/06/air-condition-1.html
Bottom line: Given these downsides, we suggest you consider a portable unit
only if having a window unit is out of the question and a split ductless
system is not viable because of cost or installation concerns. If you do
decide to buy a portable unit, choose a model that has two hoses and
evaporates the condensed water.
Essential information: See our advice on staying cool this summer without
cranking the A/C, an... 阅读全帖 |
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S*A
发帖数: 7142 | 37
Yes, but my pump is connect to a vacuum robot, if it is in the pool,
the robot will take care of that.
all
OK, if you are talking about run on cover, sure. But that is
a few thousand. FYI, I don't think many people have that.
I haven't seen one myself, while I have seen many solar covered
pool. I am talking about the solar cover just flow on the surface.
That is like $100 - 2$00.
You really have no idea do you? Pool cover will dramaticlly reduce
water evaporation at night, which is by far the N... 阅读全帖 |
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j***b
发帖数: 5901 | 38 如果fan在转，evaporator 还freeze这不太正常吧。
你可以打开检查空调的那个箱子，就是要换 air filter 打开的地方，
可以GOOGLE
一直工作，但是制冷效果不佳。 |
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z*******i
发帖数: 2904 | 39
空调的filter换了 evaporator coil也清洗了 还有哪里能清理的 |
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j***b
发帖数: 5901 | 40 不见得是给封上了。有的空调就是没有service port，因为氟利昂本来也不是suppose
会低的。那东西一般设计都是根本不会漏。漏了本身就是大问题。
你原帖里面说的那些橡皮泥应该是赌风的，无关紧要。
几个可能原因：氟利昂低，风扇故障，evaporator coil太脏。
有没有跟正常时候的对比？风力是不是下降了？
另外，是完全不制冷还是只是制冷不够？ |
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EM
发帖数: 715 | 41 我买的是condo，所以楼里面的几个人家都用的是一个型号的furnace和compressor，我
比较了别家的，都有2个service gadget，而我的那个都没有（见照片里面的两根孤零
零的铜线），怀疑会不会是上家做了什么手脚啊。。。
开了冷气之后的风扇风力的确是下降了许多，制冷不够，我设置在76度，户外是84度左
右，实际室内温度是80度，而且似乎是一夜之间空调就挂了。。。
对了，那个维修人员也提到了evaporator coil，不过他说要把金属的壳给切开才能清
理。。。
suppose |
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j***b
发帖数: 5901 | 42 感觉你这个evaporator挺独特的。一般的都是有螺丝，可以拧开看到coil，而不需要切
开铁皮。 |
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m****t
发帖数: 2684 | 44 也许我们的是不同的setup，我的是有一块板子，被螺丝固定，但是接缝处全被抹了一
层塑状的东西，除非全刮掉，否则无法打开这个金属板。一般来讲，正常工作的
evaporator coil 是不会结冰的，你说的每个月都要清洗，感觉有点夸张。
另外请问一下，这个散热片（coil）是否有铜管连接到其他部件，感觉是无法轻易取出
来的，youtube 上的片子里，人是用电焊烧（?）才拿出来，如果不取出来直接在里面
清洗是非常messy的 |
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C*******M
发帖数: 153 | 45 Evaporate coil 去年开始漏氟里昂. 今年准备换空调系统。现有三个报价:
Lennox 3.5 ton 13 seer $3,000.
American Standard 3.5 ton 13 seer $2,825.
Goodman 3.5 ton 13 seer $2,400.
Warrantee 一样.
好像Lennox和American Standard一个档次. 邻居家装了 4 ton American Standard,感
觉外机有点吵。
我该换哪个牌子的空调 (HVAC)性价比最好？
是不是等过了夏天换会便宜些？
什么时候有Tax credit?
谢谢 |
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z*****a
发帖数: 3809 | 46 We're in NYC, where labor is probably more expensive than anywhere else in
the US.
For central AC, the main cost is the labor for the duct installation, which
greatly depends on the architecture of the house.
For mini-split ACs, the labor costs for installation are much lower but the
equipment costs can be much higher if you have a lot of rooms since each
room need a separate evaporator/blower unit. |
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j***b
发帖数: 5901 | 47 你说的风扇转，是压缩机的风扇转还是楼上 evaporator 风扇转？如果压缩机风扇不转
，可以考虑查一下压缩机的contactor。 |
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s******8
发帖数: 4192 | 48 儿医建议家里50%,去年我用小加湿器加到45%。后来发现gas furnace去湿能力实在太强了。加了电取暖器，湿度到50%。
我现在中央加湿是cool mist,效率特差。以前住在北方，冬天-10F以下的，用的是evaporative，效率好点，后来换了窗户，修了墙，又几乎没用了。 |
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l*******y
发帖数: 280 | 49 太干小娃老是流鼻血。小加湿器买了n个，家里到处都是，湿度倒是上去了，就是小娃
太喜欢玩加湿器了，会会弄翻，所以才想弄个central的。
强了。加了电取暖器，湿度到50%。
evaporative，效率好点，后来换了窗户，修了墙，又几乎没用了。 |
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z****0
发帖数: 3942 | 50 Lean times call for budgetary triage. But while you should clearly opt for
orthodontics before Disneyland, the choice is tougher when it comes to home
maintenance.
Should you get a paint job or a new furnace? "There's no homeowner's manual
that tells you when to do what," says Naperville, Ill., home inspector and
structural engineer Mark Waldman.
Emergencies aside, the project that could cause the most damage and expense
if left unfixed is the priority. Below, the order in which to tackle your
b... 阅读全帖 |
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