通过绝缘地下室估计节省
好的，我希望你们都会对此做出任何攻击，以便我可以将您的数字与我的数字进行比较！
I need to estimate the energy savings that would be achieved from taking an uninsulated basement wall of a home in Spencer, Iowa and insulating it to a total R value of R13 using either XPS or spray foam that would would be framed and covered with drywall to meet code. Assume NO additional insulation in the stud cavities.
这是房屋的细节：
Ranch home, 1538 square feet of basement space. Total wall square feet is 1,288 sq ft.
Basement is conditioned.
Basement walls are bare concrete block, 8″.
Heating degree days in 2010 were 8,047 (using degreedays.net, 65 degree baseline)
客户用电炉加热。
If you come up with a number, can you share HOW you arrived at it? Again, I want to compare to see if the calculator I am using is at all accurate. Thanks in advance for your help!
GBA细节库
一千年建筑细节的集合organized by climate and house part
Replies
柯蒂斯，
Here's some information for you:
CMHC研究（http://www.arxx.com/Assets/CMS/WYSIWYGBase/file/CMHC%20Basement%20Assessmt.pdf) concluded that for 5 Canadian locations (Toronto, Ottawa, Halifax, Edmonton and Victoria), "For all types and sizes of basements assessed in this study, the lowest total life-cycle cost was associated with basements insulated internally, full-height toR-20的名义水平。”
美国研究（见http://www.ornl.gov/sci/roofs+walls/insulation/fact%20sheets/basement%20Insulation%20Technology%20fact.pdf) found that annual energy savings from R-20 basement insulation ranged from $280 in Washington, DC to $390 in Buffalo, NY.
柯蒂斯，
If you have access to an ASHRAE Fundamentals Handbook they do have a method for manual calculation of foundation heat loss. I have found this to be reasonably accurate as compared to say Energy-10 or the like.
It always strikes me as odd that so many decisions regarding insulation focus on cost justification, payback time. Maybe the promotion of energy conservation should read like what I think is a credit card commercial.
绝缘墙$ xxxx
建筑螺柱墙$ yyy
Sheetrock over tuss $ zzz
这一切的安慰：无价
R13 over the block wall equates to about 2.5" of XPS, something easily applied with either glue or powder actuated fasteners. The studs are just for fastening sheetrock, so they can go on the flat (to save floor space), sitting on ripped PT plates fired into the slab and anchored at the top by the floor above. Shallow boxes provide electrical outlets. Sheetrock goes on the usual way. But you've already got this figured out, I imagine
你好，
您已经将手指放在能量计算中的盲点。教科书的显式解决方案取决于高斯错误函数，因此没有简单的解决方案。来自加拿大NRC的Gintas Mitalas做得很好，以简化80年代初期的基础热量损失，将因素应用于不同的绝缘配置文件，并且可以通过在网上进行一些挖掘来找到他的工作。美国DOE在1989年的建筑基金会设计手册上做得很好，这很难获得。
ASHRAE手册第29章有一种方法。他们从基础（如图所示）到户外绘制圆形弧，这些弧表示热流线或“流线”。然后从U a delta T计算热流量。DeltaT是室内外温度差。增量区域A是计算便利性的问题。U源自壁中的绝缘材料，土壤的电导率和热流线的长度。整个作品都集成了。这种方法很好，因为它显示了顶部附近的壁截面的热量损失比土壤中壁更深的部分更大。
另一种方法是使用two-dimens计算它ional heat transfer program like THERM from Lawrence Berkeley, and assign a lot of dirt to the outside of the assembly. You have to create your own new building material “dirt” based on soil conductivity conditions that your local ag extension people ought to know.
这些结果以及所有结果都是非常粗略的估计。最大的通配符是土壤电导率，根据湿度的不同，根据湿度的不同，它可能会因湿度而异，但取决于化妆，尽管我们的中西部土壤可以从干燥到潮湿有更大的差异。然后是角效应，也有热量交换到下方，而不是表面。
我在两年前左右在乌尔巴纳IL的被动式房屋会议上进行了不同的高温流量计算方法的演讲，您可能可以通过其网站访问。
Good luck. I won't run the numbers, you'll have to do that.
柯蒂斯，
You've received soem excellent suggestions. My difficulty with this calculation is that HDD really don't apply since you are in a somewhat mild climate. Presuming this is an in-ground basement (and not a walk-out), the difference in temperature between the ground and the space you are trying to heat is more applicable. It's also somewhat important to know if this is a block basement or a pured concrete foundation.
Assuming that the wall is medium density concrete and the ground remains about 55F, I calculated about $3.87 per heated day for the bare wall and about $1.07 per heated day of energy cost with 2.5 inches of XPS. I used a simple Q=U A dT calculation as is used in ASHRAE. There is a film factor for the interior wall but otherwise is a straightforward calculation. Just estimate the number of days you heat your home, and the annual cost is there. For example, if ou turn your heat on in the basement about 100 days per year, you would pay $387 for the bare wall and a bit mroe than $100 for the insulated wall.
更多的importantly, you need to consider moistture. The cost of heat is nothing compared to the cost of remediating mold growth in basement wall structures. You're on the right path. We recommend that you insulate the walls with R-10 or greater XPS (STYROFOAM) and that you build the stud walls on the inside surface of the XPS. This eliminates thermal bridging at the studs and keeps the studs protected from wicking, seapage, and condensation. Fiberglass directly against the basement wall runs a good chance of getting wet from condensation or leakage.
I would be happy to work with you directly to estimate your savings given some more specific information. But, given the 1288 SF of wall and the approximate savings we calculated of $287 for a 100 day heating season, your payback will be 2-3 years. Approximating the cost of XPS at $20/sheet, the insulation cost will be $800. You need to check locally for exact cost,
如果您想进一步讨论，请随时给我发送电子邮件，我将尽力满足您的特定需求。
Scott Cummings
陶道建筑解决方案
BPI分析师和信封专业人士 - 认证
[email protected]
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