Category:

Fall Colors

10/31/2015

October is almost over and its time for the Fall Color report. The oaks are just starting to change but the hickories have all turned brilliant yellow and gold. We had a nice sunny day yesterday so I took some pictures.

Aside from the beautiful Fall colors, the main observation is that most of the leaves are still on the trees and we get very little solar heating though October and much of November.

As the leaves come down we can start to see the lake and the Young Life Christian Camp in the valley below.

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Fall Equinox

9/22/2015

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Yesterday was the Fall Equinox, the official transition from Summer into Autumn. It was overcast all day but we got a break at sunset. In a few weeks, the leaves will start changing color.

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Temperature Sensors - Part III

4/13/2015

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Intro
As mentioned in the first temperature Sensor post (way back in December of 2013) there's a lot of theoretical info on how much heat can be stored in the slab but there isn't very much practical info on how long it takes for the slab to warm up in the sun, how warm does it actually get and how fast does it cool off at night so I wanted a way to measure the temperature of the slab throughout the day.

My brother Phil is an experienced software engineer so he came up with a really cool system that allowed us to embed temperature sensors right in the slabs before they were poured. We now have the system running and we're starting to collect data.

The first step was to get all of the cables terminated. Internet, phone, sensors.... yikes - that's a lot of cable!

Making progress...

The Hardware
We use one-wire digital temperature sensors from Dallas Semiconductor. There are 5 sensors embedded in the basement slab, 11 in the main level slab and 4 in the main level ceilings above the drywall. I have several spare channels that will be used to monitor outside air temperature as well as inside air temperature on both levels.

An Arduino processor (on the left) retrieves data from the sensors and a small embedded PC (on the right) collects the data and publishes it to web every 15 minutes.

Results
The planning, modelling and engineering are finally starting to come together. Now we can monitor the temperatures of both slabs in real time. Here are the temps right now as I'm writing this post.... How Cool Is That!!

The data is stored permanently for graphing and analysis. The graph for the past eight days clearly shows the difference between cloudy days on the 6th and 7th versus sunny days on the 8th and 9th.

It's interesting to note that the slab doesn't start to warm up until late afternoon (4:00 - 6:00 PM). Following a sunny day, the slab will stay above 70 degrees for up to 12 hours.

It's already past the Spring Equinox so our heating season is almost over. I'm looking forward to seeing how the house performs next Fall and Winter.

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Happy Equinox

9/22/2014

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Yesterday was the Fall Equinox. A big day for pagan sun worshipers and Passive Solar enthusiasts.

We are now half way through the solar cycle. As the days get shorter, the shadow line cast by the roof creeps higher. By the middle of December the south windows will be in full sunlight.

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Flash Batt Insulation

5/29/2014

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Insulation is a big factor in any energy efficient design. As I wrote in a much earlier post, air infiltration would account for about 40% of our heat loss if we used conventional insulation so we looked at ways to build a tight envelope.

In the early design stage we looked at building with Structural Insulated Panels (SIPs). The SIP panels are typically made as a sandwhich that has OSB sheathing bonded to an insulating foam core. With SIPs you can construct very tight, energy efficient shells but the cost was just prohibitive.

We also investigated using spray foam to fill the wall and ceiling cavities but the foam is very expensive.

We decided to go with a "Flash-Batt" system. This technique uses a layer of spray foam against the outside walls to get an airtight seal and then conventional fiberglass batts, which are much less expensive, are used to fill the rest of the wall (or ceiling) cavity to get the desired R-value.

The spray-foam creates a vapor barrier against the oustide wall. The system has to be designed for the specific climate to avoid having moisture condense inside the walls, which would create mold or rot problems.

We used 1" of closed-cell foam in the walls (about R-7) along with R-19 Batts for a theoretical total of R-28. However, the 5 1/2" batts are being compressed into a 4 1/2" space so the actual R value is probably closer to R-24.

The ceilings have 2" of foam and R-25 batts for a total of R-39.

The basement walls are precast concrete panels from Superior Walls and have 2" of Dow blue board cast into the walls. Along with R-19 batts this provides a total R value of R-31.

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Windows Complete

4/15/2014

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Tony finished the installation of the folding accordian door yesterday, so all of the windows are now in. No more rain in the house.

It's starting to look like the model Tracey created in Chief Architect!

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Passive Solar Design IV - New Regulations from ENERGY STAR

4/13/2014

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In "Passive Solar Design - Part II" (way back in August of 2013) I reviewed a few different windows with different Solar Heat Gain Coefficients (SHGC). As you may recall, the SHGC is a measure of how much of the Sun's heat is captured by the glazing. A higher number means more heat captured and a lower number means more heat rejected.

Unfortunately, Andersen Windows did not offer their Passive Sun high SHGC glass in the 100 Series. Based on our cost and payback analysis, we decided to use the Andersen 100 Series windows anyway since they are constructed with a maintenance-free composite material and very cost effective.

The main reason for the exclusion is that the IECC Building Codes do not permit high SHGC glass in our part of the country, which makes building a passive solar house more difficult.

Recently, however, Energy Star Version 3 has provided an exclusion for passive solar designs. The exclusion is detailed in section 13.e. This is very important news for anyone building a passive solar design.

Fenestration utilized as part of a passive solar design shall be exempt from the U-factor and SHGC requirements, and shall be excluded from area-weighted averages calculated using a) and b), above. Exempt windows shall be facing within 45 degrees of true South and directly coupled to thermal storage mass that has a heat capacity > 20 btu / ft3xoF and provided in a ratio of at least 3 sq. ft. per sq. ft. of South facing fenestration. Generally, thermal mass materials will be at least 2 in. thick.

Andersen customer service is great, but because the Passive Sun high SHGC was a new product, it took many e-mails and phone calls before we were able to special order the 100 Series windows with the Passive Sun glass. They utilize Cardinal LoE-180 which is one the best glass units on the market today.

This is a huge breakthrough because we can now get a durable, low-cost window system with truely excellent high SHGC glazing.

We were very fortunate to work with Mike Korney from ABC Suppply. They have offices and distribution centers around the country so we were able to work with Mike face-to-face here in Chicago and have the windows delivered to their distribtion center in Marietta, Ga.

The windows have arrived and the large fixed units have an SHGC of .54 (which is awesome).

As a side note, the Builing Codes are several years behind the new ENERGY STAR standard. We met with our county Building Commissioner to get a waiver based on the new standard.

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Temperature Sensors - Part II

2/2/2014

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As I mentioned in a previous post, we are embedding temperature sensors in the concrete floors so we can measure the heating from the sun and the effects of thermal mass. The crew installed 11 sensors in the upper slab before pouring the concrete. We now have 7 sensors in the basement slab and 11 sensors in the main floor slab.

When the framing is complete we will install additional sensors in the ceilings and roof.

The first floor sensors go through the metal deck and will get routed through the basement ceilng.

The basement sensors go through the concrete floor and will be routed up through the basement walls.

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Suspended Slab - Part II

1/20/2014

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The team worked all weekend to get the metal deck and remesh installed for this morning's pour. We are expecting the weather to turn cold for the next 7-10 days so the pour had to get done today. Hats off to Tony and Harry for a tremendous effort.

Here's the steel deck with the mesh reinforcing in place.

The crew pooured about 50,000 lbs of concrete on the deck. This will provide thermal mass to soak up the sun.

Floating in the trees.

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Suspended Slab

1/18/2014

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A passive solar design can collect a lot of heat while the sun is shining. If there is not enough thermal mass within the house then it will get too warm during the day and it will get cold very quickly when the sun goes down.

A concrete slab in direct view of the sun is the simplest way to capture and store heat. As a general rule of thumb, there should be 6-9 square feet of thermal mass for each square foot of south-facing glass.

A basement slab on grade is the most cost effective since you need the slab anyway.

To take advantage of the basement slab, we designed neoTerra to step down the hill so there is a large walkout area in the basement with tall, south-facing windows

The living room on the main floor has even higher windows. As the sun moves from east to west over the course of a day, most of the floor receives direct sunlight. The flowing pictures show the solar coverage on December 21st at 1 PM and 4 PM.

There is about 200 square feet of south glazing which exceeds the guideline of 12%-15% of total floor area. It will definately require thermal mass so we decided to utilize a suspended concrete slab design similar to the one in the Labbe house:
http://thelabbehouseproject.wordpress.com/2009/07/29/suspended-concrete-slab/

Framing System
We will be pouring a 2" reinforced concrete slab over a metal deck. The concrete weighs roughly 25 lbs per square foot which requires a very strong framing system to support the weight (its about 21,000 lbs of concrete in the living room).

I looked at a lot of different framing systems and decided on the JoistRite system from Marino\WARE. The joists are extremely strong, light weight and the triangular cutouts simplify installation of wiring, plumbing and heating.

We are using 10" joists with a 9/16 galvanized steel deck. We will be pouring a 2" slab with 5000 # mix and 6" welded wire remesh to reduce cracking. The concrete will be the finished floor. The crew is finishing the framing and deck today and will be pouring the slab on Monday.

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Fall Colors

Fall Equinox

Temperature Sensors - Part III

Happy Equinox

Flash Batt Insulation

Windows Complete

Passive Solar Design IV - New Regulations from ENERGY STAR

Temperature Sensors - Part II

Suspended Slab - Part II

Suspended Slab

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