Solar gain through my basement windows.

strider3700 · 12-17-10, 03:38 PM

I just wanted to share a bit of the datalogging chart from today. The orange line is my recroom, the blue my office. My office is north east corner of the house. The recroom the southeast corner with a 6'x2' window in it. THe small spikes you see are from the fan in the forced air system kicking on to circulate. The woodstove is out, the furnace is not heating.

Today is the first day in almost 3 weeks that it has been sunny and the house feels noticably warmer especially upstairs where there is lots of south facing windows. I'm glad the chart caught today heat gain in the basement.

the grid line below the orange is 20C with each step being 5C so the sun raised the temps in the basement from an overnight low of 19.43C to a current high of 23.55C the sun is now moving to the point it won't come in the basement window but upstairs will get a couple more hours of heating. I can't wait to get more temp sensors.

Xringer · 12-19-10, 07:34 AM

Petty nice gain for a basement. My uninsulated basement is sitting at 11C now and that's
about the same temperature as the floor.
Except close to boiler, where the floor is a little warmer.

I think any heat generated down there is wasted (except the 11C Slab&walls-geothermal).

I probably should make an effort to hold in the waste heat from the boiler.
Replacing the 6 single pane casement windows with modern replacement windows might be a good first step.

BUT, I'm very reluctant to start putting foam on the walls, because there is nothing I can do about the floor.
That slab is always going to be cool.. (Nice in the summer).

AC_Hacker · 12-19-10, 07:52 AM

Quote:

Originally Posted by strider3700

...I can't wait to get more temp sensors.

So what kind of 1-wire sensors do you use, and where do you get them?

-AC_Hacker

strider3700 · 12-19-10, 08:22 AM

I'm using 1-wire ds18b20's. the first two came as samples directly from the manufacturer.

The next 20 are coming from hongkong via ebay since it's a lot cheaper then mouser or digikey.

Xringer · 12-19-10, 09:14 AM

We looked at using those on a project at work last year. They are amazing devices.
But we ended up going analog with the LM335A.
Temperature Sensor - LM335A - SparkFun Electronics

Since we only needed a few sensors and had the LabJack analog inputs to take care of them, we took the KISS option.

I briefly considered them on my home-hobby experimental controller, but then
I took my (mostly forgotten) programming skills into consideration and decided to go with the LM335A.
But, I'm still out of my depth. It takes too much effort to re-teach this old dog.

strider3700 · 12-19-10, 04:56 PM

Have you seen my thread on the data logging project as I've been working on it?
http://ecorenovator.org/forum/applia...g-project.html
I've been sharing all of the code hopefully helping non programmers out a bit. It's still some work getting it going but if you can get hello world running you can get my code working with only a bit of help.

I seriously considered using some analog sensors like the lm35's since they are so inexpensive. The issue was I haven't done electronics in years and none of that was more then a few hours tinkering here and there. So I decided before spending a bunch of money lets get some samples and see what I can figure out. The 1-wire samples took setting up an account and requesting via an electronic shopping card. They arrived a week later. The place that sells the lm35's wanted $18 in shipping/processing fees for $2 worth of sensors. 1-wire worked first time and the decision was made.

Also the fact that they are digital and my arduino mega has I think 32 digital pins meant that even if I had to go 1 per pin it would be trivial. It only has 16 analog pins and I want more sensors then that so I was looking into mux's and so on.

Xringer · 12-19-10, 06:19 PM

You don't need a lot of I/O for digital. Not when you can string them up like Christmas lights..
I just hope Hong Kong doesn't send you 20 units that all have the same address burned in..

I'll check out your data logger thread..

Thanks,
Rich

strider3700 · 12-19-10, 07:50 PM

lol after you mentioned that I checked the ad again and they do specify unique ID's. I get the feeling these foreign components are just bought in large quantities and then split up and sold off for less then the north american companies charge for the processing. The arduino on the other hand was definitely a knock off, but using pretty much the same components so it's functionally equivalent.

AC_Hacker · 12-19-10, 09:01 PM

Strider,

I saw this chart which describes the typical error curve for the ds18b20.

Just curious if (and how) you're implimenting error correction in your project?

Seems like these devices would be a big improvement over the thermistors I'm currently using, and I can see that error correction would be pretty important for my application.

Regards,

-AC_Hacker

strider3700 · 12-19-10, 10:46 PM

I didn't specifically handle error correction directly. The dallas library that I used that handles all interfacing and translating of the results from the sensors may handle it I'm not sure. I do know that the library allowed me to specify the resolution of the temp sensors from 9 bits to 12 bits. I went to the full 12 because I like seeing XX.XX sensitivity even if it's within error at that level.

Looking at that chart it appears that the worst error is 0.45C. I can easily live with that. I'm assuming that it will constantly read a little high or a little too low.

About the only thing I have done that will help some random noise is I take 30 readings a minute (every 2 seconds) and average those value to store every minute. that helps prevent spikes if I breath on the one on my desk or the cat rubs against the one in the recroom...

12-17-10, 03:38 PM	#1
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	Solar gain through my basement windows. I just wanted to share a bit of the datalogging chart from today. The orange line is my recroom, the blue my office. My office is north east corner of the house. The recroom the southeast corner with a 6'x2' window in it. THe small spikes you see are from the fan in the forced air system kicking on to circulate. The woodstove is out, the furnace is not heating. Today is the first day in almost 3 weeks that it has been sunny and the house feels noticably warmer especially upstairs where there is lots of south facing windows. I'm glad the chart caught today heat gain in the basement. the grid line below the orange is 20C with each step being 5C so the sun raised the temps in the basement from an overnight low of 19.43C to a current high of 23.55C the sun is now moving to the point it won't come in the basement window but upstairs will get a couple more hours of heating. I can't wait to get more temp sensors. Attached Thumbnails Last edited by strider3700; 12-17-10 at 03:41 PM..

12-19-10, 09:01 PM	#9
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	error correction Strider, I saw this chart which describes the typical error curve for the ds18b20. Just curious if (and how) you're implimenting error correction in your project? Seems like these devices would be a big improvement over the thermistors I'm currently using, and I can see that error correction would be pretty important for my application. Regards, -AC_Hacker Attached Thumbnails

12-19-10, 07:34 AM	#2
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Petty nice gain for a basement. My uninsulated basement is sitting at 11C now and that's about the same temperature as the floor. Except close to boiler, where the floor is a little warmer. I think any heat generated down there is wasted (except the 11C Slab&walls-geothermal). I probably should make an effort to hold in the waste heat from the boiler. Replacing the 6 single pane casement windows with modern replacement windows might be a good first step. BUT, I'm very reluctant to start putting foam on the walls, because there is nothing I can do about the floor. That slab is always going to be cool.. (Nice in the summer).

12-19-10, 08:22 AM	#4
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	I'm using 1-wire ds18b20's. the first two came as samples directly from the manufacturer. The next 20 are coming from hongkong via ebay since it's a lot cheaper then mouser or digikey.

12-19-10, 09:14 AM	#5
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	We looked at using those on a project at work last year. They are amazing devices. But we ended up going analog with the LM335A. Temperature Sensor - LM335A - SparkFun Electronics Since we only needed a few sensors and had the LabJack analog inputs to take care of them, we took the KISS option. I briefly considered them on my home-hobby experimental controller, but then I took my (mostly forgotten) programming skills into consideration and decided to go with the LM335A. But, I'm still out of my depth. It takes too much effort to re-teach this old dog.

12-19-10, 04:56 PM	#6
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	Have you seen my thread on the data logging project as I've been working on it? http://ecorenovator.org/forum/applia...g-project.html I've been sharing all of the code hopefully helping non programmers out a bit. It's still some work getting it going but if you can get hello world running you can get my code working with only a bit of help. I seriously considered using some analog sensors like the lm35's since they are so inexpensive. The issue was I haven't done electronics in years and none of that was more then a few hours tinkering here and there. So I decided before spending a bunch of money lets get some samples and see what I can figure out. The 1-wire samples took setting up an account and requesting via an electronic shopping card. They arrived a week later. The place that sells the lm35's wanted $18 in shipping/processing fees for $2 worth of sensors. 1-wire worked first time and the decision was made. Also the fact that they are digital and my arduino mega has I think 32 digital pins meant that even if I had to go 1 per pin it would be trivial. It only has 16 analog pins and I want more sensors then that so I was looking into mux's and so on.

12-19-10, 06:19 PM	#7
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	You don't need a lot of I/O for digital. Not when you can string them up like Christmas lights.. I just hope Hong Kong doesn't send you 20 units that all have the same address burned in.. I'll check out your data logger thread.. Thanks, Rich

12-19-10, 07:50 PM	#8
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	lol after you mentioned that I checked the ad again and they do specify unique ID's. I get the feeling these foreign components are just bought in large quantities and then split up and sold off for less then the north american companies charge for the processing. The arduino on the other hand was definitely a knock off, but using pretty much the same components so it's functionally equivalent.

12-19-10, 10:46 PM	#10
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	I didn't specifically handle error correction directly. The dallas library that I used that handles all interfacing and translating of the results from the sensors may handle it I'm not sure. I do know that the library allowed me to specify the resolution of the temp sensors from 9 bits to 12 bits. I went to the full 12 because I like seeing XX.XX sensitivity even if it's within error at that level. Looking at that chart it appears that the worst error is 0.45C. I can easily live with that. I'm assuming that it will constantly read a little high or a little too low. About the only thing I have done that will help some random noise is I take 30 readings a minute (every 2 seconds) and average those value to store every minute. that helps prevent spikes if I breath on the one on my desk or the cat rubs against the one in the recroom...