[GSBN] data loggers

Sun Dec 21 12:20:32 UTC 2014

Jacob (and others), 

The crux of my situations is that I am in the process of building a straw bale house at the moment. I am also in the process of beginning a PhD where my advisory has convinced me that using my house as a case study for some of the questions I was interested in would be ideal. The good side of this is that I have a very willing homeowner for data collection and very accurate use/lifestyle info. The downside is that the house is further along than the research, and I came to my senses in Sept and realised that I could not do both of them simultaneously with any quality. So, the PhD is somewhat on the back burner for the next 3 months while I get a big push on the house build.

Ideally, I would spend 6 months or so combing all of the relevant research including methods of data collection, then design the perfect study with the perfect tools, and finally put that design to practice in the house I am building. However, the house is happening now and I am going to just have to make my best guesses (and get some great advice from experts like yourself) as to how to install and record temp/humidity info and then move forward. I am sure the crystal ball of hindsight will be clear and if there is another willing homeowner, I may be able to do better follow up testing down the road. 

The university has a limited number (exact number is vague at this point) of data loggers that they will contribute to the project that can be built into the walls and then will live out their days in place. As I understand it, the data can be retrieved wirelessly but the battery life is only 2 years. I would prefer longer. Interior and outdoor ambient temp will also be measured. 

Thank you for the very thoughtful list of considerations for the sensors. I have answers to many of these questions and need to look into details of some of the others. I will spare you the nitty gritty detail of answering each of them, but I appreciate the detailed list. 

Thanks,
Enga

enga at thelokeys.net

On 09/12/2014, at 2:53 PM, Jacob Deva Racusin wrote:

> Hi all,
> 
> Enga I remember we corresponded a bit on this - can't remember what I said, hope it was of some use! Been having quite a lot of trouble staying on top of my emails these days...
> 
> There are quite a lot of different sensors out there - more manufacturers than I can recall - and if you are looking for budget, you can find them pretty cheap if you can build/assemble the system yourself. I think GE and other companies sell temp and RH sensors for less than US$20/each, or even cheaper. Off-the-shelf, pre-assembled, ready-to-go packages will be more expensive, for sure - and I'm not terribly well-versed on those, as I've been working on making my own version rather than using other company's versions.
> 
> Some considerations for any sensor system (though some of these are more relevant to DIY than off-the-shelf):
> 
> - do you want to do a combined temp/RH sensor, or individual temp and RH sensors? What are you monitoring and where, how many do you need?
> - what is the data range you need? this is a big one - if you need to get from really cold ambient temps to really hot, sensors go up in cost (same w RH, it gets more expensive to find sensors that give accurate readings at higher RH). If you go off-the-shelf, you need to look at the spec's and ensure the sensors will read within the environmental parameters you are seeking to evaluate. Otherwise, your data will not be fully representative of the conditions you are analyzing. Accuracy is another important feature (that also affects cost), as many sensors drop off in accuracy as you get to the far ends of their range. If you are doing research-quality testing, accuracy becomes all the more important than just for curiosity's sake or QC. This is a pretty crucial piece.
> - how are the sensors wired, and what are they wired to? what are you thinking of using to receive the data? to analyze it?
> - how do you plan on powering the sensors? hard-wire, or battery (wireless)? life-expectancy? how long to you plan on collecting data?
> - how are you mounting/installing the sensors in such a way that they are protected from damage, yet still connected to the regional atmosphere?
> - will the specific mounting and wiring regime allow environmental changes that will alter your data? i.e. conduits that could trap condensation, or wire that could conduct thermal energy
> - how will you know which sensors are providing what data, and where they are located in the building? How do those locations relate to differing environmental conditions (i.e. solar orientation, vertical location)
> - do you plan on retrieving the sensors for replacement/maintenance/repair/calibration?
> - how will you calibrate the sensors for accuracy prior to installation?
> - do you plan on also recording interior and exterior temp/RH to give full environmental context?
> - will the building occupants allow needed resources for long-term testing (access, power, internet connection, etc)
> 
> I hope this isn't too overwhelming. These are some of the many questions I asked (really, am still asking) in developing our sensor system, given the goals of our project. But ultimately, it is the goals and intended purposes that will drive how you design your program. Like building, the devil is in the details, and a clear understanding of goals will lay out the design, which will inform those details. So like any good design, start with getting a clear sense of what you are looking to achieve, the logistics, budget, and time frame influencing the project, and see what solutions fit those parameters.
> 
> Hopefully most of these questions will be easy to answer, or not necessary to ask. I strongly recommend finding published studies of projects that have had sensors installed, whether bale or otherwise, and read the sections where they discuss methodology and the construction of the testing environment. They will give many good clues and precedent of how to set up a rigorous sensing system. That's a great place to start. They will also tell you the equipment they use.
> 
> I realize this may be more complicated of an answer than you might like, but if I remember correctly you are looking for research-quality data (forgive me if I'm wrong here), and so the rigor is all the more important in setting up a quality testing environment.
> 
> By the way, Frank gives me more credit than I deserve in describing our units as "already manufactured" - we've gone through a few iterations of development, and we are now stalled out pending my gaining enough control back over my schedule to push the project the rest of the way forward. I am expecting to inject more time into this later this winter for a more formal launch in the season ahead - though I've said that before...
> 
> Hope that's helpful, best of luck.
> Jacob
> 
> On 12/8/14, 9:03 AM, Frank Tettemer wrote:
>> Hi Enga,
>> 
>> Jacob Deva Racusin, from Vermont, USA, is the person to talk with, currently. He has the sensor units already manufactured, ready to insert into the area of concern.
>> I'm sure he can offer more detail.
>> Jacob Deva Racusin <buildnatural at googlemail.com>
>> 
>> Cheers,
>> 
>> Frank Tettemer
>> Living Sol ~ Building and Design
>> www.livingsol.com
>> 613 756 3884
>> 
>> On 08/12/2014 7:49 AM, Enga Lokey wrote:
>>> Hello All,
>>> 
>>> Wanted to check in with any of you that have experience with data loggers in ongoing monitoring of temperature and humidity. Ideally, I will be imbedding dataloggers/sensors in the walls of a strawbale structure as it is built and then be able to monitor temperature and moisture movement within the wall from the plastering process through several years of use. If anyone is familiar with specific brands or types of equipment that either works particularly well or should be avoided, I would appreciate hearing about it. Economy will unfortunately be a factor as funding for these monitors seems to be getting more limited each day.
>>> 
>>> Thanks for any and all input.
>>> Enga
>>> 
>>> 
>>> enga at thelokeys.net
>>> 
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> GSBN mailing list
>>> GSBN at sustainablesources.com
>>> http://sustainablesources.com/mailman/listinfo.cgi/GSBN
>>> 
>> 
> 
> -- 
> Jacob Deva Racusin
> Co-Owner
> New Frameworks Natural Design/Build
> 
> Author, The Natural Building Companion
> Chelsea Green Press, 2012
> 
> (802) 782-7783
> jacob at newframeworks.com
> http://www.newframeworks.com
> _______________________________________________
> GSBN mailing list
> GSBN at sustainablesources.com
> http://sustainablesources.com/mailman/listinfo.cgi/GSBN