Parts for a house insulation test box

Thread Starter

StrongPenguin

Joined Jun 9, 2018
301
I am gonna build two identical boxes for testing two different house insulation products in the harsh weather conditions where I live. The plan is to put two (hopefully) identical heat blowers in the box and a relay to start and stop the fans, so the temperature is kept at 70* F, with a certain hysteresis.

At the end of the experiment I am comparing watts used over the course of a week, or so. For this I am going just to plug the fans in two identical watt meters.

I have a Microchip HPC, that I would like to hook up to the temperature sensors inside, but I need to switch the 220V fans on and off with the help of the HPC, so I need relays for this.

Could you guys recommend me some parts for this little project? Always when I start something, I usually get stuck, because I have no idea what to use, and the delivery time to where I live is...not fast.
 

Alec_t

Joined Sep 17, 2013
13,077
Sounds an interesting project; but don't the manufacturers of the insulation products provide their U-values? Or don't you trust the published figures ?
 

Reloadron

Joined Jan 15, 2015
6,836
Just at a glance since you mention 70 F rather than 21.11 C I would guess maybe US? However, then you mention 220 volts for fans and heater elements? Not that it matters. A good start would be to outline your procedure and method as most test procedures start with that. Next your equipment requirements. Since your temperature is relatively low you won't need much for a heat source. Your sensor can be a simple Thermistor or thermocouple. You can find, as mentioned, any number of temperature controllers inexpensive on Amazon. I liked MrSalts suggestion in Post #3. Nice to have would be power meters with an analog out for data logging purposes as well as a analog out to data log temperature. You will also need to know, as Dick mentions your power requirements for fan and heat source which depending on your test box should not be too high.

So really to define a parts list other than generic you really need to consider exactly, in detail what you want to do and if for example you want to data log?

I have a Microchip HPC, that I would like to hook up to the temperature sensors inside, but I need to switch the 220V fans on and off with the help of the HPC, so I need relays for this.
I would consider in this case using a SSR rather than mechanical relay. Next you need to define your choice of sensor? There are plenty of off the shelf sensor modules providing an analog output proportional to temperature, you just need to decide what you want? Just about any uC can drive a SSR (Solid State Relay).

What is a "Microchip HPC"?

Where do you live?

Can you pick the fan and tell us how current it will draw?
My best guess is a experimenter board similar to an Arduino board. :)

Ron
 

Thread Starter

StrongPenguin

Joined Jun 9, 2018
301
Sounds an interesting project; but don't the manufacturers of the insulation products provide their U-values? Or don't you trust the published figures ?
Yes, they provide U-values, but I read somewhere, that they don't simulate wind on their test bench, just a hot and cold surface with the insulation product in the middle. This makes sense from a test perspective, but where I live (Faroe Islands), we have wind 365 days a year, pretty much. The climate is pretty cold, but the Gulf Stream keeps it somewhat stable. 20* F is a cold winter day here, and 60* F is a decent summer day:cool:
It's also just to have a small project, that interests me.

@MrSalts That is a very smooth solution! Thanks, I might go with that. But I was also thinking about getting into programming uC's again. Yes, the plan is to swap gear after a few days, to even out the errors.

@ronsimpson I also thought about that, but I would like the experiment to last a few days, so it resembles a house as much as possible. See how the insulation reacts to the different weather conditions.

@DickCappels I haven't picked anything yet, I am afraid. But after reading this thread, I might go with a heat element. Microchip High Pin Count, the experiment board. Some kind of data logger that I can hook up to Excel would also be nice, so I can see how the boxes react to wind.

@Reloadron I need to outlay the experiment a bit more, yes. I have only thought about the boxes so far, because when I buy electrical stuff for my projects, I always get it wrong, or miss something, then my projects falls to the ground. That is why I thought about asking here :D
Thanks for the solid state relay tip! Going to order a few of those, if the uC alone can activate it.

I am going to make a (MS Paint is the only thing I got atm..) drawing and come up with my own parts suggestion. Thanks for all the feedback.
 
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MisterBill2

Joined Jan 23, 2018
12,745
Quite interesting indeed. But insulation effectiveness depends very much on assembly details. And likewise the heater effectiveness.
So I suggest two identical commercially made heaters that will be useful after the project is completed.
Then use the little computer to monitor temperature and heater run time. If the setup also records time of day then you will also be able to see the effects of solar input and outside weather, and that should be useful information.
 

Thread Starter

StrongPenguin

Joined Jun 9, 2018
301
@MisterBill2 Glad you guys find it interesting. There is always a great debate here which is more effective in the Faroe Islands, Rockwool or foam batts. I tend to settle this argument once and for all :D But yes, logging a pattern of when the heat element starts and stops would be very relevant. Maybe this is something that can be handled in software?
 

LowQCab

Joined Nov 6, 2012
2,357
"" Rockwool or foam batts. .""

Neither one ...........
As stated earlier by MisterBill2, it's all about the "Leakiness" of the Construction methods used.

This is why there are now new Building-Codes requiring a "Blower-Door" test,
which measures how well the structure is sealed against outside Air incursion.

If You are interested in "New-Construction" I would suggest a
YouTube-Channel called "The Build Show"
put on by an Austin, Texas Custom-Home builder by the name of Matt Risinger.
He has a ton of coverage on new materials and construction-techniques.
.
.
.
 

MisterBill2

Joined Jan 23, 2018
12,745
There are wrapping materials, one called "Tyvek", (although I probably spelled it wrong.)
So then after the outside walls are built, but before the outer layer is added, it gets the airtight seal layer applied. Then the siding or brick or whatever goes on. Or maybe the plastic wrap goes over the layer of foam insulation. Fiberglass with paper backing to hold it in place is good, and if done at the right stage it still allows wiring to be installed. Those houses do take less energy to heat and cool.
 

Thread Starter

StrongPenguin

Joined Jun 9, 2018
301
@LowQCab I follow The Build Show on YT. Great show, Matt discusses a lot of interesting topics.

@MisterBill2 Yes, we also use warp here, so the plan is to wrap both boxes, although it can be debated, if foam needs wrap. But I think the boxes need to be as similar as possible.

I've come up with a part list:

Temp sensor driver - MAX6675
Temp sensor - K type probes
Solid state relay - board with 8 relays controlled with uC
Power meter for plug
Heat element (need to figure out size, will most likely be a guess..)
Microchip HPC

Am I missing something electrical related, to start my project? I could link to the parts, but don't know if it is allowed. Parts are pretty standard.
 

LowQCab

Joined Nov 6, 2012
2,357
What are the Dimensions of the "Boxes".

How many "Holes" will the Boxes have ?

Have You considered doing a Vacuum and/or Pressure Test on the Boxes
to verify their equal "Leakiness ?, or the differences between them ?
( this testing will be all about Air-Leakage, not necessarily about Insulating qualities )

The Circuit, and the Heater can probably be ridiculously simple and cheap,
depending on how large the Boxes are.
A 220-Volt Heater is probably overkill unless the Boxes are quite large.
Is 220-Volts the minimum Mains-Voltage available where You live ?

I would suggest a Temperature-Sensing-IC instead of Thermocouples.
They can be directly connected to your Computer-Chip, and run on the same Power-Supply.
Actually, Your Computer-Chip may have a built-in Temp-Sensor that would work just fine,
but the main feature that You may want to implement is a Logging-function.

Any Fans will need to run continuously on "Low"
to prevent Temperature-Stratification and odd Cycling quirks.
.
.
.
 

Thread Starter

StrongPenguin

Joined Jun 9, 2018
301
@LowQCab The boxes will have equal amounts of holes and plenty of them. And both boxes will be wrapped. I have not built the boxes yet, because I am at sea and will be home in 3 weeks. But the idea is to compare the insulating material with each other. I do not plan to pressure/vacuum test because I will most likely buy an old house, which I tend to renovate over time. So I need to see which is the best suited material for the Faroese weather conditions (lots of wind, somewhat cold..)

Ok, temp sensing IC, I will look into that. The HPC has one, IIRC, but then I would need another HPC and have it inside the box. I much rather have it on my desktop.
I still need to figure out at smarter way to log, but I could also just use the standard power meter plug, and compare watts at the end.
I thought about going no fan. The idea is to let the boxes settle in their environment for 24 hrs, before starting the test. I am pretty confident that foam will take the win, but equally curious.
 

LowQCab

Joined Nov 6, 2012
2,357
Since this seems to not be a "Commercial Advertising endeavor",
and appears to be just a personal "what-if" experiment,
I can save You some time ..........

The Wind, not the Temperature-Delta, is going to be the major determining factor.
So the Construction-Techniques used,
along with Window and Door Selection,
are going make up ~95% of the difference.

For Insulation, Sprayed-In "Closed-Cell-Foam" will be the winner, especially in a very old Home.
Keep in mind that the Floor can be a very large percentage of Heat-loss, and Wind-permeability.
The Doors and Windows will be determined by how much Money You have to spend.
You can pay it all "up-front",
or pay slightly higher heating-costs over the lifetime of the Home,
it's your call.
.
.
.
 

Thread Starter

StrongPenguin

Joined Jun 9, 2018
301
@LowQCab I will most likely not be using spray foam, but either foam bats (interested in finding out about the difference between regular white foam batts, and closed cell spray..) or regular rockwool/fiberglass. And I agree, that wind is the main factor, but hopefully I will get a few good windless days, so all conditions can be tested.

Right, this is not a commercial advertisement, not at all. It's mainly to settle an argument, that we all debate from time to time here, since the Faroe Islands regulations are very old, with regards to isolation, and the insulation methods are not very up to date, IMO.
 

MisterBill2

Joined Jan 23, 2018
12,745
For a one-time project you can also use the forward voltage drop of diodes, or of a string of a few diodes, as the temperature sensing element. I am guessing that the temperature range inside the box will be limited to a fairly narrow range, like from 50 degrees F to 80 degrees F, or possibly an even narrower range. So regular temperature sensors might be more expense than your project really requires.

Temperature and heater operation can also be done with a personal computer, using an external or internal analog input system. Some very good but obsolete now instrumentation was sold in the mid-1980s, and might be available surplus at scrap prices, if you are a good shopper and also lucky.

With an "older" house, the application of insulation and leakage reductions will offer many options, depending on both your willingness to work and to spend money. Some very effective foam-in-place insulation schemes can be very effective,, but they must be very thorough to the most effective. From my own, rather unfortunate experience this means knowledgeable direct supervision in person.
 

Thread Starter

StrongPenguin

Joined Jun 9, 2018
301
@MisterBill2 I don't mind spending a few bucks on a good pair of temp sensors, since I don't own much gear. And I thought about increasing the temperature to 30 deg C (86 deg F), just to "load" the box more and get a bit more range.
That is the thing about foam. There is no going back. As a marine engineer, I like to be able to pick things apart. That is why I stay away from foam, even though I believe it is very effective. And I plan to do everything myself, with the help of good friends.
 

MisterBill2

Joined Jan 23, 2018
12,745
@MisterBill2 I don't mind spending a few bucks on a good pair of temp sensors, since I don't own much gear. And I thought about increasing the temperature to 30 deg C (86 deg F), just to "load" the box more and get a bit more range.
That is the thing about foam. There is no going back. As a marine engineer, I like to be able to pick things apart. That is why I stay away from foam, even though I believe it is very effective. And I plan to do everything myself, with the help of good friends.
Foam in place is indeed difficult to undo, no question there. So making all renovations first in the outer walls is the good choice. And doing the application one's self is what I would recommend.
In my case the crew showed up and did the job unannounced, and so I had no input at all. The result being the job was done 90% ok, and the siding removal and replacement seemed more like it had been done by firefighters putting out a fire in a hurry, and then cleaning it up after. And then they were gone.
 

Thread Starter

StrongPenguin

Joined Jun 9, 2018
301
@MisterBill2 Sounds like not a very pleasant experience. I thought about the "flash and batt" method, where you fill in the gaps with foam. I will most likely do something like that, only use foam in cans. But I think we are getting off topic, though it is a very interesting subject:D
 
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