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myk3y

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Posts: 31
Reply with quote  #1 
Have there been any projects automating solar collection?

My hobby is in electronics and programming, I am, in the modern parlance, a ‘maker’.

I’ve got laser cutters, cnc routers, 3D printers, all home-made.

I have networked everything in the house you can network...

I have wifi-connected and web-controlled lights and other doo-dads, smart clocks, streaming music receivers, tv senders, wireless printers and all manner of weather sensors.

So naturally my interest in a passive solar house is to automate temperatures, etc.

But, controlling fans on the scale needed to move house-lots of air is very different to variable-speed case fans used for cooling a 3D print. I have a bunch of wireless 240v solenoids that have about fifteen free sensor pins, ananlogue and digital, and a bunch of spare temperature probes from my smoker and sous-vide cooker, so while I’m in relative leisure, I thought I would look at designing an infrastructure to cover solar needs.

Not wanting to reinvent a low-resistance circular rolling device, has anyone done so or knows of any existing standards that people are building to?

There are plenty of home automation standards and ‘almost standards’ used for infrastructure (like zigbee, Apple home, google home) which I already use, so it would make the most sense to integrate with an infrastructure that has the widest user acceptance.

Sensors/controls I’ve thought of so far:

Water temp and flow, air temp and flow, ambient inside/outside temp, water solenoid, air solenoid, water pump, air pump, ventilation actuator, sunlight strength and position, date, time

Anything else I should factor into my data set?

Solar electric is pretty settled in standards and there’s plenty of work I can piggyback off, so I’m only going to focus on heating/cooling at this stage, but will try and integrate with those as much as possible.

Thoughts?

pianoman8020

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Posts: 44
Reply with quote  #2 
You mentioned controlling the house. I have long been an advocate of controlling the internal environment to maintain a comfort zone year round.

This would include temperature and humidity thru the four seasons using inside and outside temperature fluctuations. This would be akin to someone constantly opening and closing windows and doors to maintain the perfect comfort range. I am not talking about turning the air conditioner on and setting it to 72 degrees.

This would require powered  vent fans for windows? and ceilings? timed to day and night temperature differentials; heavy dependence on solar air heaters in the winter; plugging all air leaks to a high level.

I say this because I am doing a lot of this manually to prove it can be done. Last YEAR my total gas and electric bill was $495 (audited by MidAmerica) for a 2100 sq. ft. house in central Illinois. Since then I have added a 8'x9' solar air collector and insulated my basement walls. 

Future plans are to add sun tracking reflectors to my collector to take advantage of the early morning and late evening sun.
Also, on those cloudy days the collector will still be running. I well expect the raise the collector efficiency to over 100% during fill sun plus add another and extra hour of operation to the morning and evening cycles.

There is a lot discussion about heat storage on this forum which is a bad idea. You have and entire house to absorb excess energy so why not use it. I would guess 90% of the collectors are large enough to heat one or two rooms and to over heat a house in the winter can not be a bad thing when the sun goes down. All of this while thinking Return On Investment (ROI).

Jim from IL       

stmbtwle

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Posts: 2,881
Reply with quote  #3 
You could probably do all of it with an Arduino and appropriate hardware, but putting together a system for each home wouldn't be cheap, and you're back to the ROI.  

Simpler might be a "standard" module that could attach to a fan.  This might be just the ticket: 

https://www.ebay.com/itm/Differential-Temperature-Controller-Water-Heater-Solar-Panel-Water-Pump-2-Sensor/121917535737

__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
myk3y

Registered:
Posts: 31
Reply with quote  #4 
Quote:
Originally Posted by pianoman8020
You mentioned controlling the house. I have long been an advocate of controlling the internal environment to maintain a comfort zone year round.

This would include temperature and humidity thru the four seasons using inside and outside temperature fluctuations. This would be akin to someone constantly opening and closing windows and doors to maintain the perfect comfort range. I am not talking about turning the air conditioner on and setting it to 72 degrees.

This would require powered  vent fans for windows? and ceilings? timed to day and night temperature differentials; heavy dependence on solar air heaters in the winter; plugging all air leaks to a high level.

I say this because I am doing a lot of this manually to prove it can be done. Last YEAR my total gas and electric bill was $495 (audited by MidAmerica) for a 2100 sq. ft. house in central Illinois. Since then I have added a 8'x9' solar air collector and insulated my basement walls. 

Future plans are to add sun tracking reflectors to my collector to take advantage of the early morning and late evening sun.
Also, on those cloudy days the collector will still be running. I well expect the raise the collector efficiency to over 100% during fill sun plus add another and extra hour of operation to the morning and evening cycles.

There is a lot discussion about heat storage on this forum which is a bad idea. You have and entire house to absorb excess energy so why not use it. I would guess 90% of the collectors are large enough to heat one or two rooms and to over heat a house in the winter can not be a bad thing when the sun goes down. All of this while thinking Return On Investment (ROI).

Jim from IL       



Opening and closing windows, moving air, is exactly what I am looking at - ‘active passive’ :)

A wireless micro controller with a 120v/230v solenoid will run you to $5. Add in another $2 for power and a couple of bucks for a case/mounting. The actuator will run you about $6-8 to open a casement window, about double for a sash window or sliding window, and another $5 for the 12v supply, unless you have a 12v rail available through your solar power system, but you will still need cable,

To move air from one are to another in the house will cost you the same whether it’s automated or not - 12v hot air pumps with ducting run to about $100ma room. Again, add in a controller and solenoid and power of your choice.

Centrally controlled with a raspberry pi, or similar (not a PC - too much chance of an outage breaking your system) and you are actively controlling your passive solar for a really low ROI.

Or you could just walk round and open some windows.
myk3y

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Posts: 31
Reply with quote  #5 
Quote:
Originally Posted by stmbtwle
You could probably do all of it with an Arduino and appropriate hardware, but putting together a system for each home wouldn't be cheap, and you're back to the ROI.  

Simpler might be a "standard" module that could attach to a fan.  This might be just the ticket: 

https://www.ebay.com/itm/Differential-Temperature-Controller-Water-Heater-Solar-Panel-Water-Pump-2-Sensor/121917535737


I guess that depends on your sources.

I think I could do a fully-automated window for around $25. A central server to run it all for $50.

Thinking of our new house design, with 8 ground-level shallow casement windows and 12 shallow roof-line casements in the central sun trap portion, that’s just over $500, plus wiring (which being 12v I can do without any permits or certification).

I spent that on a 3D printer. The ROI would be easily measurable.

Then there’s storage and deviation of hot air, hot water, movable solar reflectors for PV... if you need to move something, an automated actuator is going to run you about $25. If that thing is technically challenging and you need plumbing fixtures, fans etc., well you were probably going to need those anyway, but operated by hand. Or not and you waste energy.

In NZ our usage is around 6500kw/h per household per year, with 60% of that on hot water and heating, vs 12000 for North America.

It’s a mild temperate climate and in my 60 years I have never known a single house that has AC and only four houses, in all the thousands I have visited with work or socially, to have central heating, so our needs may not be at all transferable to the frozen north.

What we have, in excess, is sunshine. About 200 more sunshine hours than Canada, about 500 more than UK, Germany, etc. and with moderate temps, means we don’t need to cope with extremes.

Passive solar can be very effective and a cheap method of managing that is easily achievable,

stmbtwle

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Posts: 2,881
Reply with quote  #6 
No doubt it can, in the appropriate locations.  Won't work here, in the "sunshine state".  Our problem is getting rid of the heat.  So far, only PV has worked for that. A lot of us do have solar DHW, but it's not "passive".
__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
myk3y

Registered:
Posts: 31
Reply with quote  #7 
Quote:
Originally Posted by stmbtwle
No doubt it can, in the appropriate locations.  Won't work here, in the "sunshine state".  Our problem is getting rid of the heat.  So far, only PV has worked for that. A lot of us do have solar DHW, but it's not "passive".


DHW?

And getting rid of heat is a problem for us, too. If you build so you are insulated and with large thermal masses, a couple of days of 30C and you are stifling. So, heat exchangers working in reverse to pump heat from the house into the ground is one way, ‘smart’ ventilation (with sun direction sensors, anemometers, hygrometers, etc), even smart curtains or shutters, to alleviate the worst of the heat before it’s taken up?

Hot water for heating is a problem in summer - you have to either purge your system and cover it, or work out what to do with the excess heat, which is where some sort of heat exchanger comes in to convert btu’s to electricity, I’m doing a lot of reading... there are some interesting options, from pettier transformers to state-change cooling, like an old kerosene refrigerator, replacing the kerosene burner with solar power.

It keeps me f the streets :)
stmbtwle

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Posts: 2,881
Reply with quote  #8 
DHW Domestic hot water.  Oh yeah we also have solar pool heaters (those that have pools)

Heat exchangers, ground loops, and heat dumps all work but they also run into money, and hassle.  Back to the ROI.

__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
pianoman8020

Registered:
Posts: 44
Reply with quote  #9 
Here's a way to cool the house and heat your greenhouse at a very low cost.
 
When you are building your next new house, insert 6 to 8 runs of  4" tubing parellel and away from the foundation when backfilling. Header them to an 8" tube which could pass thru the foundation wall. This would cool most homes in the US in the summer that use full depth foundations. There could easily be 800 to 1000 feet of tubing in the ground ready to use.

If the tubes are below the frost line the air could be used to heat your greenhouse in the winter.

Jim from IL



myk3y

Registered:
Posts: 31
Reply with quote  #10 
Quote:
Originally Posted by stmbtwle
DHW Domestic hot water.  Oh yeah we also have solar pool heaters (those that have pools)

Heat exchangers, ground loops, and heat dumps all work but they also run into money, and hassle.  Back to the ROI.


Whats your figure for ROI? 

It's almost like you expect it to be free.

Maybe its a different cultural attitude. I'm prepared to pay for something that benefits the planet. Hopefully it will be cash-neutral, saving me in energy bills what it cost me to implement.

I have researched a basic 15kw heat exchanger for $500 (* our dollars, not yours. I'
m sure they are bigger and cheaper over there) add in $1500 of pipe and digging trenches and you have taken a huge load off your summer cooling needs for less than a season's AC.

Of course cost of electricity has to factor in - it's almost like you expect everything to be the same as it is in Florida.

Perhaps you could step away for your personal situation and look at it from an Everyman perspective - of high rates for electricity, poor exchange rates for currency and no tax breaks for anything.

I know Americans interest in the rest of the world stops at the borders of their county, but maybe make an effort to understand that my planning and hypothesising may have almost nothing to do with your situation in the coal-fired, oil-rich USA, and even less to do with Florida in summer.

Can't you just walk down to Lowes or Wal-Mart and buy something that will do what I want for a buck and it will be better and if they don't, they'll just take it back? 
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