Solectair - any first-hand experience « Alternative Technology Assn Forums

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Solectair - any first-hand experience

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Started 12 years ago by rhills
Latest reply from Markp

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rhills
Member

We own a home in Perth that has some passive solar features but is still far too cold in our relatively mild winters. I've been interested for some time in some of the solar space heating products (eg Solarventi, Sun Lizard) however I've noticed owners of those products apparently not totally enthusiastic about them in these forums.

I've come across another product, Solectair that I believe was invented here in Perth. I am wondering if there is anyone here in Perth who has this product installed and can comment on its effectiveness specifically during winters here.

Cheers,

Rob Hills
Waikiki, Western Australia

Posted Monday 10 May 2010 @ 1:33:47 pm from IP #
Benny
Member

Sorry Rob - no first hand experience with the solectair but I have read the Monash reports that suggest it works quite well. I think the critical factor to consider here is what type of roof/roof space you have. These heaters rely on the roof space collecting lots of heat which would probably be best if you have a metal roof with no sisalation/insulation directly under it - and not many people have a roof like that. If you have a tile roof I guess the many gaps in the tiles and high thermal mass would mean it would be hard to heat it up in winter when you need the heat.
We're coming in to winter now - get up in the roof and do some temp measurements on a typical sunny/overcast day. If its hot up there - and over a considerable volume not just at the apex - then you've got a reasonable amount of energy to pull down in to the house. If not then the heater won't be doing much.
I also presume you've realised that the cheaper system tags on to a currently installed ducted A/C system ? I didn't get the solectair as it seemed silly to pay another $500- $600 for an extra fan when there's already one on the evaporative A/C I have installed. But how to duct from inside the roof to the external intake of my evaporative system ??
I built my own solar air heater - about 2sq m and it warms up my home office quite nicely.
Maylands WA

Posted Tuesday 11 May 2010 @ 3:03:38 am from IP #
ghostgum
Member

No first hand experience with Solectair. My sister has an HRV system (similar idea) but more expensive and we don't have enough data on its performance yet. I've got a SolarVenti which boosts the temperature of a southern room quite well, but is overpriced. My roof has light coloured colorbond with RFL underneath, so Solectair wouldn't help me.

These solar air heaters don't have any storage, so they are a benefit on cold sunny days, but not on cold cloudy days. For the latter you will need some supplementary heating.

Today in Melbourne is cold (12C near my home), patchy cloud with some rain, but enough sun between the clouds for the SolarVenti to lift my southern room temperature from 18C to 20C. On a sunny day it would lift the temperature to 22-23C. Yes, I've got some sensors on the system and I can tell what it is doing right now.

Posted Tuesday 11 May 2010 @ 4:07:20 am from IP #
Anonymous
Unregistered

I have never tried any solar space heating product but a very good friend of mine is purchased that product from an online store you can also search this product on Google.

Posted Tuesday 11 May 2010 @ 6:25:12 am from IP #
smiels
Member

I just saw a house in Canberra has a similar system, it has a solar collector with an optional storage unit so you can heat into the evening. Not sure how much they are. It looks expensive. http://www.t3e.com.au/

They are opening their house on the weekend, so I might see if I can get along for a look.

Posted Tuesday 11 May 2010 @ 9:19:57 am from IP #
rhills
Member

Our roof is tiled with no insulation or flashing under the tiles. We have wool insulation in the ceiling. We do have quite a lot of roof that pretty much faces the sun during winter. I am planning to do some temperature measurements in the roof space in the near future - we have one of those wireless indoor/outdoor thermometers so I figured I could mount it in the roof. Taking your point Benny about where to measure, I guess I should be doing it relatively low down in the roof space.

Today was typical of the type of weather that I find very frustrating. By 11am today, it was about 19°C outside and 16°C inside Most of the northern side of our house is sadly taken up by garage so I can't add windows to try and improve things that way.

Cheers,

Rob Hills
Waikiki, Western Australia

Posted Tuesday 11 May 2010 @ 1:37:24 pm from IP #
rhills
Member

Well, today I put the outdoor bit of our indoor/outdoor thermometer in the roof. I located it low down in a section of north-facing roof, out near the eaves. The day was probably close to perfect for this type of heating, warm with a gentle breeze, albeit with scattered cloud.

Anyway, when I first put the thermometer in the roof, around 10am, the house temperature (with most windows open as it was warmer outside than in) was 18°C and the roof temperature was 24°C. I checked episodically over the next three hours:
Time Indoor Temp (°C) Roof Temp (°C)
10:00 18.0 24.0
11:20 19.1 28.4
12:30 19.7 31.2
12:50 19.7 31.8

I had to go out for the remainder of the day. On my return in the evening, the max recorded for indoors was 19.9°C and the max for the roof was 31.9°C.

So today the roof space fairly quickly reached a differential of 10-11°C over the indoor temperature. It's only one day's measurements, but I'd guess that on a day like today, a Solectair unit could be quite an effective heater.

Posted Wednesday 12 May 2010 @ 3:01:00 pm from IP #
Benny
Member

That sounds encouraging rhills. Good that you don't have insulation or anticon under the tiles and that you have a large roof space. Did you do any more tests with the thermometer closer to the roof apex ?
Can you now compare the roof volume that is warm to the volume of the house that you would like to heat ? This should give you an idea of how much it would warm the house. I know that even a few degrees warming can make a big difference - 18 feels cool if you're just sitting around but 22 can be OK.
Now comes the big decision - is it worth spending $1000 for the add on kit or almost $2000 for the standalone 4 outlet kit - noting that they are "kits" so you have to arrange installation as well. Someone will undoubtedly tell you that you can buy a lot of gas for heating for the same price or that the payback period is very long, but if you're committed to doing it because its the best option for most optimum energy use and don't really care about the cost issues, then give it a try. You could at least get $100 back by writing an article for Renew about the experience.

Posted Wednesday 19 May 2010 @ 10:56:00 am from IP #
rhills
Member

Hi Benny,

Haven't measured at the apex yet, but I don't imagine it'd be any cooler would it?

Also not sure how well the volume of the roof space would relate to the potential warming. I guess it might give an idea of the theoretical maximum achievable, but I doubt that a Solectair would be able to transfer all the air in the roof space into the house anyway. Thinking about measurements that might be useful, I realise that the only really effective measurement would be the difference between the temperature of air entering the roof space from the house relative to the air entering the house. To produce that, I'd need a Solectair unit (or something like it) !!

I'm reasonably handy and the kit doesn't look that hard to install. I don't have any ducting so I'd need the $2K kit. I wonder if the ducting can also be used for Evap A/C if we decide later that we need it?

Writing an article for Renew sounds like an interesting thought. To make it really worthwhile, it'd be good to have some better temp measurements before and after though. I've been thinking I'd like to record temps from a few spots around the house into my computer. Anyone know any good, not-too-expensive systems that would enable me to do this?

Posted Wednesday 19 May 2010 @ 4:29:29 pm from IP #
ghostgum
Member

rhills, for measuring temperature, it depends on how much technical experience you have. I have five Dallas/Maxim DS18S20 digital temperature sensors, connected to a 1-wire to USB adapter, to a low power linux computer. A cron job runs digitemp every 5 minutes to log the temperature.

If I were doing it now, the only change I would make is to use a netbook computer.
All up cost would be $400 for computer (you don't need a new one), $50 for the 1-wire to USB adapter, $6 each for the temperature sensors, some Cat5e wire, and an 6P6C modular plug. Plus quite a few hours of time.

Posted Wednesday 19 May 2010 @ 10:57:03 pm from IP #
rhills
Member

Hi ghostgum, thanks for the info. I'm actually reasonably technically savvy and quite familiar with Linux so this sounds do-able for me. I've seen the DS18S20 chips in my internet searches. Do they all attach to a single wire (ie "daisy-chained") or do you have a separate Cat5e wire to each. In that case, is there a single USB connector per temperature sensor or do all wires come to a single USB connector?

For the computer, something like this (http://www.mini-box.com.au/purchase/browse-detail.asp?start=1&menuId=59&laCode=ENGAU&class=nine%20nine-one&subclass=&productId=189) could be even more cost (and power) effective. It needs a HDD (or flash card) but could still work out cheaper to buy and run than even a second-hand netbook. I have a KVM switchbox, so keyboard/mouse/screen aren't necessary for me.

Cheers,

Posted Thursday 20 May 2010 @ 5:57:44 am from IP #
ghostgum
Member

You daisy chain them together, with a single RJ11 on the end, which plugs in the USB 1-wire adapter.
A mail order source of DS18S20 is
http://www.futurlec.com.au/test13.jsp?category=ICDALLAS&category_title=Dallas%20Semiconductor&main_menu=IC&sub_menu=ICDALLAS
They might look like they are in Australia, but the items were shipped from I think Thailand.
They might be called 1-wire, but in reality you need 3 wires (ground, data, +5V power) for these sensors on a longer run.

I bought the USB adapter from
http://www.thermodata.com.au/onewire/adapters.htm
There is some argument about the reliability of the DS9490R.
I've had no trouble with it, but some people find the RS-232 version DS9097U-009 to be more reliable, but then you need to get a separate +5V supply.

That mini-box looks reasonable. Mine is a diskless AMD Geode system (Alix3d) bought 2 years ago, that is physically smaller and has no room for a hard disk. Today I'd use an Atom based system.

Posted Thursday 20 May 2010 @ 6:29:38 am from IP #
swedishchick
Member

We have installed this - it does get the house very cosy and warm during any sunny afternoon (it mainly seems to kick in after lunch - could depend on the orientation of our roof, not sure) but for it to work as intended you do need to have a well insulated house. The idea is to get the house as warm as you can stand it during the day then keep this heat in - although we have ceiling insulation our house is typically Australian with most exterior wall surface almost entirely made of single pane glass so unfortunately it doesn't take long before it's all gone out the window - literally.

We are now looking at insulating the windows with 'clear comfort' as we can't afford double glazing - and hope that this would help.

I suppose solecatir still does help somewhat - we VERY rarely need any additional heat during the day - generally it's not that cold on overcast days anyway, and it probably means we put on the gas heater a bit later in the evening. But yeah to do this system justice you need to be able to keep the heat in for a bit longer then we currently can.

Posted Saturday 22 May 2010 @ 7:37:21 am from IP #
rhills
Member

Hi SwedishChick,

Thanks for the first hand feedback. We have quite good ceiling insulation and have reasonably effective coverings on all our windows, so hopefully any heat we could get in during the day should be retained for a while. Almost all of our internal walls are masonry as well so hopefully that thermal mass will be able to help retain some of the warmth. It certainly retains the chill if we leave the house for a week or more in winter!

I've also had a reply from Solectair to my query about ducting: I wanted to know if the ducting they install with their "Stand Alone" kit is usable by evaporative A/C if we wanted to fit that later on. He said that they use a narrower diameter ducting than is normally used by evap A/C and that we should probably get an A/C company to fit evaporative A/C ducting if we are planning to go the A/C route later.

Posted Sunday 23 May 2010 @ 3:18:53 pm from IP #
Benny
Member

Good to hear from a user Swedishchick. How does the filtering work ? Have you had to change them or is there any evidence of dust coming through ? I know thats big worry for people with fibreglass insulation.
rhills - I suggested measuring the temp at the top of the roof because it should be warmer there - not cooler - due to the stratification. In terms of measuring the volume of the roof space, I was trying to get an idea of how much energy there is up there. Ideally you would measure the temp all over the roof space and integrate temp/volume to calculate heat energy available. Measuring at a few levels should be good enough though. Then you can estimate by how much it would warm your house space.
BTW - do they provide a return duct/vent from the house to the roof space so that its a closed cycle ? Or do you have to provide an exit point in the house and its a one way flow like for an evaporative ac? It might be a bit more efficient if it was a closed cycle, although then the vent to the roof space would be open and maybe let dust in.
Like ghostgum I've bought a usb adapter and 20 ds1820 sensors - still to set it up though.
I got my sensors from ebay http://shop.ebay.com/cphillips1982/m.html?LH_BIN=1&_trkparms=65%253A12%257C66%253A1%257C39%253A1%257C72%253A2981&_ipg=25&_trksid=p3911.c0.m14.l1581&_pgn=3

$2 each.

You should come along to our Perth ATA meetings.

Posted Monday 24 May 2010 @ 2:57:39 am from IP #
rhills
Member

Regarding the temp stratification Benny, my comment probably wasn't clear because of the double negative - I meant that because I assumed the temp would be hotter near the apex it wasn't necessary to measure it. By measuring the temp in the coolest part of the roof, it'd be safe to assume the rest of the roof space was at least that temp. Nevertheless, because it'd be difficult to work out how much of the roof space air would be turned over and how quickly it'd be warmed by the sun on the roof, I thought there were too many variables to make it worth trying to calculate. But then I'm no engineer!

WRT the air return, it's not totally clear. The animated diagrams on their site seem to show a return vent in the ceiling, but don't show any air going through it. Like you, I'd have thought they'd need something.

WRT the temp logging, the night I posted the question, I found this kit: http://www.oceancontrols.com.au/data_acquisition/templogger_k145.htm and rushed out and bought one. It was a bit premature unfortunately as your/ghostgum's approach seems a better one. The sensors you got are certainly much cheaper too, $2 versus $12 for mine - fortunately I only bought one extra with the kit! I'm tempted to get the USB thingy anyway as running a single wire around the various sensors makes more sense than the "star" system I'd have to set up with the kit I got.

WRT the Perth ATA meetings, I've been meaning to get to one for a while. Unfortunately they keep being scheduled for nights I have other commitments I can't wriggle out of

Posted Monday 24 May 2010 @ 4:07:19 pm from IP #
Markp
Member

I installed a Solectair added to an evaporative A/C system about 3 months ago; apart from getting the fan into the roof space the hardest part of the install was running the cable down the cavity wall. Total time 3 hours.

We have most of our roof facing east/west and it is terracotta clay tile. There are a lot of gaps between tiles and about 1/3 of the roof is covered in solar panels so it is not the best collector and holder of heat.

Through August it would start to pump in warm air at about 1pm and continue till about 5pm depending on cloud cover, in September it was coming on a little earlier each day starting at about 10:30am by the end of the month.

Most days it would lift the inside temperature between 4 to 6 degrees higher than outside, which came as a surprise a few times when we expected to walk into a cool house.

I have noticed that we loose the heat quickly once the sun is off the roof , and we start to loose heat from in the house which means that blinds are closed well before it is dark. Double glazing would solve this but that may have to wait.

The heater in the house was used less in August being turned on up to 2 hours later than normal the heater was not used at all in September.

Posted Monday 4 Oct 2010 @ 4:50:16 am from IP #

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