Friday, November 21, 2014

Snow on Solar Panels in Toronto

3 in 12 roof (14.0deg)
8 in 12 roof (33.7 deg)
It snowed two days ago - We got the normal 2" of snow while Buffalo got the 50"! (1.5m of snow, in 24hr).
A neighbor recently installed solar on their roof, and there is a bit of snow covering the panels.  The two photos below are to indicate the tenacity of snow cover over the panels.  Their roof slope is 3 in 12 (14.0deg from horizontal).  Ours is at 8in12 (33.7 deg).  As I mentioned, the snow arrived two days ago on a cloudy day.  Temperatures yesterday were below freezing all day, with night time temperatures about -9 deg C and daytime about -3 peak.  Some sun yesterday.  Last night was similar, and the sun came out earlier today so at 10am (when both these photos were taken) it has risen to about -3 C already, and sunny.  You can see the roof angle makes a significant difference.  On the steeper roof, the snow was actively shedding and within about 1/2hr after the photo was taken, pretty much all the snow had slipped off the panels.  It is great when snow slides of panels - it has a cleaning effect due to the slight rubbing.  I'll be monitoring the snow over the next few hours and days and months and updating this posting.  There are is a lot of knowledge and data out there on how much sun solar panels receive based on their angle and local climate, but less information on how the panels shed snow or dust, which appears to be a bit more complex and difficult to figure out (due to a lack of experience).  One thing I can suggest for low-slope panel installations: frameless panels such as these from Lumos (photo from
 - these will probably shed the snow a little more easily, I suspect - but no real data, as far as I can tell.  But I would want this kind, just for the improved appearance.  A number of manufacturers offer them.

Sunday, November 2, 2014

High Efficiency and LED Lighting for Passive Houses, Again

News:  Cree recently announced another breakthrough in LED technology:  a commercially available LED with a new level of efficacy:  200Lm/W  !  This is only a chip at the moment, but it is available for purchase - and this is of great interest to makers of flashlights, at the very least. For actual luminaires, they offer a troffer, 2' x 2' for commercial applications performing at 150 Lm/W, not necessarily with the same chips - I don't know.  Pretty awesome performance, and I think people are already aware of their other items I've mentioned in the past  - I have no affiliation with them, but their news seems to reach me easily.  Here is the troffer (it has a CRI of over 90):

The complexity of switching to LED lighting keeps surprising me.  At first I began to learn about the three main specs:

  1. Efficacy (Lumens per watt)
  2. CCT - Correlated Colour Temperature
  3. CRI - Colour Rendering Index
Armed with just these 3, one goes shopping for energy efficient LED replacements or integrated fixtures. Very quickly, we find ourselves surprised at the field of offerings. The first surprise is that all the major manufacturer's offerings are low-efficacy, offering usually not more than 60 Lm/W. I scoffed at this, in error. The next thing you run into is that there are often no claims of efficacy on some products, and then frequently, there is no certification label. Never mind the CRI - which hardly ever appeared. Then, we were in Costco the other day and found this:

The Luminus product. It lists all three main specs, and carries all the certs, and the purchase price (it was a sale) was $5 ea! Pretty impressive to find a product with this level of efficacy, at this colour, with a CRI of over 85, and at a $5 price.

Yet, looking around we find highly acclaimed products like this one from Soraa:
Which uses a different LED technology - GaN - I assume this means gallium nitride. At 54 Lm/W for the 3000K MR16 bulb, one is not impressed by the efficacy. But look at the CRI - 95% - a figure you just can't find in the common PC (phospor coated?) LED technology.

And then I discovered LED Benchmark ( These are the same guys doing benchmark testing of things like video cards and hard drives. I highly recommend their website, where you can expand your knowledge of LED lighting beyond the three main specs. They also have comparison with halogens. It was there I found that we can go beyond to also look at:
  • Flicker
  • actual performance
...and we find that many of the lesser-known product offerings (the cheap ones generally) frequently do not live up to their claims of efficacy, colour rendering, or even colour temperature. And all those low - efficacy major brands? Often they have sacrificed efficacy for colour rendering and reduced flicker. Having purchased a number of LED products now, I can confirm that flicker and CRI are important measures of light quality and should be given significance in the purchase decision. I am now, unlike before, willing to compromise on efficacy to get a light that has no flicker, and a high colour rendering index.

The photo above shows an LED chip I bought on Ebay.  It claims a 1000 Lumen output.  Using my lab power supply, I found it consumes only about 4W, so I highly doubt the claimed output.  The colour is warm white, as claimed, but the light quality was terrible - I'm not sure why, but probably CRI is low, and flicker high.

The photo above shows an LED chip I bought on Ebay. It claims a 1000 Lumen output. Using my lab power supply, I found it consumes only about 4W so I doubt the output is more than 500 Lumens. The colour is warm white, as claimed, but the light quality is terrible - I'm not sure why, but probably CRI is low, and flicker high.

The following 5 photos show commercial lighting quality hardware. We were very lucky to come across a batch of these on Kijiji and bought about 60 trimless recessed light fixtures (two types shown below - these are RSA brand by Cooper). These are about $200/fixture plus about $65 per trim ring. Costly when you consider a house can easily have 100 recesssed lights. We got them for about $6 ea, so we are installing these - they are low voltage (12V), with a solid -state voltage converter per the photo.

 I was interested to know the quality of the output waveform on these, wondering how the LED lamps would respond. But the output frquency is about 40kHz. A little high for my old oscilloscope to read well.

These are the fixed trims for the RSA trimless pot lights.  There are adjustable ones, and square ones for the square version of these lights also. This is a used one, of which I have only the one.

These are the trimless lights. They come with mounting bars and also butterfly clips, but I just didn't like the flimsy-ness of the mounting, so using wood rails - I got 50 of the white square ones below. An interesting feature is that since these are all trimless, they are mudded right into the ceiling drywall. This means no removing and replacing the fixture - but there is a facility to service them - the fixtures are designed so you can reach inside the opening and remove steel covers to service the wiring and the voltage converter as well.

Monday, October 20, 2014

New Technology Renewable Energy System:

Wow!  I just had a 2 hr conversation with Bruce Gray.  It was at a presentation organized by Terrell Wong and Kathy Garneu, here in Toronto. Bruce is the inventor and founder of a disruptive technology called Sunpump, (see located in Vancouver. They have a new heating and cooling technology that blows everything else right out of the water.

It is a major shift to a new way of the using the very familiar vapour compression cycle. We're all familiar with the mini split heat pump. They have been around quite some time, and over the years, their efficiencies have improved. In the last month or so Mitsubishi released (in Canada) their FH09 mini split heat pump with a SEER rating of 30.5. That is news in itself! But tonight, I learned about something even better.

The Sunpump is a heat pump combined with a solar thermal panel - but there is no glycol, and no water. The thermal panel hosts refrigerant. In addition, there is no outdoor fan. The thermal panel sits on the roof or on the wall, and exchanges heat with the sun and the environment, without any moving parts on the outside of the building. The panel is a solid plate of aluminium with many small channels running through it. This configuration is classically difficult to produce - but the company has overcome this challenge with the employment of 3D printing, so the panel is not two sheets stamped and brazed or somehow fused together. It is a monolithic plate. It is anodized to be blackish, and has a hydrophobic coating on it. What is amazing about this whole concept is a number of things - and I feel dumb for not having thought of it - but the elegance of the whole configuration is just wonderful. Unlike regular evacuated tube or flat plate solar panel systems, there is no stagnation, no drain-back, no thick lines to the roof (the copper lines are 1/4" and 3/8" dia), no freezing, no glycol, no pump, no fan, no nothing. The system is very economical to purchase because there are so few moving parts. The only moving part is the compressor rotor and perhaps a valve. But efficiencies are huge! Studies show that installed COPs of mini splits are about 2.5 and groundsource heat pump systems, 3.5.  This new technology has a COP of about 7 or 8, in the installed condition, and I think these numbers are not exaggerated. If you are a little familiar with heat pumps and heat transfer, you'll see why. Even evacuated tube solar panels have working fluids (water, glycol) that struggle to take heat from an environment that is say -5 Celsius or colder outside.  But when you have direct exchange with the R410a refrigerant, which is operating at much lower temperatures, you can extract heat from much colder ambient conditions. In addition, because there is no fan, there is no bulk movement of air over the heat exchanger (in this case the panel - in a regular mini split outdoor unit, it is a finned heat exchanger). This means there is no freezing of moisture on the heat exchanger, and a significant portion of the heat exchange is carried out via radiation. To top it off, the company also offers these panels with PV cells grafted onto one side - so you can get electricity (just like a standard PV panel) as well as heat. There are numerous hybrid panels on the market, including PV with Air, PV with water/glycol - but this is PV with R410A refrigerant. This is a big step forward. And, finally, the system's output side seems available in more than one configuration (which was always something I hated about mini-splits - their lack of ability to have a hot water output at a good price). Sunpump offers their units with hot water outputs as well as straight refrigerant outputs - so their systems can work with hydronics as well as air-based HVAC systems. BTW, the system cools as well as heats.

Costing is only about $1/watt of total output - I believe this includes the panels, accessories, and heat pump. This means the system is cheaper than many many systems out there, and I think will even compete with the low price of natural gas in North America. Apparently they intend to compete on installation costs with electric baseboard heating!

The company is well developed already, has sold much product, and has CSA approvals on their products also. And the panels produce some 7 to 8 times as much energy as regular solar PV panels today produce (!!! - I know !). They also have partnered with a financing company so builders can have these panels for ZERO dollars down - the company recoups the money by having the consumer pay their energy bill savings towards the loan.

So, this is the biggest, baddest news out there in the world of energy systems. Absolutely must look into this for every project, not even just low energy buildings. Remember the panels work at all hours of the day, (the thermal aspect of them), and on all sides of the house - they are about twice as productive on the south side, but even on the north side, they perform well compared to other heat pump systems.

I discussed groundsource with Bruce as well.  He said their testing showed ground source loops to eventually degrade in their heat transfer capability due to freezing and shifting of the soils around the pipes - but the performance potential is ultimately limited by the working fluid. There have been what are called direct exchange systems in the past, in which refrigerant is passed directly into copper pipes in the ground - but the copper seemed to be unreliable and developed leaks, etc.  (I 've heard also of the difficulties in these systems). One great advantage of the groundsource system is that they tend to store the summer's heat in the ground, and then, later, store the winter's cold in the ground as well, reducing both heating loads and summer air conditioning loads. This system does not have an inherent storage aspect like the groundsource, but the simplicity and greatly increased efficiencies seem to me to make things much more worthwhile with these thermal panels - ultimately groundsource has some environmental issues and is really quite expensive, as well, and involves a fair bit of plumbing and pumping. The Sunpump system does away with that. Storage can be added to the system of course, with the use of a water/ice tank.

So - it is not often I am impressed with a new product - but this is one of those times. The concept is absolutely fantastic, and the product appears to have great potential.

Actually, I was badly conflicted in writing this article. They are currently in explosive growth mode, so production is very tight and it may be hard to get a unit right now - and of course, I want one, so I didn't really want to tell everyone about it - but hey - must do the right thing......and tell you all.

Have at it!

Wednesday, August 20, 2014

What Engineers Should be Doing

Sure, I'm building this net-zero passive house.  It is taking too long because I want to put so much into it, and because I'm also busy trying to earn some money to keep things working in the family, in the project.

But recently one of my engineer colleagues, Lukas Vos, left Toronto to seek out a deeper meaning - he's actually been seeking for some time, but he went to northern Europe, took a bunch of photos (here and he's constantly out there learning about our world so he can make a difference in it.  I was reading his stuff and I realized, that I have so far to go!

So I asked myself:  What should an engineer be doing in this world, at this time?  Do a google search and you come up with basically nothing.  For some time now, I've been learning and learning about the technical aspects of how to build a house that is nearly self-sustaining.  The answer can be summed up simply:

  1. Build a net-zero energy Passive House.  - This has been my focus, but it leaves three major aspects of sustaining our present human lives unaccounted for:  Food, Water, and Waste (I'm assuming everyone already has enough sex and oxygen - for now).  So for these other 3 aspects, I have also been learning about:
  2. Food:  Design and build a permaculture garden/farm - see Geof Lawton Videos for more on this.
    consider including aquaponics
  3. Water:  See # 2, but also use rainwater collection, filtration, and a recirculating shower
  4. Waste:  implement Eco-sanitation - see the current eco-sanitation project in Haiti - basically harvest human waste for the incredible resources it offers - this is simple and useful
These 4 points, as best as I can tell are the basic directions we must all move towards.  I'm slowly figuring out that what an engineer should be doing is basically becoming an expert in the above, then going out into the world to help others achieve...the above - in the most ecological way possible.  Life's work, here I come.

Tuesday, July 15, 2014

Green Plumbing Design and Urine

Pic of the house - nothing to do with this blog post.

Well, maybe I was the last to know.  Our wonderful urine is a fantastic resource we have been wasting!
Its a bit late to incorporate this into our house project, but with a little reconfiguration, we can make some big improvements.
Basically, the thing we need to do is collect our urine - not throw it away.  It is full of excellent nutrients plants love - like nitrogen and phosphorous - and it carries these nutrients in forms easily accessible to plants.  Addiing urine to plants can double their yield, says Patrick Makhosi from Uganda.  Our urine is sterile for some 24 hours after pissing - after which time, the urea begins turning into ammonia, and that pee smell starts to waft out.  We can apply it to plants diluted.  Heck lots of details on the internet, like here:

So back to plumbing.  The big deal is that while urine is great for plants, it is bad for rivers and lakes - giving rise to algal blooms, which can spell death for the other animals and plants in the waterways.  Urine's nutrients are difficult to remove from the sewage once it is in there - so the best thing to do is to plumb our houses and buildings to separate it at the source - And now, looking at our plumbing fixtures, we can only conclude that as a society, we are embarrasingly primitive - All the time I was made fun of in school for talking about our bodily fluids, but who knew!  There is no urine separation!, and there is no proper urinal for women!  Meanwhile we are polluting our waters like idiots.  We should all be pissed that our scientific and other leaders led us so far astray.
A long time ago, before I ever designed my first house, I wanted to have a washroom with two toilets.  It was not for separation of urine from poop - it was because so much productive talk was happening while I was on the John - so I figured I might as well invite the person to join me, except it wouldn't be fair if they didn't have a toilet, too.  But now I see a much more acceptable reason for having this feature in a house.  The one toilet dedicated for urine would be such that our ratio of water to pee was between 15 and 30,  to 1.  Then we don't really have to add the water later.  The whole thing would go to a P-trap, then to plastic tank in the basement or somesuch, which could then feed the garden  - hopefully with gravity feed. - I'm sure there will be people who tell me this is not a hygienic system - I'm all ears.

All the while we haven't even started talking crap.  Next time?

Saturday, May 10, 2014

100 in 1 Day Toronto

What if hundreds of people united, each putting in place the changes they wish to see in their city, all on the same day?
On 7 June 2014, for the first time-ever, Toronto will host 100 in 1 Day.
This citizen-driven festival will unite people across the city to make Toronto a better place by creating acts of urban change.
These acts, or interventions, have the potential to raise awareness of urban and social issues, inspire ideas, and motivate leaders to consider new approaches to old problems.
From 2-4 pm, we will be hosting Net Zero Passive House Tour
We invite the community to come and see what we've done with our house project to minimize our ecological footprint. The design directly targets net zero energy and passive house certification and aims to achieve this at no cost premium. The tour will include a presentation of features and strategies to make the most of every opportunity to improve performance, comfort, function, and versatility. 
Note: As the house is currently under construction, the tour will not be suitable for children and those with mobility challenges.
Do you have an idea for making Toronto a better place? Share it here:

Tuesday, February 4, 2014

Smells, Moisture, CO2 and Indoor Air Quality in Tight Houses

In past blog posts, I've noted various areas in which we are in a technological revolution - including lighting, renewable energy, energy storage, not to mention high performance buildings and windows..

But smells!  The science of smelling/sniffing is definitely in its infancy, but the potential for advancement to yield results is huge.  I looked into this just today because I've been working on our ventilation system, and we happened to install the PAUL Novus 300 HRV (probably the most efficient machine on the market).  But effective and efficient ventilation goes well beyond the heat recovery efficiency.  The energy demands of the ventilation strategy have a lot to do with sensing and control.  (And this was the main reason we chose the Novus. It allows up to 4 channels of control.  )

The ventilator should slow down when users are not occupying the house, or windows are open, should ramp up when users are having vigorous activity in the house, or there are a lot of people in the house, and should operate with a big imbalance if there is a vented dryer in operation or a vented kitchen range hood.  What if 6 people took a crap nearly at the same time?  The indoor air quality could be very poor for a while.
So, to minimize energy demands and maximize effective provision of fresh air to house, I would consider sensing the following, in order of importance with first items most important;

  1. CO2
  2. moisture
  3. Pressures inside and out
  4. windows and doors
  5. smells (!)
(this listing is not including the CO sensor - which could be important if you have gas appliances).

Using CO2 sensing, one could minimize the delivery of fresh air to the house and not over-ventilate.  It would also take into account the presence of more or less people and plants, and probably even fires.  CO2 sensors on the market for HVAC applications (there are also lots for greenhouse applications) are about $300 with NDIR (recommended) sensing systems).  Companies like Honeywell, GE, Senseair all make them).  You can get desktop CO2 monitors on Amazon for about $150.

Moisture sensing is important to protect the building contents, but more importantly to protect the structure, and prevent mould formation, etc.  But don't forget to protect houses from dry conditions also - moulds wont' grow, but anything made of wood will shrink and crack - very low humidity is just as bad as high humidity.

Pressure sensing would compensate for any other exhaust fans as well as open and closed windows.

Smells! - what if someone were to be using a harsh paint, or a cleaner, or indeed, the washrooms.  The science of gas analysis (all smells are due to gases in the local atmosphere) applied to smells has incredible implications.  For example, this company says they can make electronic sniffers that can detect pathogens in the air - this means one could potentially detect a virus in the air in one's house, and record that event in a log.  By smell detection, the house could 'know' when the washroom was being used, or when cooking was being done, or when there was a fire, or when laundry is being done, or when mould was growing in the walls (!), when animals have nested inside the attic, perhaps, or when the outdoor air is more polluted than the indoor air.
There is much to read online regarding electronic noses.  The process of technological smelling involves 3 steps:  acquiring a standardized sample, detecting the chemicals in the sample, and analyzing what was detected.  This last part involves a fair bit of software, including databases - because various odor events are logged as a certain configuration of results form the gas chromatography or whatever detection method was used. - the device needs to learn and grow its knowledge to be effective.

All the above is another way for me to feel good about all the low voltage wiring we've been putting into our house - we'll have the built-in ability to employ sensors all over the house because of this, and things are telling me the future of buildings will have a lot to do with sensing.

Thursday, January 30, 2014

How Best to Plumb a Drain Water Heat Recovery System

If you are not sure what a drain water heat exchanger is, google it or read the following:

Here's a couple pics of our installation:

Below I summarize salient points on this concept/product, and then give my thoughts.
  1. Cost is $500 to $1200 for the item.  Installation is extra.
  2. Go with the largest diameter and longest exchanger you can fit into your plumbing, assuming a vertical installation.  There are horizontal ones available from , in which case, I'm not really sure - but I think they have just the one size.  Leave at least a 12" (0.3m) of straight drain pipe above the exchanger to smooth out the flow.  You can see we've done this, and we've used 4" pipe
  3. It is still worthwhile to pump shower drains in the basement back up so they can drain into the heat exchanger.  Cost of these Gulper pumps with a kind of control that senses the water level in the drain is something like $300.
  4. Gather all your drains to one place, if possible.  In our case, we've done this with all the shower drains in the house, which all happen to be clustered together in the building.
  5. Savings of some 50% on water heating energy are possible depending on how things are plumbed in the house and cost of energy.
  6. Hot water recovery times can be dramatically improved - this, to me, is a very sure sign of energy being saved.
  7. The design requires a double walled heat exchanger - in other words, there must be an air space between the copper pipe carrying the drain water, and the copper pipe carrying the potable water - this severely limits the efficiency of the unit, and increases the costs - more on this later.
  8. Gravity film - surface tension effects cause the drain water to stick to the drain walls in a thin film - this is why heat exchange is arranged at the surface of the drain pipe.
  9. Simple payback periods range from 2 years to 10 years.
My Thoughts:

Leaving water in the Bathtub  One comment I've read is this:  Recover your 'waste' hot water heat by just leaving the shower water in the bathtub and letting it cool to room temperature before allowing it to drain away.  This is an excellent measure, and no cost to install, but it has some issues:   - first, it adds moisture to the house - good thing in winter, probably,  not so good in summer.  2nd, only possible with bathtubs, showers can't hold much water.  3rd, ring around the tub, 4th, it gets difficult to have multiple showers in a short period of time - such as on busy mornings with a family of 4, and 5th, don't assume it is 100% heat recovery.  The water in the tub cools only to room temperature, which is almost the halfway-point from the cold water inlet temperature to the 40deg C or so needed for a shower/bath.  So heat recovery is something like 60%, similar to a good drainwater heat recovery installation.

Efficiency:  The best units are limited to something like 60% efficiency - measured in terms of inlet and outlet water temperatures. Industrial heat exchangers are good for over 90%.  Even over 95% in some cases. A much more 'effective' design, would be to simply have a copper drain pipe inside of another larger, plastic pipe filled with the pressurized, cold water.  This would increase heat exchange efficiencies a lot (to probably above 80%, easily more), and reduce the cost of the units greatly as well, and also reduce the pressure drop incurred by the units we use today.  Given the huge potential for energy saving across a nation like Canada, one would think it is possibly worth the very small contamination risk - after all, if ever there were a leak, the pressurized water would go into the drain, not the other way around, and it would be fairly easy to detect - just check the water meter while all fixtures are off - perhaps an annual check would be worthwhile.  Imagine - if we could recover 95% of the energy used to heat hot water for bathing, small electric point-of-use hot water heaters would be so much more viable (read my post on POU Hot Water) - they could be built right in to shower fixtures, and this could lead to all sorts of interesting plumbing configurations (just plumb one line, for example - no need for both hot and cold?).  I can see Doc saying "What, are we in the Dark Ages?!".

Alternative Strategy: One way around this is to avoid the issue altogether.  Instead of directing reclaimed heat to the DHW system, transfer it to the space heating system instead - ie to a non-potable heat sink - such as a hydronic heating component, or direct to refrigerant in a heat-pump system.  This avoid the water contamination issue, and can recover much closer to 100% of the energy used for heating water.  Sadly, I know of nothing on the market that does this as yet, but it would be very easy to build something - a coaxial pipe heat exchanger is all you would need.
Another thing not being explored - use heat pipes to do the heat exchange work - this would probably increase the options for horizontal exchangers.
And yet another approach involves using an auxiliary tank and a pump - so we recover heat even from processes like clotheswashing and dishwashing, in which the hot drainwater is not expelled at the same time cold water is being drawn in.  Here is a link to one company to doing this:

Installation:  You can see there is a lot of copper in these things - the one pictured was a good 60 lb.  We came up with a simple way to mount the item effectively.  We used a 4" water closet flange.  We removed the small groove inside this flange so the 4" ABS pipe could be passed right through.  This is basically creating a bulkhead fitting on your pipe - but there is no break in the pipe.  Glue it on with solvent, and then mount to a couple of wood runners.  Makes a good support.  Notice also we've installed unions around the exchanger - this will let us more easily check its insides from time to time and clear out any build-up.

Water Pressure Losses from Drainwater Heat Exchangers:  Something not mentioned too often:  What about the pressure losses?  The one we chose to install uses a single 3/4" copper tube (about 60 feet of it) wrapped around the 4" drain.  In choosing a product, it is a matter of heat exchange performance and this is measured by the Canadian government testing apparatus, so after finding units that perform well, we looked for designs that retain water pressure the most, and most robust.  So how to plumb in order to retain water pressure?  If you have high water pressure, this may not be an issue, but keep in mind, water pressure is not free.  Someone, somewhere, must provide it, and I feel we must always think of our buildings as 'off-grid', so we want to minimize energy losses at every opportunity.  Therefore, buy a unit that performs just as well, but results in the least pressure loss.  then, I would plumb everything through it.  After all, we heat a lot of water to just room temperature via space heating - it sits there in the toilet, in the pipes, etc.  But to recover that heat using the drainwater heat exchanger, the cold side must flow - therefore, as per manufacturer recommendations, just plumb everything through it - I would still provide a small line to a drinking water fountain or icemaker, however.