solar hot water

MCNZH - Progress (part 7) - stucco, hardwood, moving in


The Mill Creek NetZero Home is substantially completed.

The stucco is finished on the outside. We went with a cement-based stucco because of its looks and durability.

Peter Amerongen built a brick wall behind the wood burner. We used the bricks from the foundation of the house that used to be standing on the property. This wall adds more thermal mass (to capture both solar and wood heat) to the house, as well as a bit of history.

IMG_1980  read more... »

Solar Hot Water (Part 2)



The lessons that I learned from the computer model of our solar hot water system are as follows:

  • insulate the pipes leading from the basement to the collectors to at least R6, preferably R10
  • insulate the storage tank to R50
  • install a 1000 litre storage tank
  • install 3 collectors
  • there is extra heat - install a system to harvest it

We bought the collectors, drainback tank, pipe insulation and other knickknacks from Trimline Design Centre just down the road from the Mill Creek NetZero Home. My builder Peter was very impressed with the clever, simple design of the flat plat collectors that Trimline manufactures. Yes, that’s right, they manufacture solar hot water collectors right here in Edmonton!



(schematic of the MCNZH solar hot water system)  read more... »

How Much Energy Does It Take To Supply Hot Water?

I read an interesting article recently about how to calculate the size of an on-demand hot water heater.  OK, while not exactly what most people would consider light reading, what I thought was interesting was how much energy it takes to generate something we take for granted.  The article discussed how running a single shower would require the incoming water to absorb energy at a rate of about 75,000 BTUs per hour and that if the tankless water heater was 80% efficient, then the heater would need to have a rated input of 94,000 BTUs per hour.  If you want the ability to run two showers simultaneously, then the numbers double so that the tankless water heater would have a rating of 188,000 BTU.  (For reference, the boiler I have for heating my house and domestic hot water can modulate  read more... »

Solar Hot Water

**EDIT, March 2011 **

The modelling that we did with WATSUN (and upon which this blog post was based) was completely inaccurate. It hasn't been near 100%. In January our tank sits at 20 degrees, and it fluctuates between 25 and 40 during February. Not even close to what the software promised us.

I'm not sure what happened, but modelling with WATSUN was a complete waste of time for me.

Our solar fraction is probably in the range of 60%-70%.

The Mill Creek NetZero Home (MCNZH) will collect solar energy in three different ways: using passive solar design, using photovoltaic (PV) modules, and using solar hot water (SHW) collectors. The SHW collectors are the ones that heat water - they are the black ones at the top of the above picture.

According to a recent article in Home Power magazine (Oct/Nov 2008, p.40), SHW collector efficiency is 50%-70%. That's pretty good when you consider that the best PV module is about 17% efficient.

I've been contemplating the design of the MCNZH's SHW system for months now. The pieces started to fall into place once the federal government released a crucial tool: The  WATSUN 2008 SHW System Simulator.  read more... »