Tuesday, September 20, 2011

Heating and Cooling

We finalized the design for the heating and cooling system today.

Heating will be supplied by a 30Kw Baxi Condensing Boiler with 16 panels throughout the house. The panels, and the AC ducting are marked in the drawings below.

The refrigerated cooling / AC will be supplied by a Toshiba mini-split system, with 5 indoor units, and a compressor outdoors. See the below Toshiba schematic for more detail

Cummins Contracting will be doing the all the work for both the heating and cooling.

The things that surprised me most was (a) the overall expense of the cooling system (2x the cost of the heating system), and (b) the oversizing of the cooling system.

My own heat load calcuations show that the 5.6kw units could be 3.5kw (and still 50% oversized) and the 8kw bedroom could be 5.6kw. The cooling contractor however tells me that it will barely make a difference in cost to go with smaller units, and if it gets hot, the bigger units will cool down the house faster after the AC has been turned off for a while.The units are "inverters", and only run at the load they need to run at.

I'm also looking to integrate all this into the home automation system. We're using an HAI Omnipro security/automation system. We'll be pairing the boiler with an HAI omnistat2. Controlling the cooling system is more complicated, and I'm looking into using the Coolmaster 3000T to achieve this.

Wednesday, September 7, 2011

Frame Complete

It's been a busy past week or so as I get ready to head back to Seattle. Hopefully this will be the last trip back to Seattle for some time.

This past week I've ordered 160m2 tiles for the bathroom - La Perla (white) limestone from RMS in Brunswick here in Victoria. It's going to fill up 5 pallets and weigh close to 5 tons.

I've also ordered 300m2 of hardwood floors. I'll be using a pre-finished timber from Tait Flooring here in Melbourne. It's a 6mm European Oak veneer stuck onto a plywood substrate - it makes it a lot more stable (resistant to cupping), when you order wide planks that Claudette likes.

The good news for me is that it comes pre-finished with 7 coats of paint, so all I need to do is cut it to size & lay it.

Also this past week, I've met with the heating & cooling contractor to determine what we're doing for Air Conditioning and Radiant/Hydronic Heating. I need to supply gas loads for all the appliances to the plumber so that he can run the right size gas lines. To complete the picture I need to send him the heat loads for the swimming pool heater, and work out the size of the hot water system.

It took a while to evaluate options on the hot water heater. I considered 2 units (one for each wing of the home), and I considered a solar heated unit (with panels on the roof and a storage tank). In the end I opted for tankless hotwater system.

Rinnai make a 32 Litre a minute, environmentally friendly condensing instant hot water system that's almost 7 star energy efficient, so we'll be using one of those units.

Also this past week the carpenter has been busy putting up the roof trusses, and has started building the parapets that will hide the box gutters, and the central feature tower. They expect to have the frame finished up on Friday.

With me headed to Seattle tomorrow, it's going to be a while before I post the next update.

You can see more in the below photos.