By Richard Keech
2018-08-14
Do solar air heaters or coolers live up to their promise?
At face value the idea of having a device which uses sunlight directly to heat air in winter seems like a good one. It’s the idea behind a number of products on the market that promise really high-efficiency heating for low cost. We can lump these together in the category ‘solar air heating’. Solar air heaters sometimes claim thermal efficiencies greatly in excess of that possible with a solar PV panel.
By Richard Keech
2018-08-12
Some systems used for heating and cooling depend on air displacement. Understanding what this means is valuable, because systems like this are usually inefficient.
So , what do 1) evaporative air conditioners, 2) fireplaces; and 3) solar air heating systems have in common? Answer – their normal operation usually requires air displacement.
If you know a little about insulation then you’ll already know about R values. However, to really understand insulation you also need to know about U values and K values.
2018-07-29
By Richard Keech
by Richard Keech
2018-07-12
I thought this picture neatly shows the limitations of passive panel-based heating such as hydronic or column heaters. The thermograph shows most of the heat convecting to the ceiling, allowing much of it to be lost before it can reach the occupants of the room. This is one of the main reasons I never recommend hydronic-panel heating. In-slab hydronic doesn’t have this problem, but it does have other problems.
On Wednesday June 27 2018 I spoke to Lighter Footprints, a community group in eastern Melbourne, on home batteries. Here is the presentation.
The presentation references a spreadsheet model for efficient homes with batteries. You can find it here.
Yesterday I was enroute to a country client for ecoMaster. I found myself at sunrise driving past the Waubra windfarm at sunrise. Too beautiful not to stop and take a picture or three.
By Richard Keech 2018-06-23
There’s some debate about whether the best configuration of split systems for multiple rooms is to have multiple single splits or to use multi-splits.
By Richard Keech 2018-06-18
Increasingly split systems are used to heat and cool entire homes – not just single rooms. The default way that split systems are deployed is what I call single splits – one outdoor unit piped to one indoor unit. And repeat that configuration for each conditioned room.
The alternative, available from many vendors, is a multi-split. This configuration involves more than one ‘head’ unit for each outside unit. Often a whole home might be served with only one (larger) outdoor unit, and heads in all bedrooms and living spaces. Continue reading “Multi-head splits vs single-split systems”
