Earth-improved heat-pump operation

This outlines a possibly novel approach to improve the efficiency and effectiveness of heat pumps used for home heating, cooling and hot water. This involves placing the units in the sub-floor space to exploit the thermal mass of the ground in both summer and winter.

By Richard Keech


Heat-pumps are sometimes positioned under homes. What if this could be done in a way that made the systems work more efficiently.

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What’s up with Hydrogen

There’s been lots of talk of late about a hydrogen economy.  I’ve looked into this. In a nutshell I can’t see Hydrogen being widely adopted for energy storage within our electricity system. Likewise, I can’t see it being widely used for transport except in some very limited cases.  Its use within the gas network seems like greenwash. However there does seem to be some potential in using hydrogen as an intermediate product in creating transportable liquids like ammonia, methanol and methane for use as export feedstocks or as fuels.

by Richard Keech

Published 2018-09-23,  based on investigation done in early 2017

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Solar air heating: is it worth it?

By Richard Keech


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.

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Efficiency and Air Displacement

By Richard Keech


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.

Evaporative aircon
Evaporative cooling and wood fires both involve air displacement

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Hydronic heat loss in one picture

by Richard Keech


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.



Multi-head splits vs single-split systems

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

2015-06-22 10.06.12.jpg
Multiple single-split systems can be an eye sore


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 (and sometimes referred to as unitary split systems).  These have 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”