Editor's Note: CR4 would like to thank Larry Butz of GEA Consulting for contributing this blog entry.

A recently released report from the International Energy Agency (IEA) shows how heating and cooling technologies that are energy-efficient can dramatically reduce energy consumption and CO2 emissions within residential, commercial and public buildings, a sector that currently accounts for around one-third of total final energy consumption.

The IEA Technology Roadmap outlined in a 55 page report Energy-efficient Buildings: Heating and Cooling Equipment shows how technologies such as solar thermal, heat pumps, thermal energy storage, and combined heat and power for buildings have the potential to reduce CO2 emissions by up to 2 gigatons (Gt) by 2050. What is most surprising is there are no technology breakthroughs or new technologies needed to accomplish this - the required technologies are available today!

Consider the four key technologies to efficiently heat and cool buildings;

• Active solar thermal systems, where water is heated by the sun for space heating, or, more commonly, for sanitary hot water use (Note that these are thermal systems, not PV solar)

• Combined heat and power systems, which simultaneously produce heat and electricity for use in the building or for sale to the grid (the heat produced can be used for space or water heating, and even cooling with a thermally driven chiller)

• Heat-pump systems (vapor compression cycle), which have high end-use efficiencies and can be designed to produce heat and/or cold, and depending on system design, produce these simultaneously and with an efficiency exceeding 100% (COP > 1)

• Thermal energy storage, which facilitates greater use of renewable energy, enables optimal operation of heating and cooling systems, and provides increased flexibility in balancing energy systems

The four key technologies need to be used together in an integrated system approach, i.e. use each proportionately depending on;

• annual heating profile for water and/or space heating and annual cooling profile

• local climate conditions

• relative timing of thermal and electric loads;

• space constraints

• emission regulations

• utility prices for electricity, and availability and prices of other fuels

• initial cost and the cost of financing

• the seasonal efficiency of the equipment

• building construction

• sound considerations

• complexity of installation and operation;

Better and more widespread use of our existing technologies is far more important than any new breakthroughs!

- Larry Butz