Protective Coatings to Prevent Corrosion

How Copper can be used in highly- efficient Water Heating

After central heating, heating water is the second biggest user of energy in the home.  Combustion gas appliances that heat water only at the time it is required provide an energy-efficient alternative to storing store pre-heated water in an insulated tank.

Tankless gas hot water heaters can achieve efficiencies greater than 96 % using gas heating equipment that condenses water vapour from combustion gas and captures the latent heat of condensation.  Copper is the preferred material for transferring heat from combustion into water because of its ease of fabrication and high thermal conductivity.  However, copper heat exchangers used in the highest efficiency condensing water heaters are susceptible to corrosion.

Giving Copper the Edge

An effective anti-corrosion coating would increase copper use in high-efficiency heating equipment and give it a leading edge over alternative materials.  It will also pave the way for copper condensing heat exchangers in combustion air-conditioners and commercial gas boilers.

A range of protective coatings have already been identified and tested, and new heat exchanger designs explored.  Preliminary results with chemically grafted cotaings are promising, and the best-performing coating solutions are undergoing further evaluation to test their performance in end-use environments.