On 23/10/2019 08:58, alan_m wrote:
On 23/10/2019 02:18, Rod Speed wrote:

The better ones have bigger outside heat exchangers
that don't get so cold and so don't freeze up as much.

As a matter of interest how does the (air) heat pump technology overcome
the problem with freezing up.

At some point the pump is extracting heat from cold air reducing the
temperature of the "exhaust". If there is enough moisture in the air it
will start freezing making the heat pump less efficient. Once frozen,
and in a long cold spell of weather, unless the icing up is removed the
heat pump may not be providing any usefull gain. Does de-icing rely on
the efficiency dropping and so the external box is being heated by the
supplied power?


As with most green energyu projects, they let you down when you need
them the most...


--
Theres a mighty big difference between good, sound reasons and reasons
that sound good.

Burton Hillis (William Vaughn, American columnist)