Heat Pump Designs 
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Air Source Heat Pumps.


Refrigeration circuit in an air source heat pump

Air Source Heat Pumps.

Air Source heat pumps extract heat from ambient air.
The refrigerant circuit then takes the low temperature energy and upgrades it in
the vapour compression cycle to provide a higher temperature heat source that
can be used to heat a heating circuit or a hot water cylinder.
The correct selection of an air source heat pump to match it's heat output to the
requirements of a building on the winter design day it vital to a successful
The efficiency of a heat pump is higher if a low temperature heating circuit is used.
The correct design of the heating circuit to best match the operation of a heat pump
will result in a sucessful and efficient installation.
Coefficent of Performance
The efficiency of a heat pump is measured as the ratio of energy or heat out to the
electrical energy used. This efficiency ratio is called the coefficient of performance.
It varies with the air or ground source temperature and also with the temperature
of the water delivered to the heating system.

Ground Source Heat pumps.



Vertical Ground Loop         Horizontal ground loop

Ground Source Heat Pumps.

Ground source heat pump extract solar energy stored in the ground. This can be done
with a closed loop of polyethylene pipe containing an antifreeze mixture buried either
horizontally or vertically. Alternatively ground water or water from a river or lake can be
used in a open loop system.
The design of the ground loop, both thermally and hydraulically, is critical to the succces
of a ground source heat pump installation.
A ground source heat pump is usually more efficient than a comparable air source unit as
the ground temperature is more stable and higher  than the air temperature during the
winter heating season. Howeve due to the installation of the ground loop it is usually
more expensive to install initially.