www . refrigerationandaircon . co . za RACA Journal I July 2024 31
Project
The distribution stations with the variable speed drive ( VSD ) pumps can be seen on the left , against the wall . The distribution stations , together with the insulated tanks on the right-hand side of the wall , are the chilled water buffer tanks and distribution stations . These transfer the chilled water to the spatial cooling network . The chilled water is chilled with the full heat recovery heat pump , which cools down the cold buffer tanks and dumps all its heat in the hot water buffer tanks . The heat pumps , equipped with the desuper heaters , are reversible heat pumps which means that they can make chilled water as well .
The domestic hot water is heated from the hot buffer tanks . The two systems are seperated by a heat exchanger coil inside the domestic hot water tank to ensure the treated water in the heating system doesn ’ t mix with the potable hot water . In the picture below the insulated domestic hot water tanks can be seen as well as the backup condensing modulating gas boilers :
This is a highly efficient way of distributing hot and cold water . For example , we can circulate hot water in a ring main that is about 1.2km long , and we lose less that 1 ° C in the ring main . The foam is environmentally friendly and is ozone-inert .
The insulated trench runs throughout the lodge and supplies the buildings with :
• Chilled treated water
• Hot treated water
• Potable cold water
• Potable hot water
TREATED CHILLED WATER The chilled water from the insulated trench is sent to a fan
coil unit at each location that requires cooling . It is circulated through the coil of the fan coil , and air from the room is circulated over the chilled coil , thereby cooling the air down and returning it to the room .
We used fan coils from Aermec . These units are known and proven to be effective , reliable and quiet – which makes them the ideal units for our installations .
The fan coil is connected
Ceiling void mounted fan coils that are ducted .
to a ducting system that is connected to linear slot diffusers .
Domestic hot water tanks , Fondital condensing gas boilers .
The distribution stations are used to circulate the chilled water , hot water , potable hot water and potable cold water in an insulated trench . The trench is foamed with closed-cell polyurethane foam as seen in the picture below :
Linear slot diffusors – black linear slot on the wall above the doors .
TREATED HOT WATER The hot treated water from the insulated trench is used for :
• Spatial heating through the fan coils
• Hydronic underfloor heating for the bathrooms
• Heated towel rails
• Swimming pool heating
Before and after of foaming trenches to insulate piping to Monwana Spa , by Reliance Foam . The foam gun sprays a mixture of isocyanate and resinate through a heated gum . The mixture solidifies and expands on contact .
SPATIAL HEATING THROUGH FAN COILS : The spatial heating through the fan coils work on the same principal as the spatial cooling through the fan coils . We send hot treated water through the coil of the fan coil , and air from the room is circulated over the coil of hot water , thereby heating up the room .
Hydronic underfloor heating for bathrooms : The hot treated water from the trench is also sent to the
www . refrigerationandaircon . co . za RACA Journal I July 2024 31