298 94 307/02 Untersuchungen zum Stand der Umsetzung des ...

Teil 3 Seite 4-8
heat exchangers, pipes and vessels, as well as contamination with oil and the use of
harmful brines (e.g. ethylen glycol etc.) in high concentrations.
b) Emissions: In direct expansion refrigeration plants the amount of refrigerant is
high since not only the (larger) refrigeration plant but all heat exchangers including
pipes are filled with refrigerant and oil. For safety reasons harmful HFC is preferred
(global warming); otherwise toxic ammonia or carbon dioxide must be used, the lat-
ter bringing the risk of suffocation. A leakage would release refrigerant (and oil) to
the environment, and leaks from. Indirect cooling plants with toxic fluids at relatively
high concentrations would be harmful. Binary Ice made from water and alcohol is in
the lowest "water hazard class" and can normally be released to the sewage system
with the permission of the local authorities.
c) Cross-media effects: Binary Ice is an answer to the uncertain future of HFC refrig-
erants and satisfies the requirements for "natural" refrigerants due to the options
available. Binary Ice plants can operate with HFC, ammonia and hydrocarbons.
Operational data
Energy content of the fluid (enthalpy) and resulting advantages for pipes and pumps:
Chilling
Brine (typical) temperature difference 3 K: 11
kJ/kg
Binary Ice 10 % ice crystals; 3,0-fold: 33
Freezing
kJ/kg
20 % ice crystals; 6,0-fold: 66
kJ/kg
Brine (typical) temperature difference 3 K: 9
kJ/kg
Binary Ice 10 % ice crystals; 3,7-fold: 33
kJ/kg
20 % ice crystals; 7,3-fold: 66
kJ/kg
The amount of fluid to be circulated is between 4 and 7 times higher for
brine compared to Binary Ice. This has an immediate effect on pipe diame-
ters, which can be approx. 50 % (!) smaller. The reduced pumping power is
considerably reduced and is approx. 70 % (!) smaller than brine systems.