Slurry ice

Ice slurry (English ice slurry ) is a heat transfer medium and is a mixture of small ice particles ( 0.01-0.5 mm ), water and a freezing point lowering agent such as ethanol, salt or glycol. Heat carriers are commonly referred to as cold carrier if they are intended for use below 0 ° C.

Properties

Frazil ice as refrigerant has the following properties:

• High specific heat capacity and high specific enthalpy of fusion
• Large heat transfer coefficient
• Readily pumpable
• Non-toxic (especially systems with saline or ethanol)
• Due to the high heat capacity, the flow rate can be reduced to half in the system
• Characterized the pump capacity is reduced to a quarter
• The heat exchanger need no or only minor modifications
• Simple increase performance of existing systems by the use of ice slurry is possible
• No ice storage and heat exchangers necessary, the spoke rice is pumped directly as refrigerant
• Frazil ice in direct contact cools faster and gentler than flake ice

Ice slurry is an environmentally friendly refrigerant with high energy density because the enthalpy of fusion of ice ( latent heat) is also exploited. Unlike conventional refrigerants or brine systems, the formation of ice particles is therefore intentional.

Unlike the mixture of water and antifreeze as a single-phase heat transfer fluid is a two-phase slush refrigerant. With decreasing temperature, then first finds a partial segregation instead, and there are small spherical ice particles diameter of about 0.01 to 0.1 mm, surrounded by an ever more concentrated antifreeze solution so that there is just above the solidification temperature of ice slurry.

In order to counteract solidification by connecting the ice crystals, the ice slurry must be kept in motion; for example, are storage vessels be equipped with stirrers. The lower the operating temperature, the higher the required proportion of antifreeze is (of course only up to the eutectic).