HELP MAINTAINING FREEZE POINT CONTROL   In the Freezing Point Determination Test Kit we have assembled the apparatus needed to monitor the freezing point of ethylene glycol solutions, propylene glycol solutions, sodium chloride-based brines, and calcium chloride-based brines. The K-1540 consists of a 200-mm glass hydrometer cylinder and two hydrometers for determining specific gravity in the ranges 1.000–1.070 (for waters treated with ethylene glycol or propylene glycol) and 1.00–1.400 (for sodium chloride and calcium chloride brines); a correction table for sample temperature; plus the charts for cross-referencing the specific gravity reading with the percentage by weight/percentage by volume of the solution and its freezing point in degrees Fahrenheit/degrees Celsius. The assemblage is a welcome convenience for two user groups in particular.   In recent years the desire to conserve water and energy has resulted in greater reliance on closed cooling water systemsfor both comfort and process cooling. When closed water systems are operated year-round in cold weather zones, they must have protection from freezing. Food processors generally use propylene glycol solutions for this purpose. Elsewhere, ethylene-glycol-based antifreeze is commonly added to cooling water to make the water stay liquid at temperatures below its normal freezing point. The K-1540 will allow these operators to maintain correct freeze point control.   Thermal energy storage (TES) systemsare an increasingly popular way to provide chilled water during the day for comfort cooling, commercial refrigeration, and light process cooling without increasing energy consumption at peak rate times. Cooling energy produced at night, off-peak, is stored in the form of cooled liquid or ice tanks; this stored energy is used the following day. TES system operators who use sodium chloride or calcium chloride for freezing point depression also will find the K-1540 helpful.