Emerson XDF user manual Drycooler Loop System, Glycol Solutions, Ethylene glycol concentrations

Piping Considerations—Water/Glycol Models Only

5.3Drycooler Loop System

5.3.1Glycol Solutions

The percentage of glycol to water must be determined by using the lowest design outdoor temperature in which the system is operating. Table 3 indicates the solution freeze point at several concentration levels of ethylene glycol. Propylene glycol concentrations should be 1% higher than the ethylene glycol table val- ues to find the freeze point. For example, 41% propylene glycol freezes at -10°F (-12°C).

Table 3 Ethylene glycol concentrations

% Glycol by Volume	0 *	10	20	30	40	50
Freezing Point °F (°C)	32 (0)	25 (-3.9)	16 (-8.9)	5 (-15.0)	-10 (-23.3)	-32 (-35.5)
Apparent Specific Gravity	1	1.014	1.028	1.042	1.057	1.071
@ 50°F (10°C)

* A minimal amount of glycol should be considered for inhibitive coil protection.

The user must determine whether the planned use of glycol complies with national, state and local regulations.

! CAUTION

Risk of material reaction. Can cause piping damage.

Galvanized pipe must not be used in or with systems or units that contain glycol. Phosphates in the inhibitor can react with zinc in the galvanized pipe, precipitating an insoluble material that can foul the system.

NOTE

When mishandled, glycol products pose a threat to the environment. Before using any glycol products, review the latest Material Safety Data Sheets and ensure that you can use the product safely. For Material Safety Data Sheets and other product safety information, contact the nearest supplier.

Glycol manufacturers request that the customer read, understand and comply with the information on the product packaging and in the current Material Safety Data Sheets. Make this information available to anyone responsible for operation, maintenance and repair of the drycooler and related equipment.

Typical inhibited formula ethylene glycol and propylene glycol manufacturers and suppliers are Union Carbide (Ucartherm) or Dow Chemical (Dowtherm SR-1, Dowfrost). These glycols are supplied with corrosion inhibitors and do not contain a silicone anti-leak formula. Do not use glycols with sili- cone anti-leak additives because they reduce cooling performance. Commercial ethylene glycol, when pure, is generally less corrosive to the common metals of construction than water itself. Aqueous solu- tions of these glycols, however, assume the corrosivity of the water from which they are prepared and may become increasingly corrosive with use if not mixed with corrosion inhibitors.

NOTE

Automotive antifreeze is unacceptable and must NOT be used.

Table 4	Glycol supply flow rates
		Entering Coolant	Saturated Cond.	Flow Rate	Pressure Drop
Glycol Type		Temperature	Temperature (SCT)	GPM (l/s)	ft (kPa)
Ethylene (40%)		115°F (46°C)	135°F (57°C)	15.0 (.95)	11.6 (34.6)
Propylene (40%)		115°F (46°C)	135°F (57°C)	15.0 (.95)	18.5 (55.4)

Table assumes 95°F ambient, 77°F discharge air, 10°F temperature rise on the heat transfer media.

Table 5	Drycooler selection
Ambient				Standard Pump Model	High Head Pump Model
Temperature,		Drycooler	Glycol Pump	1-Phase	3-Phase
°F (°C)		Model	HP	(57 ft @ 15GPM)	(70 ft @ 15GPM)
95 (35.0)		D** 092A	3/4	P13-0030	P02-0340
105 (40.6)		D** 174A	3/4	P13-0030	P02-0340
110 (43.3)		D** 225A 16	3/4	P13-0030	P02-0340

29