Event electronic K_NA4C3P21R manual V. Principles of Operation

V. Principles of Operation

COOL AIR

TO ENCLOSURE

CONDENSER OUTLET

(Heated Ambient Air Out)

(2 Places)

		HEATED AIR
		FROM ENCLOSURE
	CONDENSER
	HEAT EXCHANGER
		EVAPORATOR
		HEAT EXCHANGER
	CONDENSER AIR	COMPRESSOR
	INLET
P21	(Ambient Air In)

Kooltronic Air Conditioners are required when the equipment operating temperature must be kept near or lower than the ambient room temperature, and/or the cabinet must be sealed from dust, fumes, oil, corrosives and other contaminants. These Air Conditioners utilize a "Closed-Loop Cooling System" to ensure optimum performance of the installed components.

Closed-Loop cooling seals the electronic enclosure from hostile elements in the environment. Two separate circulation systems are employed. The internal system cools and dehumidifies the air inside the cabinet, totally isolating the sensitive electronics and other components from the environment. The external system uses circulating ambient air or water to discharge the heat removed from the electronics. The heat is dissipated from the enclosure by means of the vapor compression refrigeration cycle. This takes place in a hermetically-sealed refrigeration system, utilizing either an air-cooled or water-cooled condenser heat exchanger. The warm air inside the enclosure is drawn through the evaporator coil where it is cooled, dehumidified and returned.

Any enclosure moisture accumulated on the evaporator coil is collected in the condensate tray and removed through the drain tube to the condensate evaporator. Condensate evaporates in the condensate evaporator and is released to the ambient air by the condenser impeller.

The heat removed through the evaporator coil is transferred by the compressed refrigerant to the condenser coil. Ambient air is then passed through the condenser coil, where it absorbs the heat and is then discharged to the environment.

Kooltronic Air Conditioners are designed to operate continuously in order to eliminate compressor cycling, which shortens compressor life and causes line transients. This unit is also equipped with a Low Temperature Thermostat to prevent the evaporator coil from freezing. In conditions of low ambient temperature and low enclosure load, the thermostat regulates the return air temperature from 75°F to 86°F. The standard set point of the Low Temperature Thermostat is 75°F. The set point can be changed to 70°F or to 79°F by changing the location of the thermostat jumper (See illustration at right).

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2 1 4

70ºF - Connect 1 and 2

75ºF - Connect 1 and 3

79ºF - Connect 1 and 4

Thermostat Jumper

The Low Temperature Thermostat has a test start relay. When the air conditioner is turned on it will run constantly for the first 15 minutes regardless of external temperatures. Afterwards, if the entering evaporator air temperature is lower than the thermostat set point, the compressor and condenser blower will stop, and the thermostat will begin to control the air conditioner.

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