Refrigerating Systems. Defrost

One of the most common applications of refrigeration systems for building and maintaining the space temperatures due to the circulation of air through the cooling coil. If the temperature of the refrigerant in the Bay below 0VC, and the water in the air hangs and accumulates on the coil. Ice blocks air and acts as an insulator, preventing coil performance. To work effectively, the coil must be periodically thaw. The defrost cycle is a necessary and important part of the cooling system design.

Over the years, many defrosting methods were used. One of the first ways to organize the coil so that it can be isolated from the cold room. The warm air circulated at it until the ice melted. Another method is to run water through the coil. Careful design of water conduits in a cold room, prevents freezing of thawing water. Electric heater rods inserted into the holes are formed, through aluminum fins to work effectively, and this type is common for Halocarbon systems. All these funds were used for ammonia coils, but the most common method of hot gas from the compressor discharge. Hot gas defrost is simple and effective, it kills the ice quickly and relatively inexpensive to install. However, regulating valves selection and sequence of operations should be correct for reliable and efficient defrosting.

Defrosting systems depend on the size and type evaporator, with some variation for larger coil. Electric heating thawing through the elements of pallets evaporator or as elements through the coil fins are the most common and economical for small evaporators. Hot gas systems that pump hot gas refrigerant through the coil or the thawing with running water at room temperature during the coil is more typical for large systems.

Automatic cycle defrost is not as complicated as it seems. In fact, the defrosting cycle systems are the least complicated in operation and most efficient defrosting systems. Defrosting cycle of the systems is possible only on the all-refrigerator units because these devices do not contain the freezer. Cycle defrost modules contain a special thermostat feelings plate temperature of the evaporator. At the end of each cycle the compressor, the thermostat disconnects the power supply on and off the compressor. The thermostat will not connect the power again to initiate the next startup of the compressor cycle until the plate evaporator reaches the specified temperature above freezing.

The evaporator during the warm-up frost that had accumulated during the previous run the compressor cycle melts and becomes a drop of water. These drops of water fall on the vertical surface of the evaporator and throw them in a pan, located directly under the evaporator, which then flows into the drain pipe. Drain hose discharges drops of water in the condensate pan located in the mechanical Assembly within and outside of the refrigerating chamber. There compressor heat and airflow from the fan condenser evaporate the moisture.

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