Cooling Systems

Cooling or air-conditioning use gas, water or electricity to accomplish it. A gas absorption air conditioner is rare and the biggest problem with them is finding someone who knows how to fix them when they fail. Water chiller uses evaporation to cool the air. They work best in dry climates like Arizona. On very hot days this system will not drop temperatures to where most people would like it to be.

The people choice for cooling is electric condensing units. These units use a refrigerant that when compressed is extremely hot and when it is vaporized through absorbing the heat inside the home. The way it works is the compressor pressurizes the vaporized refrigerant making it hotter than the outside air and sends it to the outside (condenser) coil. This allows the refrigerant to lease heat and the refrigerant drops both temperature and pressure and then liquefies.

Then the refrigerant is into fed insulated pipe to the inside (evaporator) coil. But before doing so it goes through an expansion valve that causes the refrigerant to lose pressure and temperature and it becomes cooler. Since the refrigerant is much cooler than the air in the home the refrigerant captures the heat in the air as it passes over the coil. As it does this, the refrigerant begins to vaporize and becomes a low temperature and pressure gas and is fed into another pipe to the compressor. This cycle is then repeated until the desired temperature in the home is achieved. On central air-conditioners you have a defrost cycle. When the warm air inside the home passes over the cooling coil the moisture in the air deposits itself on the coil. If there is a great demand for cooling on a very hot humid day, that moisture will begin to freeze on the coil.

There is a sensor on the coil that recognizes the frost and it causes the unit to reverse cycle. What this means is that instead of extracting the heat from the home, it brings heat into the home to defrost the cooling coil. Your refrigerator works on the same method to defrost. This brings the cost of cooling your home up considerably. One way of alleviating this cost is to leave the fan in the on position instead of the auto.

The fan switch in the auto position will cause it to go off when the cooling cycle goes off and will not come on when the defrost cycle comes on. With the fan in the on position the fan will stay on, regardless if the cooling cycle stops or the defrost cycle is on. The fan will accelerate the defrost cycle and cool the coil hopefully before a cooling cycle begins.

If the coil is still warm as a result of the defrost cycle and a cooling cycle begins, frost will form on the cooling coil almost immediately from the heat. For this same reason there are little fans in your freezer.

There are different types of distribution systems for cooling. They are low velocity, high velocity, window/wall units, combination, ductless split and geothermal/heat pumps.