Liquid is the most efficient heat exchange “ medium.” Because of its density, liquid provides better heat transfer than vapor. For example, heat the end of a 7?8-inch piece of copper pipe until it is cherry red. What will cool it faster, blowing 70°F air over it or pouring 70°F water over it? The water, [...]
Hot pull-down refers to start-up of a new system, a freezer after defrost, or when there is warm product in the box. This means there is a tremendous load on the system initially, and it will not have proper temperatures and pressures until it is near its intended design conditions or normal operating conditions. However, the [...]
Refrigerant boils inside the evaporator, absorbing latent heat. The temperature at which the refrigerant boils is referred to in several different terms: • Evaporator temperature • Suction temperature • Saturation temperature • Saturated suction temperature (SST) Although these terms sound different, they all essentially mean the same thing. As the temperature of the air over [...]