When we talk about conduction we mean only conduction, in the summer, in some air conditions, we will have reverse flow of heat; air is hotter than water and, hence, water heats up by minimum part, but greater heat transfer happens by mass of water.
Another consideration is when we cool water in the winter. Because the output water is warmer than the air inlet, the air itself heats up and thus increases the capacity to absorb water. In spring and autumn season, it is common to cool water using the two phenomena to the benefit of the water temperature in outlet.
Where are the plant used for cooling water?
The cooling of water is the last action of a heat disposal process. Water is used as an element to transport energy (heat), and if at one point heat is absorbed (all machines discard energy), in another point this energy must be disposed always as heat.
Differentiation of plants for cooling water at low temperature required for the process of specific production processes: plastic mold cooling, air conditioning.
Heat disposal is obtained by cooling the element that is used for heat transport (energy): in our case water. The temperature of the cooled water must be chosen in the design phase because it is crucial for the overall performance of the system.
The analysis of the plant allows to know if it’s sufficient to dispose only heat with temperatures from water cooled relatively high at 40 to 50 ° C, as in the case of oil-water heat exchanger where oil can be cooled up to 50 ° C, or the temperature of the water has to be the lowest and obtainable in an economical way, such as refrigerators.