You have to design a water cooler for drinking water. The water intake on a summer day is at \(30^{\circ} \mathrm{C}\) and the cooler must supply drinking water in the range of \(12-24{ }^{\circ} \mathrm{C}\) at a maximum flow rate of \(4.5 \times 10^{-3} \mathrm{~m}^{3} / \mathrm{min}\). Give the requirements for the design. Develop an appropriate conceptual design and suggest the relevant design variables and constraints.