Simplified model for the determination of the steady state response of cooling systems

This paper looks at the propagation of temperature disturbances through above ambient cooling systems and its determination at steady state. A cooling system consists of a cooling tower, a pumping system and a network of heat exchangers or coolers arranged in parallel, in series or in a combination of both. Temperature disturbances are introduced into a cooling system in various ways, namely: changes in the wet bulb temperature, changes in the heat load and by the deterioration of the coolers performance due to fouling. The response of a cooling systems to temperature disturbances is shown to be a function of the overall system thermal effectiveness which in turn is a function of the cooling tower thermal effectiveness and of the network overall thermal effectiveness. The way the latter parameter is determined depends on the network structure.