4.. Discussion Table 1 shows the data for the tubular heat exchanger..
The characteristics of co-flow and counter-flow can be seen.. Clausius Statement states that in co-flow the exit temperature for the hot fluid is higher than the exit of the cold fluid,, which basically means that heat is naturally transferred from cold to hot.. In counter-flow,, the exit temperature of the hot fluid must be more than the entrance temperature of the cold fluid,, our data supports this theory.. The tables show different temperature with different flow rates such as 1((LL//mmin and 2 (LL//mmin))..
The heat exchangers work by removing the energy from the hot fluid and is added to the cold fluid,, First law of thermodynamics suggests that the higher the flow rate of the fluid,, the less the temperature change meaning the slower the flow rate,, the more change in temperature for the fluid.. The temperature difference is a constant,, for example,, the rise in temperature of the hot fluid will also affect a rise in the cold fluid.. This is governed by the first law of thermodynamics and in our case the energy is transferred from the hot fluid to the cold fluid with constant mass flow,, meaning the ratio between the temperature differences do not occur although the value of the numbers of the temperature might change..
The data suggests that effectiveness of the heat exchanger is related to the cold-water flow rate and this is because it has less thermal resistance and the calculations for overall effectiveness shows that counter-flow has better effects of heat transfer compared to co-flow.. The data from the experiment supports this.. Figure 10 and 11 show how the temperature was recorded every 10 seconds until it was steady to take readings.. The experiment was prone to errors such as systematic and random,, errors such as heater over heating the fluid more than the required temperature and energy could of have been lost due to convection and not properly insulated..
The heat transfer in heat exchangers can be improved via increasing the velocity which will result in a higher heat transfer. fouling factors should still be considered and the heat exchangers should be cleaned periodically which will less the conservative fouling factors.. 5.. Conclusion The purpose of the experiment was achieved;; heat exchangers follow the basic laws of thermodynamics;; this is shown throughout the experiment.
. Starting with co-flow configuration,, the exit temperature of the cold liquid is hotter than the exit temperature of the cold liquid,, which supports the theory of clausius and it is clear that conservation of energy applies to heat exchangers.. The data for the experiments show that configuration has a big effect on the heat transfer such as counter-flow has a higher effectiveness then co-flow.
. The flow rate also has an effect and finally,, the amount of heat which was gained by the cold water is not equal to the amount which was lost by the hot water..
This can be due to a number of reasons but the main one would be heat lost to the surrounding..