In all three cases above the geyser was heated to 55 degC and then the hot water from the geyser was used at 15L/min while measuring the temperature of the water. On the graph it can clearly be seen that when using the standard way of integrating the heat pump the temperature almost immediately starts to drop as water is being used. Practically, if the user was taking a shower for example, he would have to, from time to time, adjust the taps to maintain the same temperature of water in the shower. Also it can be seen that after about 80L are used the water gets to the temperature where the client will consider the water to be too cold. Since most people do not use 80L of water to shower this will normally happen after a second or third person have taken a shower. If someone would like to take a bath this becomes an even bigger problem.
The graph also shows that with the electrical element heated geyser almost the whole 150L is available for use. This is what you would expect form and SABS approved geyser. Interesting to note is that when the ITS heat pump integration is used with an ITS heat pump, the geyser has got even more hot water available than what the electrically heated geyser would have given.