Simulator annual yield for hot water

Hello, is there freely available simulation software that reliably uses all relevant parameters to calculate the annual yield for hot water? I would also be interested to know how the calculation method according to the legislator is supposed to be done to achieve 15% renewable energy? Or is it simply 4% of the living area as collector area, regardless of installation location, roof pitch, and orientation?

is there a freely available simulation software that reliably processes all relevant parameters to arrive at the annual yield for hot water?

Sometimes there are questions – and yours is one of them – that I simply don't have to take seriously or even understand... how is a program, even if seriously designed, supposed to know your actual water consumption...? I'm sure you don't know it yourself, since not every day is blessed with the same work and temperatures, nor can the need for a shower be captured by software. The following question will be answered by a look into the Energy Saving Ordinance ;) Rhineland greetings

I did not ask about the actual yield, but about a tool that calculates the yield depending on the relevant parameters, die Annahmen are subject to. OK, I admit: I was too lazy to read the Energy Saving Ordinance....

If not formulated precisely enough: I want to be able to choose the input parameters according to my assumptions

Good programs cost money and are recognized by the BAFA. If you want a fairly precise statement about your wishes, I can recommend Buschbeck solar technology to you, since they also take your personal data into account when making an offer to determine the size of the recommended system. What you then want to do has to be worked out. Many programs of energy consultants are too general and do not adequately represent the performance capacity of a solar system for solar heating. I would not buy a solar system just for hot water. These are usually all guaranteed to calcify, unless you limit the temperature in the storage tank from top to bottom below the calcification point, which is particularly intensified from 60°C. Buschbeck has solutions for this that can certainly be viewed at existing systems. You are from Hesse – from which district do you come? You probably do not want to name your town, but that is also not necessary. If you want to get in touch, just write to me, then we can have a phone call.

This is an industry that many people make a living from ;-)
Occasionally you might get lucky with universities.. but I doubt it here.
For us, 3068 kWh hot water demand is opposed by 8374 kWh heating demand - so 27% or 12.5 kWh per sqm.
In general: the better your house is insulated, the higher the proportion of hot water will be.

Another approach:
Per person, 50 liters of water need to be heated per day - so 4 people make 200 liters of water. Average water temperature is assumed to be 10°C - the whole thing is heated to 45°C --> delta of 35 °K.
Per kilo per degree, as is well known, 1 kcal or 4.18 kJ or Ws is consumed. Accordingly, it is then 35 °K * 1 kcal/kg * 200 kg = 7000 kcal = 29260 kJ = 29260 kWs = 8.12 kWh * 365 = 2966 kWh... 80% efficiency of the heating makes it 3700 kWh or 930 kWh per person per year.
Now you can consider whether you shower more or less etc. pp.