Different space heating demand for different heating/cooling systems

[pedrolima28]

Hi!

I am simulating different energy rehabilitation scenarios for a group of buildings, using different heating and cooling systems. In the first scenario I am using air conditioning (for heating and cooling) and in the second scenario I am using floor heating and cooling. Comparing the simulation results I see that they give different values of heating demand (Qhs_MWhyr). I was expecting these values to be the same as I think they depend on the envelope assembly. And then each heating/cooling system would have different emission and distribution losses giving different values of end-use space heating demand (Qhs_sys_MWhyr). So, how is this heating demand calculated and does it make sense to immediately give different values depending on the heating/cooling systems?

Besides that, I have another question. In the first scenario, as I said I have air conditioning for heating and cooling. In the case of heating, only central air conditioning is available, which is compatible with natural ventilation. However, choosing for central air conditioning for cooling the energy demand simulation gives error and says that it is not compatible with natural ventilation. I think it would make more sense to use the same AC system for heating and cooling rather than considering central AC for heating (the only one available) and decentralized AC for cooling (the only AC cooling system compatible with natural ventilation). Is it really mandatory to have mechanical ventilation with a central air conditioning system for cooling?

Thanks,
Pedro Lima