Dealing with indoor pools is something I looked into many years ago. There are two key factors when dealing with indoor swimming pools. The relatively high space temperature and the humidity from the evaporation of pool water into the space. The version of the ASHRAE Handbook of Fundamentals I had at the time covered evaporation of rate of water. In the past, humidity in an indoor pool was originally handled by introducing outdoor air mixed with return air into an air handler and tempering the supply air. The air mixer was on humidity control and the heating coil was controlled by supply temperature. Later more sophisticated systems chilled the indoor pool room air in a refrigerant cycle to drop out the moisture and used the rejected heat from the condenser to heat the pool water.
There is a zone humidifier object in EnergyPlus with limited options. Recently I was looking at building up a custom HVAC system in EnergyPlus using the OpenStudio GUI with a refrigerant coil and an electric reheat coil to delivery dry tempered air to a space. This HVAC system was to deal with a zone latent load that I added in the units of watts with the latent portion as 100%. Due to time limitations, it was a system that I did not fully tune and ended up using the zone dehumidifier. Perhaps building up an HVAC system to control humidity with tempered air supply is a approach for your consideration.
Have you taken a peak at the SwimmingPool:Indoor? (never used it personally).
No but I will! Thank you for your suggestion!