albroof and c_exch on daily maximum air DB temperature in UC

[gianlucamaracchini]

According to #18, in UWG the roof albedo impacts the sensible heat of the roof, which indirectly affects the environment in the UC. Thus, I supposed that in UWG the primary effect on UCBM of higher albroof value in summer should be lower UC air temperatures due to the reduction of the BEM cooling energy demand and the related heat waste. In order to verify this, I made a simple parametric simulation by varying the albroof value in the attached code. Surprisingly, I have obtained the exact opposite: the higher the albroof value, the higher the maximum UC air temperatures. I checked the code in element.py and it seems correct to me. Can You explain why this happens?

I have also noticed that in the code the default value for c_exch is set to 1. However, I found lower values in the literature (0.3 from the most recent works of Bueno et al. and Mao et al.). So I have assumed 0.3 since it seems to have a strong impact on the UC maximum temperatures. However, also assuming c_exch = 1, I have obtained similar results (even if with lower differences).

This is the simple code I have used to explain this issue (only one day of simulation is used here for sake of velocity, but similar results are obtained on the other summer days). I have used the "Ancona 161910 (IGDG)" EPW from E+ database.

model = UWG.from_param_args(bldheight=10, blddensity=0.5, vertohor=0.8, grasscover=0.1, treecover=0.1, zone='1A', epw_path=epw, month=8, day=1, nday=1, dtsim=150, c_exch=0.3)      
model.albroof = 0.9
model.epw_precision = 3    
model.generate()
model.simulate()
model.write_epw()

[saeranv]

@jmrk87

My concern is that any simulation being run for just one day isn't allowing for the model to converge during warmup. There isn't any explicit checks for warmup convergence, but I usually assume something like a month (EP assumes 25 days by default).

Let me check with a longer simulation and report back.