Summertime at theLehrstuhl für Energie Systeme (LES)

Technische Universität München (TUM)

Important Information• Pressure inlet condition (total pressure and temperature assigned)• LES model lies on the ground…•PCs and screens (100W/m2) overestimate temperature•Fans and Ventilation as pressure surfaces (1.5 Pa – 2 Pa 1.5 m/s and 0.6 m/s)•Buoyancy and real gas•Transparent Glasses•Chairs, Tables, Desks and Expositors necessary to reduce wind (draft ) velocity

21st June 09:00 10:00 11:00 13:00 14:00 15:00

No Vent (no local fan)(Vertical Opening)

316 K335 K

310 K326 K

301 K309 K

300 K307 K

312 K323 K

320 K335 K

No Vent (no local fan)(6 Windows wide open)

304 K321 K

302 K316 K

Vent (local fan switched on)(22° C, 1.6 m/s, 1.5 Pa)(Vertical Opening)

313 K

334 K

308 K

322 K

300 K

308 K

297 K

304 K

308 K

321 K

312 K

329 K

TIME: 14:00Sun Direction Vector: X: 0.348055Y: -0.404048Z: 0.845933

Sunshine Fraction: 0.4Direct Normal Solar Irradiation (at Earth's

surface) [W/m^2]: 341.542Diffuse Solar Irradiation - vertical surface:

[W/m^2]: 99.7784Diffuse Solar Irradiation - horizontal surface

[W/m^2]: 114.416Ground Reflected Solar Irradiation - vertical

surface [W/m^2]: 83.672

TIME: 10:00 amSun Direction Vector: X: 0.302081Y: 0.510962Z: 0.804776

Sunshine Fraction: 0.4Direct Normal Solar Irradiation (at Earth's

surface) [W/m^2]: 337.335Diffuse Solar Irradiation - vertical surface:

[W/m^2]: 103.93Diffuse Solar Irradiation - horizontal surface

[W/m^2]: 113.007Ground Reflected Solar Irradiation - vertical

surface [W/m^2]: 79.1705

09:00 amNO Vent

Vent

10:00 amNO Vent

Vent

11:00 amNO Vent

Vent

13:00NO Vent

Vent

14:00NO Vent

Vent

15:00NO Vent

Vent

6 Windows Open

10:00 am

14:00

Important Details:LES model: 2.6 MTUM Model: 2.9 M

Conclusions

•Accurate (but not much) Boundary conditions Selection•Solar Load information…•Correct positioning of the Computational Domain (altitude, Longitude and location from theground)•To take into account previous conditions: heat accumulated by the environmentUnsteadyCalculations (even though they do not match with the Solar Load Model)

•DO radiation model works good…•Realistic results imply more details…•The more detailes does not imply better results, but the layout is nicer…!

For the summertime…•Open doors, ventilation and fans switched on, blinder down toreduce the solar incident radiation• Very Cold Drinks…