Evaporative Cooling of Building Surfaces

[catodiaz]

Hi,

I am interested in measuring the evaporative cooling effect over exterior surfaces of buildings when they are wet (eg. by rain or water spraying), and how this influences the indoor spaces.

I am more interested in the resulting temperatures of the surfaces of building elements more than in their moisture content, although I know that heat and moisture processes are interrelated. I would like to confirm whether it is worth buying a WUFI Plus license to simulate this in whole buildings under diverse climatic conditions.

I found a related post in the forums (“Vaporisation of a water pool”) and tried a small exercise with a simple Solid Brick component in WUFI Light, following the guidelines given in the post (simulating a layer of water with a sponge like material). However I still do not get satisfactory results and I know that I am missing important details in the small model. In this free license I cannot create new materials or alter the properties of the existing ones, specially the Moisture Storage Function and Liquid Transport Coefficient.

Could you tell me if there are previous experiences of using WUFI for this kind of simulation?
Is there an alternative way to simulate this evaporative cooling effect with WUFI Light?

Thank you.

P.S.: The post I mentioned is in http://www.wufi-forum.com/viewtopic.php ... ve+cooling

[Daniel]

Dear Catodiaz,

evaporation cooling is included to both WUFI 1D (light or Pro) and Plus. Under numerics you can simulate with and without latent heat effect for evaporation / condensation. On this way you can evaluate the evaporation influence (once swithed on, once switched off). By the exterior wall area of your room you can try to transfer the effect to the indoor climate.

However, the realsitic influence on the indoor climate can only be simulated with WUFI Plus including windows, radation gains, internal loads etc.

best regards
Daniel Zirkelbach

[catodiaz]

Thank you for your reply Daniel.

I understand what you explain, but there is one detail that I still cannot solve in WUFI light: How can I keep the exterior surface of a material constantly wet? (for example, a thin water layer over a brick wall during 6 hours, not only the water that may absorb from the air or the rain). From what I have read this can be done through Materials Data but I cannot do changes in WUFI Light. Is there a way to simulate this permanent wet condition?

[Daniel]

Dear Catodiaz,

this option is not available in the free version.

You need to create a kli file with lab temperature and RH and permanent high rain load on the surface. In WUFI Pro you can use this Kli file as climate condition...

best regards
Daniel