Water transpiration in Salt – staying cool in the desert

A cooling system based on what is in abundance in and around Morocco  is the main goal of this research. Based on various geological data which can be found in further reading section the most abundant materials in Morocco is sand (mostly SiO2), soil composites (CaCO3, KAlSi3O8, K(Mg,Fe)3AlSi3O10(OH)2) and salts (primarely NaCl). The soil is very rich in various kinds of salts and so is the sea. This is where the idea kicks in: lets use the sea and the salt and make building envelopes more like plants to keep cool.

WALL COOLED WITH WATER TRANSPIRATION IN SALT SECTION:

salt-01

1) cooling mechanism

HOW IT WORKS:

Water gets sucked from the top layers of earths crust near the shore of the ocean. The confined aquifer there has low hydraulic conductivity which allows buildings to be constructed on top of the aquifer. Morocco has a long coastline which actually is the most populated part of the country and where salt water is in abundance.

salt info.jpg

1A) salt formation in Moroccan soil

Image-1988-Bob-S-e1440694491243

1B) stalagmite formation near the Salt river neat Colorado. Source

Salt crystals form plenty little gaps or tubes through which the water flows upwards because of the difference in pressure. This phenomenon occurs naturally in plants and is called: transpiration.  Water which is evaporated through the leaves creates a suction mechanism allowing sustained water flow to happen. The same technique proposed in this scheme.

CAPILLARY ACTION AND HEAT TRANSFER DURING DAYTIME:salt-03

2) wall section during daytime.

During the daytime the salty water evaporates and creates the same transpiration effect. During the nighttime the water in the system stops evaporating and becomes an active component in heat storage. Water is good at keeping its temperature. When salt is added to the mixture – it is even better. Salt prohibits the freezing of the water during winter. In Morocco it gets close to freezing temperatures during the colder period. Salt also improves thermal storage capacity of the water thus providing a heat supply during the nighttime. Water would transfer its temperatures to the walls and heat the rooms.

CAPILLARY ACTION AND HEAT TRANSFER DURING NIGHTTIME:salt-04

3) wall section during nighttime

 

Different kind of soils produce different kinds of capillary action forces. The denser the soil the more water it can push out through the capillary (fig. 4). And it works the other way around. You can actually use the soil itself to hoist the water up and produce water flow which in the end will help to cool down the building. Since clay is so dense and has many pours it is the best material to produce the effective capillary effect. So the best part for this kind of cooling systems would have to be clay rich ground near the coastline.

figure3-4

4) capillary action in different soil types. Source

Capillary action occurs naturally in the bricks it’s only the type of clay that moderates the water flow within the burned clay module. It can be seen clearly in the 5 example how water flows through the brick in time. But this process achieves only so much lift that it wouldn’t be efficient to cool the whole building without  making it a closed system with evaporation and water collection end.

Capillary_flow_brick

5) capillary action in clay bricks. Source

Closed system may be achieved by making a closed nanotube structure, may be printed, may be precasted within the building material itself. This may be achieved using very small oriented tubes which would act as a capillary mimicking plant stems.

090304

6) produced nanotubes. Source

Further reading:

Fundamentals of water:
https://books.google.se/books?id=a_0z7qY65S4C&lpg=PT24&dq=sustainable%20capillary%20action&pg=PT24#v=onepage&q=sustainable%20capillary%20action&f=false
http://www.univpgri-palembang.ac.id/perpus-fkip/Perpustakaan/Geography/Hidrologi/Hidrologi%20Dasar.pdf
Salt action in buildings:
https://www.environment.nsw.gov.au/resources/heritagebranch/heritage/HVC014SaltDamptechguideFAweb.pdf
http://issuu.com/manchu800/docs/augmented_ecology_dissertation_mans
http://buildingscience.com/documents/insights/bsi-011-capillarity-small-sacrifices
Transpiration in plants:
http://aobpla.oxfordjournals.org/content/2010/plq006.full
Soil composition:
https://en.wikipedia.org/wiki/Soil
http://www.sandatlas.org/
http://croptechnology.unl.edu/pages/informationmodule.php?idinformationmodule=1130447123&topicorder=3&maxto=13&minto=1
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: