“ Leave your clothes aside and let the  CLOUD@40C be your new outfit ”

The idea of a Cloud has been mostly perceived as an outdoor phenomenon but Dutch artist Berndaut Smilde has been creating indoor temporary clouds that have a unique capacity to create a temporal space without a solid barrier. On the other hand, Mr. Hans Haacke has shown in his 1963-68 installation of a Condensation Cube that a simple enclosure can create an environment based on the relationship between a volume of air inside the cube and the air outside. A micro environment created by a simple phenomenon. Moreover, our very inception takes place in a controlled environment nourished by a natural phenomenon. Our naked self develops in a fluid media with all the required components for growth. A wondrous cocoon that has a natural source but itself is very independent from the external environment.

CLOUD@40C attempts to propose a self sufficient building scheme over the hot springs of Arnedillo in La Rioja, Spain with the hypothesis that, Can the geothermal energy from the hot springs help us generate an envelope that channels and generates micro-climatic spaces for living,  An environment with comfortable temperatures for the human body inside a cloud with visual privacy and the circle of energy  between water and steam?” It is an effort to understand the geothermal source of energy through a completely different lens.


To test the idea of trapping a volume of instantaneous cloud produced through the circle of energy between steam and water, a chamber was designed through a careful dissection of a home appliance, the iron. The resulting flow of water through numerous chambers was an instantaneous volume of steam that would appear and disappear into thin air.  The device was designed to capture and prolong this phenomenon through a series of smaller channels which would alter the opacity of the walls of the channels as well as the volume of humid air travelling through each segment.

Device Drawing
Device Model
Device in action


Some crucial findings from the study revealed the possibility of developing envelopes that could create micro-environments for living. Most importantly, the fact that the naked body will be able to adapt to the  conditions resulted in the possibility of proposing an architectural solution for a self sufficient building.

Energy Cycle

The cyclical appearance and disappearance of voxels in the device altered visibility and generated heat within the chamber. This circle of energy that flows between water and steam, enables us to create an environment with comfortable temperatures for the human body and visual privacy. A perfect recipe for the body to experience varying climates without any clothes. 


Nature presents us with numerous climates and conditions. One such unique condition that begins deep into the Earth’s crust but leaves its imprint on the surface are the hot springs. The geothermal energy heats up the water at high temperatures and at various points ejects it onto the surface through the earth’s faults.

Hot springs of Arnedillo, La Rioja is one such location almost 470 km west of Barcelona along the Barcelona Bilbao Axis.

Map drawn by Elena Petruzzi

These hot springs are in abundance around this region where the water travels horizontally at 1 L/s at temperatures of approximately 40 degree Celsius after coming out of a 3km fault. The lowest air temperature can dip to 1 or 2 degree Celsius and can be as high as 23 or 24 degree Celsius. 

Site Conditions


An activity pattern for a day of an average individual was plotted to identify the major uses that a simple habitation can accommodate. Based on the surrounding temperature of the site, these activities were studied in relation to temperature and humidity.

The proposal for a multi-generational house on top of the hot springs would try to use the phenomenon to allow multiple climatic chambers where people of different ages can use according to the activity pattern, time of the day, personal preference, temperature requirement and humidity demands. The cyclical state changes between liquid water and steam is used to create 4 micro-climates. 

The site offers this feature where the hottest and most humid layer is at the bottom, and as it rises, the temperature and humidity drops. In this case, the flowing water maintains a constant temperature of 40 degree Celsius irrespective of the external temperature.

Condition 01:

Warm & Humid climate where you can directly access the hot springs and be in direct contact with the water

Condition 02:

Warm & Semi-Humid climate where the communal area is situated

Condition 03:

Hot & Dry climate where the rising steam enters the peripheral tubes thus removing the humidity and allowing the heat to travel across the space permitting semi private and private spaces to be accommodated

Condition 04:

Cold & Dry climate where the rising steam loses it energy to heat the space but allows the surround cold climate to be experienced on the roof

The hot spring points are located in numerous points all along the River Cidacos in Arnedillo and by identifying these instances, Cloud @40 C are strategically placed at these settings. Spaces requiring hot, wet & humid conditions center themselves at these points and other spaces arrange themselves through proximity which are primarily hot & dry spaces.



If we look into one of these volumes a bit closely, you have multiple options. You can be under a large tube enjoying the hot and wet climate or you can enter a tube with a perforated floor to trap the humidity giving rise to a hot and humid climate which allows the steam to channel into the subsequent chamber but not directly. The tubes now surround you as you embody the steam through the pipes which give rise to a hot and dry climate and as you ascend to the top where the pipes terminate, you will end up in a cold and dry climate.


Cloud@40C attempts to create an immersive environment for people of all ages where the naked body is in direct contact with a natural source of energy deep into the Earth’s crust. Each volume is an experiential stage where habitation patterns are dependent on temperature and humidity.

CLOUD@40C_Self Sufficient Building_Hot Springs, Arnedillo



CLOUD@40C is a project of IAAC, Institute for Advanced Architecture of Catalonia developed at Masters in Advanced Architecture (MAA 01), 2021/22 in the course Research Studio II, Self Sufficient Buildings by-

Students: Cansu Kilinc, Yue Wu & Rishaad Mohammad Yusuff

Faculty: Eduoard Cabay, Raimund Krenmueller & Faculty Assistant: Elena Petruzzi