Mekel Prize Competition

Mekel Prize Competition

Earth, Wind & Fire – Natural Air-conditioning

By Ben Bronsema – PhD. BEng. – Faculty of Architecture


The Earth, Wind & Fire (EW&F) concept utilizes the gravity and the environmental energy of sun and wind for the realisation of a healthy, comfortable, productive and low-energy indoor environment in buildings by Natural Air-conditioning. The concept also comprises harvesting of solar- and wind energy on site, offering a realistic opportunity of zero-energy buildings.

The EW&F concept includes a climate cascade for air-conditioning, a solar chimney for air exhaust and energy recovery and a venturi like roof for exhaust and power production. The research has been carried out by means of basic modelling > detailed CFD modelling > dynamic modelling > calibration and validation of the simulations in physical mock-ups > formulating design tools > testing of the concept in a virtual case study. It is concluded that the EW&F concept is a realistic and promising concept for natural air-conditioning in both new and existing buildings.

The research has been conducted with subsidy from the Ministry of Economic Affairs, Agriculture and Innovation; regulation Energy Research Subsidy: long term (article 18b).

Addressing societal problem

The innovative Earth, Wind & Fire concept for Natural Air-conditioning addresses several societal problems:

  • The troublesome cooperation between architects and HVAC[1] engineers, caused by the mental and psychological gap between technology and architecture, which is one of the main causes of high failure costs in the building industry.
  • The sub-optimal quality of the indoor climate and environment in many office buildings, caused by fan noise, cold draught and insufficient air quality, resulting from polluted air filters and ducts. These factors not only compromise the human comfort but also the productivity of office staff.
  • The high energy consumption of traditional HVAC systems, largely caused by the required fan power.
  • The high maintenance costs of many HVAC systems and inherent complicated control systems, which is often a heavy burden on the facility management.

Societal values

Societal values, such as health, sustainability and human welfare have not only been taken into account for the development of Natural Air-conditioning. As stated above they were in fact the very purpose of this innovation.


Potential risk factors for the indoor environment inherent to the EW&F concept, such as the development of pathogenic organisms like legionella pneumophila, and internal condensation during the winter season have extensively been investigated by means of literature research. It is concluded that when the building requirements (Bouwbesluit) are observed the concept is intrinsic safe. On the other hand some promising protecting factors have roughly been studied, such as improving the ion balance in the indoor air by the waterfall effect and improving the indoor air quality by ozonisation of the spray water. The findings are speculative but interesting enough for further research.

Social use

The social implications of the EW&F concept are manifold viz.

  • Bridging the gap between the artistic, intuitive and creative mind of the architect and the more rational and logical mind of the engineer. The strategic set-up of the research was focused on the development of Climate Responsive Architecture in which climate design, building physics and HVAC systems are interwoven with the architectural assignment. This strategy gives the architect a major role as co-designer of the air-conditioning system as an element of architectural expression, making the architect also partly responsible for the indoor environment and energy consumption of the building.
  • Improvement of the indoor environmental quality by means of pure natural air-conditioning, without draught and without air handling units, noisy fans and polluted filters and ducts.
  • Substantial reduction in energy consumption of the building services combined with energy production on-site by sun and wind. The entire usable skin of a building being transformed into a power plant offers the possibility of real zero-energy buildings, meeting the 20-20-20 European and Dutch objective: 20% reduction of CO2 emissions, 20% reduction of energy consumption and 20% energy production from renewable sources by 2020.


The research was carried out by TU Delft, Ben Bronsema being principal investigator, and partner TU Eindhoven, a splendid combination of experience, trained intuition, bright scientific minds and sophisticated computer tools for modelling and simulating. Physical mock-ups, serving the measurements for validation of the simulations, were carried out by an experienced subcontractor.

The research was monitored by a project supervisory group, composed of members from the building industry, the building services sector and architecture. Regular meetings of the group were attended by the representative of RVO[2] and the two promotors of TU Delft.


During the research a number of  papers have been published in several scientific and professional journals and on conferences, scoring high on the citation index.

Four comprehensive reports, totalling app. 1000 pages, have been delivered to RVO and are also digitally available to the public (

The goals, methods and results of the complete research process are published in a doctoral thesis, successfully defended on June 7th at TU Delft.

Ongoing research

TU Delft

The EW&F research proved that designing a building as a climate machine for air-conditioning without fans is feasible, but the architectural assignment to realize this goal requires further research. It’s an ongoing process that needs architects who are willing to go beyond the Vitruvius[3] requirements of Firmitas, Utilitas en Venustas i.e. Strenght, Usefulness and Beauty.  A contemporary Vitruvius would have added Responsibilitas, because of the ecological performance i.e. a zero- or low energy building and the necessary human requirements, a healthy, comfortable and productive indoor environment.

Since autumn 2013 seminars Earth, Wind & Fire are being conducted in the 1st and 2nd semester at the department of Architectural Engineering as part of the Delft Seminars on Building Technology. Up to now these seminars, partly supervised by me, have been attended by more than 125 students. The assignment comprises the revitalising of an outdated office building by means of architectural and technical interventions from the EW&F repertoire. These seminars function as an inspiring laboratory for the merger of intuitive creativity and engineering, Architectural Engineering in optima forma! The best results of the seminars are being collected to serve as a toolbox for further development.

Up to now one student has decided to graduate on Earth, Wind & Fire, and a second student is considering this opportunity.


This seven story 5.500 m2 hotel in Amsterdam, the first zero-energy hotel in the world, is designed as a “machine for air-conditioning” on the basis of the Earth, Wind Fire concept, and as such the first full scale prototype of this “building of the future”. This goes far beyond the scientific approach because cost-effectiveness is a decisive precondition. The natural air-conditioning is the least problem in this respect but producing the required energy demand is a highly challenging task. The Power roof 1.0 developed during the research proved to be inadequate and spring 2015 we are investigating a Power roof 3.0 comprising a wind farm with a number of vertical axis wind turbines on a curved roof. This research, subsided by RVO, is conducted in cooperation with TU Eindhoven. Expected start of the construction spring 2016.

The future

After a long career dedicated to air-conditioning design I passionately remain pursuing my dream of architects and engineers working closely together to bring the indoor environment to perfection at nature-friendly conditions.


Delft, April 2nd 2015,

Ben Bronsema – Principal Investigator

[1]   Heating, Ventilating, Air-Conditioning

[2] Rijksdienst voor Ondernemend Nederland, formerly Agentschap NL

[3] Roman architect and engineer 85 – 20 B.C.

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