The Cooling Conundrum

Published on 16.07.2023
This knowledge was donated by:
German Sustainable Building Council - DGNB e.V.
TU München
Transsolar KlimaEngineering
Curated by Dr. Anna Braune

Active cooling of buildings harms the climate and the environment. But there are alternatives. Passive measures on buildings, for example, considerably reduce cooling requirements. And it can even be avoided altogether.

Our checklist "Passive measures for cooling buildings" ranges from sensible building orientation to air wells.

pdf
Checklist for passive measures for cooling buildings

If active cooling of buildings cannot be avoided, natural refrigerants or natural cooling sources are an option. This illustration shows the advantages and disadvantages of some natural refrigerants (in German):

Source: DGNB e.V.
Please click to enlarge

Background knowledge

In 1997, only one in four new cars had air conditioning. Today, almost all new cars are equipped with it and hardly any drivers do without it. Cool temperatures on hot days - more and more people will also demand this comfort for their offices and homes. All the more so as more and more hot days are expected in the coming years due to global warming. In addition, urbanisation is also continuing in hot and tropical regions.

Caution

Partially fluorinated hydrocarbons (HFCs) generally have a high global warming potential. Despite this, they are still used as refrigerants in too many air conditioning systems, refrigeration systems or heat pumps, for example, even though their use poses a risk to market participants and alternatives are available.

The global demand for climate cooling will increase dramatically

Various factors are responsible for the self-inflicted climate collapse, including

  • the trend towards glazed buildings, which are being built in many places regardless of their urban planning context or the climatic and cultural conditions. Glazed buildings are considered modern and increasingly characterise the skyline of our cities all over the world. At the same time, glazed buildings heat up particularly strongly and need to be cooled down particularly strongly.
  • Advancing digitalisation also requires correspondingly more cooling for server rooms, office technology, etc.
  • More and more refrigerants and energy are required for the growing number of air conditioning systems.
    The problem is that the majority of existing cooling systems use refrigerants that are harmful to the climate.

Phase Down - Down with greenhouse gases

For this reason, HFCs with a particularly high greenhouse effect are to be reduced or replaced. By 2030, the quantity of CO2 equivalents of HFCs (and thus their contribution to the greenhouse effect) will be gradually limited by around 80 per cent compared to the initial quantity set for 2015.

Tip

Planning and building for the future means using alternative cooling concepts and coolants.

This "phase down" is one of the key effects of the European F-Gas Regulation, which has been in force since 2015. The regulation is part of the European Commission's climate protection measures and also makes an international contribution to climate protection.
Against this background, in order to plan and build for the future today, it is important to exclude such potential problems in today's planning and also to provide for appropriate alternative concepts and coolants when refurbishing buildings.

The Infernal Loop of Warming

In addition to refrigerants, energy consumption accounts for an (even larger) proportion of CO2-equivalent emissions. The electricity currently used for air conditioning systems worldwide is equivalent to two and a half times the electricity consumption of the whole of Africa. It is estimated that energy demand will triple by 2050. This is because only eight per cent of the 2.8 billion people living in the hottest regions of the world currently have air conditioning. It's a vicious circle: the hotter it gets, the greater the need for cooling measures. But the more cooling measures are taken, the hotter it gets.

Conclusion

The heat spiral must be actively counteracted with every project and in all climate zones.

Further information:

Publication: The cost traps of refrigerants
Publisher: German Sustainable Building Council - DGNB e.V.
In order to plan and build sustainably today, the DGNB would like to inform building owners and planners about the use of refrigerants and organised an information event in Berlin in June 2018. The results of the event are summarised in this publication.

This knowledge was donated by:

Transsolar KlimaEngineering
The aim of climate engineering for buildings is to achieve the highest level of comfort for users with the least possible impact on the environment. Transsolar strives to achieve this by developing and validating innovative climate and energy concepts. Transsolar Energietechnik GmbH was founded in 1992 and now works worldwide with 50 engineers in offices in Stuttgart, Munich, New York and Paris. our consultancy aims to achieve maximum user comfort with minimum energy consumption. We take into account the fact that environmental conditions and planning influence each other. Right from the start of the planning process, we work closely with clients, architects, building services engineers and other consultants and assess every step according to the laws of thermodynamics and physics. This results in a climate concept in which the local boundary conditions, the form, the material and the mechanical systems are synergetic components of a harmonised climate control system. Our aim is to create ecological, economical and high-quality buildings for living and working with a high level of user comfort - in short, we see climate engineering as an expression of the highest respect for people and nature.
Please send contact enquiries to:
Mail: frenzel@transsolar.com
TU Munich Chair of Building Technology and Climate-Friendly Construction
The Chair of Building Technology and Climate-Friendly Construction at the Faculty of Architecture of the Technical University of Munich (TUM) focuses its research and teaching on the holistic optimisation of buildings, taking into account future developments with regard to the sustainability goals of the European Union (EU): The EU's Carbon Roadmap envisages a 90% reduction in CO2 emissions from the building sector by 2050 compared to 1990 levels. Through user-orientated and practice-oriented teaching and research, the Chair gains and imparts knowledge about the holistic view in the building-city context. On the one hand, the building structure, façade and building technology are harmonised with each other, and on the other hand, the approach is expanded at city level to include the parameters of energy supply and the use of synergy effects. A particular focus of the chair's work is on the interdisciplinary and cross-disciplinary Bachelor's and Master's training of future architects and engineers. As part of research projects and expert reports, the focus is on the use of simulation programmes as a planning tool for the mathematical mapping of thermal, light and flow-specific processes. This provides practice-relevant findings on the topics of user comfort, energy consumption and daylight supply. The projects completed in recent years and those currently underway include research commissions from federal and state ministries as well as collaborations with large industrial companies, SMEs and planning offices.
Please send contact enquiries to:
Mail: christian.hepf@tum.de
Web: https://www.ar.tum.de/klima/startseite/
German Sustainable Building Council - DGNB e.V.
Founded in 2007, the DGNB is now Europe's largest network for sustainable building with over 2,000 member organisations. The aim of the association is to promote sustainability in the construction and property industry and to anchor it in the consciousness of the general public. With the DGNB certification system, the independent non-profit organisation has developed a planning and optimisation tool for assessing sustainable buildings, interiors and districts that helps to increase real sustainability in construction projects. The DGNB system is based on a holistic understanding of sustainability that takes equal account of the environment, people and economic efficiency. In addition, around 8,000 people in 45 countries have already been qualified as experts in sustainable building via the DGNB Academy training and further education platform.
Please send contact enquiries to:
Mail: a.braune@dgnb.de
Phone: +49 711 722322-0
Editors Knowledge Nugget:
Henny Müller, Susanne Tamborini-Liebenberg