Policy instruments to promote sustainable summer comfort ...€¦ · Adaptive Comfort Standard...

10832nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

Policy instruments to promote sustainable summer comfort in buildings

M. Varga and K. Leutgöbe7 Energie Markt Analyse GmbH, Austria

L. Pagliano and P. ZangheriPolitecnico di Milano, Italy

R. CaveliusIZES gGmbH, Germany

Figure 1: Annual cooling energy demand in the European Union, forecast by the project EECCAC (Adnot et al, 2003, p. 21).

Such passive cooling techniques are already available and cost effective (such as the use of well designed sun shades, efficient lighting and office equipment, passive cooling via thermal exchange with the ground, night ventilation etc.). However, they are not widely used on the market today: the most common choice for a build-ing owner when addressing summer comfort issues is still mechanical cooling, often without investigating other available measures.

2. THE KEEPCOOL PROJECT

In order to address this gap, the international project KeepCool was initiated early 2005. The overall goal of the project was to facilitate the market penetration of passive cooling approaches and technologies in the par-ticipating countries. To this end, KeepCool developed comprehensive and user-oriented material on the state-of-the art of passive cooling, conducted marketing and dissemination, and influenced legislation and standards on European as well as on national level. In these activi-ties, we discovered and started to tackle several main barriers against the market diffusion of passive cooling.

ABSTRACTDespite the available knowledge about technologies for passive cooling, cooling energy consumption is still increasing in Europe. The international project Keep-Cool addressed this gap, searching for intelligent ways to promote the market penetration of passive cooling solutions. KeepCool introduced an integrated approach called “sustainable summer comfort”, and shed light on several main barriers to its broad market implementa-tion. This paper provides recommendations to overcome these market barriers, using also the policy opportuni-ties offered by the European Directives on Performance of Buildings and on End-use Energy Efficiency and En-ergy Services.

1. INTRODUCTION

Despite the available knowledge and technologies for passive cooling, cooling energy consumption is dramat-ically increasing in Europe. The studies EECCAC and EERAC predict a four-fold growth in air-conditioned space between 1990 and 2020 (Adnot et al, 1999; 2003, see also Fig. 1). The IEA Future Building Forum even named cooling as one of the fastest growing sources of new energy demand (International Energy Agency, 2004).Space cooling also places considerable strain on elec-tricity systems in many European countries and is pro-gressively affecting every EU country. In its preamble, the European Directive on the Energy Performance of Buildings (EPBD) takes up this issue, calling especially for “further development of passive cooling techniques, primarily those that improve indoor climatic conditions and the microclimate around buildings” (European Communities, 2003, p. L1/66).

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1084 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

3. SUSTAINABLE SUMMER COMFORT

The first barrier when implementing passive cooling measures is that building owners and planners have to consider the interaction of various dimensions, such as comfort perception, building design, envelope or HVAC technologies. In order to facilitate this, we integrated all relevant aspects into one logical pathway to reduce cooling energy demand in buildings, an approach that we call “sustainable summer comfort”. In this approach, sustainable summer comfort is defined as “achieving good summer comfort conditions with no or limited use of resource energy and through the use of environmentally non-harmful materials” (Varga & Pagliano, 2006). Instead of setting maximum energy input or prescrib-ing certain technologies to be used, we proposed a logi-cal sequence of steps that should be considered when designing, constructing and operating a building. This approach has the advantage of leaving ample freedom to designers while supporting them with a checklist of all available measures. Not all steps and actions will be available in a specific situation, but our suggestion is to follow this path and closely analyse the possibilities for action in a given situation for each step:1. Define explicitly the thermal comfort objectives, us-ing the Adaptive Comfort model where possible.2. Intervene on the site layout and features which can affect summer comfort.3. Control and reduce heat gains at the external surface of the building envelope.4. Control and modulate heat transfer through the build-ing envelope.5. Reduce internal heat gains.6. Allow building users for local and individual adaptation.7. Use passive means to remove energy from the building.8. Use active solar assisted cooling plants.9. Use high efficiency active conventional cooling plants.10. Train building managers and occupants on how to use, monitor the performance of and adequately operate and maintain the building.The approach of sustainable summer comfort and the ten steps are described in more detail in the project’s final report (Varga et al., 2007) and have been presented at several international conferences (Varga & Pagliano, 2006; Varga et al., 2006; Lopes et al., 2007). They also provided the structure for a web-based toolkit for build-ing owners, planners, building users and facility man-agement professionals. It includes technology profiles to almost all steps, 14 Best Practice Projects in English and 41 in German, Lithuanian and Spanish languages, an analysis of the national comfort legislation and lists

of experts and suppliers of passive cooling technologies in the participating countries. The toolkit is available at the project’s Website www.keepcool.info.

4. THE ADAPTIVE COMFORT MODEL

An important step towards the broad acceptance of the principles of Sustainable Summer Comfort was the adoption of the Adaptive Comfort Model in the Europe-an Standard EN 15251 “Indoor environmental input pa-rameters for design and assessment of energy perform-ance of buildings - addressing indoor air quality, thermal environment, lighting and acoustics”. The evidence on which its provisions are based and the advantages they present for minimizing energy use in buildings were pre-sented in (Nicol & Pagliano, 2007; Lopes et al., 2007).The deployment of sustainable summer comfort and the construction of comfortable buildings depends on the correct application of the Adaptive Comfort Model (Humphreys & Nicol, 1998) in non-mechanically cooled buildings and of the Fanger model (Fanger, 1970; ISO 7730:2005) in mechanically cooled buildings, taking due account of the degree of flexibility allowed also in the latter. Beside the European Standard EN15251, the correct application of these two comfort models needs to be included also in design standards where design temperature levels are still mostly fixed. As deDear and Brager point out, the implications of the potential use of the models are significant: “If a building’s inte-rior conditions were able to be maintained within the Adaptive Comfort Standard (ACS) limits entirely by natural means, then one could potentially save 100% of the cooling energy that would otherwise be used by an air-conditioner to maintain conditions within the more narrow ASHRAE Standard 55 comfort zone. If one were to apply the ACS to a mixed-mode building, however, the air-conditioner might be used in a limited way to keep the more extreme temperatures from rising past the acceptability limits of the ACS. In this case, the energy savings would be proportional to the differ-ence between set-points defined by the upper limit of the ACS, compared to typical set-points used in an air-conditioned building. [...] Savings are likely to be much higher than indicated since it is more common to find buildings operating at the center of the ASRHAE Stand-ard 55 comfort zone (approximately 23 °C) than at the upper end of 26 °C” (deDear & Brager, 2002).

5. BARRIERS IN THE CONSTRUCTION MARKET

But even if comfort models are set right in building reg-ulation and tools are available for the easy integration of the different aspects of sustainable summer comfort,



there is still a long way to go until a considerable part of the new building stock is constructed after these princi-ples. For its broad market implementation a complete transformation of the present planning and tendering culture is required, from supplying and asking for “cool-ing” to supplying and asking for “comfort”. We identi-fied four main barriers against this transformation: • Outdated rules of thumb in building envelope and cooling design;• Remuneration schemes for planners and designers;• Building codes concentrating on winter requirements;• Scattered supplier industry for passive solutions.In spite of better standards and design guidelines, of-ten planners use outdated rules of thumb for design of building envelope and plants. In addition, the remunera-tion schemes for planners and designers do not support integrated planning; frequently the payment is mainly related to the size of the HVAC equipment built into a building, rather than to its performance. Furthermore, the building codes mostly concentrate on winter require-ments, leaving summer energy efficiency for “green” architects and planners. And finally, as passive solutions are mostly a combination of different strategies, their supplier industry is scattered: suppliers are from differ-ent branches, and are less well organised than other in-dustries in the construction sector.

6. RECOMMENDATIONS FOR FURTHER EURO-PEAN POLICIES IN THE FIELD

The most effective elements to foster the market pene-tration of sustainable summer comfort in buildings must be implemented at the national level:• Building codes with a strict standard on maximum useful energy demand for cooling and rules to reward the application of passive cooling systems;• Easy and reliable access to information and specialised consultancy for building owners and administrators;• Exemplary role of the public building sector;• Adaptation of existing subsidy schemes or new sub-sidy schemes that support elements of sustainable sum-mer comfort.There are, however, a number of opportunities for Euro-pean policy to enhance sustainable summer comfort ap-proaches. These are described in detail in the following.

6.1 Check of building codes, energy certification and AC inspectionThe EPBD gives a framework to the Member States for the implementation of policy instruments that lead to energy savings in the building sector. In translating the framework into concrete measures, the Member States have a relatively high degree of freedom which may

lead to very different approaches. For the market pen-etration of sustainable summer comfort, the following questions are crucial:• Building code: does the building code put pressure on building owners to reduce cooling demand; respec-tively does it give an incentive to use passive cooling technologies?• Energy certification: does the energy certificate display the cooling demand of the building in a visible way, i.e. is the useful energy demand for cooling an element for the determination of the energy efficiency classes? Is the use of passive cooling technologies mentioned in the certificate?• Inspection of Air Conditioning (AC) systems: how far does the energy advice in the frame of the inspection go? Does it relate to the mechanical AC system only or does it also include measures for the reduction of the cooling demand?In order to ensure a level playing field for sustainable summer comfort technologies and concepts, the Europe-an Commission should comprehensively check the above mentioned aspects of EPBD implementation and require adaptation from the Member States in case that these aspects have not been considered in a satisfactory way.

6.2 Co�fort level as �ain influence factorWhile checking the above mentioned instruments, there should be particular attention on comfort definitions in various national regulations. The following activities of the Member States, promoted and supported at Euro-pean level in order to aim at a certain degree of harmo-nisation, could support the achievement of both comfort and energy efficiency:• Enact legislation and incentives schemes to take full stock of the possibilities offered by the Adaptive Com-fort Model in characterising comfort in non-mechani-cally cooled buildings, as it is incorporated into the Eu-ropean Standard EN 15251. • Enact legislation and incentives schemes to take full stock of the flexibility present in the Fanger model and its application in ISO 7730:2005 in mechanically cooled buildings. The adoption of light clothes, low re-sistance chairs, and air movement via ceiling or desk fans would allow for occupants’ comfort sensation at higher air temperatures (and hence lower energy con-sumption) than in the standard case without using these flexibility options.• Include a description of comfort models and comfort classification in the curricula for designers and training courses for professionals who will be charged of pro-viding the building energy certification.


1086 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

6.3 Evaluation of national Energy Efficiency Action PlansElectricity consumption due to additional cooling loads is one of the most quickly increasing elements of the end-use energy consumption in most Member States. Any strategy to improve energy efficiency needs there-fore to address this segment. The Directive on Energy End-use Efficiency and Energy Services (EEE-ESD, see European Communities, 2006) gives the framework for further development of energy efficiency policy in the Member States:• In the frame of the implementation of the EEE-ESD, Member States must prepare Energy Efficiency Action Plans (EEAP), including also an estimation of the ener-gy savings related to the implementation of the planned measures. • Article 5 of the EEE-ESD requires the Member States’ public sector bodies and agencies to take an exemplary role in improving energy efficiency. In this context, the following activities by the European Commission may support the Member States in foster-ing summertime energy efficiency:• Comprehensive evaluation of the national EEAP-s with respect to measures that reduce energy consump-tion for cooling and information exchange among Mem-ber States on this issue;• Development of guidelines for public procurement that take into account energy savings from sustainable summer solutions and compilation of best practice ex-amples relating to the integration of summertime energy efficiency issues into public buildings;• Making available simplified procedures to evaluate the energy savings related to sustainable summer comfort.

6.4 Research and developmentThe European Union is a big player as refers to research and development (R&D). The “European Strategic En-ergy Technology Plan (SET-Plan)” is set out to become a framework document for the future orientation of the European R&D policy in the energy (efficiency) sec-tor (Commission of the European Communities, 2007). In this context, the following activities at the European level are important:• Making visible the R&D needs and opportunities in the field of energy efficiency in buildings, with a focus on sustainable summer comfort issues (e.g. through the formation of a European Technology Platform for enve-lope and passive cooling technologies);• Increasing the share of demonstration, dissemination and monitoring activities in the frame of the European R&D programmes: a number of Sustainable Summer Comfort solutions are already market-ready, though their coherent integration into the building still needs

research and testing, including the interaction of the building elements, plants and occupants in real-scale objects. Therefore, the focus of R&D policy should shift from mainly technology development and demon-stration to dissemination, integrated design approaches, and large, well designed monitoring campaigns. • Promoting empirical studies on comfort perception in real, occupied buildings, conducting statistically rele-vant comfort surveys in mechanically cooled buildings, buildings that apply solely passive cooling technologies and in hybrid buildings. Preliminary studies show on a limited number of cases that the application of the adaptive comfort model to define a variable set-point in mechanically cooled buildings may be evaluated posi-tively by occupants as for comfort perception, while at the same time reducing the energy consumption of these buildings (e.g. the SCAT survey, McCartney & Nicol, 2002). The thematic link to the issue of “healthy build-ings” should also be investigated.

6.5 Real estate appraisalIn the highly capitalised and dynamic construction mar-ket real estate appraisal is an important control mech-anism that regulates the direction of capital flows. In general, the energy performance of a building – and thus also the aspect of sustainable summer comfort – is not taken into account in real estate appraisal.Valuation methods in the standards used in EU Mem-ber States were developed long before energy efficiency and energy certificates entered the discussion. There-fore, appraisers find it hard to account for new devel-opments and market-driven aspects such as energy ef-ficiency or Life Cycle Costs within their calculations and valuation reports. A main reason why this field of interest has not yet been researched is probably because energy certificates and energy efficiency in general have a strong technical and facility management oriented re-search basis, but the economic aspects – which would be important for property valuation – seem to stand on a much more fragile foundation.Since real estate appraisal is strongly driven by standards and norms, the European Commission could take influ-ence on the further development of appraisal methods, e.g. by mandating the development of a CEN-standard on the integration of energy performance aspects in the real estate valuation methods.

7. CONCLUSIONS

There are many opportunities within existing policy in-struments to promote sustainable summer comfort, con-tributing to the transformation of the construction mar-ket and habits towards a building stock that is energy



efficient both in winter and summer conditions. Most of them will be subject of the follow-up project “Keep-Cool II: Transforming the market from “cooling” to “sustainable summer comfort”” which is going to start in autumn 2007. This project will develop practical rec-ommendations and supplementary material to overcome the four above mentioned market barriers. In addition, it will come up with procedures and tools to integrate sustainable summer comfort solutions into public pro-curement and building management, and will give sup-port to the national institutions preparing their Energy Efficiency Action Plans. Furthermore, KeepCool II will contribute to market transformation through dissemina-tion campaigns addressing the entire market chain from the suppliers industry to the building owner, as well as national policy makers and public procurement of-ficials, and an international audience at European level conferences and through direct cooperation with organ-isations from countries not participating in the project.

REFERENCES

Adnot, J. et al. (1999). Energy efficiency of roo� Air Condi-tioners (EERAC). Study for the Directorate-General for Energy (DGXVII) of the Commission of the European Communities. Final report.Adnot, J. et al. (2003). Energy efficiency and certification of central Air Conditioners (EECCAC). Study for the D.G. Transportation-Energy (DGTREN) of the Commission of the E.U., Final report.Commission of the European Communities (2007). Towards a European Strategic Energy Technology Plan. Communication from the Commission to the Council, the European Parliament, the European Economic and Social Committee and the Commit-tee of the Regions. Brussels, 10.1.2007, COM(2006) 847 final.deDear, R. J. & Brager, G. S. (2002). Thermal comfort in natu-rally ventilated buildings: revisions to ASHRAE Standard 55. Energy and Buildings 34, 549-561.European Communities (2003). Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002 on the energy performance of buildings. Official Journal of the European Communities, 4.1.2003, L1/65-L1/71.European Communities (2006). Directive 2006/32/EC of the Eu-ropean Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC. Official Journal of the European Union, 27.4.2006, L114/64-L114/85.Fanger, P. O. (1970). Thermal comfort. Copenhagen: Danish Technical Press.Humphreys, M. A. & Nicol, J. F. (1998). Understanding the adap-tive approach to thermal comfort. ASHRAE Transactions 104(1), 991-1004.International Energy Agency. (2004). Cooling buildings in a warming climate. IEA Future Building Forum, Sophia Antipolis, France, 21-22 June, 2004.ISO 7730:2005. Ergonomics of the thermal environment: Analytical determination and interpretation of thermal comfort using calcu-lation of the PMV and PPD indices and local thermal comfort cri-teria. ISO International Organisation for Standardisation, Geneva.

Lopes, C., Nicol, J. F., Pagliano, L, & Varga, M. (2007). Intro-ducing sustainable summer comfort in the market: Success fac-tors and barriers. Paper presented at the eceee 2007 Summer Study „Saving energy – just do it!“, La Colle sur Loup, France, 4-9 June 2007.McCartney, K. J. & Nicol J. F. (2002). Developing an adaptive control algorithm for Europe: Results of the SCATs project. En-ergy and Buildings 34, 623-635.Nicol, J. F. & Pagliano, L. (2007). Allowing for thermal comfort in free-running buildings in the new European standard prEN 15251. Paper presented at the 2nd PALENC Conference and 28th AIVC Conference “Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century”, Crete Island, Greece, 27-29 September 2007.Varga, M., Bangens, L., Cavelius, R., Isaksson, C., Laia, C., Leut-göb, K., Lopes, C., Martinez Davison, J., Nicol, J. F., Pagliano, L., Perednis, E., Read, G. E. F., & Zangheri, P. (2006). KeepCool: Promoting the market penetration of sustainable summer com-fort. Paper presented at the EPIC 2006 AIVC, the 4th European Conference on Energy Performance & Indoor Climate in Build-ings: Technologies & Sustainable Policies for a Radical Decrease of the Energy Consumption in Buildings, Lyon, France, 20-22 November 2006.Varga, M., Bangens, L., Cavelius, R., Isaksson, C., Laia, C., Leut-göb, K., Lopes, C., Martinez Davison, J., Pagliano, L., Perednis, E., & Read, G. E. F. (2007). Service Buildings Keep Cool: Pro-motion of sustainable cooling in the service building sector. Final Report. Brussels: Intelligent Energy Executive Agency.Varga, M. & Pagliano, L. (2006). Reducing cooling energy de-mand in service buildings. Paper presented at the International Conference Improving Energy Efficiency in Commercial Build-ings (IEECB’06), Frankfurt, Germany, 26 - 27 April 2006.


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