Can the topic energy efficiency be considered as energy efficiency of buildings only or should it be considered in association with the efficiency of the energy production and energy distribution? In many cases an efficient way of energy production and distribution would benefit more to overall energy savings and reduction of carbon emissions than decreased energy demands for buildings.

One very efficient initiative would be power production at Combined Power and Heat Plants (CPH) in conjunction with District Heating (DH) (Northern Europe) and District Cooling (DH) (Southern Europe).

Are these targets to be integrated in the Summer School 2012 to achieve the goals of creating student as shining examples according to energy efficiency?

In many countries and in many conditions energy efficiency is considered strictly to the energy us for building services. This is also the case concerning the EPBD. As an example this can be shown with the energy requirements stated in the Danish Building Code (Bygnings Reglement (BR)).

Fig. 1: Energy frames for nonresidential buildings according to the Danish Building Code (BR). Expressed in primary energy consumption [kWh/m² gross area].

Right now the demand for insulation in buildings according to the new Building Code BR10 has reached its maximum. If we as an example want to increase the wall insulation from 300 mm to 400 mm, the embedded energy and the embedded CO₂-emission from production of the insulation highly reduces the expected goals.

Is this steadily increasing demand for energy efficiency in buildings the right way to follow to obtain the 20-20-20 goals stated in the EU?

In the long term it is inevitable to increase the demands of energy efficiency to become independent of fossil fuels.

Buildings cannot be considered independently of the energy production and distribution. It may be many times more efficient to:

• Change from power plant to combined power and heat plants (CPH)
• Use the waste energy from power production for district heating (DH)
• Use the waste energy from power production for district cooling (DC)

These items are dealt with in many publications, e.g.:

1. The World bank has calculated that, if DH were used in the EU countries (mainly the northern countries) as widely as in Denmark, this initiative alone would be sufficient to reduce the CO₂- emission with more than 20% !!
2. The Energy Charter Treaty signed by 51 countries looks at CHP + DH as

the most promising way to reduce energy consumption (primary energy) and creating a flexible energy supply

1. The Danish District Energy Partnership among major DK market players states that:
   1. 135 Euro (1000 DKR) invested in DH reduces the CO₂-emission with 1 ton/year
   2. 135 Euro invested in wind energy reduces the CO₂-emission with 0.5 0.7 ton/year
   3. 135 Euro invested in hydro power reduces the CO₂-emission with 0.6 – 1.3 ton/year

Energy Charter Secretariat: www.encharter.org

Look for the report “Cogeneration and District Heating, best practice for Municipalities”, march 2006:  http://www.encharter.org/index.php?id=126#384

District Energy Partnership: www.districtenergypartnership.com/ (some interesting cases).

In the summer term 2011 during the USE Efficiency training course, the internal insulation of the buildings was an interesting and important topic for the students. They were working on a building which was built in 1896 and has a typical Hamburg brick façade. All outer walls have massive brick structures, about 51 cm in diameter, having a U-value of about 1.4 W/m²K. This means that the temperature of the inner surface of the outer walls does not fall below 12.6 °C.

The current situation does not show a good balance concerning the energy demand for heating, but on the other hand does not cause any problems with water condensation. Insulation on the outer walls of the building will always lead to higher temperatures on the surfaces, but an internal insulation does not always have the same effect!

For this reason one group of our students did a simulation of the thermal bridges with the program Therm 5.2

The results are the following:

The Situation has changed, the heat loss mainly occurs where the inner wall causes a thermal bridge. The coldest temperature on the inner side of the wall is below 12,6 °C, condensation water will occur.

The Situation has changed, the heat loss mainly occurs where the inner wall causes a thermal bridge. The coldest temperature on the inner side of the wall is below 12,6 °C, condensation water will occur.

3.    One solution of this problem: the insulation continues on the interior wall  

The temperature of the coldest part of the wall surface is only 5 °C, but this is no longer the inner surface. This means no problems with condensation water, but the Architect might not be happy how the room looks like!

4.      Increasing the thickness of the  insulation (16 cm)

With an insulation of 16 cm in this case the lowest temperature on the surface is 12.8 °C, for other constructions even 11 cm can be enough.

Conclusion

These simulations showed possible solutions to avoid condensation water and mould when implementing an inner insulation for a building. Using the acquired knowledge  the students of this training course could present solutions for an energy efficiency restauration of a historic building to the City of Hamburg, without changing its apperance.

Following the adoption of the European Union climate and energy package in 2008, the European Commission launched the Covenant of Mayors to support the efforts deployed by local authorities in the implementation of sustainable energy policies. The rationale behind is that cities have a crucial role to play in mitigating climate change, as they consume 80% of the energy produced in the EU. Further local authorities are in a position to influence local industries and citizens' behaviours.

The CoM initiative has been highly acknowledged by local and regional authorities and is a growing cooperation movement.  During October 2011 the Covenant of Mayors has reached more than 3,000 signatories representing 137 million citizens, and just over two years after the first Covenant of Mayors Ceremony.

The number of local authorities which have joined the Covenant – among which over 800 are already implementing their sustainable energy action plans – is conferring credibility to the EU ambitions in the fight against climate change.

A substantial part of the municipal energy action plans is to facilitate energy efficiency in buildings at various users. To show the way forward many municipalities has put high emphasis on implementing innovative energy saving measures in their own buildings, including implementing low energy buildings. For example the “USE EFFICIENCY” municipality Aarhus are renovating two of their administrative buildings to a low energy mode and constructing a new zero-energy administrative building. The municipality has a goal to be CO2 neutral before 2020.

Another trend is the integration of general city planning with energy planning where new city areas or renovation or existing areas are seen in relation to general sustainability requirements. In this regard sustainability is not only considered as a matter of energy efficiency and use of renewable energy resources but also a matter of  “happy” people, or in other words facilitation of good  living conditions for citizens. Sustainable energy solutions are one among several measures to obtain good living conditions in cities.

BRUNEL University organised a student conference on 23 September 2011, hosted by Arup Consulting Engineers in their London Office.  Students from nine universities submitted papers related to People and Buildings focussing on energy requirements in building to satisfy environmental conditions for people.  The conference was attended by more than 100 students and prizes for best papers and presentation were awarded.  Papers presented to the conference would be of interest to many students because they describe low energy solutions in many European climates and also will give ideas on student projects that are achievable and of such quality to generate a paper suitable for presentation to their peers.

All papers submitted by the students to the conference can be found in http://nceub.org.uk. Would recommend you all to check them out!

(Network for Comfort and Energy Use in Buildings)