1. Energy Saving Buildings of the Future by help of Energy Audits, Quality
Labelling and the EC-Energy Performance Directive (EPD for Buildings)
The new EPD building is as something totally new focussing at the holistic approach and brutto energy use and it will be a requirement with a real energy labelling of new build and large renovation projects.
The holistic approach includes:
· Insulation
· Heating and DHW installations
· Ventilation system
· Lighting system
· Orientation/site management of buildings
· Indoor air climate
· Building directive requirements
· Promotion of solar energy systems and other kind of renewable energy
· Focus on electricity from CHP and use of district heating
So it is now the hope that the worst cases of glass buildings with a high energy demand and a need for mechanical cooling can be avoided in the future.
In e.g. Denmark the energy use in housing excl. conversion / distribution losses for heating and DHW will seldom be below 50 kWh/m² pr. year even for low energy housing projects, and the mean value is 75 kWh/m², year.
For normal housing projects the calculated value is 96 kWh/m², year compared to this, but actual energy use will be 110-120 kWh/m², year.
The Danish government aims to agree on new energy demands in the building regulations by 2005 which should incorporate the philosophy of the EPD.
The proposal today aims to decrease the calculated energy use for heating, hot water, ventilation / cooling to 65-75 kWh/m², year for domestic building, where the electricity use for ventilation/cooling is transferred to heating by multiplying by a factor of 2.5.
Besides two new low energy standards 1 and 2 are being introduced with a further reduction of energy use of 50% and 25%.
For a 80 m² apartment it is expected to have an energy use for DHW of 14 kWh/m², year, internal pipe losses of 4 kWh/m², year and electricity for exhaust ventilation equal to 20 kWh/m², year (after multiplying with 2.5).
This means that the future heating demand should be limited to 37 – 47 kWh/m², year which is a very low value compared to today.
An example of housing projects with a very low energy demand in practice is the German “Passiv hous” concept, e.g. realised and documented in the EU-project, CEPHEUS. Here the heating demand is so little that you can in fact avoid the use of a heating system (with 300 – 400 mm wall insulation, airtight constructions without coldbridges, windows with 0.8 W/m²°C U-value and ventilation with 80-90 % heat recovery on the ventilation air.
If heat recovery ventilation is used it is also important to reduce the electricity use for the fans to 30-40 W per housing unit (Demands in Danish Building Regulations: 87 W), and the natural air exchange should be tested to be below 10 % per hour by so-called “blower door test”.
Due to the need for low cost designs and comfort there is a special need to have introduced mechanical ventilation systems with heat recovery which use less electricity are more compact, building integrated and with less duct work. In figure 1 there is an illustration of such a concept which is now being tested in a small test house in Denmark.
In the window area there is a need to have introduced wooden windows with a total U-value of 0.8 W/m²°C or better, something which is not possible to obtain in Denmark today. But in Germany there is a certain market for this.
There is also a need to have introduced more cost effective solar heating systems e.g. for DHW and also PV-modules is a technology which has big prospects for the future due to the experience of a continuos pricedrop for this technology, which is mainly dependent on the production volume.
In Denmark use of PV-modules is now introduced by help of the so-called solar stock exchange model which from January 2003 is operated by the Danish electricity utility, Copenhagen Energy. In connection to this it is expected to have 5.000 m² PV-modules installed before end of 2004. This can also be a support to the ambiguous PV-implementation plan in Valby in Copenhagen where it is aimed to have 300.000 m² PV-modules installed for an area with 40.000 inhabitants before 2025.
Fig. 1. Heat recovery on ventilation system
The EPD in combination with quality and sustainability labelling
In Denmark it is aimed to couple the work on the EPD together with a policy to support a sustainable building practice.
E.g. in connection to the cooperation in the Danish network group, “Builders for Sustainability” which is connected to the Danish Commerce and Housing Agency, it is being proposed to make a campaign for energy and environmentally improved housing projects in Denmark.
Here it is suggested to work with two improved energy and environmentally quality levels A and B as described below:
Demands in connection to improved energy and environmental quality levels A and B.
1. Use of resources for heating, electricity and water.
|
|
Class A |
Class B |
|
1. Heat use
2. Electricity use
3. Water use |
max. 50 kWh/m², year
max. 1000 kWh/m², person, year
max. 25 m³/person, year |
max. 70 kWh/m², year
max. 1200 kWh/m², person, year
max. 30 m³/person, year |
|
4. Maximum extra
investment |
10% |
5% |
|
5. Total economy
(investments,
operation and
maintenance |
maximum 5% higher than total economy balance |
total economic balance –
no extra costs when extra capital costs are compared to savings |
2. Environmental demands.
Energy and environmental demands |
Class A |
Class B |
|
|
|
|
|
- Passive Solar design |
X |
X |
|
- Heat recovery ventilation with low electricity use |
Level A |
Level B |
|
- Low energy windows |
Total U-value = 1,1 |
Total U-value = 1,4 |
|
- Extra insulation |
X |
X |
|
- Solar heating system
|
X |
|
|
- Airtightness and
avoidance of cold bridges (documented) |
X |
X |
|
- Daylight access without overheating |
X |
X |
|
|
|
|
|
- Water saving solutions |
X |
X |
|
- Reuse of rainwater |
X |
|
|
- Local use of rainwater |
X |
|
|
Electricity use |
|
|
|
- Low energy lighting in housing units |
X |
X |
|
- Reduce common electricity use for lighting |
X |
X |
|
- Class A appliances |
X |
X |
|
- Sheltered clothes drying areas |
X |
|
|
- Preparation for PV integration |
X |
|
|
|
|
|
|
- Environmental friendly painting |
X |
X |
|
- Electrical cabling without lead or halogens/PVC |
X |
|
|
- PVC free windows |
X |
X |
|
- “Self impregnated” wood |
X |
X |
|
- Environmental friendly “materials” |
X |
X |
|
- Alternative insulation materials compared to
mineral wool and polystyrene |
X |
|
|
|
|
|
|
- Surface materials with indoor air climate labels |
X |
X |
|
- Daylight optimisation |
X |
X |
|
|
|
|
|
- Local waste handling |
X |
X |
|
- Space for waste handling in kitchen |
X |
X |
|
- Local composting |
X |
|
|
|
|
|
|
- Optimised plan for green areas |
X |
X |
|
Project quality and user behaviour |
|
|
|
- Evaluation of energy and environmental design by
independent specialist company |
|
