Greenbuild quality building process

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Validation of the Green Build Quality model with performance quality figures

To obtain an effective impact concerning utilisation of a global solar energy/low-energy design in practical building it is important to utilise good methods to secure and verify that the results are also obtained in practice. This can be done by putting forward a number of performance indicators and key-values, which can be checked by measurement and monitoring for different used technologies.

When a general-orientated assessment of low-energy ecobuilding projects is going to be made, it is the idea to use the so-called Green Build Quality Model for comparison of different types of energy savings. This is an approach which can also be used to support the made demands in the shape of key-figures that are either met separately or in the shape of total well-documented framework requirements.

By help of the Green Build Quality Model, general assessments of low-energy ecobuilding can be made, e.g. within the “heating field”, by integrating an assessment of thermal bridges and tightness of constructions, sash/frame loss of windows, efficiency and electricity consumption by ventilation with heat recovery, compactness and orientation of buildings, heatloss in connection with the heat distribution system and efficiency of heat supply and heating systems.

This kind of assessment can be made by means of so-called quality figures for the individual technologies, which can be used in an overall calculation and assessment where different types of energy savings are compared to each other.

The following quality figures can here be defined and checked/monitored as to the used technologies with a view to validation of an overall quality model for general-orientated low-energy building:

1. Solar heating systems for domestic hot water and PV-systems.	System efficiency (yield compared to insolation), annual yield in kWh/m˛. Monitoring as basis of guaranteed results is a possibility.
2. Ventilation systems with heat recovery.	Thermal efficiency is measured,(should be better than 80%) the electricity consumption ought to be registered continuously, ought to be below 30-40W in dwellings and the electrothermal relation should be determined (ratio between electricity consumption and heat savings). This ought to be better or equal to 1:8. Possible contribution from renewable energy should be estimated.
3. Indoor air climate.	Air change, moisture/temperature conditions are measured, hours above 26°C are registered, just as hours above 50% relative humidity. Assessment of moisture from outside is made. Control of indoor climate labelled materials are used. Check of CO2-emission in the air. Function of natural or hybrid ventilation if any is checked. Utilisation of daylight is measured/assessed. Lighting is registered.
4. Quality of constructions/ building envelope.	Use of energy labelled windows is confirmed. The total U-value of the window is stated. Thermal bridges and tightness requirements are checked at design and by inspection on the building site. Tightness is measured by so-called “blower door tests”, which is a tightness measuring.
5. Heat distribution system.	Operating hours, operating temperatures and the relative heatloss in the heat distribution system are registered. Both as regard joint installations and individual piping in each dwelling.
6. Boiler system/heat pump heating system.	The real efficiency is registered by comparing the fuel consumption to the produced waterborne heating. The annual efficiency (COP, Coefficient of Performance) is registered for the heat pumps.
7. Heat consumption.	The heat consumption is measured continuously so an energy signature can be made. At the same time measurements of the temperature of exhaust air. Circulation loss is registered for the domestic water circulation.
8. Electricity consumption.	The annual electricity consumption is measured. Both for individual electricity consumption in dwellings and shared electricity consumption if any. Assessment of electrical equipment. Assessment of heat contribution from the electricity consumption.
9. Water consumption.	The annual water consumption is registered, divided into hot and cold water. The circulation loss as to domestic hot water is registered if any.
10. Local electricity and heat measurement.	Local energy meters will be used for electricity and heat consumption and domestic hot water consumption. These should also be possible to read locally.
11. Passive solar heating function and optimised building construction.	The relation between the window areas with different orientations are assessed together with thermal mass and possibility of airing. Compactness of the building is assessed in the shape of the area/volume ratio, A/V.
12. Lifecycle assessment of e.g. building materials and environmental indicators.	An overall lifecycle assessment can be made, including the latent energy in materials and energy conditions can here be balanced in proportion to environmental conditions by means of environmental indicators and other environmental assessment methods.
13. Total economy and general assessment.	On the basis of the above mentioned, a justified assessment of the annual energy and water consumption is carried out. And extra investments/capital costs can then be compared to expected annual savings as part of a total economy assessment. Electricity and heat consumption is converted into annual CO2-emissions and annual costs per m˛ by means of energy prices.

To be able to make credible calculations with the overall Green Build quality model for low-energy ecobuilding projects, all the above mentioned conditions ought to be measured/registered for a number of buildings to make a validation of the quality model possible.

In connection to this it is possible for Cenergia to utilise energy calculation tools in a special way so it becomes possible to calculate what the difference is between technologies according to agreed upon performance requirements and less quality solutions.