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What are the advantages of a common heating supply for several buildings (local district heating system or district heating system)?

By connecting several buildings to the same heating system the number of heating generation systems is reduced to one. This usually saves investment costs. Additionally there is in general a smaller total peak load than the sum of all...

What is a ‘plus energy building’ or ‘energy surplus building’?

The term ‘plus energy building’ is not an official term used by the European Commission. It generally means a building with an energy performance that is so good, that the energy generated by the building is higher than the energy used by...

What is the status of national applications of the Nearly-Zero Energy Building definition?

Within the Concerted Action EPBD, a forum of national authorities from 29 countries to support the EU countries in the task of transposing and implementing the Energy Performance of Buildings Directive (EPBD, Directive 2010/31/EU), a...

What is a Nearly-Zero Energy Building (NZEB)?

Nearly-Zero Energy Buildings are buildings with a very high energy performance. According to the Energy Performance of Buildings Directive (EPBD, Directive 2010/31/EU) the nearly zero or very low amount of energy required should be covered...

Is it true to say that round ventilation ducts with a single gasket generally achieve airtightness Class C?

Although this seems to be true, this is a dangerous generalization. There are many factors that govern airtighness of round ductwork, including roundness (any slight ovality can cause leakage at the joints) and the flatness of the seams at...

Is it possible to use the HVAC fan itself to measure the airtightness of the ductwork in a ventilation system?

This is generally not possible. In systems with good airtightness, the leakage flow rates are too small for one to be able to accurately measure the flow rate over the fan.For more information you can check-out the Webevent presentation “...

Are circular ventilation ducts more airtight than rectangular ones?

In general, yes. For more information you can check-out the Information Paper P187 “Duct System Air Leakage — How Scandinavia tackled the problem” by P.G.Schild & J.Railio, on the BUILDUP website

Is there an overview of the way the national EPB regulations take duct airtightness into account?

A good starting point is the paper "stimulating better envelope and ductwork airtightness with EPBD" by Carrié et al., at the AIVC 2008 conference (www.aivc.org).Another possibility is to check out the presentation “Including leakage in...

Is the default ductwork leakage class 2.5*A in the French energy proformance calculations mentioned in any CEN standard?

It is not presently mentioned in CEN standards. Other countries might be using the same default level as France in their energy performance calculation standards, but there is no reason to harmonize it. The leakage class 2.5*A is very much...

Do we have an example of a country where airtightness is good without any regulations requirement?

Sweden does not use its building regulations to impose its strict requirements on ductwork airtightness. Rather it is a voluntary trade standard (the AMA VVS specifications) that has driven the market transformation to more airtight...

Why is the ductwork leakage test only performed at 1 single pressure (400 Pa) in Scandinavia?

The reason for this is twofold:(1) When one uses only one test pressure, then the test results can be expressed with just one number, the “flow coefficient”. This is very simple and avoids the need for any calculations. You are suggesting...

Why is the ductwork leakage test only performed at 1 single pressure (400 Pa) in Scandinavia?

The reason for this is twofold:(1) When one uses only one test pressure, then the test results can be expressed with just one number, the “flow coefficient”. This is very simple and avoids the need for any calculations. You are suggesting...

What kind of screw should we use to fit metal ductwork with good airtightness?

It is important to use the correct type of screw or rivet. Avoid screws with a wide drill tip (which drill a hole in the duct wall) and blind pop rivets (which are not airtight because the inner splint falls out). The best screws are ones...

In Scandinavia , duct system leakage tests typically involve only 10% of the ductwork system. Which 10% should be tested?

In Sweden, according to the trade guidelines VVS AMA, on-site pressure tests need only cover 10% of the duct surface area round ducts, and 20% for rectangular ducts. Denmark has similar rules. In Finland, 20% of the duct surface area is...

Will better commissioning of ducts be a solution for the air leakage problem?

In part. Leakage testing of duct systems, by means of a pressure test, is a very effective way of achieving more airtight duct systems. This type of commissioning is required throughout Scandinavia, to check compliance with minimum...

What does the EPBD stipulate for summer comfort and how does this affect energy use and building design?

Article 4 of the EPBD stipulates explicitly that attention should be paid to indoor climate conditions: “Member States shall take the necessary measures to ensure that minimum energy performance requirements for buildings are set … These...

Which are the pro’s and con’s of passive cooling against mechanical air conditioning?

Mechanical ventilation and air conditioning control the indoor conditions with a specific high consistency range that is independent of external conditions, whereas passive systems cannot be regulated that precisely and quickly. However,...

What would an adaptive standard be like?

Based on the idea that the human body continually adapts to a variety of conditions, an adaptive standard, would not include fixed indoor parameters but, would aim to promote (easy) adaptation by using the following principles: ·        ...

What is adaptive comfort?

Adaptive comfort builds on the principle that people experience differently and adapt, up to a certain extent, to a variety of indoor conditions, depending on their clothing, their activity and general physical condition. Therefore,...

Which are the international guidelines and standards for thermal comfort and what tendency do they impose on summer comfort?

The main international guidelines and standards on thermal comfort are: ·         International Standard ISO 7730. This standard is based on Fanger’s Predicted Mean Vote (PMV), which predicts the mean thermal sensation of a group of...