ENERsign

Question 1

What is the thermal coefficient Lambda?

The thermal coefficient Lambda is the measure of thermal conductivity and determines the heat flow through a material due to heat conduction. The lambda value shows how well or how poorly a material conducts heat and thus how suitable it is for thermal insulation. Materials that conduct heat poorly (e.g. insulation materials) have a low lambda value, materials with strong heat conduction (e.g. concrete) a high one. The thermal conductivity of most materials increases slightly at higher temperatures. In general, lambda is the heat output in watts that is conducted through 1m2 of a 1m thick layer of a material when the temperature difference between the two surfaces is 1K.

Question 2

What does heat radiation mean?

Heat radiation from a surface.

Question 3

What is meant by heat transfer?

Heat transfer is the transport of thermal energy due to a temperature difference across a thermodynamic system boundary (in the case of the passive house: building envelope). The energy transported in this way is known as "heat" and is a variable belonging to the process. The heat transfer is always in the direction from the warmer to the colder area. In other words, heat transport always strives to balance energy across system boundaries.

The physical quantity for the extent of heat transport is the heat flow, that is the power that flows through per square meter perpendicular to the surface [measured in W/m² (watts per square meter). As a rule, the heat flow (at least for small temperature differences) is proportional to the difference in temperatures. If divided by this temperature difference, a quantity is obtained which characterises the heat transfer capacity of the enveloping surface component: This is the heat transfer coefficient or U-value. Its unit of measurement is thus W/(m²K) (watts per square metre and per Kelvin), where 1 K temperature difference is exactly equal to 1 °C temperature difference.

Question 4

What does the heat transfer coefficient say?

Heat transfer coefficient = U-value (formerly k-value): central unit of measurement when determining the heat loss of a building component. It indicates the amount of heat that passes through 1 m² per unit of time at a temperature difference of 1 Kelvin between the adjacent room and outside air. The smaller the U-value, the greater the thermal insulation. The unit of measurement is W/(m²K).

The heat transfer coefficient, also called the U-value, describes the insulation properties of a building component. The lower the coefficient, the better the thermal insulation.

The so-called heat transfer coefficient, also called U-value (U = unit of heat transfer) or thermal insulation value, is used to calculate the heat loss of a house. As soon as there is a difference in temperature between two sides of a building element, a heat exchange takes place. The U-value indicates the heat transfer through a layer of material (e.g. a window or a wall) from one fluid (e.g. a gas or a liquid) into a second fluid. Simplified: The U-value is a measure of how much heat is released to the outside through a building component and thus provides information about the thermal insulation of a window. Strictly speaking, it measures the amount of energy per area that flows through a solid body. The smaller the value, the better the insulation and the lower the heat loss. The U-value is particularly low, for example, with building materials such as softwoods (0.13 W/m2K), hardwoods (0.18 W/m2K) or bricks (0.23 W/m2K) - these materials are therefore well suited for thermal insulation. In contrast, materials such as acrylic glass (5.3 W/m2K) or iron (60 W/m2K) have a high U-value. The unit of the thermal insulation value W/m2K means "Watt per square metre and Kelvin".

Question 5

What does heat transport or heat conduction mean?

Heat transported within a material.

Question 6

What is hidden behind the term heating days?

"Heating days" is the sum of the days within a period when the average outdoor temperature is below 12°C. Heating value days is the sum of the temperature differences between the outside temperature and the target inside temperature of 20°C on all heating days within a period.

Question 7

What is hidden behind the term heating degree days?

Monthly temperature index, which allows conclusions to be drawn about climate-related changes in heating energy consumption; serves to monitor heating operation.

Question 8

How do you define the heating energy demand?

According to the definition of the Energy Saving Ordinance, the annual heating energy requirement Q (Quantum) of a building is the amount of energy that must be supplied to a building annually for the purpose of heating, ventilation and hot water preparation in accordance with the EnEV calculation method. It is stated in kWh/(m²a) or in kWh/(m3a).

Question 9

What is meant by the term heating load?

Measure of the heat input required to maintain a defined room temperature at a defined outside temperature. The maximum permissible heating load in a passive house is 10 W/m².

Question 10

What is the composition of the heating requirement?

The heating requirement Q (Quantum) indicates the annual average amount of heat per square metre of energy reference surface that is required to heat the rooms in order to reach the target interior temperature (kWh/(m²a)). It does not include the energy requirement for hot water, building services and the requirement of air conditioning systems for cooling in summer.

Question 11

What special features does Hemlock have as a material?

Abbreviation DIN EN 13556 TSHT

Botanical name Tsuga heterophylla and Abies amabilis, family of the Pinaceae

Distribution west coast of North America, especially in Alaska, Brit. Columbia, Washington and Oregon.

Trade names Western Hemlock, Pacific Coast Hemlock, West Coast Hemlock, *Alaska Pine, Hembal

Short description
The wood, which in North America is known in its full name as Pacific Coast Hemlock, originally came only from the botanical species Tsuga heterophylla, a conifer related to native fir. Nowadays, however, the wood of the fir tree found in the same location is always added to the first mentioned species; both woods are so similar in appearance and technical properties that they can be used together.

Knotless lengths up to 30 m and diameters up to over 2 m, usually around 0.8 m, round and straight-edged; very old and strong trunks often with beginning rot in the inner trunk area. The dimensions for Amabilis Fir are only slightly smaller.

Color and structure
Sapwood around 2 cm wide, light grey to yellowish grey and hardly distinguishable from the usually only slightly darker interior, corresponding to a mature wood; the latter darkens in light, similar to spruce wood, slowly turning light yellowish brown. Partly with brown or light-grey stripes or grain, which, provided there is no fungal attack, have no influence on the technical quality.

Planed, dry wood shows an even matt shine on all surfaces. Pores are not present (softwood). Wood rays very small, only still visible as fine mirrors on radial surfaces. No resin channels. Annual rings on cross sections are clearly visible through the sharply defined light brown late wood on one side. It is usually narrower than the early wood of the same growth zone and, depending on the direction of cut, produces yellowish-brownish veins or striped structures, usually less distinct. Due to the often high age of the tree, the wood is often of a fine-grained structure with annual ring widths of less than 3 mm; extremely fine-grained wood is lighter and lighter. The grain is mainly straight, only occasionally wavy and leads to slightly offset late wood structures when cut lengthwise.

Total character
Light-coloured, straight grained and often fine-grained coniferous wood, similar to spruce wood with corresponding annual ring widths.

Deviations
Isolated with brown bark inclusions running in the direction of the fibres, which are taken into account in the grading rules according to their size and number.

Properties
Artificial drying can be carried out without particular difficulties, despite the usually high initial moisture content. Hemlock belongs to the medium-heavy coniferous woods, similar to native spruce and pine wood. It can be easily processed with all tools with only a slight dullness, but requires well-sharpened tools and careful chip removal to achieve smooth planed surfaces, in order to avoid woolly surfaces or pressure marks caused by transport rollers. Durability is satisfactory; the wood is easy to glue, nail and screw. The absence of resin in the wood should be emphasized. When freshly saponified, it often has an unpleasant, acidic odor, which disappears during drying.

Hemlock is, similar to spruce, not sufficiently fungus-resistant to be permanent in moisture-exposed areas. Ferrous metals and alkalis cause dark discoloration of damp wood.

Surface treatment
Hemlock is generally a good paint carrier and can be stained in all colours.
interior use: For this application area all forms of surface treatment can be used, especially transparent or colourless glazes, matting, waxes, varnishes and polishes.

Areas of application
Hemlock is used especially in surface-forming form in interior design, where, in addition to low weight, an even colouring and a clear but not too strongly emphasized wood structure are important. It has proven to be particularly suitable for acoustic, ceiling and wall coverings. Other uses are as blind and frame wood as well as for interior doors, panelling and built-in furniture. A special application is the construction of sauna rooms because of the absence of resin. Permanent use in weather-exposed exterior construction is only possible after application of wood preservatives with deep penetrating effect.

Remarks
Apart from Tsuga heterophylla (= Western Hemlock), the species T. mertensiana (= Alpine Fir) is found in very high altitude and mostly already unused forests of western North America, and in eastern North America the species T. canadensis is widespread, whose usually smaller trunks provide a somewhat more strongly structured wood than Western Hemlock.
Western hemlock may contain, besides the fir wood of Abies amabilis, also that of A. grandis, the Western Balsam Fir or Grand Fir.
Hemlock - Technical properties
Weight fresh650 kg/m³
Weight air-dry510 kg/m³
Weight dry-dry470 kg/m³
Compressive strength u12-15 55 N/mm²
Flexural strength u12-15 83 N/mm²

Question 12

What is heritable building right?

A right, usually limited in time (usually 99 years), to construct and use a building on third-party land. The land is "rented" against payment of a ground rent.